Academic literature on the topic '620.015 1'

SummaryAntibodies directed against ADAMTS13 have been detected in the majority of patients with acquired thrombotic thrombocytopenic purpura (TTP). We have previously localized a major antigenic determinant within the spacer domain of ADAMTS13. To identify the amino acid residues of the spacer domain that are involved in binding of anti-ADAMTS13 antibodies, we constructed a series of fifteen hybrids (designated A-O) in which 5–10 amino acids of the spacer domain were exchanged for the corresponding region of ADAMTS1. Plasma from six patients with antibodies directed against the spacer domain was analyzed for reactivity with the ADAMTS13/ADAMTS1 chimeras. Exchange of amino acid residues 572–579 (hybrid C) and 657–666 (hybrid M) completely abolished the binding of antibodies from all six patients analyzed. Regions 580–587 (D), 602–620 (G, H), 629–638 (J), and 667–767 (N) contributed to binding of antibodies from patients 2, 4, and 5 (epitope present within regions CDGHJMN). Antibodies derived from patient 1 required region 602–620 (G, H) for binding (CGHM-epitope). For antibodies of patient 3, residues 564–571 (B), 580–587 (D), and 629–638 (J) were required (BCDJM-epitope), whereas replacement of residues 602–610 (G) and 629–638 (J) greatly diminished binding of antibodies from patient 6 (CGJM-epitope). Despite the presumably polyclonal origin of the antibodies present in plasma of patients, our results suggest that residues 572–579 (C) and 657–666 (M) comprise a common antigenic core region that is crucial for binding of anti-ADAMTS13 antibodies. Other regions that spatially surround this antigenic core further modulate binding of antibodies to the spacer domain.

Thin poly-Si layers deposited at 625 °C by LPCVD that are used in silicon technology for microelectronics exhibit a pronounced additional x-ray diffraction peak at about 0.334 nm. High-resolution electron microscopy (HREM) reveals that this peak stems from {010} reflections of a diamond hexagonal (dh) Si phase, which occurs as small inclusions with the orientation relationship (01) ‖ (0001), [011] ‖ [20] to the diamond cubic (dc) Si matrix. Due to the high density of planar faults on {111}, the dh-Si phase also exists in the form of the 2H silicon polytype with the orientation relationship (1) ‖ (0001), [011] ‖ [20]. In the first case the formation of the dh-Si phase may be understood by a multiple twinning transformation process, and in the second case by glide of Shockley partial dislocations on {111} planes. Various other hexagonal polytypes occur, which have all the {010} reflections in common and make a major contribution to the 0.334 nm peak. The medium temperature of 625 °C for layer deposition leads to a 〈011〉 preferential orientation and a high density of twins as well as to high compressive stress in the poly-Si layer itself. This seems to promote the formation of dh-Si. The strong twinning behavior produces a typical tilt grain boundary between adjacent dh-Si grains: [20], (016), Θ = 35°with a translation vector t = 1/2[031] parallel to it. The dh-Si phase vanishes in this poly-Si film after annealing at temperatures above 1000 °C due to grain growth by recrystallization.

Fabrication of integrated circuits on SOI (Silicon-On-Insulator) material is very attractive because it offers high component density, immunity to latch-up and radiation hardness. Among various SOI techniques SIMOX Separation by IMplantation of OXygen) provides the best material, with carrier mobilities and defect densities approaching bulk silicon values, Early SIMOX wafers were implanted at temperatures below 600°C and annealed at high temperature (>1300°C), which gave a high defect density (109cm−2), including threading dislocations and narrow stacking faults (SFs), as shown in Figure 1. Higher temperature (>600°C) implantation of SIMOX reduced defect densities to 106cm-2 with pairs of narrow SFs in the top silicon layer, as shown in Figure 2. This paper describes a further reduction of defect density in SIMOX material through various annealing conditions, which has resulted in a defect density less than 105cm−2. A new formation mechanism for stacking fault tetrahedra is also discussed.Silicon (100) wafers were sequentially implanted (620°C) and annealed (at 1320°C for 5 hours) to doses of 0.5, 0.5, and 0.8×l018cm-2.

The objective of this study is to investigate the impact of polypropylene fibers on fire resistance of concrete. In order to achieve this, concrete mixtures are prepared by using different percentages of polypropylene; 0%, 0.5% and 1%, by volume. The samples are heated to 200, 400 and 600 °C, for exposures up to 6 hours, and tested for compressive strength. Based on the results of the study, it is concluded that the relative compressive strengths of concretes containing PP fibers were higher than those of concretes without PP fibers. Furthermore, it can be concluded that concrete mixes which are prepared using 0.5% PP fibers, by volume, can significantly promote the residual compressive strength during the heating. Santrauka Tyrimo tikslas – išnagrinėti polipropireno pluošto įtaką betono atsparumui ugniai. Buvo gaminami betono mišiniai su 0%, 0,5% ir 1% polipropireno dalimis. Bandiniai buvo kaitinami iki 200, 400 ir 600 °C, laikomi šiose temperatūrose 6 valandas ir bandomi nustatant gniuždomajį stiprį. Remiantis bandymų rezultatais daroma išvada, kad betono su polipropireno pluoštu stipris buvo didesnis už betono be šio priedo stiprį. Kita straipsnio išvada ta, kad betono mišiniai, kurių 0,5% tūrio sudaro polipropireno pluoštas, leidžia labai padidinti liekamajį gniuždomajį įkaitinto betono stiprį.

Complex impedance spectra of ferroelectric mixed ceramic system ( Na 0.5 Bi 0.5)1-x Ca x Bi 4 Ti 4 O 15 with x=0, 0.1, 0.3, 0.5, 0.7 and 1 was studied as a function of frequency and temperature in the range 1 KHz to 10 MHz and 30°C to 620°C respectively. Equivalent circuits involving resistive and capacitive elements at different temperatures, activation energies of relaxations and conduction were evaluated using impedance plots. A comparative study of impedance and conductivity facilities an insight in understanding the electrical nature of these electroceramics.

Purpose:Cross-country-ski races place complex demands on athletes, with events lasting between approximately 3 min and 2 h. The aim of the current study was to compare the aerobic and anaerobic measures derived from a short time trial (TT) between male and female skiers using diagonal cross-country skiing.Methods:Twenty-four highly trained cross-country skiers (12 male and 12 female, age 17.4 ± 1.4 y, body mass 68.2 ± 8.9 kg, height 174 ± 8 cm) participated. The submaximal VO2–speed relationship and VO2max were derived from an incremental ramp test to exhaustion (RAMP), while the accumulated oxygen deficit (AOD), peak VO2, and performance time were measured during a 600-m TT.Results:The female skiers took longer to complete the TT than the males (209 ± 9 s vs 166 ± 7 s, P < .001) and exhibited a lower relative anaerobic contribution (20% ± 4% vs 24% ± 3%, P = .015) and a higher fractional utilization of VO2max (84% ± 4% vs 79% ± 5%, P = .007) than males. Although there was no significant difference in AOD between the sexes (40.9 ± 9.5 and 47.3 ± 7.4 mL/kg for females and males, respectively; P = .079), the mean difference ± 90% confidence intervals of 6.4 ± 6.0 mL/kg reflected a likely practical difference (ES = 0.72). The peak VO2 during the TT was significantly higher than VO2max during the RAMP for all participants combined (62.3 ± 6.8 vs 60.5 ± 7.2 mL · kg−1 · min−1, P = .011), and the mean difference ± 90% confidence intervals of 1.8 ± 1.1 mL · kg−1 · min−1 reflected a possible practical difference (ES = 0.25).Conclusions:These results show that performance and physiological responses to a self-paced TT lasting approximately 3 min differ between sexes. In addition, a TT may provide a valid measure of VO2max.

