178 research outputs found
A new approach for improving the silicon texturing process using gas-lift effect
A new cost-effective and efficient approach is proposed for texturing the crystalline silicon using the gas-lift effect (GLE). The advantages of this approach over the conventional ones are that significantly lower amounts of IPA is used and much shorter etching time is required to achieve the same reflectivity. GLE is generated by taking advantage of the hydrogen bubbles evolved between the silicon wafer being etched and a glass plate, placed in parallel, creating a gap of 1–2 mm. This effect then acts as a pumping mechanism detaching more bubbles from the silicon surface, accelerating them to the top and out of the system, as quickly as they are generated. Experiments were carried out with various combinations of TMAH/IPA concentrations for two different GLE conditions to analyse and determine their influence on etching time, etching rate, surface morphology and reflectivity of the textured silicon surface. The use of this new approach in surface texturing, allowed the reduction of the required IPA by 50% and etching time by more than 60% to achieve the same reflectivity. This can ultimately lead to a significant reduction in cost by increasing the efficiency of the texturing process. A combination of 3.5% IPA and 2 mm GLE resulted in a textured silicon surface having a low specular solar-weighted reflectivity of 0.15%
Modelling and optimizing the gas-lift effect system for texturing silicon
Modelling and simulation techniques were used to understand the fluid flow patterns inside the silicon texturing system operating under the gas-lift effect (GLE) for solar cell applications. Experiments were performed which confirmed the validity of the simulation model and the simulated results. It was determined that due to the original non-optimal inlet, the fluid flow pattern and the non-uniform fluid velocity distribution inside the system resulted in the generation of lower velocity regions on the surface of the textured silicon. The simulation tool validated the correlation of the lower fluid velocity with the reduced surface coverage, uniformity and subsequent less optimal surface reflectivity. Various inlet designs were modelled and evaluated for optimal performance. The best-case inlet design was fabricated and tested resulting in the validation of the simulation work and significant improvement in the GLE texturing system performance. With the new inlet design, as the fluid velocity reaches and goes beyond some critical value (in this case 0.047 m s−1) in areas that had shown lower velocity in the original inlet design (mainly close to the inlet and side walls), the observed morphology and surface reflectivity improve significantly with values very similar to those of the higher velocity areas
Heritability and genetic gain of some morphophysiological variables of durum wheat (Triticum turgidum var. durum)
The purpose of this work is to estimate genetic variability parameters and relationship among 11 agrophysiological traits studied on 18 experimental durum wheat and two checks under rainfed condition. The studied traits included the grain yield (YLD), plant height (PH), number of tiller per plant (NT), peduncle length (PL), flag length (FL), leaf dry weight (LDW), stem dry weight (STW), spike dry weight (SPW), spike height (SH), leaf area index (LAI), crop growth rate (CGR), relative growth rate (RGR), leaf area ratio (LAR) and net assimilation rate (NAR). Analysis of variance showed a significantly variation among genotypes for the characters PH, NT, PL, FL, LDW, STW, SPW, SH, LAR and NAR. High correlations were found among the PL, LDW, STW, SPW, LAR and NAR. Heritability estimates were high for PH, PL, LDW, STW and NAR. High genetic gains were observed for YLD, NT, PL, LDW, STW, SPW, LAR and NAR
Baffle-Enhanced Scour Mitigation in Rectangular and Trapezoidal Piano Key Weirs: An Experimental and Machine Learning Investigation
