Academic literature on the topic 'Non-restoring division'

The use of linear methods, for example, the Combined Synthetic Aperture Focusing Technique (C–SAFT), does not allow one to obtain images with high resolution and low noise, especially structural noise in all cases. Non-linear methods should improve the quality of the reconstructed image. Several examples of the application of the maximum entropy (ME) method for ultrasonic echo processing in order to reconstruct the image of reflectors with Rayleigh super-resolution and a high signal-to-noise ratio are considered in the article. The use of the complex phase-shifted Barker code signal as a probe pulse and the compression of measured echoes by the ME method made it possible to increase the signal-to-noise ratio by more than 20 dB for the image of a flat-bottom hole with a diameter of 1 mm in a model experiment. A modification of the ME method for restoring the reflector image by the time-of-flight diffraction (TOFD) method is considered, taking into account the change of the echo signal shape, depending on the depth of the reflector. Using the ME method, 2.5D-images of models of dangling cracks in a pipeline with a diameter of 800 mm were obtained, which make it possible to determine their dimensions. In the object with structural noise, using the ME method, it was possible to increase the signal-to-noise ratio of the reflector image by more than 12 dB. To accelerate the acquisition of echoes in the dual scan mode, it is proposed to use code division multiple access (CDMA) technology based on simultaneous emission by all elements of the array of pseudo-orthogonal signals. The model experiment showed the effectiveness of applying the ME method.

Background:Monitoring vitamin D levels in athletes and determining their response to supplementation in cases of deficiency is thought to be necessary to modulate the risks associated with vitamin D deficiency.Hypothesis/Purpose:To report the results of a 5-year-long surveillance program of vitamin D in the serum of football players on a National Collegiate Athletic Association (NCAA) Division I team and to examine whether factors including age, body mass index (BMI), race, position played, and supplement type would affect the response to 12-month oral vitamin D replacement therapy in athletes with deficiency. We hypothesized that yearly measurements would decrease the proportion of athletes with vitamin D insufficiency over the years and that the aforementioned factors would affect the response to the supplementation therapy.Study Design:Cohort study; Level of evidence, 3.Methods:We measured serum 25(OH)D levels (25-hydroxyvitamin D) in 272 NCAA Division I football players from our institution annually between 2012 and 2017. Athletes with insufficient vitamin D levels (<32 ng/mL) received supplementation with vitamin D3 alone or combined vitamin D3/D2. The percentage of insufficient cases between the first 2 years and last 2 years of the program was compared, and yearly team averages of vitamin D levels were calculated. Associations between player parameters (age, BMI, race, team position, supplement type) and failed supplementation were evaluated.Results:The prevalence of vitamin D insufficiency decreased significantly during the study period, from 55.5% in 2012-2013 to 30.7% in 2016-2017 ( P = .033). The mean 25(OH)D level in 2012 was 36.3 ng/mL, and this increased to 40.5 ng/mL in 2017 ( P < .001); however, this increase was not steady over the study period. Non-Hispanic athletes and quarterbacks had the highest average 25(OH)D levels, and Black players and running backs had the lowest overall levels. There were no significant differences in age, BMI, race, or playing position between athletes with and without failed vitamin D supplementation. Athletes receiving vitamin D3 alone had a more successful rate of conversion (48.15%) than those receiving combined vitamin D3/D2 (22.22%; P = .034).Conclusion:To decrease the prevalence of vitamin D deficiency in football players, serum vitamin D measurements should be performed at least once a year, and oral supplementation therapy should be provided in cases of deficiency. Black players might be at increased risk of vitamin D insufficiency. Oral vitamin D3 may be more effective in restoring vitamin D levels than combined vitamin D3/D2 therapy.