Atlantic salmon (Salmo salar) smolts were exposed for 80 h to seven water qualities: pH 5.6 with 31 and 46 µg labile Al · L-1, pH 6.0 with 18 and 24 µg labile Al · L-1, and pH 6.2 with 12 and 18 µg labile Al · L-1 and control water at pH 6.8 and <10 µg labile Al · L-1. The three groups with the highest concentrations of labile Al (31 and 46 µg labile Al · L-1 at pH 5.6 and 24 µg labile Al · L-1 at pH 6.0) suffered high mortalities and showed a disturbance in osmoregulation and a massive secretion of mucus, as seen from a decrease in number of skin mucous cells. Furthermore, an increase in skin mucous cells containing acidic mucosubstances was observed. The loss of plasma chloride and skin mucous cells showed a significant linear correlation (R2 = 0.68, p < 0.001). The increased secretion of mucus on skin and gills and the increase in acidity of mucosubstances are consistent with their prior presumed defensive role in binding of Al.

Extending the investigations on (Na0.5K0.5)NbO3-based solid solution for lead-free piezoelectric ceramics, this paper consider the complex solid-solution system (Na0.5K0.5)NbO3Bi0.5(Na0.90K0.10)0.5TiO3 [NKN-BNK. (Na0.5K0.5)NbO3 with 1 ~ 5 mol% Bi0.5(Na0.90K0.10)0.5TiO3 has been prepared following the conventional mixed oxide process. It can be concluded that the NKN-BNKT ceramics have orthorhombic structures in the case x 0.03. With increasing BNKT content (x=0.04 to 0.05), however, the structure changes from orthorhombic to rhombohedral phase. Above results demonstrated that the MPB between orthorhombic and rhombohedral phases exits in the solid solution with the BNKT content of x=0.03. At the MPB composition, the cryctalline structure of ceramics is considered to be a coexistence of orthorhombic and rhombohedral phase. Owing to the phase coexistence at the phase boundary, there exists a different symmetry regions (DSR) near the MPB. The DSR boundary motion increases the dielectric permittivity and piezoelectric coefficients. The electromechanical coupling factor and dielectric constant are higher for compositions near the MPB. The dielectric constant (KT33), planar coupling coefficient (kp), thickness coupling coefficient (kt) and piezoelectric constant (d33)of 0.98NKN-0.02BNKT ceramics were 1180, 30%, 58%, and 180, respectively.

Die Expression von natriumabhängigen und natriumunabhängigen Transportern für Sulfat in Nieren und Leber ist für die Sulfathomöostase unabdingbar. Ein natriumunabhängiger Transporter für Sulfat ist der Sulfat-Anionen-Transporter 1, sat-1, der Sulfat im Austausch gegen Oxalat, Bicarbonat, Chlorid und Glyoxylat sowohl in die Zellen aufnehmen als auch in das Blut abgeben kann. In dieser Arbeit wurde die Transportfunktion des Sulfat-Anionen-Transporters 1 der Ratte, rsat-1, untersucht. Das Ziel war eine genauere Kenntnis über den Einfluss von Chlorid, des intrazellulären pH-Wertes und der extrazellulären Calciumkonzentration auf den Sulfattransport durch rsat-1 zu erlangen. Als Expressionssystem für rsat-1 wurden Oozyten des Krallenfrosches Xenopus-laevis verwendet. Elektrophysiologische Versuche, die im „Current-Clamp-Modus“ durchgeführt wurden, ermöglichten die Messung von substratinduzierten Potentialänderungen. Durch radiochemische Versuche konnte die Sulfataufnahme durch sat-1 unter variierenden Bedingungen bestimmt werden. Die Rolle des Chlorids in Hinblick auf den Sulfattransport durch sat-1 konnte nicht gänzlich geklärt werden. Da Thiosulfat und Nitrat in den durchgeführten Versuchen die Aufnahme von [35S]Sulfat über rsat-1 hemmten, könnte das Stickstoffatom den Transport von Sulfat beeinflussen. Intrazellulär an Chlorid verarmte rsat-1-exprimierende Oozyten nahmen in den durchgeführten Versuchen vermehrt [35S]Sulfat auf. Des Weiteren konnte eine Steigerung der [35S]Sulfataufnahme in chloridreduzierten, gluconat- beziehungsweise mannithaltigen Lösungen beobachtet werden. Die Ergebnisse dieser Arbeit sind mit einer allosterischen oder kompetitiven Hemmung der Aufnahme von Sulfat durch Chlorid vereinbar. Eine genauere Untersuchung des Chloridtransports über sat-1 wäre durch Versuche mit radioaktiv markiertem Iod¹²⁵ möglich, das wie Chlorid transportiert wird. Die intrazelluläre Ansäuerung der Oozyten durch Ammoniumchlorid führte zu einer erhöhten [35S]Sulfataufnahme in die rsat-1-exprimierenden Oozyten. Diese könnte durch eine verminderte Bicarbonatkonzentration an der äußeren Zellmembran mit einer reduzierten kompetitiven Hemmung begründet sein. Ebenso könnte Ammoniumchlorid durch eine protonierende Wirkung eine Konformationsänderung mit einer Affinitätssteigerung von sat-1 für Sulfat zur Folge haben. Mit steigender Calciumkonzentration wurde die Depolarisation rsat-1-exprimierender Oozyten in chloridreduzierten und gluconathaltigen Lösungen geringer. Dies ist mit bereits vorliegenden Daten vereinbar, in denen Xenopus laevis Oozyten in chloridreduzierten Medien depolarisieren.

