920 research outputs found
Inactivation of Medial Prefrontal Cortex Impairs Time Interval Discrimination in Rats
Several lines of evidence suggest the involvement of prefrontal cortex in time interval estimation. The underlying neural processes are poorly understood, however, in part because of the paucity of physiological studies. The goal of this study was to establish an interval timing task for physiological recordings in rats, and test the requirement of intact medial prefrontal cortex (mPFC) for performing the task. We established a temporal bisection procedure using six different time intervals ranging from 3018 to 4784 ms that needed to be discriminated as either long or short. Bilateral infusions of muscimol (GABAA receptor agonist) into the mPFC significantly impaired animal's performance in this task, even when the animals were required to discriminate between only the longest and shortest time intervals. These results show the requirement of intact mPFC in rats for time interval discrimination in the range of a few seconds
Clinical and microbiologic characteristics of tcdA-negative variant clostridium difficile infections
BACKGROUND: The tcdA-negative variant (A(-)B(+)) of Clostridium difficile is prevalent in East Asian countries. However, the risk factors and clinical characteristics of A(-)B(+)C. difficile infections (CDI) are not clearly documented. The objective of this study was to investigate these characteristics. METHODS: From September 2008 through January 2010, the clinical characteristics, medication history and treatment outcomes of CDI patients were recorded prospectively. Toxin characterization and antibiotic susceptibility tests were performed on stool isolates of C. difficile. RESULTS: During the study period, we identified 22 cases of CDI caused by tcdA-negative tcdB-positive (A(-)B(+)) strains and 105 cases caused by tcdA-positive tcdB-positive (A(+)B(+)) strains. There was no significant difference in disease severity or clinical characteristics between the two groups. Previous use of clindamycin and young age were identified as significant risk factors for the acquisition of A(-)B(+) CDI (OR = 4.738, 95% CI 1.48–15.157, p = 0.009 and OR = 0.966, 95% CI 0.935–0.998, p = 0.038, respectively) in logistic regression. Rates of resistance to clindamycin were 100% and 69.6% in the A(-)B(+) and A(+)B(+) isolates, respectively (p = 0.006), and the ermB gene was identified in 17 of 21 A(-)B(+) isolates (81%). Resistance to moxifloxacin was also more frequent in the A(-)B(+) than in the A(+)B(+) isolates (95.2% vs. 63.7%, p = 0.004). CONCLUSIONS: The clinical course of A(-)B(+) CDI is not different from that of A(+)B(+) CDI. Clindamycin use is a significant risk factor for the acquisition of tcdA-negative variant strains
Guidance for dental treatment of patients with disabilities during COVID-19 pandemic
People with disabilities are challenged managing their oral hygiene and more often burdened with oral diseases. They often require immediate dental treatment for severe pain and greater precautions are needed to cope with COVID-19. The potential for COVID-19 infection can be relatively high in patients with disabilities due to concomitant systemic diseases, unique individual circumstances, relationship with caregivers and the living conditions of long-term care facilities, which make them vulnerable to the virus. For behavior management, dental treatment is often provided under general anesthesia with meticulous preoperative evaluation and the use of high-quality viral filters. In response to COVID-19, additional considerations should be taken for dental procedures on patients with special needs. These recommendations for dental treatment of the disabled are based on 6 months of authors COVID-19 pandemic experience
Homogeneous and Heterogeneous Photocatalytic Water Oxidation by Persulfate
Photocatalytic water oxidation by persulfate (Na2S2O8) with [Ru(bpy)3]2+ (bpy=2,2′‐bipyridine) as a photocatalyst provides a standard protocol to study the catalytic reactivity of water oxidation catalysts. The yield of evolved oxygen per persulfate is regarded as a good index for the catalytic reactivity because the oxidation of bpy of [Ru(bpy)3]2+ and organic ligands of catalysts competes with the catalytic water oxidation. A variety of metal complexes act as catalysts in the photocatalytic water oxidation by persulfate with [Ru(bpy)3]2+ as a photocatalyst. Herein, the catalytic mechanisms are discussed for homogeneous water oxidation catalysis. Some metal complexes are converted to metal oxide or hydroxide nanoparticles during the photocatalytic water oxidation by persulfate, acting as precursors for the actual catalysts. The catalytic reactivity of various metal oxides is compared based on the yield of evolved oxygen and turnover frequency. A heteropolynuclear cyanide complex is the best catalyst reported so far for the photocatalytic water oxidation by persulfate and [Ru(bpy)3]2+, affording 100 % yield of O2 per persulfate.Waterworld: Homogeneous and heterogeneous catalysis and mechanisms of photocatalytic oxidation of water by persulfate with [Ru(bpy)]32+ are compared and discussed including the conversion from homogeneous precatalysts to heterogeneous catalysts.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137224/1/asia201501329.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137224/2/asia201501329_am.pd
Requirement of estrogen receptor alpha DNA-binding domain for HPV oncogene-induced cervical carcinogenesis in mice
Cervical cancer is caused by human papillomavirus (HPV) in collaboration with other non-viral factors. The uterine cervix is hormone responsive and female hormones have been implicated in the pathogenesis of the disease. HPV transgenic mice expressing HPV16 oncogenes E6 ( K14E6 ) and/or E7 ( K14E7 ) have been employed to study a mechanism of estrogen and estrogen receptor ? (ER?) in cervical carcinogenesis. A chronic exposure to physiological levels of exogenous estrogen leads to cervical cancer in the HPV transgenic mice, which depends on ER?. The receptor is composed of multiple functional domains including a DNA-binding domain (DBD), which mediates its binding to estrogen-responsive elements (EREs) on target genes. A transcriptional control of genes by ER? is mediated by either DBD-dependent (classical) or DBD-independent (non-classical) pathway. Although molecular mechanisms of ER? in cancer have been characterized extensively, studies investigating importance of each pathway for carcinogenesis are scarce. In this study, we employ knock-in mice expressing an ER? DBD mutant (E207A/G208A) that is defective specifically for ERE binding. We demonstrate that the ER? DBD mutant fails to support estrogen-induced epithelial cell proliferation and carcinogenesis in the cervix of K14E7 transgenic mice. We also demonstrate that cervical diseases are absent in K14E7 mice when one ER? DBD mutant allele and one wild-type allele are present. We conclude that the ER? classical pathway is required for cervical carcinogenesis in a mouse model
Single- and Multiple-Junction p-i-n Type Amorphous Silicon Solar Cells with p-a-Si1-xCx:H and nc-Si:H Films
Excess mortality and the COVID-19 pandemic: causes of death and social inequalities
Background
During the coronavirus diseases 2019 (COVID-19) pandemic, population’s mortality has been affected not only by the risk of infection itself, but also through deferred care for other causes and changes in lifestyle. This study aims to investigate excess mortality by cause of death and socio-demographic context during the COVID-19 pandemic in South Korea.
