Journal articles: 'X-Ald amn'

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Stradomska, T. J., J. Kubalska, R. Janas, and A. Tylki-Szymańska. "Reproductive function in men affected by X-linked adrenoleukodystrophy/adrenomyeloneuropathy." European Journal of Endocrinology 166, no. 2 (February 2012): 291–94. http://dx.doi.org/10.1530/eje-11-0490.

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BackgroundX-linked adrenoleukodystrophy (X-ALD) is the most frequent, severely neurodegenerative, clinically heterogeneous peroxisomal disorder, the signs of which are a consequence of myelin, adrenal cortex, and testes impairment.ObjectiveWe studied testosterone, LH, and FSH levels in X-ALD/adrenomyeloneuropathy (AMN) patients. We evaluate the ability to procreate of these patients by analysis of pedigree and family screening by detection of very long-chain fatty acid (VLCFA) levels.Subject and methodsSeventeen patients with X-ALD/AMN (16 with AMN and one asymptomatic) aged 24–48 (mean±s.d., 34.7±5.9) years, were identified based on the clinical picture, magnetic resonance imaging, and the presence of increased serum VLCFA levels. Nine X-ALD/AMN patients' daughters, mean ages ±s.d.=7.7±3.8 years, were identified as heterozygote by elevated VLCFA levels.Serum VLCFA levels were determined as ester derivatives by a gas chromatography method. Serum testosterone, LH, and FSH levels in X-ALD/AMN patients were detected by IRMAs.ResultsSerum testosterone levels were at the lowest levels of normal range but serum LH and FSH concentrations were increased in 57.1 and in 42.9% of X-ALD/AMN patients respectively. Among the 11 investigated of X-ALD/AMN married adult men, nine had produced offspring, a total of 13 children. All patients' daughters showed elevated serum VLCFA at heterozygote levels.ConclusionIn this study, we report that in a group of X-ALD/AMN married adult men, we did not find a significant decrease in fertility compared with the Polish population (18.2 vs 15%).

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Singh, Jaspreet, Shailendra Giri, Hamid Suhail, and Mandar Deshpande. "Loss of AMPKα1 in neuroinflammatory phenotype of X-linked adrenoleukodystrophy (HUM2P.335)." Journal of Immunology 192, no. 1_Supplement (May 1, 2014): 53.8. http://dx.doi.org/10.4049/jimmunol.192.supp.53.8.

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Abstract X-linked adrenoleukodystrophy (X-ALD) is the most common inherited neuroinflammatory demyelinating leukodystrophy. All X-ALD patients present with mutations in the ABCD1 gene, which encodes a peroxisomal adenosine triphosphate (ATP)-binding cassette transporter protein (ABCD1). X-ALD is a complex disease where the same mutation in the ALD gene (ABCD1) can lead to clinically very distinct phenotypes; a fatal neuroinflammatory childhood cerebral ALD (ALD) or the relatively benign disease of adrenomyeloneuropathy (AMN). Further, no relationship could be established between genotype and severity of the disease as same mutation is known to give different phenotypes, even within a family. We recently documented a role for decreased AMP kinaseα1 (AMPKα1) levels in initiating severe inflammatory and demyelinating phenotype in the CNS of AMPKα1-knockout mice. Abundant data is also available that implicates loss of AMPK in generating spontaneous inflammatory response in several cell types including immune cells. Our data using healthy control, AMN and ALD patient-derived skin fibroblasts and lymphocytes documents, for the first time, loss of a metabolic gene- AMPKα1 in ALD patient-derived fibroblasts and lymphocytes. Consistent with this, the basal expression of inflammatory cytokines (iNOS and IL-6) were increased in ALD patient-derived lymphocytes. Together these observations suggest that AMPKα1 may be involved in the progression of benign AMN to neuroinflammatory ALD phenotype.

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Petrillo, Sara, Jessica D’Amico, Francesco Nicita, Caterina Torda, Gessica Vasco, Enrico S. Bertini, Marco Cappa, and Fiorella Piemonte. "Antioxidant Response in Human X-Linked Adrenoleukodystrophy Fibroblasts." Antioxidants 11, no. 11 (October 28, 2022): 2125. http://dx.doi.org/10.3390/antiox11112125.

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Redox imbalance, mitochondrial dysfunction, and inflammation play a major role in the pathophysiology of X-linked adrenoleukodystrophy (X-ALD), an inherited neurodegenerative disease caused by mutations in the ABCD1 gene, encoding the protein responsible for peroxisomal import and degradation of very long chain fatty acids (VLCFAs). Therefore, VLCFAs accumulate in tissues and plasma, constituting a pathognomonic biomarker for diagnosis. However, the precise role of VLCFA accumulation on the diverse clinical phenotypes of X-ALD and the pathogenic link between VLCFAs and oxidative stress remain currently unclear. This study proposes ferroptosis as a crucial contributor to the disease development and progression. The expression profiles of “GPX4-glutathione” and “NQO1-CoQ10” ferroptosis pathways have been analyzed in fibroblasts of one patient with AMN, the late onset and slowly progressive form of X-ALD, and in two patients with cALD, the cerebral inflammatory demyelinating form of early childhood. Furthermore, as no effective treatments are currently available, especially for the rapidly progressing form of X-ALD (cALD), the efficacy of NAC treatment has also been evaluated to open the way toward novel combined therapies. Our findings demonstrate that lipid peroxides accumulate in X-ALD fibroblasts and ferroptosis-counteracting enzymes are dysregulated, highlighting a different antioxidant response in patients with AMN and cALD.

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Baker, Craig V., Alyssa Cady Keller, Richard Lutz, Karen Eveans, Krystal Baumert, James C. DiPerna, and William B. Rizzo. "Newborn Screening for X-Linked Adrenoleukodystrophy in Nebraska: Initial Experiences and Challenges." International Journal of Neonatal Screening 8, no. 2 (April 26, 2022): 29. http://dx.doi.org/10.3390/ijns8020029.

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X-linked adrenoleukodystrophy (X-ALD) is a neurodegenerative disease caused by pathogenic variants in ABCD1 resulting in defective peroxisomal oxidation of very long-chain fatty acids. Most male patients develop adrenal insufficiency and one of two neurologic phenotypes: a rapidly progressive demyelinating disease in mid-childhood (childhood cerebral X-ALD, ccALD) or an adult-onset spastic paraparesis (adrenomyeloneuropathy, AMN). The neurodegenerative course of ccALD can be halted if patients are treated with hematopoietic stem cell transplantation at the earliest onset of white matter disease. Newborn screening for X-ALD can be accomplished by measuring C26:0-lysophosphatidylcholine in dried blood spots. In Nebraska, X-ALD newborn screening was instituted in July 2018. Over a period of 3.3 years, 82,920 newborns were screened with 13 positive infants detected (4 males, 9 females), giving a birth prevalence of 1:10,583 in males and 1:4510 in females. All positive newborns had DNA variants in ABCD1. Lack of genotype-phenotype correlations, absence of predictive biomarkers for ccALD or AMN, and a high proportion of ABCD1 variants of uncertain significance are unique challenges in counseling families. Surveillance testing for adrenal and neurologic disease in presymptomatic X-ALD males will improve survival and overall quality of life.

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Baker, Craig V., Alyssa Cady Keller, Richard Lutz, Karen Eveans, Krystal Baumert, James C. DiPerna, and William B. Rizzo. "Newborn Screening for X-Linked Adrenoleukodystrophy in Nebraska: Initial Experiences and Challenges." International Journal of Neonatal Screening 8, no. 2 (April 26, 2022): 29. http://dx.doi.org/10.3390/ijns8020029.

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X-linked adrenoleukodystrophy (X-ALD) is a neurodegenerative disease caused by pathogenic variants in ABCD1 resulting in defective peroxisomal oxidation of very long-chain fatty acids. Most male patients develop adrenal insufficiency and one of two neurologic phenotypes: a rapidly progressive demyelinating disease in mid-childhood (childhood cerebral X-ALD, ccALD) or an adult-onset spastic paraparesis (adrenomyeloneuropathy, AMN). The neurodegenerative course of ccALD can be halted if patients are treated with hematopoietic stem cell transplantation at the earliest onset of white matter disease. Newborn screening for X-ALD can be accomplished by measuring C26:0-lysophosphatidylcholine in dried blood spots. In Nebraska, X-ALD newborn screening was instituted in July 2018. Over a period of 3.3 years, 82,920 newborns were screened with 13 positive infants detected (4 males, 9 females), giving a birth prevalence of 1:10,583 in males and 1:4510 in females. All positive newborns had DNA variants in ABCD1. Lack of genotype-phenotype correlations, absence of predictive biomarkers for ccALD or AMN, and a high proportion of ABCD1 variants of uncertain significance are unique challenges in counseling families. Surveillance testing for adrenal and neurologic disease in presymptomatic X-ALD males will improve survival and overall quality of life.