Her2-positiver Brustkrebs, der Subtyp des Mammakarzinoms, bei dem eine Überexpression des epidermalen Wachstumsfaktor-Rezeptors-2 (ErbB2/Her2) vorliegt, hat für die betroffenen Frauen eine besonders schlechte Prognose. Eine positive Korrelation zwischen der ErbB2-Expression in Brusttumoren und der Expression des Makrophagen-Migration-inhibierenden Faktors (MIF), einem inzwischen gut bekannten tumorfördernden Protein, konnte bereits gezeigt werden. Ferner konnte gezeigt werden, dass MIF durch das Hitzeschockprotein 90 (Hsp90) in einem Mausmodell des Her2-positiven Brustkrebses stabilisiert wird. Der zugrundeliegende Mechanismus war bisher unverstanden. In dieser Doktorarbeit konnte erstmalig demonstriert werden, dass Hitzeschockfaktor-1 (HSF-1), der Transkriptionsfaktor der stressinduzierten Hitzeschockproteine (HSP), einschließlich Hsp90, in ErbB2-überexprimierenden SK-BR-3-Brustkrebszellen konstitutiv durch ErbB2 aktiviert wird. Durch eine Behandlung mit dem ErbB2-Inhibitor CP724.714 konnte die aktivierende Serin326-Phosphorylierung von HSF-1 verhindert werden. Als Folge wird, wie durch Western-Blot-Analysen gezeigt, die HSP-Maschinerie inhibiert und tumorfördernde Hsp90-Klienten wie MIF, Akt, mutiertes p53, ErbB2 und HSF-1 destabilisiert. Außerdem konnte die unterbleibende HSF-1-Aktivierung durch quantitative PCR-Analysen und Immunfluoreszenzmikroskopie bestätigt werden. Die mechanistischen Untersuchungen konnten die hier erstmalig beschriebene ErbB2-Akt-HSF-1-Achse aufdecken, über die HSF-1 in SK-BR-3-Zellen reguliert wird. Ferner konnte eine ErbB2-Inhibition sogar die HSF-1-Aktivierung durch einen Hitzeschock unterbinden. Unsere Ergebnisse zeigen zum ersten Mal, dass die ErbB-2-Überexpression in SK-BR-3-Zellen eine konstitutive HSF-1-Aktivierung bewirkt, mit der Folge, dass tumorfördernde Hsp90-Klienten wie MIF, HSF-1 selbst, ErbB2 und mutiertes p53 stabilisiert werden. Die neu entdeckte ErbB2-Akt-HSF-1-Hsp90-Klienten-Achse legt möglicherweise neue Angriffspunkte für zusätzliche Pharmaka bei der Therapie Her2-positiven Brustkrebses offen.

El libro “Las ciencias sociales en épocas de crisis: Escenarios, perspectivas y exigencias en tiempos de pandemia”, es una compilación de capítulos resultado de investigaciones de varios autores de distintos grupos de investigación; en torno a 4 ejes temáticos: 1) Los aportes de las ciencias sociales para pensar la coyuntura actual; 2) Las profesiones de las ciencias sociales frente al futuro; 3) Perspectivas, retos y cambios sobre la educación en las ciencias sociales y 4) Futuros posibles. El libro es de relevancia para entender el contexto actual de las ciencias sociales, primero, por la importancia de articular categorías fundamentales para las reflexiones críticas de las ciencias sociales frente a los fenómenos sociales, culturales, políticos y económicos que engloba la dimensión de la cultura política y de las prácticas sociales, políticas, educativas y culturales, puestas en contexto en la coyuntura de la pandemia; situando subjetividades, dinámicas

El libro presenta la importancia de la familia y la escuela en el desarrollo de las competencias ciudadanas, en donde el diálogo y el manejo de las relaciones con el entorno favorece el poder obtener una comunidad con mayor tolerancia y empatía para resolver diversas situaciones, demostrando que las competencias aportan a la construcción de ciudadanía. A partir de la prueba piloto, se buscó establecer, en primera instancia,el estado actual de las competencias ciudadanas con el propósito de identificar los aspectos de mayor grado de deterioro y dar inicio al planteamiento de estrategia en pro del mejoramiento del entorno y con ello lograr un ambiente óptimo para fortalecer las competencias.

Abstract Low genetic diversity and autogamous reproduction limit genetic improvement of Coffea arabica L. As a consequence, susceptibility to biotic and abiotic stresses increases. Induced mutagenesis is an alternative strategy for increasing genetic variability and for the development of varieties tolerant or resistant to biotic and abiotic factors. In the present study, the effect of three mutagenic agents (NaN3, EMS and ⁶⁰Co gamma-rays) on survival of Arabica coffee zygotic embryos was evaluated. The zygotic embryos were immersed for 10 min in a solution of NaN3 (0, 2.5, 5.0, 7.5, 10.0, 12.5, 15.0 and 20.0 mM) or for 2 h in a solution of EMS (0, 0.5, 1, 1.5, 2, 4 and 6% v/v) or irradiated with 0, 20, 40, 60, 80 or 100 Gy. As the concentration or dose of the applied mutagen increased, survival decreased. The LD50 values for sodium azide, EMS and ⁶⁰Co were 12.5 mM (51.6%), 1% v/v (48.3%) and 40 Gy (50.0%), respectively. Our results indicated that coffee zygotic embryos are suitable for chemical and physical mutagenesis and this offers an alternative for the genetic improvement of agriculturally important traits in coffee.

This paper reports a novel method for the realization of small differential pressures in the range of 1 Pa and 1 kPa by using a precision wind tunnel with Laser Doppler Anemometer (LDA) and a Prandtl tube. The LDA system measures the wind speed of the precisely controlled wind tunnel and provides traceability to SI. A Prandtl tube immersed into the wind tunnel, relates the well-controlled airflow speed to the pressure difference of total pressure and static pressure at the point of measurement. Experiments have been performed in the range between 0.5 and 60 m/s air velocity corresponding to about 150 mPa and 2.2 kPa. The measurement uncertainty of the generated differential pressures between 1 Pa and 1 kPa are calculated to be around 0.8% (k = 2).

Accuracy of long-term creep life prediction of creep strength enhanced ferritic steels is improved by region splitting analysis method in consideration of 50% of the 0.2% offset yield stress. According to JIS and ASTM standards for tensile test, however, specified strain rates for evaluation of yield strength are slightly different from each other. The conditions specified in JIS G0567 and ASTM E21-03a are 0.3 ± 0.2%/min and 0.5 ± 0.2%/min, respectively. Strain rate influences on yield strength and 0.2% offset yield stress of ASME T91 at 600 and 650°C under strain rate of 0.5%/min was about 10% higher than that under strain rate of 0.3%/min. Influence of difference in strain rate between JIS and ASTM regulations on the long-term creep rupture life prediction by region splitting analysis method was insignificant. With decrease in stress, magnitude of creep strain at the onset of accelerating creep stage decreased from about 2% in the short-term to less than 1% in the long-term. Life fraction of the time to 1% total strain tended to increase with decrease in stress. It was indicated that the initiation of tertiary creep should be a more important parameter for the stress intensity limit, St, than time to a total strain of 1%, since 80% of the minimum stress to cause initiation of tertiary creep was definitely smaller than 100% of the average stress required to obtain a total strain of 1% in the long-term.

In the present paper, the effects of deformation temperature on phase transformations behavior of the steel BR1500HS during isothermal and non-isothermal deformations are described and discussed. Thermal mechanical simulation tests were carried out on GLEEBLE 1500 thermal simulator, Some specimens are uniaxially extended with strain rate 10/s and their largest deforming degree reaches 15% at 950°C. After deformation, the specimens are cooled to room temperature at different cooling rates, 0.5, 1, 5, 10, 20, 30°C/s, respectively. And the others are nonisothermal uniaxially extended with strain rate 10/s with strain value 15% from the initial deformation temperature of 800°C, and simultaneously cooled to different temperature, 400, 450, 500, 550, 600, 650 and 700°C, respectively. The isothermal deforming microstructures of steel BR1500HS are mainly composed of ferrite and pearlite at a cooling rate range of 0.5 to 1°C/s. When the cooling rate gets to 5°C/s, the microstructures are mainly bainite and some martensite. And the cooling rate is higher than 30°C/s, fully martensitic transformation are accomplished in the experimental steel. The non-isothermal deforming microstructures, however, no martensite phase can be seen. Even the amount of bainite phase is minimal, too.