Methods
Mortality data within the period 2015–2020 were obtained from Statistics Korea, and deaths from COVID-19 were excluded. We estimated 2020 daily excess deaths for all causes, the eight leading causes of death, and according to individual characteristics, using a two-stage interrupted time series design accounting for temporal trends and variations in other risk factors.
Results
During the pandemic period (February 18 to December 31, 2020), an estimated 663 (95% empirical confidence interval [eCI]: -2356–3584) excess deaths occurred in South Korea. Mortality related to respiratory diseases decreased by 4371 (3452–5480), whereas deaths due to metabolic diseases and ill-defined causes increased by 808 (456–1080) and 2756 (2021–3378), respectively. The increase in all-cause deaths was prominent in those aged 65–79 years (941, 88–1795), with an elementary school education or below (1757, 371–3030), or who were single (785, 384–1174), while a decrease in deaths was pronounced in those with a college-level or higher educational attainment (1471, 589–2328).
Conclusion
No evidence of a substantial increase in all-cause mortality was found during the 2020 pandemic period in South Korea, as a result of a large decrease in deaths related to respiratory diseases that offset increased mortality from metabolic disease and diseases of ill-defined cause. The COVID-19 pandemic has disproportionately affected those of lower socioeconomic status and has exacerbated inequalities in mortality.This work was supported by Korea Environment Industry & Technology Institute (KEITI) through "Climate Change R&D Project for New Climate Regime.", funded by Korea Ministry of Environment (MOE) (2022003570006)
A pictorial review on clinicopathologic and radiologic features of duodenal gastrointestinal stromal tumors
Duodenal gastrointestinal stromal tumors (GISTs) are rare, and studies on their management are not sufficient. Owing to the complex anatomy of the duodenum and pancreatic head, GISTs can be misdiagnosed as pancreatic head tumors. Surgical resection is the first treatment for localized duodenal GISTs; thus, noninvasive imaging is important for the diagnosis and treatment of GISTs. Computed tomography, magnetic resonance imaging and endoscopic ultrasonography findings can be helpful for the diagnosis of duodenal GISTs and can help differentiate GISTs from other adjacent tumors
The effects of improved sanitation on diarrheal prevalence, incidence, and duration in children under five in the SNNPR State, Ethiopia: study protocol for a randomized controlled trial.
BACKGROUND: Diarrhea is one of the leading causes of death, killing 1.3 million in 2013 across the globe, of whom, 0.59 million were children under 5 years of age. Globally, about 1 billion people practice open defecation, and an estimated 2.4 billion people were living without improved sanitation facilities in 2015. Much of the previous research investigating the effect of improved sanitation has been based on observational studies. Recent studies have executed a cluster-randomized controlled trial to investigate the effect of improved sanitation. However, none of these recent studies achieved a sufficient level of latrine coverage. Without universal or at least a sufficient level of latrine coverage, a determination of the effect of improved latrines on the prevention of diarrheal disease is difficult. This cluster-randomized trial aims to explore the net effect of improved latrines on diarrheal prevalence and incidence in children under five and to investigate the effect on the diarrheal duration. METHOD/DESIGN: A phase-in and factorial design will be used for the study. The intervention for improving latrines will be implemented in an intervention arm during the first phase, and the comparable intervention will be performed in the control arm during the second phase. During the second phase, a water pipe will be connected to the gotts (villages) in the intervention arm. After the second phase is completed, the control group will undergo the intervention of receiving a water pipe connection. For diarrheal prevalence, five rounds of surveying will be conducted at the household level. The first four rounds will be carried out in the first phase to explore the effect of improved latrines, and the last one, in the second phase to examine the combined effects of improved water and sanitation. For documentation of diarrheal incidence and duration, the mother or caregiver will record the diarrheal episodes of her youngest child on the "Sanitation Calendar" every day. Of 212 gotts in the project area, 48 gotts were selected for the trial, and 1200 households with a child under 5 will be registered for the intervention or control arm. Informed consent from 1200 households will be obtained from the mother or caregiver in written form. DISCUSSION: To our knowledge, this is the second study to assess the effects of improved latrines on child diarrheal reduction through the application of Community-Led Total Sanitation. TRIAL REGISTRATION: Current Controlled Trials, ISRCTN82492848
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