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Singh, Jaspreet, Hamid Suhail, and Shailendra Giri. "Loss of AMP-Activated Protein Kinase Induces Mitochondrial Dysfunction and Proinflammatory Response in Unstimulated Abcd1-Knockout Mice Mixed Glial Cells." Mediators of Inflammation 2015 (2015): 1–10. http://dx.doi.org/10.1155/2015/176983.

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X-linked adrenoleukodystrophy (X-ALD) is caused by mutations and/or deletions in the ABCD1 gene. Similar mutations/deletions can give rise to variable phenotypes ranging from mild adrenomyeloneuropathy (AMN) to inflammatory fatal cerebral adrenoleukodystrophy (ALD) via unknown mechanisms. We recently reported the loss of the anti-inflammatory protein adenosine monophosphate activated protein kinase (AMPKα1) exclusively in ALD patient-derived cells. X-ALD mouse model (Abcd1-knockout (KO) mice) mimics the human AMN phenotype and does not develop the cerebral inflammation characteristic of human ALD. In this study we document that AMPKα1 levelsin vivo(in brain cortex and spinal cord) andin vitroin Abcd1-KO mixed glial cells are similar to that of wild type mice. Deletion of AMPKα1 in the mixed glial cells of Abcd1-KO mice induced spontaneous mitochondrial dysfunction (lower oxygen consumption rate and ATP levels). Mitochondrial dysfunction in ALD patient-derived cells and in AMPKα1-deleted Abcd1-KO mice mixed glial cells was accompanied by lower levels of mitochondrial complex (1-V) subunits. More importantly, AMPKα1 deletion induced proinflammatory inducible nitric oxide synthase levels in the unstimulated Abcd1-KO mice mixed glial cells. Taken together, this study provides novel direct evidence for a causal role for AMPK loss in the development of mitochondrial dysfunction and proinflammatory response in X-ALD.

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Rodríguez-Pascau, Laura, Anna Vilalta, Marc Cerrada, Estefania Traver, Sonja Forss-Petter, Isabelle Weinhofer, Jan Bauer, et al. "The brain penetrant PPARγ agonist leriglitazone restores multiple altered pathways in models of X-linked adrenoleukodystrophy." Science Translational Medicine 13, no. 596 (June 2, 2021): eabc0555. http://dx.doi.org/10.1126/scitranslmed.abc0555.

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X-linked adrenoleukodystrophy (X-ALD), a potentially fatal neurometabolic disorder with no effective pharmacological treatment, is characterized by clinical manifestations ranging from progressive spinal cord axonopathy [adrenomyeloneuropathy (AMN)] to severe demyelination and neuroinflammation (cerebral ALD-cALD), for which molecular mechanisms are not well known. Leriglitazone is a recently developed brain penetrant full PPARγ agonist that could modulate multiple biological pathways relevant for neuroinflammatory and neurodegenerative diseases, and particularly for X-ALD. We found that leriglitazone decreased oxidative stress, increased adenosine 5′-triphosphate concentration, and exerted neuroprotective effects in primary rodent neurons and astrocytes after very long chain fatty acid–induced toxicity simulating X-ALD. In addition, leriglitazone improved motor function; restored markers of oxidative stress, mitochondrial function, and inflammation in spinal cord tissues from AMN mouse models; and decreased the neurological disability in the EAE neuroinflammatory mouse model. X-ALD monocyte–derived patient macrophages treated with leriglitazone were less skewed toward an inflammatory phenotype, and the adhesion of human X-ALD monocytes to brain endothelial cells decreased after treatment, suggesting the potential of leriglitazone to prevent the progression to pathologically disrupted blood-brain barrier. Leriglitazone increased myelin debris clearance in vitro and increased myelination and oligodendrocyte survival in demyelination-remyelination in vivo models, thus promoting remyelination. Last, leriglitazone was clinically tested in a phase 1 study showing central nervous system target engagement (adiponectin increase) and changes on inflammatory biomarkers in plasma and cerebrospinal fluid. The results of our study support the use of leriglitazone in X-ALD and, more generally, in other neuroinflammatory and neurodegenerative conditions.

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Vargas, Carmen R., Daniella de M. Coelho, Alethéa G. Barschak, Carolina F. M. de Souza, Ana C. S. Puga, Ida V. D. Schwartz, Laura Jardim, and Roberto Giugliani. "X-linked adrenoleukodystrophy: clinical and laboratory findings in 15 Brazilian patients." Genetics and Molecular Biology 23, no. 2 (June 2000): 261–64. http://dx.doi.org/10.1590/s1415-47572000000200002.

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Adrenoleukodystrophy (X-ALD) is an X-linked recessively inherited peroxisomal disorder, phenotypically heterogeneous, characterized by progressive white-matter demyelination of the central nervous system and adrenocortical insufficiency. We investigated 15 male X-ALD patients varying in age from 7 to 39, diagnosed among 108 suspected patients referred for investigation. Plasma levels of very long chain fatty acids (VLCFA) were measured at our laboratory using gas chromatography (GC). Eleven cases of childhood X-ALD and four cases of adrenomyeloneuropathy (AMN) were diagnosed. Adrenal leukodystrophy insufficiency and limb weakness were the most frequent symptoms, appearing in 12, 8 and 6 of the patients, respectively. Physician awareness of X-ALD seems inadequate to judge by age at diagnosis and lengthy interval between the start of symptoms and diagnosis. This is the first published series of Brazilian patients with X-ALD. We determined signs and symptoms relevant for diagnosis, as early identification seems important for treatment outcome. In addition, diagnosis identifies carriers, who could benefit from genetic counselling and prenatal diagnosis.

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Richter Jr., John E., Charitha Vadlamudi, Sarah K. Macklin, Ayesha Samreen, Haytham Helmi, Daniel Broderick, Ahmed N. Mohammad, et al. "Characterization of a Pathogenic Variant in the ABCD1 Gene Through Protein Molecular Modeling." Case Reports in Genetics 2020 (January 25, 2020): 1–7. http://dx.doi.org/10.1155/2020/3256539.

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Background. The ATP-binding cassette, subfamily D, member 1 (ABCD1) protein is a peroxisomal half-transporter that allows for very long chain fatty acid (VLCFA) degradation. Pathogenic variants of ABCD1 cause VLCFAs to build up in various tissues and bodily fluids, resulting in a disorder called X-linked adrenoleukodystrophy (X-ALD). This disorder is most commonly marked by adrenocortical insufficiency and high VLCFA concentration, and has varying levels of neurological involvement depending on phenotype. For example, the Addison-only form of X-ALD has no neurological impact, while the cerebral form of X-ALD often causes severe sensory loss, motor function impairment, cognitive decline, and death. Methods. A newly characterized and suspected pathogenic variant in ABCD1 was analyzed using our protein informatics platform (PIP). Personalized protein-level molecular studies were completed on genetic testing data, complementing the analysis and clinical study. Results. A case of adult onset adrenomyeloneuropathy (AMN) and a novel ABCD1 variant are presented. The unique ABCD1 protein is discussed, and the proband’s case is compared to existing reports of AMN. Conclusions. Data fusion from multiple sources was combined in a comprehensive approach yielding an enriched assessment of the patient’s disease and prognosis. Molecular modeling was performed on the variant to better characterize its clinical significance and confirm pathogenicity.

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Dong, Bingzi, Wenshan Lv, Lili Xu, Yuhang Zhao, Xiaofang Sun, Zhongchao Wang, Bingfei Cheng, Zhengju Fu, and Yangang Wang. "Identification of Two Novel Mutations of ABCD1 Gene in Pedigrees with X-Linked Adrenoleukodystrophy and Review of the Literature." International Journal of Endocrinology 2022 (February 7, 2022): 1–13. http://dx.doi.org/10.1155/2022/5479781.