This paper reports on the machining of a construction material (aerated concrete) with a rapid prototyping device, Shapemaker III, which is based on waterjet technology. Preliminary machining tests were carried out to investigate machining conditions (speed and pressure) of separation cuts. Cutting speeds for the waterjet were investigated for two aerated concrete construction materials; autoclaved aerated concrete (AAC) in two strengths (348 and 580 psi compressive strength) and a non-autoclaved, fiber reinforced aerated concrete (FRAC) with a 450 psi compressive strength. Cutting samples were prepared in four thicknesses (0.5, 1, 2, and 3 inches) and cut at two pressures (40 and 60 ksi). The 0.5 and 1 inch specimens were cut with good surface finish at over 600 in/min at 40 ksi. The 2 and 3 inch specimens could be cut at 320 and 80 in/min at 40 ksi, respectively. The experimental data was used in the fabrication of rapid prototyping houses with a pure waterjet machine. As results, full scale houses were fabricated with FRAC and Styrofoam. Additionally, a sub-mold of an outdoor fireplace was manufactured with Styrofoam for casting of customized aerated concrete blocks.

The high-affinity heparin pentasaccharide (H5) and an 8000 Mr high-affinity heparin (H26) have been compared with respect to their interaction with antithrombin III (AT) and their accelerating effect on AT inhibition of thrombin (T) and factor Xa by rapid kinetic and equilibrium binding studies at pH 7.4, 25°C. Kds of .068 μM at I 0.15 and 0.57 μM at I 0.3 were determined for tne AT-H5 interaction, which were 5 and 2.5-fold weaker, respectively, than affinities determined for H26. Comparison of the kinetics of binding of H5 and H26 to AT at I 0.15 under pseudofirst order conditions ([H]o>> [AT]o) demonstrated a saturable dependence of the observed rate constant for both reaction with indistinguishable limiting rate constants of 700 +/-120 s-1 and 520 +/-90 s-1 , but somewhat different Kds for the initial binding interaction of 20 and 29 μM for H5 and H26, respectively. These results indicate that H5 induces the same conformational change in AT as the larger heparin, but that the rate of reversal of this conformational change is greater for H5 which is the basis for its weaker AT affinity. Bimolecular rate constants for neutralization of factor Xa and thrombin by AT-H5 and AT-H26 complexes were determined by p-aminobenzamidine displacement under pseudo-first order conditions([AT-H] >> [T]o or [Xa]o). I-in-dependent values of .62 μM-1 s-1 were obtained for Xa inhibition by AT-H5 at I 0.15 and 0.3, compared to I-dependent values of 1.4 and 0.91 μM-1 s-1 for AT-H26. For thrombin inhibition by AT-H5, and I-independent enhancement of 1.6-fold in the bimolecular rate constant from .0098 to .016 μM-1 s-1 was observed, in sharp contrast to the marked I-independent enhancement by AT-H26 of the bimolecular rate constant ranging from 4000 to 200-fold at I 0.15 and 0.3, respectively. These results are consistent with a primary ionic strength-independent contribution of the AT conformational change to heparin enhancement of factor Xa but not thrombin neutralization by AT, with an ionic strength-dependent component for both reactions, compatible with a differential role for a protease-heparin interaction. Supported by grant HL-30237

Kyushu Electric Power Co., Inc., in constructing the recently completed first phase of the No. 1 Group of Shin-Oita Power Plant, Oita Prefecture (Kyushu Island), achieved further improvements over previous combined cycle plants, especially in the area of plant overall operation. It is composed of six combined cycle power units of the single-shaft, non-reheat type, based on Hitachi-GE MS7001E gas turbines, with a total output of 690 MW. Trial operations of the first unit began in May, 1990. Commercial operations of the first unit began in November 1990, and the last unit in June, 1991. The NO.1 Group incorporates two major advances over previous combined cycle plants. The first advance is a two-stage multiple nozzle dry-type low-NOx combustor. This combustor is a new development for keeping the level of NOx emissions below 62.5 ppm (16% O2 at gas turbine exhaust). The second advance is a new functionally and hierarchically distributed digital control system. By the control system, the plant was designed to bring the following notable features: 1 The individual units can be started and stopped automatically from the load dispatching directive center at the head office. 2 The plant can be operated for high efficiency with short starting and stopping time and large load variations. 3 Plant operating characteristics for emergency operations can be improved remarkably, for instance, load run back operations and fast cut back operation, etc. The results of trial operations have shown that the output per unit is about 0.5 to 4.2% higher, and the unit efficiency about 1.9 to 3.7% higher, than the planned values (all percentages relative), and tangible improvements and starting characteristics and load fluctuation are also satisfactory with the specified target values in the overall operation of the plant over that of previous combined cycle power plants. This plant has satisfactorily been operated since the start of commercial operation.

The aim of this study is to evaluate blood coagulation changes in Ph positive chronic myeloid leukemia (Ph + CML) patients undergoing allogeneic bone marrow transplantation (BMT), T-depleted with the monoclonal antibody Campath 1, and to find a possible correlation between changes of procoagulant proteins, physiological inhibitors and venoclusive disease (VOD). VOD is a major complication in, the early period following BMT.Out of 13 patients, two of them developed VOD. Von Willebrand Factor Antigen (vWF:Ag), Factor VII antigen (F.VII:Ag), Plasminogen antigen (PLG:Ag), Factor V activity (F.V:C), Antithrombin III activity, Protein C antigen (PC:Ag) and fibrinogen activity (FG) were evaluated in all patients following sampling times: day 10 (before conditioning regimen), day 0 (day of BMT), day + 10 (after BMT), day + 28 (median day of engraftment) and day + 60 (after BMT).PLG:Ag, F. VII:Ag and PC:Ag levels decreased significantly (p values < .05, < .025, < .001 respectively). In particular, in 5 patients whose PC:Ag levels dropped below the limit considered at risk for thrombosis (< 60 U/dl), two of them developed VOD. vWF:Ag, F. V:C and FG increased significantly (p values < .04, < .05, < .05 respectively). Antithrombin III activity did not change significantly throughout the period of observation.In conclusion, the reduction of PC, PLG and the contemporary rise of vWF and FG can increase the risk of developing thromboembolism in the early stage following BMT.