This is the final version. Available on open access from MDPI via the DOI in this recordData Availability Statement: Some or all of the data, models, or code that support the findings of this study are available from the first author upon reasonable request.The assessment of scour depth downstream of weirs holds paramount importance in ensuring the structural stability of these hydraulic structures. This study presents groundbreaking experimental investigations highlighting the innovative use of baffles to enhance energy dissipation and mitigate scour in the downstream beds of rectangular piano key weirs (RPKWs) and trapezoidal piano key weirs (TPKWs). By leveraging three state-of-the-art supervised machine learning algorithms—multi-layer perceptron (MLP), extreme gradient boosting (XGBoost), and support vector regression (SVR)—to estimate scour hole parameters, this research showcases significant advancements in predictive modeling for scour analysis. Experimental results reveal that the incorporation of baffles leads to a remarkable 18–22% increase in energy dissipation and an 11–14% reduction in scour depth for both RPKWs and TPKWs. Specifically, introducing baffles in RPKWs resulted in a noteworthy 26.7% reduction in scour hole area and a 30.3% decrease in scour volume compared to RPKWs without baffles. Moreover, novel empirical equations were developed to estimate scour parameters, achieving impressive performance metrics with an average R2 = 0.951, RMSE = 0.145, and MRPE = 4.429%. The MLP models demonstrate superior performance in predicting maximum scour depth across all scenarios with an average R2 = 0.988, RMSE = 0.035, and MRPE = 1.036%. However, the predictive capabilities varied when estimating weir toe scour depth under diverse circumstances, with the XGBoost model proving more accurate in scenarios involving baffled TPKWs with R2 = 0.965, RMSE = 0.048, and MRPE = 2.798% than the MLP and SVR models. This research underscores the significant role of baffles in minimizing scouring effects in TPKWs compared to RPKWs, showcasing the potential for improved design and efficiency in water-management systems
The frequency of eight common point mutations in CYP21 gene in Iranian patients with congenital adrenal hyperplasia
Background: Congenital Adrenal Hyperplasia (CAH, the inherited inability to synthesize cortisol) is one of the most common (1 in 10000 to 1 in 15000) autosomal recessive disorders. More than 95 of cases of CAH are caused by 21-hydroxylase deficiency (21-OHD). Females with severe, classic 21-OHD are exposed to excess androgens prenatally and are born with virilized external genitalia. Most patients cannot synthesize sufficient aldosterone to maintain sodium balance and may develop potentially fatal salt wasting crisis if not treated. Methods: We applied allele specific PCR to detect the eight common mutations in the CYP21 gene in patients. Fifty unrelated patients with symptoms of classical CAH were studied. Results and Conclusion: Seventy percent of our subjects had these mutations. The most frequent mutations were found to be I2G and del-8bp (28 and 13, respectively). The frequencies of other alleles were as following: I172N, 9; V281L, 3; exon 6 cluster (I236N, V237E and M239K), 4; Q318X, 9; R356W, 5; and P30L, 0. The frequency of mutations did not differ substantially from other ethnics, however, a higher rate of del-8 bp (13) was found in our population. The aim of this study was to detect common mutations for setting up a molecular method for prenatal diagnosis
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ARHGEF9 disease: Phenotype clarification and genotype-phenotype correlation.
ObjectiveWe aimed to generate a review and description of the phenotypic and genotypic spectra of ARHGEF9 mutations.MethodsPatients with mutations or chromosomal disruptions affecting ARHGEF9 were identified through our clinics and review of the literature. Detailed medical history and examination findings were obtained via a standardized questionnaire, or if this was not possible by reviewing the published phenotypic features.ResultsA total of 18 patients (including 5 females) were identified. Six had de novo, 5 had maternally inherited mutations, and 7 had chromosomal disruptions. All females had strongly skewed X-inactivation in favor of the abnormal X-chromosome. Symptoms presented in early childhood with delayed motor development alone or in combination with seizures. Intellectual disability was severe in most and moderate in patients with milder mutations. Males with severe intellectual disability had severe, often intractable, epilepsy and exhibited a particular facial dysmorphism. Patients with mutations in exon 9 affecting the protein's PH domain did not develop epilepsy.ConclusionsARHGEF9 encodes a crucial neuronal synaptic protein; loss of function of which results in severe intellectual disability, epilepsy, and a particular facial dysmorphism. Loss of only the protein's PH domain function is associated with the absence of epilepsy
Comprehensive genotype‐phenotype correlation in AP‐4 deficiency syndrome; Adding data from a large cohort of Iranian patients