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Background. X-linked adrenoleukodystrophy (ALD) is an inherited peroxisomal metabolism disorder, resulting from the loss-of-function mutation of ATP-binding cassette protein subfamily D1 (ABCD1) gene. The dysfunction of ALD protein, a peroxisomal ATP-binding cassette transporter, results in the excessive saturated very long-chain fatty acids (VLCFAs) accumulation in organs including the brain, spine, and adrenal cortex. X-ALD is characterized as the childhood, adolescent, adult cerebral ALD, adrenomyeloneuropathy (AMN), adrenal insufficiency, and asymptomatic phenotypes, exhibiting a high variety of clinical neurological manifestations with or without adrenocortical insufficiency. Results. In this study, we reported two cases of X-ALD, which were first diagnosed as adrenal insufficiency (Addison’s disease) and treated with adrenocortical supplement. However, both of the cases progressed as neurological symptoms and signs after decades. Elevated VLCFAs level, brain MRI scan, and genetic analysis confirmed final diagnosis. In addition, we identified two novel mutations of ABCD1 gene, NM_000033.3 (ABCD1): c.874_876delGAG (p.Glu292del) and NM_000033.3 (ABCD1): c.96_97delCT (p.Tyr33Profs ∗ 161), in exon 1 of ABCD1 gene. Sanger sequencing confirmed that the proband’s mother of the first case was heterozygous carrying the same variant. Adrenal insufficiency-only type is very rare; however, it may be the starting performance of X-ALD. In addition, we summarized reported mutation sites and clinical manifestations to investigate the correlationship of phenotype-genotype of X-ALD. Conclusions. The early warning manifestations should be noticed, and the probability of X-ALD should be considered. This report could be beneficial for the early diagnosis and genetic counseling for patients with X-ALD.

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Olgac, Asburce, Çiğdem Seher Kasapkara, Betül Derinkuyu, Deniz Yüksel, Semra Çetinkaya, Ayşe Aksoy, Serdar Ceylaner, et al. "Retrospective evaluation of patients with X-linked adrenoleukodystrophy with a wide range of clinical presentations: a single center experience." Journal of Pediatric Endocrinology and Metabolism 34, no. 9 (June 24, 2021): 1169–79. http://dx.doi.org/10.1515/jpem-2021-0032.

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Abstract Objectives X-linked adrenoleukodystrophy (X-ALD), is a peroxisomal inborn error of metabolism caused due to the loss of function variants of ABCD1 gene that leads to accumulation of very long chain fatty acids (VLCFAs) in several tissues including the neurological system. Childhood cerebral X-ALD (CCALD) is the most common and severe form of X-ALD, if left untreated. Allogenic hematopoietic stem cell transplantation (HSCT) is the only available therapy that halts neurological deterioration in CCALD. We present 12 patients with several subtypes of X-ALD that were followed-up in a single center. Methods Data of 12 patients diagnosed with X-ALD were documented retrospectively. Demographics, age of onset, initial symptoms, endocrine and neurological findings, VLCFA levels, neuroimaging data, molecular genetic analysis of ABCD1 gene, and disease progress were documented. Results Mean age of initiation of symptoms was 7.9 years and mean age of diagnosis was 10.45 years. Eight patients had the CCALD subtype, while two had the cerebral form of AMN, one had the adult form of cerebral ALD, and one patient had the Addison only phenotype. The most common initial symptoms involved the neurological system. Loes scores varied between 0 and 12. Seven patients with CCALD underwent HSCT, among them three patients died. The overall mortality rate was 25%. Conclusions Patients with X-ALD should be carefully followed up for cerebral findings and progression, since there is no genotype–phenotype correlation, and the clinical course cannot be predicted by family history. HSCT is the only available treatment option for patients with neurological deterioration.

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Vargas, Carmen R., Alethéa G. Barschak, Daniella M. Coelho, Vivian Furlanetto, Carolina F. M. de Souza, Simone M. Karam, Laura Jardim, Moacir Wajner, and Roberto Giugliani. "Clinical and biochemical findings in 7 patients with X-linked adrenoleukodystrophy treated with Lorenzo's Oil." Genetics and Molecular Biology 23, no. 4 (December 2000): 697–701. http://dx.doi.org/10.1590/s1415-47572000000400001.

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X-Linked adrenoleukodystrophy (X-ALD) is a hereditary disorder of the peroxisomal metabolism biochemically characterized by the accumulation of very long chain fatty acids (VLCFA) in tissues and biological fluids. The major accumulated acids are hexacosanoic acid (C26:0) and tetracosanoic acid (C24:0). The disorder is characterized clinically by central and peripheral demyelination and adrenal insufficiency closely related to the accumulation of fatty acids. The incidence of X-ALD is estimated to be 1:25,000 males. At least six phenotypes can be distinguished. The most common phenotypes are childhood cerebral ALD and adrenomyeloneuropathy (AMN). The recommended therapy consists of the use of the glyceroltrioleate/glyceroltrierucate (GTO/GTE) mixture, known as Lorenzo's Oil, combined with a VLCFA-poor diet. There are alternative treatments such as bone marrow transplantation and immunosuppression, as well as the use of lovastatin and sodium phenylacetate. In the present study we report the clinical and biochemical course of 7 male patients with X-ALD treated with Lorenzo's Oil and a VLCFA-restricted diet. Treatment produced 50% reduction in C26:0 and 42.8% reduction in the C26:0/C22:0 ratio. Most patients remained clinically well, although approximately 30% of them presented a rapid clinical deterioration. The results showed a poor biochemical-clinical correlation for treatment, indicating that new therapies for X-ALD are needed in order to obtain a better prognosis for patients.

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Chary, Priyanka Kesavan, Aziz Ur Rehman, and Tamis Marie Bright. "Adrenoleukodystrophy as a Cause of Spastic Paraparesis and Hyperpigmentation." Journal of the Endocrine Society 5, Supplement_1 (May 1, 2021): A113. http://dx.doi.org/10.1210/jendso/bvab048.227.

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Abstract Background: X-linked Adrenoleukodystrophy (X-ALD) is caused by an abnormal gene mutation on the X chromosome which codes for an abnormal ABC transporter, preventing transport of very long chain fatty acids (VLCFAs) into peroxisomes for beta oxidation. These VLCFAs, unable to be broken down, thus accumulate in the CNS, adrenal cortex, and Leydig cells of the testes. The clinical presentation depends upon the anatomical involvement, which most often includes the CNS and adrenal glands, and can be a cause of adrenomyeloneuropathy (AMN) or adrenal insufficiency. Case Report: We report a 44 year old male who presented with 9 years of progressive spastic paraparesis. Physical exam was significant for lower extremity spasticity, 3/5 bilateral lower extremity weakness, and hyperpigmentation. His initial work-up for autoimmune disease, MRI brain, and lumbar puncture were unremarkable, and genetic testing for Hereditary Spastic Paraparesis was negative. However, due to advancing symptoms over the years with progression of spasticity, polyneuropathy, development of erectile dysfunction and significant hyperpigmentation, re-evaluation with MRI brain and EMG revealed diffuse symmetrical cerebral and cerebellar volume loss and axonal motor peripheral neuropathy, respectively. Due to hyperpigmentation, further work-up for VLCFAs was positive and presence of the ABCD1 mutation confirmed the diagnosis of X-ALD. Evaluation of adrenal glands yielded high ACTH of >2000 pg/mL (normal: 7.2–63.3) and low AM cortisol of 2.5 ug/dL (normal: 6.2–19.4). Insignificant increase of cortisol from 2.5 ug/dL to 2.7 ug/dL with cosyntropin confirmed primary adrenal insufficiency as the cause of hyperpigmentation with elevated ACTH. Surprisingly, his testosterone level was normal at 542 (normal: 250–1100 ng/dL) and suggestive of Leydig cell-sparing and neuropathy-induced erectile dysfunction. The patient was started on hydrocortisone for adrenal insufficiency with improvement in his fatigue and feelings of well-being. He received physical therapy and is being monitored closely for progression of AMN by Neurology. Conclusion: Our case suggests that ALD should be considered in the differential diagnosis of unexplained paraparesis with associated hyperpigmentation in males. Moreover, timely diagnosis and medical intervention can prevent life-threatening adrenal crisis in such patients.