Introdução: A quimioterapia da doença de Chagas tem demonstrado nítidas diferenças de suscetibilidade ao Benzonidazol (Benz). Caracterizações biológicas e moleculares realizadas por diversas técnicas classificaram as cepas de Trypanosoma cruzi em diferentes graus de suscetibilidade como a Y (suscetível) e a Colombiana (resistente). Esses achados revelam que o tratamento com Benz, além determinar a destruição do parasito tem ação sobre o sistema imunológico. Objetivo: analisar a influência do tratamento com o Benzonidazol sobre a resposta humoral em camundongos infectados com as cepas Y e Colombiana. Material e métodos: Foram utilizados 150 camundongos, subdivididos em grupos experimentais: Infectados tratados cepa Y (YT) e não tratados (Y-NT); Colombiana tratados (COL-T) e não tratados (COL-NT), Tratados não infectados (TNI) e Controles sem tratamento (CI). O inóculo foi de 1,0 x 104 por via intraperitoneal. A parasitemia foi iniciada no sétimo dia nos animais infectados. Os procedimentos experimentais estiveram de acordo ao protocolo CEUA, 013/09. O tratamento foi iniciado no pico parasitêmico de cada cepa, sendo no 7º dia após a infecção nos animais infectados: pela cepa Y e, nos tratados e não infectados, no 18º dia de infecção com os da cepa Colombiana. A quimioterapia foi realizada em 60 doses (100mg/kg/dia de Benz). Investigou-se a resposta humoral pela sorologia (Imunofluorescência indireta) e pela reação de Elisa. Resultados: Os títulos sorológicos confirmaram a susceptibilidade e resistência, pois, variaram de negativo nos grupos YT - 1/640 e de 1/80 a 1/640 Y-INT, e no grupo COL-T, de 1/80 a 1/2560 COL-NT, de negativo a 1/10 nos grupos TNI e CI. A dosagem das imunoglobulinas IgM, IgG1, IgG2a e IgG total, mostraram-se mais elevadas no grupo COL-NT em relação aos grupos avaliados, o que indicam auxílio dessas imunoglobulinas na resposta celular citotóxica mediada. Conclusão: Os dados sugerem que o tratamento com Benzonidazol foi capaz de influenciar a resposta imunológica humoral em camundongos.

The simplest experimental approach for a theoretical description of platelet aggregation is based on kinetics of early multiplet formation (‹4 platelets per aggregate)occurring with diffusion-dependent particle collisions (no flow). The Smoluchowski theory was used to calculate collision efficiencies, αβ, from a linear plot of platelet particle count (Nt)−1 vs time (t) following addition of adenosine diphosphate (ADP) to citrated platelet-rich-plasma (PRP) for 7 human (H) and 2 rabbit (R) donors. A 0.1 ml sample of PRP was stirred with ADP for 0.5s, then immediately transferred to a 37°C bath for no-stir (diffusion) studies or further stirred with ADP for stir-induced aggregation studies. Samples were fixed with 0.5 ml 0.8% glutaraldehyde with particle count (Nt) determined with a resistive counter and % aggregation (PA) computed (reproducibility/sensitivity ‹ 5%). For stir conditions, R platelets were as sensitive and as rapidly aggregated by ADP (2-10 μM) as H platelets, with ∼ 1 s time lag for onset of PA. However, for no-stir conditions, linear regression analysis of data for ADP (5-10 μM) induced PA for H platelets for 0-30 s gave αβ = 7.5±4.6 (r = 0.9±0.05). Analysis at longer “diffusion” times showed a second phase (60-300 s) in some H donors with aB = 0.5±0.4 (4/9 donors), while R platelets showed only 1 phase with αβ = 0.65±0.15 (0-60 to 0-900 s) (r = 0.8±0.1). The ADP sensitivity ([ADP]½ corresponding to 50% of maximal changes) for the abnormally rapid PA in no stir H PRP for early times, measured over 0.4-100 μM range, was found to be ∼9 μM (5-17 μM range) and 3.5 μM (3-10 μM) for measurements respectively at 5-10 and 20-30s; these values were ∼ 3-8 × greater than lADPji measured for stirred suspensions for rate/extent of PA or rate of turbidometrically-measured macroaggregation (TA), while › [ADP] threshold for secondary aggregation in TA (10 H donors). These abnormally large aB values and their ADP sensitivity observed for human platelets are consistent with long-range interactions mediated by“chemotactic” agents released from the cells but distinct from normal dense granule release requiring macroaggregation, or by as yet uncharacterized membrane or polymetric bridges.

Heat production (HP) or energy expenditure for activity (EEa) is of fundamental nutritional importance for livestock because it determines the proportion of ingested nutrients available for productive functions. Previous estimates of EEa are unreliable and vary widely with different indirect methodologies. This leads to erroneous nutritional strategies, especially when intake on pasture does not meet nutritional requirements and supplementation is necessary for acceptable production. Therefore, the objective of this project was to measure EEa in different classes of livestock (beef cattle and goats) over a wide range of ecological and management conditions to develop and evaluate simple means of prediction. In the first study in Israel, small frame (SF) and large frame (LF) cows (268 and 581 kg) were monitored during spring, summer, and autumn. Feed intake by SF cows per unit of metabolic weight was greater (P < 0.001) than that by LF cows in both spring and summer and their apparent selection of higher quality herbage in spring was greater (P < 0.10) than that of LF cows. SF cows grazed more hours per day and walked longer distances than the LF cows during all seasons. The coefficient of specific costs of activities (kJ•kg BW-0.75•d-1) and of locomotion (J•kg BW-0.75•m-1) were smaller for the SF cows. In the second study, cows were monitored in March, May, and September when they grazed relatively large plots, 135 and 78 ha. Energy cost coefficients of standing, grazing, and horizontal locomotion derived were similar to those of the previous study based on data from smaller plots. However, the energy costs of walking idle and of vertical locomotion were greater than those found by Brosh et al. (2006) but similar to those found by Aharoni et al. (2009). In the third study, cows were monitored in February and May in a 78-ha plot with an average slope of 15.5°, whereas average plot slopes of the former studies ranged between 4.3 and 6.9°. Energy cost coefficients of standing, grazing, and walking idle were greater than those calculated in the previous studies. However, the estimated energy costs of locomotion were lower in the steeper plot. A comparison on a similar HP basis, i.e., similar metabolizable energy (ME) intake, shows that the daily energy spent on activities in relation to daily HP increased by 27% as the average plot slope increased from 5.8 and 6.02 to 15.5°. In the fourth study, cows grazing in a woodland habitat were monitored as in previous studies in December, March, and July. Data analysis is in progress. In the first US experiment, Boer and Spanish does with two kids were used in an experiment beginning in late spring at an average of 24 days after kidding. Two does of each breed resided in eight 0.5-ha grass/forb pastures. Periods of 56, 60, 63, 64, and 73 days in length corresponded to mid-lactation, early post-weaning, the late dry period, early gestation, and mid-gestation. EEa expressed as a percentage of the ME requirement for maintenance plus activity in confinement (EEa%) was not influenced by stocking rate, breed, or period, averaging 49%. Behavioral activities (e.g., time spent grazing, walking, and idle, distance traveled) were not highly related to EEa%, although no-intercept regressions against time spent grazing/eating and grazing/eating plus walking indicated an increase in EEa% of 5.8 and 5.1%/h, respectively. In the second study, animal types were yearling Angora doeling goats, yearling Boer wether goats, yearling Spanish wether goats, and Rambouilletwether sheep slightly more than 2 yr of age. Two animals of each type were randomly allocated to one of four pastures 9.3, 12.3, 4.6, and 1.2 ha in area. The experiment was conducted in the summer with three periods, 30, 26, and 26 days in length. EEa% was affected by an interaction between animal type and period (Angora: 16, 17, and 15; Boer: 60, 67, and 34; Spanish: 46, 62, and 42; sheep: 22, 12, and 22% in periods 1, 2, and 3, respectively (SE = 6.1)). EEa% of goats was predicted with moderate accuracy (R2 = 0.40-0.41) and without bias from estimates of 5.8 and 5.1%/h spent grazing/eating and grazing/eating plus walking, respectively, determined in the first experiment; however, these methods were not suitable for sheep. These methods of prediction are simpler and more accurate than currently recommended for goats by the National Research Council.