Mutations in adaptor protein complex‐4 (AP‐4) genes have first been identified in 2009, causing a phenotype termed as AP‐4 deficiency syndrome. Since then several patients with overlapping phenotypes, comprised of intellectual disability (ID) and spastic tetraplegia have been reported. To delineate the genotype‐phenotype correlation of the AP‐4 deficiency syndrome, we add the data from 30 affected individuals from 12 out of 640 Iranian families with ID in whom we detected disease‐causing variants in AP‐4 complex subunits, using next‐generation sequencing. Furthermore, by comparing genotype‐phenotype findings of those affected individuals with previously reported patients, we further refine the genotype‐phenotype correlation in this syndrome. The most frequent reported clinical findings in the 101 cases consist of ID and/or global developmental delay (97%), speech disorders (92.1%), inability to walk (90.1%), spasticity (77.2%), and microcephaly (75.2%). Spastic tetraplegia has been reported in 72.3% of the investigated patients. The major brain imaging findings are abnormal corpus callosum morphology (63.4%) followed by ventriculomegaly (44.5%). Our result might suggest the AP‐4 deficiency syndrome as a major differential diagnostic for unknown hereditary neurodegenerative disorders
Whole genome sequencing identifies a duplicated region encompassing Xq13.2q13.3 in a large Iranian family with intellectual disability
Background The X chromosome has historically been one of the most thoroughly investigated chromosomes regarding intellectual disability (ID), whose etiology is attributed to many factors including copy number variations (CNVs). Duplications of the long arm of the X chromosome have been reported in patients with ID, short stature, facial anomalies, and in many cases hypoplastic genitalia and/or behavioral abnormalities. Methods Here, we report on a large Iranian family with X‐linked ID caused by a duplication on the X chromosome identified by whole genome sequencing in combination with linkage analysis. Results Seven affected males in different branches of the family presented with ID, short stature, seizures, facial anomalies, behavioral abnormalities (aggressiveness, self‐injury, anxiety, impaired social interactions, and shyness), speech impairment, and micropenis. The duplication of the region Xq13.2q13.3, which is ~1.8 Mb in size, includes seven protein‐coding OMIM genes. Three of these genes, namely SLC16A2, RLIM, and NEXMIF, if impaired, can lead to syndromes presenting with ID. Of note, this duplicated region was located within a linkage interval with a LOD score >3. Conclusion Our report indicates that CNVs should be considered in multi‐affected families where no candidate gene defect has been identified in sequencing data analysis
Mutations in NSUN2 cause autosomal-recessive intellectual disability
With a prevalence between 1 and 3%, hereditary forms of intellectual disability (ID) are among the most important problems in health care. Particularly, autosomal-recessive forms of the disorder have a very heterogeneous molecular basis, and genes with an increased number of disease-causing mutations are not common. Here, we report on three different mutations (two nonsense mutations, c.679C>T [p.Gln227( *)] and c.1114C>T [p.Gln372( *)], as well as one splicing mutation, g.6622224A>C [p.Ile179Argfs( *)192]) that cause a loss of the tRNA-methyltransferase-encoding NSUN2 main transcript in homozygotes. We identified the mutations by sequencing exons and exon-intron boundaries within the genomic region where the linkage intervals of three independent consanguineous families of Iranian and Kurdish origin overlapped with the previously described MRT5 locus. In order to gain further evidence concerning the effect of a loss of NSUN2 on memory and learning, we constructed a Drosophila model by deleting the NSUN2 ortholog, CG6133, and investigated the mutants by using molecular and behavioral approaches. When the Drosophila melanogaster NSUN2 ortholog was deleted, severe short-term-memory (STM) deficits were observed; STM could be rescued by re-expression of the wild-type protein in the nervous system. The humans homozygous for NSUN2 mutations showed an overlapping phenotype consisting of moderate to severe ID and facial dysmorphism (which includes a long face, characteristic eyebrows, a long nose, and a small chin), suggesting that mutations in this gene might even induce a syndromic form of ID. Moreover, our observations from the Drosophila model point toward an evolutionarily conserved role of RNA methylation in normal cognitive development
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