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Son, Daryeon, Zhejiu Quan, Phil Jun Kang, Gyuman Park, Hoon-Chul Kang, and Seungkwon You. "Generation of two induced pluripotent stem cell (iPSC) lines from X-linked adrenoleukodystrophy (X-ALD) patients with adrenomyeloneuropathy (AMN)." Stem Cell Research 25 (December 2017): 46–49. http://dx.doi.org/10.1016/j.scr.2017.10.003.

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Campopiano, Rosa, Cinzia Femiano, Maria Antonietta Chiaravalloti, Rosangela Ferese, Diego Centonze, Fabio Buttari, Stefania Zampatti, et al. "A Large Family with p.Arg554His Mutation in ABCD1: Clinical Features and Genotype/Phenotype Correlation in Female Carriers." Genes 12, no. 5 (May 19, 2021): 775. http://dx.doi.org/10.3390/genes12050775.

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X-linked adrenoleukodystrophy (X-ALD, OMIM #300100) is the most common peroxisomal disorder clinically characterized by two main phenotypes: adrenomyeloneuropathy (AMN) and the cerebral demyelinating form of X-ALD (cerebral ALD). The disease is caused by defects in the gene for the adenosine triphosphate (ATP)-binding cassette protein, subfamily D (ABCD1) that encodes the peroxisomal transporter of very-long-chain fatty acids (VLCFAs). The defective function of ABCD1 protein prevents β-oxidation of VLCFAs, which thus accumulate in tissues and plasma, to represent the hallmark of the disease. As in many X-linked diseases, it has been routinely expected that female carriers are asymptomatic. Nonetheless, recent findings indicate that most ABCD1 female carriers become symptomatic, with a motor disability that typically appears between the fourth and fifth decade. In this paper, we report a large family in which affected males died during the first decade, while affected females develop, during the fourth decade, progressive lower limb weakness with spastic or ataxic-spastic gait, tetra-hyperreflexia with sensory alterations. Clinical and genetic evaluations were performed in nine subjects, eight females (five affected and three healthy) and one healthy male. All affected females were carriers of the c.1661G>A (p.Arg554His, rs201568579) mutation. This study strengthens the relevance of clinical symptoms in female carriers of ABCD1 mutations, which leads to a better understanding of the role of the genetic background and the genotype-phenotype correlation. This indicates the relevance to include ABCD1 genes in genetic panels for gait disturbance in women.

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Chang, Shu-Jui, Shin-Yuan Wang, Yu-Che Huang, Jia Hao Chih, Yu-Ting Lai, Yi-Wei Tsai, Jhih-Min Lin, Chao-Hsin Chien, Ying-Tsan Tang, and Chenming Hu. "van der Waals epitaxy of 2D h-AlN on TMDs by atomic layer deposition at 250 °C." Applied Physics Letters 120, no. 16 (April 18, 2022): 162102. http://dx.doi.org/10.1063/5.0083809.

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We report the demonstration of growing two-dimensional (2D) hexagonal-AlN ( h-AlN) on transition metal dichalcogenide (TMD) monolayers (MoS2, WS2, and WSe2) via van der Waals epitaxy by atomic layer deposition (ALD). Having atomically thin thickness and high theoretical carrier mobility, TMDs are attractive semiconductors for future dense and high-performance 3D IC, and 2D hexagonal boron nitride ( h-BN) as a gate dielectric is known to significantly improve TMD device performance. However, h-BN growth requires 1000 °C temperature that is not compatible with CMOS fabrication, and ALD deposition of any high-k 2D insulator on TMD continues to be an elusive goal. The epitaxial 2D layered h-AlN by low-temperature ALD is characterized by synchrotron-based grazing-incidence wide-angle x-ray scattering and high-resolution transmission electron microscopy. In addition, we demonstrate the feasibility of using layered h-AlN as an interfacial layer between WS2 and ALD HfO2. The significantly better uniformity and smoothness of HfO2 than that directly deposited on TMD are desirable characteristics for TMD transistor applications.

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Ozgit-Akgun, Cagla, Eda Goldenberg, Ali Kemal Okyay, and Necmi Biyikli. "Hollow cathode plasma-assisted atomic layer deposition of crystalline AlN, GaN and AlxGa1−xN thin films at low temperatures." J. Mater. Chem. C 2, no. 12 (2014): 2123–36. http://dx.doi.org/10.1039/c3tc32418d.

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The authors report on the use of hollow cathode plasma for low-temperature plasma-assisted atomic layer deposition (PA-ALD) of crystalline AlN, GaN and Al_xGa_1−xN thin films with low impurity concentrations.

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Huseynov, M. K., G. D. Kardashova, A. T. Temirov, C. U. Rizakhanova, and G. A. Mutalipova. "Nanoscale Films (SiC)1-x(AlN)x Formation Technology." Herald of Dagestan State University 37, no. 4 (December 29, 2022): 60–65. http://dx.doi.org/10.21779/2542-0321-2022-37-4-60-65.

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Gong, Jiarui, Zheyang Zheng, Daniel Vincent, Jie Zhou, Jisoo Kim, Donghyeok Kim, Tien Khee Ng, Boon S. Ooi, Kevin J. Chen, and Zhenqiang Ma. "Interfacial band parameters of ultrathin ALD–Al₂O₃, ALD–HfO₂, and PEALD–AlN/ALD–Al₂O₃ on c-plane, Ga-face GaN through XPS measurements." Journal of Applied Physics 132, no. 13 (October 7, 2022): 135302. http://dx.doi.org/10.1063/5.0106485.

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Ultrathin oxides (UOs) and ultrathin nitrides (UNs) play a crucial role in forming lattice-mismatched semiconductor heterostructures that are fabricated by using semiconducting grafting approach. The grafting approach has shown its great potential to realize GaN-based heterojunction bipolar transistors by fulfilling the missing high-performance p-type nitrides with other p-type semiconductors. A handful of UO and UN dielectrics readily available by atomic layer deposition (ALD) satisfy the requirements of double-sided surface passivation and quantum tunneling for semiconductor grafting. Due to the states existing between the UO or UN conduction band and that of the GaN, the ALD deposited UO or UN layer can generate significant effects on the surface band-bending of GaN. Understanding the band parameters of the interface between UO or UN and c-plane Ga-face GaN can guide the selection of interfacial dielectrics for grafted GaN-based devices. In this study, we performed x-ray photoelectron spectroscopy measurements to obtain the band-bending properties on c-plane, Ga-face GaN samples coated by different ALD cycles of ultrathin-HfO2 or ultrathin AlN. The valence band spectra of GaN coated with ultrathin-ALD–Al2O3, ALD–HfO2, or PEALD–AlN/ALD–Al2O3 were further analyzed to calculate the valence and conduction band offsets between the ALD dielectrics and the Ga-face GaN under different thicknesses and post-deposition annealing conditions of the dielectrics.

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Beshkova, M., P. Deminskyi, C.-W. Hsu, I. Shtepliuk, I. Avramova, R. Yakimova, and H. Pedersen. "Atomic layer deposition of AlN on different SiC surfaces." Journal of Physics: Conference Series 2240, no. 1 (March 1, 2022): 012004. http://dx.doi.org/10.1088/1742-6596/2240/1/012004.

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Abstract Thin AlN films were grown using a Picosun R-200 atomic layer deposition (ALD) reactor on SiC surfaces with different crystallographic orientation: on-axis 4H-SiC (0001) and 8° off-axis 4H-SiC. TMA (trimethylaluminium) and NH3 were used as precursors while hydrogen and nitrogen plasma were applied for in-situ substrate cleaning. The substrate temperatures were 400 °C and 450 °C, with 20 ALD cycles. The surface morphology was investigated by scanning electron microscopy (SEM), which revealed nanometer-sized islands in all films. The AlN films deposited on on-axis 4H-SiC at 450 °C substrate temperature exhibited a relatively small roughness of about 0.255 nm. The chemical composition and bonding states were investigated by X-ray photoelectron spectroscopy. For all layers, high-resolution XPS showed Al 2p and N 1s spectra that are characteristic of AlN. These results are a good prerequisite of establishing the growth conditions of AlN films for surface acoustic wave (SAW) devices.