During the granting period, we performed the following projects: Firstly, we differentially measured glucan content in several pleurotus mushroom strains. Mushroom polysaccharides are edible polymers that have numerous reported biological functions; the most common effects are attributed to β-glucans. In recent years, it became apparent that the less abundant α-glucans also possess potent effects in various health conditions. In our first study, we explored several Pleurotus species for their total, β and α-glucan content. Pleurotuseryngii was found to have the highest total glucan concentrations and the highest α-glucans proportion. We also found that the stalks (stipe) of the fruit body contained higher glucan content then the caps (pileus). Since mushrooms respond markedly to changes in environmental and growth conditions, we developed cultivation methods aiming to increase the levels of α and β-glucans. Using olive mill solid waste (OMSW) from three-phase olive mills in the cultivation substrate. We were able to enrich the levels mainly of α-glucans. Maximal total glucan concentrations were enhanced up to twice when the growth substrate contained 80% of OMSW compared to no OMSW. Taking together this study demonstrate that Pleurotuseryngii can serve as a potential rich source of glucans for nutritional and medicinal applications and that glucan content in mushroom fruiting bodies can be further enriched by applying OMSW into the cultivation substrate. We then compared the immune-modulating activity of glucans extracted from P. ostreatus and P. eryngii on phagocytosis of peripheral blood neutrophils, and superoxide release from HL-60 cells. The results suggest that the anti-inflammatory properties of these glucans are partially mediated through modulation of neutrophileffector functions (P. eryngiiwas more effective). Additionally, both glucans dose-dependently competed for the anti-Dectin-1 and anti-CR3 antibody binding. We then tested the putative anti-inflammatory effects of the extracted glucans in inflammatory bowel disease (IBD) using the dextran sulfate sodium (DSS)–induced model in mice. The clinical symptoms of IBD were efficiently relieved by the treatment with two different doses of the glucan from both fungi. Glucan fractions, from either P. ostreatus or P. eryngii, markedly prevented TNF-α mediated inflammation in the DSS–induced inflamed intestine. These results suggest that there are variations in glucan preparations from different fungi in their anti-inflammatory ability. In our next study, we tested the effect of glucans on lipopolysaccharide (LPS)-induced production of TNF-α. We demonstrated that glucan extracts are more effective than mill mushroom preparations. Additionally, the effectiveness of stalk-derived glucans were slightly more pronounced than of caps. Cap and stalk glucans from mill or isolated glucan competed dose-dependently with anti-Dectin-and anti-CR-3 antibodies, indicating that they contain β-glucans recognized by these receptors. Using the dextran sulfate sodium (DSS)-inflammatory bowel disease mice model, intestinal inflammatory response to the mill preparations was measured and compared to extracted glucan fractions from caps and stalks. We found that mill and glucan extracts were very effective in downregulatingIFN-γ and MIP-2 levels and that stalk-derived preparations were more effective than from caps. The tested glucans were equally effective in regulating the number of CD14/CD16 monocytes and upregulating the levels of fecal-released IgA to almost normal levels. In conclusion, the most effective glucans in ameliorating some IBD-inflammatory associated symptoms induced by DSS treatment in mice were glucan extracts prepared from the stalk of P. eryngii. These spatial distinctions may be helpful in selecting more effective specific anti-inflammatory mushrooms-derived glucans. We additionally tested the effect of glucans on lipopolysaccharide-induced production of TNF-α, which demonstrated stalk-derived glucans were more effective than of caps-derived glucans. Isolated glucans competed with anti-Dectin-1 and anti-CR3 antibodies, indicating that they contain β-glucans recognized by these receptors. In conclusion, the most effective glucans in ameliorating IBD-associated symptoms induced by DSS treatment in mice were glucan extracts prepared from the stalk of P. eryngii grown at higher concentrations of OMSW. We conclude that these stress-induced growing conditions may be helpful in selecting more effective glucans derived from edible mushrooms. Based on the findings that we could enhance glucan content in Pleurotuseryngii following cultivation of the mushrooms on a substrate containing different concentrations of olive mill solid waste (OMSW) and that these changes are directly related to the content of OMSW in the growing substrate we tested the extracted glucans in several models. Using dextran sulfate sodium (DSS)–inflammatory bowel disease (IBD) mice model, we measured the colonic inflammatory response to the different glucan preparations. We found that the histology damaging score (HDS) resulting from DSS treatment reach a value of 11.8 ± 2.3 were efficiently downregulated by treatment with the fungal extracted glucans, glucans extracted from stalks cultivated at 20% OMSWdownregulated to a HDS value of 6.4 ± 0.5 and at 80% OMSW showed the strongest effects (5.5 ± 0.6). Similar downregulatory effects were obtained for expression of various intestinal cytokines. All tested glucans were equally effective in regulating the number of CD14/CD16 monocytes from 18.2 ± 2.7 % for DSS to 6.4 ± 2.0 for DSS +glucans extracted from stalks cultivated at 50% OMSW. We finally tested glucans extracted from Pleurotuseryngii grown on a substrate containing increasing concentrations of olive mill solid waste (OMSW) contain greater glucan concentrations as a function of OMSW content. Treatment of rat Intestinal epithelial cells (IEC-6) transiently transfected with Nf-κB fused to luciferase demonstrated that glucans extracted from P. eryngii stalks grown on 80% OMSWdownregulatedTNF-α activation. Glucans from mushrooms grown on 80% OMSW exerted the most significant reducing activity of nitric oxide production in lipopolysaccharide (LPS) treated J774A.1 murine macrophages. The isolated glucans were tested in vivo using the Dextran Sodium Sulfate (DSS) induced colitis in C57Bl/6 mice and found to reduce the histology damaging score resulting from DSS treatment. Expression of various intestinal cytokines were efficiently downregulated by treatment with the fungal extracted glucans. We conclude that the stress-induced growing conditions exerted by OMSW induces production of more effective anti-inflammatory glucans in P. eryngii stalks.

