299 research outputs found
Rapidly predicting Kohn–Sham total energy using data-centric AI
Predicting material properties by solving the Kohn-Sham (KS) equation, which is the basis of modern computational approaches to electronic structures, has provided significant improvements in materials sciences. Despite its contributions, both DFT and DFTB calculations are limited by the number of electrons and atoms that translate into increasingly longer run-times. In this work we introduce a novel, data-centric machine learning framework that is used to rapidly and accurately predicate the KS total energy of anatase TiO 2 nanoparticles (NPs) at different temperatures using only a small amount of theoretical data. The proposed framework that we call co-modeling eliminates the need for experimental data and is general enough to be used over any NPs to determine electronic structure and, consequently, more efficiently study physical and chemical properties. We include a web service to demonstrate the effectiveness of our approach. © 2022, The Author(s)
Enhancement of electronic, photophysical and optical properties of 5,5 '-Dibromo-2,2 '-bithiophene molecule: new aspect to molecular design
WOS: 000474358100002The aims of this study were to enhance electronic, photophysical and optical properties of molecular semiconductors. For this purpose, the isomers of the B-doped molecule (5,5'-Dibromo-2,2'-bithiophene) have been investigated by density functional theory (DFT) based on B3LYP/6-311++G** level of theory. The isomers were first calculated using kick algorithm. The most stable isomers of the B-doped molecule are presented depending on the binding energy, fragmentation energy, ionization potential, electron affinity, chemical hardness, refractive index, radial distribution function and HOMO-LUMO energy gap based on DFT. Ultraviolet-visible (UV-vis) spectra have been also researched by time-dependent (TD) DFT calculations. The value of a band gap for isomer with the lowest total energy decreases from 4.20 to 3.47 eV while the maximum peaks of the absorbance and emission increase from 292 to 324 nm and 392 to 440 nm with boron doped into 5,5'-Dibromo-2,2'-bithiophene. Obtained results reveal that the B-doped molecule has more desirable optoelectronic properties than the pure molecule. (C) 2019 Association of Polish Electrical Engineers (SEP). Published by Elsevier B.V. All right
Trps1 and Its Target Gene Sox9 Regulate Epithelial Proliferation in the Developing Hair Follicle and Are Associated with Hypertrichosis
Hereditary hypertrichoses are a group of hair overgrowth syndromes that are extremely rare in humans. We have previously demonstrated that a position effect on TRPS1 is associated with hypertrichosis in humans and mice. To gain insight into the functional role of Trps1, we analyzed the late morphogenesis vibrissae phenotype of Trps1Δgt mutant mice, which is characterized by follicle degeneration after peg downgrowth has been initiated. We found that Trps1 directly represses expression of the hair follicle stem cell regulator Sox9 to control proliferation of the follicle epithelium. Furthermore, we identified a copy number variation upstream of SOX9 in a family with hypertrichosis that significantly decreases expression of the gene in the hair follicle, providing new insights into the long-range regulation of SOX9. Our findings uncover a novel transcriptional hierarchy that regulates epithelial proliferation in the developing hair follicle and contributes to the pathology of hypertrichosis
Social Bioclimatic Urban House Prototype in Arid Area Energy and Economic Assessment
The energetic and economic evaluation of an evolutionary bioclimatic social house prototype designed in the research unit, for urban arid zones, is presented, calculating their respective costs. The performance of passive systems is evaluated with the Optimix Program, using the Collector Load Rate Method (Los Álamos National Laboratory). The investment alternatives are adopted from the calculation from the Net Present and Marginal Value. The results quantify the use of passive solar systems to make more efficient the thermal and economic benefits of the executed prototypes. The winter thermal load, to which the homes are exposed, is reduced by 64.1%, with technics of energy conservation and the improvement of solar systems and variants applied. Energy savings result in 20% and 22% and the amortization of 2.4 years and 2.3 years, depending on the orientation of the