Background Leg ulcerations are a serious and debilitating complication of sickle cell disease (SCD). Patients with SCD and leg ulcers have biomarkers of severe hemolytic anemia, a state associated with low bioavailability of nitric oxide (NO). Therapies directed at restoring NO bioavailability might prove beneficial. We selected topical sodium nitrite for clinical development due to its safety profile and vascular, anti-microbial, antiplatelet, and pro-keratinocyte functions. The nitrite anion is a vasodilator in vivo by generating NO in tissues with low oxygen tension and pH, conditions that are likely present in chronic wounds. Data from our successful phase 1 study showed improved regional blood flow, decreased ulcer pain, and appeared to improve ulcer healing. The dosing data informed the concentration of active ingredient to be used and suggested sodium nitrite efficacy in SCD patients with leg ulcers (Minniti, CP et al, Lancet Haematol 1, e95-e103). Study Design and Methods This is a multicenter, phase 2, prospective, randomized, placebo-controlled study of topical sodium nitrite in patients with SCD and leg ulcers. Primary aim is to determine the safety, tolerability, and effectiveness of twice a week topical application of study ointment for 10 weeks. We hypothesize that sodium nitrite will 1) accelerate wound healing (>25% improvement over placebo arm); and/or 2) decrease pain at the wound site (>20% over placebo). Ulcers measured by ImageJ planimetry software to increase accuracy. The secondary aims are to: a) evaluate the effect of hydroxyurea (HU) on leg ulcer healing in combination with topical sodium nitrite or placebo; b) assess changes in ulcer microbiome after application of sodium nitrite or placebo and how these changes may relate to healing; c) evaluate the dermal composition and microvascular structure in the ulcer beds. We plan to enroll 50 adults with all SCD genotypes and leg ulcers not individually >100 cm2, such that, after an expected 20% dropout, 40 subjects will complete > 8 weeks of treatment. Exclusion criteria: use of PDE5 inhibitors, NO, L-arginine, nitroprusside, nitroglycerine; acute bacterial infection; pre-existing methemoglobinemia (>3.5% on two different occasions); G6PD deficiency. Randomization is stratified by HU use to minimize potential confounding effects on study outcomes. Funded by the Food and Drug Administration (FDA) Division of Orphan Drug Development (# FD-R-0005729); active at two sites (ClinicalTrials.gov NCT02863068). Results We have screened 68 subjects with known history of leg ulcer: 46% were not eligible as the ulcer was closed at the time of screening. Of the 30 eligible, 13 subjects enrolled (12 at Montefiore Medical Center, 1 at the University of Pittsburgh), with 9 subjects randomized. Reasons for screen failure, other than ulcer closed, are depicted in fig 1. Three subjects experienced ulcer decrease >25% in the run-in period and did not have ointment application as per protocol. One subject withdrew due to lack of adherence. Therefore the overall dropout rate at this time is 33%, higher than the 20% anticipated. No study ointment SAEs have been noted, AEs have been minor and non-ointment related. Most SAEs have been VOCs, expected in this patient population and wound infections. Discussion As expected, enrollment of subjects with a rare complication of a rare disease is challenging. The recurrent pattern of ulcers in SCD was the reason why the majority of patients were not able to enroll, as the ulcer was closed at the time of screening. We monitor them closely for possible re-opening. Simplification of protocol-related procedures, such as decrease in number of required visits from twice to once a week by packaging dose-specific blister packs that the patient takes home for self-administration of ointment, has facilitated enrollment. Travel to the center is being addressed. A close relationship between the subjects and study team is essential. Co-location of the wound specialist in the sickle cell clinic and training the research nurse for wound care has helped with recruitment. Disclosures Ogu: Vertex Pharmaceuticals: Consultancy. Kato:Novartis, Global Blood Therapeutics: Consultancy, Research Funding; Bayer: Research Funding. Minniti:Doris Duke Foundation: Research Funding.

It is considered the generalized mathematical model which describes the processes of maintaining / restoring dynamic homeostasis (regeneration) of the liver and obviously depends on the control parameters. The model is a system of discrete controlled equations of the Lotka – Volterra type with transitions. These equations describe the controlled competitive dynamics of liver cell populations’ (hepatic lobules) various types in their various states and controlled competitive transitions between types and states. To develop this model there were accepted such assumptions: homogeneous approximation; independence of biological processes; small toxic factors. In the mathematical model the process of the liver regeneration occurs due to hyperplasia processes, replication, polyplodia and division of binuclear hepatocytes into mononuclear and controlled apoptosis. All these processes are necessary for adequate modeling of the liver regeneration. For example, single and constant toxic functions show that the above processes are not able to cope with the toxic factors that are accumulated in the body. The process of restoring the body’s functional state requires the non-trivial strategy of the liver regeneration. Numerical calculations revealed that the mathematical model corresponds to biological processes for different strategies of the liver regeneration. Based on the calculations in the case of partial hapatectomy it is concluded that the mixed strategy of regeneration should be used for the regeneration process. Henceforward it is planned to extend the mathematical model in the case of the liver regeneration, which occurs under the influence of strong toxins, that is, using the stem cells and fibrosis. It is also supposed to justify the principles and criteria for optimal regulation of the processes of maintaining / restoring liver’s dynamic homeostasis.