1.1 Resumen macroeconómico En el segundo trimestre la economía enfrentó varios choques, principalmente de oferta y de costos, la mayoría de los cuales no fueron anticipados, o los previstos fueron más persistentes de lo esperado, y que en conjunto interrumpieron la recuperación de la actividad económica observada a comienzos de año y llevaron la inflación total a niveles superiores a la meta. La inflación básica (sin alimentos ni regulados: SAR) aumentó, pero se mantuvo baja y acorde con lo esperado por el equipo técnico. A comienzos de abril se inició una tercera ola de pandemia, más acentuada y prolongada que la anterior, con un elevado costo en vidas humanas y algún impacto negativo en la recuperación económica. Entre mayo y mediados de junio los bloqueos de las carreteras y los problemas de orden público tuvieron un fuerte efecto negativo sobre la actividad económica y la inflación. Se estima que la magnitud de estos dos choques combinados habría generado una caída en niveles en el producto interno bruto (PIB) con respecto al primer trimestre del año. Adicionalmente, los bloqueos causaron un aumento significativo de los precios de los alimentos. A estos choques se sumaron los efectos acumulados de la disrupción global en algunas cadenas de valor y el incremento en los fletes internacionales que desde finales de 2020 vienen generando restricciones de oferta y aumentos de costos. Todos estos factores, que afectaron principalmente el índice de precios al consumidor (IPC) de bienes y de alimentos, explicaron la mayor parte del error de pronóstico del equipo técnico y el aumento de la inflación total a niveles superiores a la meta del 3 %. El incremento en la inflación básica y de los precios de los regulados fue acorde con lo esperado por el equipo técnico, y se explica principalmente por la eliminación de varios alivios de precios otorgados un año atrás. A todo esto se suma la mayor percepción de riesgo soberano y las presiones al alza que esto implica sobre el costo de financiamiento externo y la tasa de cambio. A pesar de los fuertes choques negativos, el crecimiento económico esperado para la primera mitad del año (9,1%), es significativamente mayor que lo proyectado en el informe de abril (7,1%), signo de una economía más dinámica que se recuperaría más rápido de lo previsto. Desde finales de 2020 las diferentes cifras de actividad económica han mostrado un crecimiento mayor que el esperado. Esto sugiere que los efectos negativos sobre el producto de las recurrentes olas de contagio estarían siendo cada vez menos fuertes y duraderos. No obstante, la tercera ola de contagio del Covid-19, y en mayor medida los bloqueos a las vías y los problemas de orden público, habrían generado una caída del PIB durante el segundo trimestre, frente al primero. Pese a lo anterior, los datos del índice de seguimiento a la economía (ISE) de abril y mayo han resultado mayores que lo esperado, y las nuevas cifras de actividad económica sectoriales sugieren que el impacto negativo de la pandemia sobre el producto se sigue moderando, en un entorno de menores restricciones a la movilidad y de mayor avance en el ritmo de vacunación. Los registros de transporte de carga (junio) y la demanda de energía no regulada (julio), entre otros, indican una recuperación importante después de los bloqueos en mayo. Con todo lo anterior, el incremento anual del PIB del segundo trimestre se habría situado alrededor del 17,3 % (antes 15,8 %), explicado en gran parte por una base baja de comparación. Para todo 2021 el equipo técnico incrementó su proyección de crecimiento desde un 6 % hasta el 7,5 %. Este pronóstico, que está rodeado de una incertidumbre inusualmente elevada, supone que no se presentarán problemas de orden público y que posibles nuevas olas de contagio del Covid-19 no tendrán efectos negativos adicionales sobre la actividad económica. Frente al pronóstico del informe pasado, la recuperación de la demanda externa, los niveles de precios de algunos bienes básicos que exporta el país y la dinámica de las remesas de trabajadores han sido mejores que las esperadas y seguirían impulsando la recuperación del ingreso nacional en lo que resta del año. A esto se sumaría la aún amplia liquidez internacional, la aceleración en el proceso de vacunación y las bajas tasas de interés, factores que continuarían favoreciendo la actividad económica. La mejor dinámica del primer semestre, que llevó a una revisión al alza en el crecimiento de todos los componentes del gasto, continuaría hacia adelante y, antes de lo esperado en abril, la economía recuperaría los niveles de producción de 2019 a finales de 2021. El pronóstico continúa incluyendo efectos de corto plazo sobre la demanda agregada de una reforma tributaria de magnitud similar a la proyectada por el Gobierno. Con todo eso, en el escenario central de este informe, el pronóstico de crecimiento para 2021 es del 7,5 % y para 2022 del 3,1 %. A pesar de esto, el nivel de la actividad económica seguiría siendo inferior a su potencial. La mejora en estas proyecciones, sin embargo, está rodeada de una alta incertidumbre. En junio la inflación anual (3,63 %) aumentó más de lo esperado debido al comportamiento del grupo de alimentos, mientras que la inflación básica (1,87 %) fue similar a la proyectada. En lo que resta del año el mayor nivel del IPC de alimentos persistiría y contribuiría a mantener la inflación por encima de la meta. A finales de 2022 la inflación total y básica retornarían a tasas cercanas al 3 %, en un entorno de desaceleración del IPC de alimentos y de menores excesos de capacidad productiva. En los meses recientes el aumento en los precios internacionales de los fletes y de los bienes agrícolas, y las mayores exportaciones de carne y el ciclo ganadero han ejercido presiones al alza sobre el precio de los alimentos, principalmente de los procesados. A estas fuerzas persistentes se sumaron los bloqueos de las vías nacionales y los problemas de orden público en varias ciudades registrados en mayo y parte de junio, los cuales se reflejaron en una fuerte restricción en la oferta y en un aumento anual no esperado del IPC de alimentos (8,52 %). El grupo de regulados (5,93 %) también se aceleró, debido a la baja base de comparación en los precios de la gasolina y a la disolución de parte de los alivios a las tarifas de servicios públicos otorgados en 2020. Como se proyectaba, la inflación SAR repuntó al 1,87 %, debido a la reactivación de los impuestos indirectos de algunos bienes y servicios eliminados un año atrás, y por las presiones al alza que ejercieron los alimentos sobre las comidas fuera del hogar (CFH), entre otros. En lo que resta del año se espera que el aumento en los alimentos perecederos se revierta, siempre y cuando no se registren nuevos bloqueos duraderos a las vías nacionales. El mayor nivel de precios de los alimentos procesados persistiría y contribuiría a mantener la inflación por encima de la meta a finales de año. La inflación SAR continuaría con una tendencia creciente, en la medida en que los excesos de capacidad productiva se sigan cerrando y registraría un aumento transitorio en marzo de 2022, debido principalmente al restablecimiento del impuesto al consumo en las CFH. Con todo esto, para finales de 2021 y 2022 se estima una inflación total del 4,1 % y 3,1 %, y una inflación básica del 2,6 % y 3,2 %, respectivamente. El comportamiento conjunto de los precios del IPC SAR, junto con continuas sorpresas al alza en la actividad económica, son interpretados por el equipo técnico como señales de amplios excesos de capacidad productiva de la economía. Estos persistirían en los siguientes dos años, al final de los cuales la brecha del producto se cerraría. El mayor crecimiento económico sugiere una brecha del producto menos negativa que la estimada hace un trimestre. Sin embargo, el comportamiento de la inflación básica, especialmente en servicios, indica que el PIB potencial se ha recuperado de forma sorpresiva y que los excesos de capacidad siguen siendo amplios, con una demanda agregada afectada de forma persistente. Esta interpretación encuentra soporte en el mercado laboral, en donde persiste un desempleo alto y la recuperación de