597 research outputs found
A Rare Presentation of Distomolar Teeth: Report of a Case
Objectives A distomolar tooth, also known as a distodens, is a supernumerary tooth located distally to the third molars. It is an uncommon phenomenon with a reported prevalence of 0.02% to 0.16% across various countries. Distomolars can manifest as singular or multiple, erupted or impacted, and can occur unilaterally or bilaterally. To the best of our knowledge, very few cases of three distomolars in one patient have been reported in the English literature.
Case This study presents the case of a healthy 22-year-old male who was found to have three impacted distomolars. These distomolars were located bilaterally in the maxilla and unilaterally on the left side of the mandible. They were discovered incidentally during a routine radiographic examination. As the patient expressed no discomfort or complaints related to this condition, no treatment was administered. Instead, the patient was placed on a regular follow-up.
Conclusion Although the occurrence of distomolars is rare, clinicians should regard it as a potential risk factor for the development of intraosseous lesions, which are often associated with an impacted tooth
Substrate Effect on the Thermal Expansion of 2D Materials: An Investigation by Machine Learning Interatomic Potentials
The thermal expansion coefficient (TEC) of suspended two-dimensional (2D) nanomaterials is usually negative due to their ability for large out-of-plane deflection as the temperature increases. The presence of a substrate can nonetheless restrict the flexibility of 2D materials and significantly change their dimensional change by temperature. In this short communication, the thermal expansion coefficients of suspended and supported four popular 2D structures of graphene, phagraphene, C3N and BC3 monolayers is systematically investigated. For this purpose, we conduct molecular dynamics simulation, in which the atomic interactions are defined by highly accurate machine learning interatomic potentials. The obtained results show that by increasing the strength of the van der Waals interactions between the monolayer and the substrate, from 2 meV to 8 meV, the TEC for graphene and phagraphene increases from a negative value to a positive one; while the negative value for the C3N and BC3 structures is still retained. Analysis of molecular dynamics trajectories reveals that the substrate can significantly reduce the formation of out-of-plane wrinkles and consequently affect the value of TEC. The obtained results provide useful vision on the role of substrate on the complex thermal expansion responses of 2D materials
Computation for ChIP-seq and RNA-seq studies
Genome-wide measurements of protein-DNA interactions and transcriptomes are increasingly done by deep DNA sequencing methods (ChIP-seq and RNA-seq). The power and richness of these counting-based measurements comes at the cost of routinely handling tens to hundreds of millions of reads. Whereas early adopters necessarily developed their own custom computer code to analyze the first ChIP-seq and RNA-seq datasets, a new generation of more sophisticated algorithms and software tools are emerging to assist in the analysis phase of these projects. Here we describe the multilayered analyses of ChIP-seq and RNA-seq datasets, discuss the software packages currently available to perform tasks at each layer and describe some upcoming challenges and features for future analysis tools. We also discuss how software choices and uses are affected by specific aspects of the underlying biology and data structure, including genome size, positional clustering of transcription factor binding sites, transcript discovery and expression quantification
Dynamic Transformations of Genome-wide Epigenetic Marking and Transcriptional Control Establish T Cell Identity
T cell development comprises a stepwise process of commitment from a multipotent precursor. To define molecular mechanisms controlling this progression, we probed five stages spanning the commitment process using RNA-seq and ChIP-seq to track genome-wide shifts in transcription, cohorts of active transcription factor genes, histone modifications at diverse classes of cis-regulatory elements, and binding repertoire of GATA-3 and PU.1, transcription factors with complementary roles in T cell development. The results highlight potential promoter-distal cis-regulatory elements in play and reveal both activation sites and diverse mechanisms of repression that silence genes used in alternative lineages. Histone marking is dynamic and reversible, and though permissive marks anticipate, repressive marks often lag behind changes in transcription. In vivo binding of PU.1 and GATA-3 relative to epigenetic marking reveals distinctive factor-specific rules for recruitment of these crucial transcription factors to different subsets of their potential sites, dependent on dose and developmental context
Best-Case Lower Bounds in Online Learning
Much of the work in online learning focuses on the study of sublinear upper
bounds on the regret. In this work, we initiate the study of best-case lower
bounds in online convex optimization, wherein we bound the largest improvement
an algorithm can obtain relative to the single best action in hindsight. This
problem is motivated by the goal of better understanding the adaptivity of a
learning algorithm. Another motivation comes from fairness: it is known that
best-case lower bounds are instrumental in obtaining algorithms for
decision-theoretic online learning (DTOL) that satisfy a notion of group
fairness. Our contributions are a general method to provide best-case lower
bounds in Follow The Regularized Leader (FTRL) algorithms with time-varying
regularizers, which we use to show that best-case lower bounds are of the same
order as existing upper regret bounds: this includes situations with a fixed
learning rate, decreasing learning rates, timeless methods, and adaptive
gradient methods. In stark contrast, we show that the linearized version of
FTRL can attain negative linear regret. Finally, in DTOL with two experts and