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Oficerova, N. V., V. I. Savina, and M. A. Zakaryaeva. "The investigation of the current-voltage characteristics of SiC–(SiC)1–x(AlN)x heterostructures." Herald of Dagestan State University 33, no. 1 (2018): 43–49. http://dx.doi.org/10.21779/2542-0321-2018-33-1-43-49.

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Vasilyev, V., J. Cetnar, B. Claflin, G. Grzybowski, K. Leedy, N. Limberopoulos, D. Look, and S. Tetlak. "Al1-x ScxN Thin Film Structures for Pyroelectric Sensing Applications." MRS Advances 1, no. 39 (2016): 2711–16. http://dx.doi.org/10.1557/adv.2016.510.

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ABSTRACTAlN thin film structures have many useful and practical piezoelectric and pyroelectric properties. The potential enhancement of the AlN piezo- and pyroelectric constants allows it to compete with more commonly used materials. For example, combination of AlN with ScN leads to new structural, electronic, and mechanical characteristics, which have been reported to substantially enhance the piezoelectric coefficients in solid-solution AlN-ScN compounds, compared to a pure AlN-phase material.In our work, we demonstrate that an analogous alloying approach results in considerable enhancement of the pyroelectric properties of AlN - ScN composites. Thin films of ScN, AlN and Al1-x ScxN (x = 0 – 1.0) were deposited on silicon (004) substrates using dual reactive sputtering in Ar/N2 atmosphere from Sc and Al targets. The deposited films were studied and compared using x-ray diffraction, XPS, SEM, and pyroelectric characterization. An up to 25% enhancement was observed in the pyroelectric coefficient (Pc = 0.9 µC /m2K) for Sc1-xAlxN thin films structures in comparison to pure AlN thin films (Pc = 0.71 µC/m2K). The obtained results suggest that Al1-x ScxN films could be a promising novel pyroelectric material and might be suitable for use in uncooled IR detectors.

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Yan, Bao Jun, Shu Lin Liu, and Lu Ping Yang. "Homogenous Thin Films Prepared on Microchannel Plates via Atomic Layer Deposition." Advanced Materials Research 1096 (April 2015): 93–97. http://dx.doi.org/10.4028/www.scientific.net/amr.1096.93.

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Oxide thin films such as aluminum oxide doped with zinc (AZO), and aluminum oxide (Al2O3) were prepared in the pores of microchannel plate (MCP) by atomic layer deposition (ALD), which is a precise control thin film thickness on substrate with high aspect ratio structure. In this paper, homogenous oxide thin films deposited on varied substrates were prepared by ALD technology under different conditions, and the morphology, element distribution and structure of deposited samples are systematically investigated by scanning electron microscopy (SEM), energy dispersive x-ray (EDX), and x-ray diffraction (XRD) respectively, The results show that ALD technique is a good method to grow homogenous thin films on MCP.

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Guseynov, M. K., T. I. Isabekova, and N. V. Oficerova. "Technological Features of (SiC)1–x(AlN)x Solid Solutions Magnetron Deposition." Herald of Dagestan State University 36, no. 1 (2021): 48–54. http://dx.doi.org/10.21779/2542-0321-2021-36-1-48-54.

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Strnad, Nicholas A., Wendy L. Sarney, Gilbert B. Rayner, Robert R. Benoit, Glen R. Fox, Ryan Q. Rudy, Thomas J. Larrabee, Jeffrey Shallenberger, and Jeffrey S. Pulskamp. "Plasma enhanced atomic layer deposition of textured aluminum nitride on platinized substrates for MEMS." Journal of Vacuum Science & Technology A 40, no. 4 (July 2022): 042403. http://dx.doi.org/10.1116/6.0001633.

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We demonstrate an N2 plasma-enhanced process for inducing (0001)-oriented ALD-grown AlN on planar substrates. We evaluate the impact of {111}-textured Pt as a growth template, precursor chemistry, dose time, stress-engineered substrates, inductively coupled plasma conditions for film bombardment during growth, and ALD equipment configurations. The thin film transverse piezoelectric coefficient e31,f determined from measurements on microelectromechanical system cantilevers coated by PEALD AlN is reported to be −0.53 ± 0.03 C/m2. An analysis of the Pt-AlN interface properties based primarily on depth-profile x-ray photoemission spectroscopy and transmission electron microscopy-energy dispersive spectra is presented. Other than the c axis wurtzite (0001) diffraction peak, no other AlN peaks were observed above the detection limits for XRD measurements. The XRD rocking-curve full-width half-maximum of the 0001 peaks was 2.9° omega, which was achieved on {111}-textured Pt. The relative dielectric constant was measured to be 8.1 < K < 8.6, and an average dielectric loss of < 0.01 was observed within the applied electric field range of ±3350 kV/cm at 10 kHz. The leakage current of the textured AlN was quite low at 1.5 × 10−6 A/cm2 over the applied field range of ±1820 kV/cm.

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Beshkova, M., B. S. Blagoev, V. Mehandzhiev, R. Yakimova, B. Georgieva, I. Avramova, P. Terziyska, and V. Strijkova. "Morphological evolution of thin AlN films grown by atomic layer deposition." Journal of Physics: Conference Series 2240, no. 1 (March 1, 2022): 012005. http://dx.doi.org/10.1088/1742-6596/2240/1/012005.

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Abstract Thin AlN films were grown using a Beneq TFS-200 ALD reactor. TMA (trimethylaluminium) and NH3 were used as precursors. The substrate temperature was 330 °C, the ALD cycles, 550. The TMA and NH3 doses (pulses) lasted 180 ms and 90 ms, followed by 2-s and 9-s nitrogen gas purge, respectively. In order to study the morphological evolution of the thin AlN films, substrates providing different surface kinetics were used: Si-face and C-face of 4°-off axis and on-axis 4H-SiC, and graphene grown on 4H-SiC by sublimation. As revealed by atomic force microscopy (AFM), the lowest RMS surface roughness of about 0.8 nm was exhibited by the AlN film deposited on Si-face on-axis 4H-SiC due to its higher surface energy which provides for better film nucleation. The chemical composition and bonding states were investigated by X-ray photoelectron spectroscopy (XPS). The existence of AlN is justified by the presence of the XPS peaks of Al 2p and N 1s at about 73.3 eV and 396.6 eV, respectively. These results are promising in view of further studies of thin AlN films properties for application in surface acoustic wave devices (SAW).

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Shakhbanova, Z. I., M. K. Guseynov, and M. A. Magomedov. "Research of the Optical and Electrical Properties of Solid Solutions (Sic)1-X (Aln)X." Herald of Dagestan State University 36, no. 1 (2021): 34–38. http://dx.doi.org/10.21779/2542-0321-2021-36-1-34-38.

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Dallaev, Rashid, Dinara Sobola, Pavel Tofel, Ľubomir Škvarenina, and Petr Sedlák. "Aluminum Nitride Nanofilms by Atomic Layer Deposition Using Alternative Precursors Hydrazinium Chloride and Triisobutylaluminum." Coatings 10, no. 10 (October 3, 2020): 954. http://dx.doi.org/10.3390/coatings10100954.

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The aim of this study is motivated by the pursuit to investigate the performance of new and as yet untested precursors such as hydrazinium chloride (N2H5Cl) and triisobutylaluminum Al(C4H9)3 in the AlN atomic layer deposition (ALD) process as well as to study effects of successive annealing on the quality of the resulting layer. Both precursors are significantly cheaper than their conventional counterparts while also being widely available and can boast easy handling. Furthermore, Al(C4H9)3 being a rather large molecule might promote steric hindrance and prevent formation of undesired hydrogen bonds. Chemical analysis is provided by X-ray photoelectron spectroscopy (XPS) and secondary-ion mass spectrometry (SIMS) techniques; surface morphology was studied using atomic force microscopy (AFM). Chlorine containing precursors such as AlCl3 are usually avoided in ALD process due to the risk of chamber contamination. However, experimental data of this study demonstrated that the use of N2H5Cl does not result in chlorine contamination due to the fact that temperature needed for HCl molecules to become reactive cannot be reached within the AlN ALD window (200–350 °C). No amount of chlorine was detected even by the most sensitive techniques such as SIMS, meaning it is fully removed out of the chamber during purge stages. A part of the obtained samples was subjected to annealing (1350 °C) to study effects of high-temperature processing in nitrogen atmosphere, the comparisons with unprocessed samples are provided.