los empleos perdidos se estancó. Adicionalmente, los aumentos en la inflación en buena medida están explicados por choques de oferta y de costos y por la disolución de algunos alivios de precios otorgados un año atrás. Los pronósticos de crecimiento y de inflación descritos son coherentes con una brecha del producto que se cierra más rápido y es menos negativa en todo el horizonte de pronóstico con respecto al informe de abril. No obstante, la incertidumbre sobre los excesos de capacidad es muy alta y es un riesgo sobre el pronóstico. Las perspectivas de las cuentas fiscales de Colombia se deterioraron, Standard & Poor’s Global Ratings (S&P) y Fitch Ratings (Fitch) redujeron su calificación crediticia, los bloqueos y problemas de orden público afectaron el producto y el país enfrentó una nueva ola de contagios de Covid-19 más acentuada y prolongada que las pasadas. Todo lo anterior se ha reflejado en un aumento de las primas de riesgo y en una depreciación del peso frente al dólar. Esto ha ocurrido en un entorno favorable de ingresos externos. Los precios internacionales del petróleo, del café y de otros bienes básicos que exporta el país aumentaron y han contribuido a la recuperación de los términos de intercambio y del ingreso nacional, y han mitigado las presiones al alza sobre las primas de riesgo y la tasa de cambio. En el presente informe se incrementó el precio esperado del petróleo para 2021 a USD 68 por barril (antes USD 61 bl) y para 2022 a USD 66 bl (antes USD 60 bl). Esta mayor senda presenta una convergencia hacia precios menores que los observados recientemente, como resultado de una mayor oferta mundial esperada de petróleo, la cual más que compensaría el incremento en la demanda de este bien básico. Por ende, se supone que el aumento reciente de los precios tiene un carácter transitorio. En el escenario macroeconómico actual se espera que las condiciones financieras internacionales sean algo menos favorables, a pesar de la mejora en los ingresos externos por cuenta de una mayor demanda y unos precios del petróleo y de otros productos de exportación más altos. Frente al informe de abril el crecimiento de la demanda externa fue mejor que el esperado, y las proyecciones para 2021 y 2022 aumentaron del 5,2 % al 6,0 % y del 3,4 % al 3,5 %, respectivamente. En lo corrido del año las cifras de actividad económica muestran una demanda externa más dinámica de la esperada. En los Estados Unidos y China la recuperación del producto ha sido más rápida que la registrada en los países de la región. En estos últimos la reactivación económica ha estado limitada por los rebrotes del Covid-19, las limitaciones en la oferta de vacunas y el poco espacio fiscal para enfrentar la pandemia, entre otros factores. La buena dinámica en el comercio externo de bienes se ha dado en un entorno de deterioro en las cadenas de valor y de un aumento importante en los precios de las materias primas y en el costo de los fletes. En los Estados Unidos la inflación sorprendió al alza y su valor observado y esperado se mantiene por encima de la meta, al tiempo que se incrementó la proyección de crecimiento económico. Con esto, el inicio de la normalización de la política monetaria en ese país se daría antes de lo proyectado. En este informe se estima que el primer incremento en la tasa de interés de la Reserva Federal de los Estados Unidos se dé a finales de 2022 (antes del primer trimestre de 2023). Para Colombia se supone una mayor prima de riesgo frente al informe de abril y se sigue esperando que presente una tendencia creciente, dada la acumulación de deuda pública y externa del país. Todo esto contribuiría a un incremento en el costo del financiamiento externo en el horizonte de pronóstico. La postura expansiva de la política monetaria sigue soportando unas condiciones financieras internas favorables. En el segundo trimestre la tasa de interés interbancaria y el índice bancario de referencia (IBR) se han mantenido acordes con la tasa de interés de política. Las tasas de interés promedio de captación y crédito continuaron históricamente bajas, a pesar de algunos incrementos observados a finales de junio. La cartera en moneda nacional detuvo su desaceleración anual y, entre marzo y junio, el crédito a los hogares se aceleró, principalmente para compra de vivienda. La recuperación de la cartera comercial y de los desembolsos a ese sector fue importante, y se alcanzó de nuevo el elevado saldo observado un año atrás, cuando las empresas requirieron niveles significativos de liquidez para enfrentar los efectos económicos de la pandemia. El riesgo de crédito aumentó, las provisiones se mantienes altas y algunos bancos han retirado de su balance una parte de su cartera vencida. No obstante, las utilidades del sistema financiero se han recuperado y sus niveles de liquidez y solvencia se mantienen por encima del mínimo regulatorio. A partir de este informe se implementará una nueva metodología para cuantificar y comunicar la incertidumbre que rodea los pronósticos del escenario macroeconómico central, en un entorno de política monetaria activa. Esta metodología se conoce como densidades predictivas (DP) y se explica en detalle en el Recuadro 1. Partiendo del balance de riesgos que contiene los principales factores que, de acuerdo con el juicio del equipo técnico, podrían afectar a la economía en el horizonte de pronóstico, la metodología DP produce distribuciones de probabilidad sobre el pronóstico de las principales variables (v. g.: crecimiento, inflación). Estas distribuciones reflejan el resultado de los posibles choques (a variables externas, precios y actividad económica) que podría recibir la economía y su transmisión, considerando la estructura económica y la respuesta de política monetaria en el futuro. En este sentido, permiten cuantificar la incertidumbre alrededor del pronóstico y su sesgo. El ejercicio DP muestra un sesgo a la baja en el crecimiento económico y en la brecha del producto, y al alza en la inflación. El balance de riesgos indica que las disyuntivas para la política monetaria serán potencialmente más complejas que lo contemplado en el pasado. Por el lado de las condiciones de financiamiento externo, se considera que el mayor riesgo es que se tornen un poco menos favorables, en un escenario en el cual la Reserva Federal de los Estados Unidos incremente con mayor prontitud su tasa de interés. Esto último, ante un crecimiento económico y del empleo mayor que el esperado en los Estados Unidos que genere presiones significativas sobre la inflación de ese país. A esto se suma la incertidumbre sobre el panorama fiscal en Colombia y sus efectos sobre la prima de riesgo y el costo del financiamiento externo. En el caso del crecimiento, la mayoría de los riesgos son a la baja, destacándose los efectos de la incertidumbre política y fiscal sobre las decisiones de consumo e inversión, la aparición de nuevas olas de contagio de la pandemia del Covid-19 y sus impactos sobre la actividad económica. En el caso de la inflación, se incorporó el riesgo de una mayor persistencia de los choques asociados con la disrupción de las cadenas de valor, mayores precios internacionales de las materias primas y de los alimentos, y una recuperación más lenta que la esperada de la cadena agrícola nacional afectada por los pasados bloqueos a las vías. Estos riesgos presionarían al alza principalmente los precios de los alimentos y de los bienes. Como principal riesgo a la baja se incluyó un alza de los arriendos menor que el esperado en el escenario central, explicada por una demanda débil y por una mayor oferta en 2022 dadas las altas ventas de vivienda observadas en el presente año. Con todo, el crecimiento económico presenta un sesgo a la baja y, con el 90 % de confianza, se encontraría entre un 6,1 % y 9,1 % para 2021 y entre el 0,5 % y 4,1 % para 2022. La brecha del producto tendría un sesgo a la baja, principalmente en 2022. El sesgo de la inflación es al alza, y se encontraría entre el 3,7 % y 4,9 % en 2021, y el 2,2 % y 4,7 % en 2022, con un 90 % de probabilidad. 1.2 Decisión de política monetaria En las reuniones de junio y julio la JDBR decidió mantener la tasa de política monetaria inalterada en 1,75 %.