binary predictions, we fully characterize the best-case sequences, which
provides a finer understanding of the best-case lower bounds.Comment: 28 page
Menopausal age and its influencing factors, Birjand, 2001
یائسگی به عنوان مرحله پایان دوره باروری در زنان، همراه با تغییراتی در سلامتی زنان می باشد. به منظور بررسی فاکتورهای مرتبط با سن یائسگی از میان زنان بالای 40 سال شهر بیرجند که به مدت حداقل یک سال قاعدگی نداشتند، 810 نفر به روش نمونه گیری خوشه ای انتخاب گردیدند و از طریق مصاحبه حضوری اطلاعات مورد نظر در یک پرسشنامه ثبت شد. نتایج نشان داد که متوســـط سن یائسگی 31/5 ±19/47 ســـال و میزان فراوانی یائسگی زود رس 8/13 بود. سن بالاتر در اولین حاملگی، سن بالای 35 سال در آخرین حاملگی، سابقه مصرف قرص های جلوگیری از حاملگی (OCP= Oral Contracrptive Pills)، ابتلا به دیابت نوع II و مولتی پاریتی با یائسگی در سن بالاتر همراه بود. فراوانی بالای یائسگی زودرس در زنان شهر بیرجند نسبت به سایر مطالعات احتیاج به مطالعات بیشتری در این زمینه دارد
Incorporating Genomics into the Toolkit of Nematology
The study of nematode genomes over the last three decades has relied heavily on the model organism Caenorhabditis elegans, which remains the best-assembled and annotatedmetazoan genome. This is now changing as a rapidly expanding number of nematodes of medical and economic importance have been sequenced in recent years. The advent of sequencing technologies to achieve the equivalent of the $1000 human genome promises that every nematode genome of interest will eventually be sequenced at a reasonable cost. As the sequencing of species spanning the nematode phylumbecomes a routine part of characterizing nematodes, the comparative approach and the increasing use of ecological context will help us to further understand the evolution and functional specializations of any given species by comparing its genome to that of other closely and more distantly related nematodes.We review the current state of nematode genomics and discuss some of the highlights that these genomes have revealed and the trend and benefits of ecological genomics, emphasizing the potential for new genomes and the exciting opportunities this provides for nematological studies
Investigating the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the Lavandula stoechas L. and Rosmarinus officinalis L. extracts on pathogen bacterias “in vitro”
The infections risk related to pathogenic germs increases at the present time considering the increased resistance which certain microbes acquire, whose usual antibiotics are ineffective to treat the infectious disease. The aim of this study was to determine antimicrobial effect of the aqueous and ethanolic extracts of Lavandula stoechas L. and Rosmarinus officinalis L. on Listeria monocytogenes PTCC 1297، Bacillus cereus PTCC 1154، Enterobacter aerogenes PTCC 1221، Enterococcus faecalis PTCC 1237 and Salmonella typhi PTCC 1609 ”in vitro”. In this experimental study, after collecting plants from of Razavi Khorasan province, the extraction was carried out by the maceration method, after antimicrobial effect of the extracts evaluated by two methods, “Collins method” (spreading of the extract on medium surface) and “disk agar diffusion method”. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) for both species determined by using a dilution method. Statistical analysis was carried out by analysis of variance (ANOVA).The results show that aqueous and ethanolic Lavandula stoechas L. extracts were quite effective in 2000 μg/ml concentration on Listeria monocytogenes، Bacillus cereus and Enterococcus faecalis. The results indicate that ethanolic extracts of Lavandula stoechas L. have the greatest effect on gram-positive bacterium. The result shows that MIC of Lavandula stoechas L. leaves of the aqueous and ethanolic extracts for Enterobacter aerogenes was 32 and 16 mg/ml respectively. The result shows that MIC of Rosmarinus officinalis L. leaves of the aqueous and ethanolic extracts for Enterobacter aerogenes was 128 and 64 mg/ml respectively.The Lavandula stoechas L. and Rosmarinus officinalis L. extracts presented the more effective impact on the growth of gram-positive bacteria than gram-negative bacteria (p<0.05).
Investigating the effects of noise exposure on intensification of diabetes mellitus, serum glucose, cortisol level and body weight of the male mice
Noise is considered as one of the harmful factors at industrial environments. It affects human health in different aspects including harmful influences on auditory, vision, neurological and psychiatric systems, hormones, physiological and mental systems. Paying attention to the importance of hormonal effects on human body seems to possess crucial importance. The aim of the present study is to investigate the effects of noise exposure on variation of serum levels of glucose and cortisol at Syrian adult male mouse. 36 Syrian male adult mice were randomly categorized into two experiment and control groups. Garlic powder was added to the mice pelleted food meal (equal to 1% of their daily diet) to study its effect on the cortisol and glucose serum levels. The mice pelleted food contains starch, glucose, isolated soya protein, etc., which are the rich resources of A, C, B1, B2 and B6 vitamins. Streptozotocin (60mg/kg) was injected to the mice at experiment group which were under noise exposure with intensity of 90dB in frequency range of 700-5700Hz. Noise were generated using CoolEdit software and distributed to the fabricated box for 30 days (8h/d). Fasting cortisol and glucose serum levels were measured for mice of both groups 24h after finishing the exposure period. Results indicated that the glucose serum level in non-diabetic and diabetic subjects under noise exposure had significant difference (p<0.002) with the subjects at control group. Also, cortisol level in non-diabetic and diabetic subjects under noise exposure indicated significant difference (p<0.002) with the subjects at control group. Exposure to noise with intensity of 90dB at frequency range of 700-5700Hz increases the glucose and cortisol serum levels
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