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Oficerova, N. V., and A. E. Akhmedkhanov. "О взаимосвязи типа проводимости и электрических свойств твердых растворов (SiC)1–x(AlN)x." Herald of Dagestan State University 37, no. 3 (September 29, 2022): 58–63. http://dx.doi.org/10.21779/2542-0321-2022-37-3-58-63.

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Frimpong-Manso, Ellen Serwaa, and Liancheng Wang. "High Reflectivity AlN/Al1−xInxN Distributed Bragg Reflectors across the UV Regions by Sputtering." Crystals 12, no. 2 (January 24, 2022): 162. http://dx.doi.org/10.3390/cryst12020162.

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To improve the performance of III-nitride compound semiconductor-based optoelectronic devices, highly reflective distributed Bragg reflectors (DBRs) are a requirement. In this report, AlN and Al1−xInxN layers were first sputtered and characterized concerning their optical, structural and morphological properties. Ellipsometry measurements were used to determine the optical constants (refractive index, n and coefficient of extinction, k, in dependence of the wavelengths of the layers. The indium content of the Al1−xInxN film was investigated by X-ray photoelectron spectroscopy analysis. Subsequently, AlN/Al1−xInxN DBRs with high reflectivity spectra operating in the UV A, B and C were designed and fabricated on Si (111) and SiO2 substrates by radio frequency (RF) magnetron sputtering. The DBRs consist of an eight-pair AlN/Al0.84In0.16N at 235 nm, 290 nm and 365 nm with reflectances of 86.5%, 97.7% and 97.5% with FWHM of 45 nm, 70 nm and 96 nm, respectively. Atomic force microscopy analysis yielded a Root Mean Square (RMS) of 2.95 nm, implying that the DBR samples can achieve reasonable smoothness over a wide area. Furthermore, the impact of an annealing phase, which is frequently required during device growth, was investigated. Our findings indicate that AlN and Al1−xInxN are suitable materials for the fabrication of deep UV DBRs.

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Yang, Seyeong, Jongmin Park, Youngboo Cho, Yunseok Lee, and Sungjun Kim. "Enhanced Resistive Switching and Synaptic Characteristics of ALD Deposited AlN-Based RRAM by Positive Soft Breakdown Process." International Journal of Molecular Sciences 23, no. 21 (October 31, 2022): 13249. http://dx.doi.org/10.3390/ijms232113249.

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Nitride film played an essential role as an excellent diffusion barrier in the semiconductor field for several decades. In addition, interest in next-generation memories induced researchers’ attention to nitride film as a new storage medium. A Pt/AlN/TaN device was investigated for resistive random-access memory (RRAM) application in this work. Resistive switching properties were examined in the AlN thin film formed by atomic layer deposition (ALD). The unique switching feature conducted under the positive voltage was investigated, while the typical bipolar switching was conducted under the application of negative voltage. Good retention and DC, and pulse endurances were achieved in both conditions and compared to the memory performances. Finally, the electronic behaviors based on the unique switching feature were analyzed through X-ray photoelectron spectroscopy (XPS) and the current–voltage (I–V) linear fitting model.

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Funahashi, Shiro, Yuichi Michiue, Takashi Takeda, Rong-Jun Xie, and Naoto Hirosaki. "Substitutional disorder in Sr2−y Eu y B2−2x Si2+3x Al2−x N8+x (x ≃ 0.12, y ≃ 0.10)." Acta Crystallographica Section C Structural Chemistry 70, no. 5 (April 18, 2014): 452–54. http://dx.doi.org/10.1107/s2053229614007414.

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A novel nitride, Sr2−y Eu y B2−2x Si2+3x Al2−x N8+x (x ≃ 0.12, y ≃ 0.10) (distrontium europium diboron disilicon dialuminium octanitride), with the space group P\overline{6}2c, was synthesized from Sr3N2, EuN, Si3N4, AlN and BN under nitrogen gas pressure. The structure consists of a host framework with Sr/Eu atoms accommodated in the cavities. The host framework is constructed by the linkage of MN4 tetrahedra (M = Si, Al) and BN3 triangles, and contains substitutional disorder described by the alternative occupation of B2 or Si2N on the (0, 0, z) axis. The B2:Si2N ratio contained in an entire crystal is about 9:1.

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Tsai, Fa Ta, Hsi Ting Hou, Ching Kong Chao, and Rwei Ching Chang. "Depositing High-Performance Conductive Thin Films by Using Atomic Layer Deposition." Applied Mechanics and Materials 764-765 (May 2015): 138–42. http://dx.doi.org/10.4028/www.scientific.net/amm.764-765.138.

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This work characterizes the mechanical and opto-electric properties of Aluminum-doped zinc oxide (AZO) thin films deposited by atomic layer deposition (ALD), where various depositing temperature, 100, 125, 150, 175, and 200 °C are considered. The transmittance, microstructure, electric resistivity, adhesion, hardness, and Young’s modulus of the deposited thin films are tested by using spectrophotometer, X-ray diffraction, Hall effect analyzer, micro scratch, and nanoindentation, respectively. The results show that the AZO thin film deposited at 200 °C behaves the best electric properties, where its resistance, Carrier Concentration and mobility reach 4.3×10-4 Ωcm, 2.4×1020 cm-3, and 60.4 cm2V-1s-1, respectively. Furthermore, microstructure of the AZO films deposited by ALD is much better than those deposited by sputtering.

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Choi, Yong June, Kyung Mun Kang, and Hyung Ho Park. "Post-Annealing Effects on the Surface Roughness of Undoped and Al-Doped ZnO Thin Films Deposited by Atomic Layer Deposition." Advanced Materials Research 734-737 (August 2013): 2492–95. http://dx.doi.org/10.4028/www.scientific.net/amr.734-737.2492.

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The post-annealing effects on the surface morphological changes of undoped and Al-doped ZnO (ZnO:Al) thin films deposited by atomic layer deposition (ALD) were investigated. The as-grown films were deposited by ALD at growth temperature of 200°C and also, post-annealing of the samples was accomplished at 300°C for 1 h under nitrogen atmosphere. The X-ray diffraction of the films was monitored to study the crystallinity of the films according to post-anneal. The field emission-scanning electron microscopy and atomic force microscopy were conducted to observe the surface morphological changes and measure the root-mean-square roughness of the films in order to analysis the post-annealing effects on the surface roughness of the films.

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Liubchenko, O. I., and V. P. Kladko. "Simulation of X-Ray Diffraction Spectra for AlN/GaN Multiple Quantum Well Structures on AlN(0001) with Interface Roughness and Variation of Vertical Layers Thickness." METALLOFIZIKA I NOVEISHIE TEKHNOLOGII 40, no. 6 (October 24, 2018): 759–76. http://dx.doi.org/10.15407/mfint.40.06.0759.

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Paikaew, Chutharat, Juthamas Inthanont, Adisak Punyanut, Ekachai Hoonnivathana, Pichet Limsuwan, and Kittisakchai Naemchanthara. "Effects of Electron Beam on Structure and Physical Properties of Natural Colorless Topaz." Advanced Materials Research 1125 (October 2015): 60–63. http://dx.doi.org/10.4028/www.scientific.net/amr.1125.60.

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The purpose of this research was to investigate physical properties, configuration and color of topaz. Topazes were irradiated with electron beam linear accelerator at different dose from 40 to 180 MGy. The color of topaz was analyzed by UV-vis and it was shown that the color of topaz was becoming strong color with increased electron beam dose. Crystal structure and function group of topaz were characterized by X- ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The results showed that the topaz has orthorhombic structure and no other crystalline. After irradiated, topaz released OH indicating higher crystallinity of topaz and this was confirmed with the results of electron spin resonance (ESR). Electron beam dose response of topaz was investigated. ESR results showed that the Al3+ ion was substituted in Si4+ site and Ti3+ impurity in Al4+ site and this result corresponds to the results of FTIR. The experiment result indicated that electron beam could be making defect on crystal structure and color enhancement of topaz.

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Zhang, Peng, Dao Bin Luo, and Jian Ke Liu. "Sol-Gel Combustion Synthesis and Properties of Nanocrystalline TbxY1-x Al₃(BO₃)4（0≤x≤0.2）Phosphors." Applied Mechanics and Materials 203 (October 2012): 295–98. http://dx.doi.org/10.4028/www.scientific.net/amm.203.295.