prototype (azimuth 0° N and ± 15° N respectively.Fil: Kurban, Alejandra Silvia. Universidad Nacional de San Juan. Facultad de Arquitectura, Urbanismo y Diseño. Instituto de Estudios en Arquitectura Ambiental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; ArgentinaFil: Cunsulo, Mario Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Arquitectura, Urbanismo y Diseño. Instituto de Estudios en Arquitectura Ambiental; ArgentinaFil: Matar, M.. Universidad Nacional de San Juan. Facultad de Arquitectura, Urbanismo y Diseño. Instituto de Estudios en Arquitectura Ambiental; ArgentinaFil: Ripoll, V.. Universidad Nacional de San Juan. Facultad de Arquitectura, Urbanismo y Diseño. Instituto de Estudios en Arquitectura Ambiental; ArgentinaFil: Ortega, A.. Universidad Nacional de San Juan. Facultad de Arquitectura, Urbanismo y Diseño. Instituto de Estudios en Arquitectura Ambiental; Argentin
Mutación en el gen EDA1, Ala349Thr en paciente con displasia ectodérmica hipohidrótica ligada a X
Hypohidrotic ectodermal dysplasia (HED) is a very rare disease characterized by the absence of eccrine glands, dry skin, scanty hair, and dental abnormalities. It is caused by mutations within the ED1 gene, which encodes a protein, ectodysplasin-A (EDA). Clinical characteristic are frontal bossing, saddle nose, pointed chin, a prominent supraorbital ridge with periorbital hyperpigmentation, and anodontia. Those affected show great intolerance to heat. We report the fi rst Mexican 2-year-old boy with an Ala349Thr missense mutation from Tamaulipas, México. (Rev Med Chile 2011; 139: 1601-1604)
Atorvastatin pretreatment diminishes the levels of myocardial ischemia markers early after CABG operation: an observational study
<p>Abstract</p> <p>Background</p> <p>Statin pretreatment has been associated with a decrease in myocardial ischemia markers after various procedures and cardiovascular events. This study examined the potential beneficial effects of preoperative atorvastatin treatment among patients undergoing on-pump CABG operation.</p> <p>Methods</p> <p>Twenty patients that had received atorvastatin treatment for at least 15 days prior to the operation and 20 patients who had not received any antihyperlipidemic agent prior to surgery were included in this study. CK-MB and troponin I levels were measured at baseline and 24 hours after the operation. Perioperative variables were also recorded.</p> <p>Results</p> <p>Twenty-four hours after the operation, troponin I and CK-MB levels were significantly lower in the atorvastatin group: for CK-MB levels, 12.9 ± 4.3 versus 18.7 ± 7.4 ng/ml, p = 0.004; for troponin I levels, 1.7 ± 0.3 versus 2.7 ± 0.7 ng/ml, p < 0.001. In addition, atorvastatin use was associated with a decrease in the duration of ICU stay.</p> <p>Conclusions</p> <p>Preoperative atorvastatin treatment results in significant reductions in the levels of myocardial injury markers early after on-pump CABG operation, suggesting a reduction in perioperative ischemia in this group of patients. Further studies are needed to elucidate the mechanisms of these potential benefits of statin pretreatment.</p
Mutations in the Cholesterol Transporter Gene ABCA5 Are Associated with Excessive Hair Overgrowth
Inherited hypertrichoses are rare syndromes characterized by excessive hair growth that does not result from androgen stimulation, and are often associated with additional congenital abnormalities. In this study, we investigated the genetic defect in a case of autosomal recessive congenital generalized hypertrichosis terminalis (CGHT) (OMIM135400) using whole-exome sequencing. We identified a single base pair substitution in the 5′ donor splice site of intron 32 in the ABC lipid transporter gene ABCA5 that leads to aberrant splicing of the transcript and a decrease in protein levels throughout patient hair follicles. The homozygous recessive disruption of ABCA5 leads to reduced lysosome function, which results in an accumulation of autophagosomes, autophagosomal cargos as well as increased endolysosomal cholesterol in CGHT keratinocytes. In an unrelated sporadic case of CGHT, we identified a 1.3 Mb cryptic deletion of chr17q24.2-q24.3 encompassing ABCA5 and found that ABCA5 levels are dramatically reduced throughout patient hair follicles. Collectively, our findings support ABCA5 as a gene underlying the CGHT phenotype and suggest a novel, previously unrecognized role for this gene in regulating hair growth
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