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Single phases of TbxY1-x Al3(BO3)4（0≤x≤0.2）phosphors were synthesized by a sol-gel combustion method with citric acid as fuel and complexing agent. Our method involves only exothermic decomposition of an aqueous citrate–nitrate gel and the gel yielded nanocrystalline TbxY1-x Al3(BO3)4 phosphors at 1000°C, without any formation of intermediate phase. The optimal doping concentration of Tb3+ ions in the serials was found to be approximately 12mol%. The decomposition of the gel was investigated by TG–DTA. The product has been further characterized by X-ray powder diffractometry (XRD) and fluorescent divide spectroscopy (FDS).

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Liu, Gui Yang, Jun Ming Guo, Li Li Zhang, Bao Sen Wang, and Ying He. "Al Doped LiMn₂O₄ Prepared by a Solution Combustion Synthesis Using Acetate Salts as Raw Materials and Acetic Acid as Fuel." Applied Mechanics and Materials 142 (November 2011): 209–12. http://dx.doi.org/10.4028/www.scientific.net/amm.142.209.

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To improve the cyclability of spinel LiMn2O4, Al3+doped LiAlxMn2−xO4(x=0, 0.01, 0.05 and 0.10) materials are prepared using a solution combustion synthesis method using acetic salts as raw materials and acetic acid as fuel. Their phase structures are characterized by X-ray diffraction (XRD). Electrochemical performances of the materials are investigated by galvanostatic charge/discharge methods. XRD results reveal that the purity of the samples increases with increasing Al3+content. Electrochemical experiments demonstrate that the charge/discharge cyclability of the LiAlxMn2-xO4increases with increasing Al3+content. Compared with the pristine LiMn2O4, the Al-doped LiAlxMn1−xO4show the obviously improved cyclability, especially for the sample LiAl0.1Mn1.9O4.

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Hirose, Fumihiko, Kensaku Kanomata, Shigeru Kubota, Bashir Ahmmad, and Kazuhiro Hirahara. "Room Temperature Atomic Layer Deposition of SiO₂ on Flexible Plastic Materials." Applied Mechanics and Materials 490-491 (January 2014): 118–22. http://dx.doi.org/10.4028/www.scientific.net/amm.490-491.118.

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Room-temperature SiO2 atomic layer deposition (ALD) on soft, flexible materials of acrylic resin and polystyrene is developed using tris (dimethylamino) silane and plasma-excited water vapor. The growth rate is measured to be 0.13 nm/cycle at room temperature on the acrylic resin surface. The SiO2 coating on the soft materials was examined by X-ray photoelectron spectroscopy and an organic solvent resistant test. This process is applicable as a surface treatment for improving chemical resistivity of the soft materials.

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Xiong, Yu, Ji Zheng, Song Lin Li, Xue Jia Liu, and Lu Liang. "Investigation on Nano-Sized ZnO Powder Doped with Al³⁺ Prepared by Sol-Gel Method." Advanced Materials Research 621 (December 2012): 3–7. http://dx.doi.org/10.4028/www.scientific.net/amr.621.3.

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Al3+-doped ZnO nano-powder was prepared by sol-gel process, using tin tetrachloride and titanium tetrachloride as starting materials. The crystallinity and purity of the powder were analyzed by X-ray diffraction spectrometer (XRD). And the size and distribution of Al3+-doped ZnO grains were studied using transmission electron microscope (TEM) and scanning electron microscope (SEM). The results showed that the Al3+ was successfully doped into the crystal lattice of tin oxide and that the electric conductivity of Al3+-doped ZnO sample was improved significantly.

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Andrews, Jared M., Mitchel T. Holm, and Jerome B. Myers. "Clinical Predictors of Abnormal Peripheral Blood Lymphocytoses Diagnosed by Flow Cytometry: An Algorithmic Approach That Can Be Applied in Routine Clinical Practice." Blood 106, no. 11 (November 16, 2005): 3932. http://dx.doi.org/10.1182/blood.v106.11.3932.3932.

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Abstract Background Elevated peripheral blood lymphocyte counts in adults can occur in benign reactive conditions as well as malignant disease processes. Chronic lymphocytic leukemia (CLL) is the most common adult hematologic malignancy of the western world affecting the middle aged and elderly. Less commonly B, T, and Natural Killer (NK) cell leukemia / lymphomas may also present with lymphocytosis. Flow cytometry has greatly improved the ability to detect low levels of abnormal lymphocyte populations in peripheral blood. It is, however, a relatively expensive test and clinical guidelines for its appropriate usage are not well defined. Methods We conducted a retrospective review of peripheral blood lymphocytoses that were submitted for flow cytometric analysis at Madigan Army Medical Center, Tacoma, WA from 2002 – 2004. Under laboratory protocol, all patients ≥ 50 years of age with an absolute lymphocyte count (ALC) of > 4 X 109 Cells/L had a peripheral smear evaluated by both a hematology technician and pathologist. Specimens determined to warrant flow cytometric analysis based on review of clinical history, prior lab values, degree of lymphocytosis, and morphology were either recommended for flow cytometry in a comment; or sent directly for analysis with the clinician’s approval. We reviewed complete blood counts (CBCs), previous flow cytometry results, as well as bone marrow and electronic clinical history. All patients with previous diagnoses of lymphoproliferative disorders (LPDs) or ALC < 4 X 109 Cells/L were excluded. Results Approximately 7,300 CBC specimens/month (3,400 from patients ≥ 50 years of age) were performed. Of these, an average of 44 specimens/month had a lymphocytosis of ≥ 4 X 109 Cells/L, from approximately 28 different patients. From this group 71 flow cytometric cases (an average of 2/month) were performed over the 2 year period. 42 cases (59%) had an abnormal phenotype. 27 had a phenotype consistent with CLL, and the other 15 were a mixture of LPDs involving B and T-lymphocytes as well as NK cells. Comparing normal phenotype to abnormal phenotype showed statistically significant differences between the mean age (n-60.4 ±7.5, abn-69.8±8.7), ALC (n-4.9±0.8, abn-9.2±8.1), and relative lymphocyte count (RLC) (n-43.9±7.5%, abn-59.3±8.8%). Conclusion Absolute lymphocyte counts ≥ 4 X 109 Cells/L in adults ≥ 50 years of age represent approximately 1% of the CBCs performed in our laboratory. Review of these cases by a pathologist is logistically feasible due to the low incidence. Our method of reviewing for morphology, clinical history, and past lymphocyte counts with comments to the ordering clinician yielded a high incidence of abnormal phenotype diagnoses when evaluated by flow cytometric analysis (59%). Age, ALC, and relative lymphocyte counts are variables that can be used to develop guidelines for determining the appropriateness of flow cytometric analysis. Patients < 52.4 years of age fall below two standards of deviation from the mean age of the abnormal phenotype group. The standard of deviation for mean ALC is very small (4.9±0.8), which indicates that counts > two standards of deviation above the mean, or 6.5 X 109 Cells/L, would correlate strongly with an abnormal phenotype. The same conclusion could be made with a RLC > 58.9%. In conclusion, patients ≥ 50 years of age with an ALC > 6.5 X 109 Cells/L or a RLC > 58.9% are likely to have a lymphoproliferative disorder and flow cytometric analysis is indicated.

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Austin, Aaron J., Elena Echeverria, Phadindra Wagle, Punya Mainali, Derek Meyers, Ashish Kumar Gupta, Ritesh Sachan, S. Prassana, and David N. McIlroy. "High-Temperature Atomic Layer Deposition of GaN on 1D Nanostructures." Nanomaterials 10, no. 12 (December 5, 2020): 2434. http://dx.doi.org/10.3390/nano10122434.

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Silica nanosprings (NS) were coated with gallium nitride (GaN) by high-temperature atomic layer deposition. The deposition temperature was 800 °C using trimethylgallium (TMG) as the Ga source and ammonia (NH3) as the reactive nitrogen source. The growth of GaN on silica nanosprings was compared with deposition of GaN thin films to elucidate the growth properties. The effects of buffer layers of aluminum nitride (AlN) and aluminum oxide (Al2O3) on the stoichiometry, chemical bonding, and morphology of GaN thin films were determined with X-ray photoelectron spectroscopy (XPS), high-resolution x-ray diffraction (HRXRD), and atomic force microscopy (AFM). Scanning and transmission electron microscopy of coated silica nanosprings were compared with corresponding data for the GaN thin films. As grown, GaN on NS is conformal and amorphous. Upon introducing buffer layers of Al2O3 or AlN or combinations thereof, GaN is nanocrystalline with an average crystallite size of 11.5 ± 0.5 nm. The electrical properties of the GaN coated NS depends on whether or not a buffer layer is present and the choice of the buffer layer. In addition, the IV curves of GaN coated NS and the thin films (TF) with corresponding buffer layers, or lack thereof, show similar characteristic features, which supports the conclusion that atomic layer deposition (ALD) of GaN thin films with and without buffer layers translates to 1D nanostructures.

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Ilyasov, V. V., T. P. Zhdanova, and I. Ya Nikiforov. "X-ray spectra and electronic structure of aluminum in AlN and B x Al1 − x N crystals with a wurtzite structure." Physics of the Solid State 48, no. 2 (February 2006): 213–15. http://dx.doi.org/10.1134/s1063783406020028.

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Gonschorek, M., J. F. Carlin, E. Feltin, M. A. Py, N. Grandjean, V. Darakchieva, B. Monemar, M. Lorenz, and G. Ramm. "Two-dimensional electron gas density in Al1−xInxN/AlN/GaN heterostructures (0.03≤x≤0.23)." Journal of Applied Physics 103, no. 9 (May 2008): 093714. http://dx.doi.org/10.1063/1.2917290.

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Khorashadizade, Elham, Hadi Arabi, and Abbas Yousefi. "Doping Effect on Crystal Structure and Magnetic Properties of Highly Al-Substituted Strontium Hexaferrite Nanoparticles." Applied Mechanics and Materials 229-231 (November 2012): 210–14. http://dx.doi.org/10.4028/www.scientific.net/amm.229-231.210.

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M-type strontium hexaferrites with substitution of Fe3+by Al3+, according to the formula SrAlxFe12-xO19(x=0, 1, 2, 3, 4, 6, 8, 10), are prepared by the sol-gel auto-combustion method. Influences of the substituted amount of Al3+on structure and magnetic properties of SrAlxFe12-xO19compounds have systematically been investigated by XRD, TEM and VSM. X-ray diffraction shows that the samples are single M-type hexagonal ferrites. Because of the resemblance of Al3+ionic radii with Fe3+the two ions are easily replaced at any substitution ratio without changing the crystal structure. The materials show structural and morphology changes upon replacement of iron by aluminum. A shift in peak position to larger angles shown by XRD is observable with increasing aluminum doping. The values of Ms, Mr and Hc decrease with the addition of Al content but there is an exception for x=3 when Hc=8.9 KOe.

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Hefni, Hassan H. H., Mohammed Nagy, Mohammed M. Azab, and Mohammed H. M. Hussein. "Esterification of chitosan with L-alanine and a study on their effect in removing the heavy metals and total organic carbon (TOC) from wastewater." Pure and Applied Chemistry 88, no. 6 (June 1, 2016): 595–604. http://dx.doi.org/10.1515/pac-2016-0301.

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AbstractIn this work, chitosan was modified by the esterification with L-alanine in the presence of H2SO4 as a catalyst to increase the number of amino groups with the aim of increasing the adsorption efficiency. Chitosan (CS) and chitosan-O-alanine (CS-Aln) were characterized and investigated by elemental analysis, Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The results obtained from elemental analysis and IR indicated the presence of sulfuric acid after neutralization as a crosslinker between CS-Aln chains. Also CS-Aln is more amorphous than CS due to the ionic bonds of crosslinker. The removal of three heavy metals (Mn2+, Pb2+ and Al3+) and total organic carbon (TOC) from wastewater by CS and CS-Aln in the batch mode has been studied at different adsorbent dosages, temperatures and contact times. The maximum metal ions removal efficiency using CS achieved 99.6%, 99.1% and 98.9%, respectively, while by using CS-Aln 95.3%, 99.3% and 98.9% were achieved. However, the maximum adsorption capacity of TOC by CS achieved 50 mg/g and 89 mg/g by CS-Aln. The total maximum adsorption capacity of CS-Aln is higher than CS.

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Altukhov, V. I., A. V. Sankin, V. F. Antonov, S. V. Filipova, and O. A. Mitugova. "Schottky barrier height value and calculation of voltage-current characteristics Al/n-(SiC)1-x(AlN)x diodes and geterotransition, based on 4H-SiC." Izvestiya vysshikh uchebnykh zavedenii. Fizika, no. 9 (2019): 113–16. http://dx.doi.org/10.17223/00213411/62/9/113.

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Hamidi, Maziidah, Syafawati Nadiah Mohamed, and Muhd Zu Azhan Yahya. "Conductivity Studies on Li_1-XAl_xTi_2-X(PO₄)₃ (X=0.0-0.5) Due to the Addition of Al³⁺ Trivalent Cation." Advanced Materials Research 418-420 (December 2011): 1869–72. http://dx.doi.org/10.4028/www.scientific.net/amr.418-420.1869.

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The Li-ion fast conductor, Li1-XAlxTi2-X(PO4)3 (LATP) compound were synthesized by a sol-gel method. Effects due to the addition of Al3+ into Li1-XAlxTi2-X(PO4)3 (x=0.0-0.5) glass-ceramics system have been investigated using electrochemical impedance spectroscopy (EIS), X-ray differential analysis (XRD) and permittivity studies. The crystalline phase of the samples obtained confirming that they had a characteristic of glass-ceramics structure.

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Hussin, Rosniza, Kwang Leong Choy, and Xiang Hui Hou. "Fabrication of Multilayer ZnO/TiO₂/ZnO Thin Films with Enhancement of Optical Properties by Atomic Layer Deposition (ALD)." Applied Mechanics and Materials 465-466 (December 2013): 916–21. http://dx.doi.org/10.4028/www.scientific.net/amm.465-466.916.

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Atomic layer deposition (ALD) is a precision growth technique that is able to deposit either amorphous or epitaxial layer on a wide range of substrates. Multilayer thin films have been widely studied because their properties are different from those of bulk materials constituents owing to the two-dimensional films and high density of interfaces. Multilayer nanostructured thin films were fabricated on silicon and glass substrates by ALD. The optical and electrical of multilayer ZnO/TiO2/ZnO films were investigated. The microstructure compositions and surface morphology of these multilayer films were analyzed by X-ray diffraction (XRD), Atomic force microscope (AFM) and Scanning electron microscope (SEM). The optical properties were characterized using photoluminescence (PL) and UV-VIS spectroscopy. XRD patterns confirmed that ZnO with wutrtize crystal structure and TiO2 with anatase structure were presented. The degree of crystallinity of multilayer thin films has been improved through the deposition of ZnO. The intensity of UV luminescence of the multilayer has increased as compared to the single layer TiO2 and bilayer ZnO/TiO2. The multilayer ZnO/TiO2/ZnO has high transmittance (above 80%) in visible region. All the result suggested that the use of multilayer thin films effectively enhanced the quality of films crystallinity and optical properties as compared to single layer ZnO and bilayer ZnO/TiO2.

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Liu, Gui Yang, Jun Ming Guo, Bao Sen Wang, and Ying He. "Flameless Solution Combustion Synthesis of Al³⁺ Doped LiMn₂O₄." Advanced Materials Research 186 (January 2011): 7–10. http://dx.doi.org/10.4028/www.scientific.net/amr.186.7.

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Single phase Al3+ doped LiMn2O4 has been prepared by flameless solution combustion synthesis method at 600oC for 1h. X-ray diffraction (XRD) and scanning electric microscope (SEM) were used to determine the phase composition and micro morphology of the products. XRD analysis indicates that the purities increase and the lattice parameters of the products decrease with increasing Al3+ content. Electrochemical test indicates that the cycling performance of the products with Al3+ doping are better than that of the product without Al3+ doping. The product LiAl0.10Mn1.90O4 gets the best electrochemical performance. At the current density of 30mA/g, the initial discharge capacity of LiAl0.10Mn1.90O4 is 124.8mAh/g, and after 20 cycles, the capacity retention is more than 89%. SEM investigation indicates that the particles of LiAl0.10Mn1.90O4 are sub-micron in size and well dispersed.

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Journal articles on the topic 'X-Ald amn'

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