Nonrecursive formulations of multibody dynamics and concurrent multiprocessing

Since the late 1980's, research in recursive formulations of multibody dynamics has flourished. Historically, much of this research can be traced to applications of low dimensionality in mechanism and vehicle dynamics. Indeed, there is little doubt that recursive order N methods are the method of choice for this class of systems. This approach has the advantage that a minimal number of coordinates are utilized, parallelism can be induced for certain system topologies, and the method is of order N computational cost for systems of N rigid bodies. Despite the fact that many authors have dismissed redundant coordinate formulations as being of order N(exp 3), and hence less attractive than recursive formulations, we present recent research that demonstrates that at least three distinct classes of redundant, nonrecursive multibody formulations consistently achieve order N computational cost for systems of rigid and/or flexible bodies. These formulations are as follows: (1) the preconditioned range space formulation; (2) penalty methods; and (3) augmented Lagrangian methods for nonlinear multibody dynamics. The first method can be traced to its foundation in equality constrained quadratic optimization, while the last two methods have been studied extensively in the context of coercive variational boundary value problems in computational mechanics. Until recently, however, they have not been investigated in the context of multibody simulation, and present theoretical questions unique to nonlinear dynamics. All of these nonrecursive methods have additional advantages with respect to recursive order N methods: (1) the formalisms retain the highly desirable order N computational cost; (2) the techniques are amenable to concurrent simulation strategies; (3) the approaches do not depend upon system topology to induce concurrency; and (4) the methods can be derived to balance the computational load automatically on concurrent multiprocessors. In addition to the presentation of the fundamental formulations, this paper presents new theoretical results regarding the rate of convergence of order N constraint stabilization schemes associated with the newly introduced class of methods

Validity of cold irrigation test (CIT) used in tertiary care for diagnosing vestibular dysfunction.

Disorders of balance cause the patient to present in different clinics like ENT, cardiology, neurology and geriatric medicine, and thus different specialities develop different protocols for evaluation and treatment in their own areas of expertise. Thus focused ways of treatment while having some advantages often cause doctors to overlook signs and symptoms other than their own speciality and further causes problems like unnecessary expensive investigations being done. This puts a strain on the patient’s scarce resources in developing countries and also burdens health care systems in developed countries that have to bear the cost of repeated referrals and expensive investigations often with no clear diagnosis. In tertiary care, all patients with giddiness should be screened with the questionnaire and those identified as symptomatics require Bithermal caloric testing to identify the site and side of the lesion before specific treatment is started. The use of cold caloric test as a screening test should be discontinued forthwith

Investigations on microbiome of the used clinical device revealed many uncultivable newer bacterial species associated with persistent chronic infections

Introduction. Chronic persistent device-related infections (DRIs) often give culture-negative results in a microbiological investigation. In such cases, investigations on the device metagenome might have a diagnostic value. Materials and Methods. The 16SrRNA gene sequence analysis and next-generation sequencing (NGS) of clinical metagenome were performed to detect bacterial diversity on invasive medical devices possibly involved in culture-negative DRIs. Device samples were first subjected to microbiological investigation followed by metagenome analysis. Environmental DNA (e-DNA) isolated from device samples was subjected to 16SrRNA gene amplification followed by Sanger sequencing (n=14). In addition, NGS of the device metagenome was also performed (n=12). Five samples were only common in both methods. Results. Microbial growth was observed in only nine cases; among these, five cases were considered significant growth, and in the remaining four cases, growth was considered either insignificant or contaminated. Culture and sequencing analysis yielded identical results only in six cases. In culture-negative cases, Sanger sequencing of 16SrRNA gene and NGS of 16SrDNA microbiome was able to identify the presence of rarely described human pathogens, namely Streptococcus infantis, Gemella haemolysans, Meiothermus silvanus, Schlegelella aquatica, Rothia mucilaginosa, Serratia nematodiphila, and Enterobacter asburiae, along with some known common nosocomial pathogens. Bacterial species such as M. silvanus and S. nematodiphila that are never reported in human infection were also identified. Conclusions. Results of a small number of diverse samples of this pilot study might lead to a path to study a large number of device samples that may validate the diversity witnessed. The study shows that a culture free, a holistic metagenomic approach using NGS could help identify the pathogens in culture-negative chronic DRIs

Impact of HIV Infection on Radiographic Features in Patients with Pulmonary Tuberculosis

Background. There is insufficient data on the radiographic presentation of tuberculosis in human immunodeficiency virus (HIV) infected patients from India. Methods. We examined the chest radiographs of 181 patients including 82 HIV positives with newly diagnosed sputum culture positive pulmonary tuberculosis before and after the completion of anti-tuberculosis treatment (ATT). Patients with smear/culture positive pulmonary tuberculosis were treated with Revised National Tuberculosis Control Programme (RNTCP) Cat-I regimen (2EHRZ3/4HR3). An independent assessor blinded to HIV and clinical status of patients read the radiographs. Results. At presentation, HIV seropositive patients were significantly more likely to have normal chest radiographs (14.2% vs 0), miliary tuberculosis (10.7% vs 1%) and pleural effusion (16.6% vs 3%), and less likely to have cavitation (17.8% vs 39.4%) as compared to HIV negative patients. At the end of treatment, HIV positive patients were more likely to have normal radiographs (42.8% vs 1.2%), and less likely to have fibrosis (17.8% vs 42.5%). Conclusions. The radiographic presentation of pulmonary tuberculosis in HIV-infected patients is atypical with less cavitation, and more dissemination. On completion of ATT, patients with HIV have less radiographic sequelae in the form of fibrosis. These features may be due to the reduced inflammatory response that patients with HIV infection may be able to mount

Does Gender or Religion Contribute to the Risk of COVID-19 in Hospital Doctors?

This webpage details and provides the research study conducted in the United Kingdom through online surveys focusing on the relationship between healthcare workplace prevention efforts, COVID-19 risks, religious identity, and gender. The research study focuses on healthcare workers, primarily hospital doctors and mental health doctors. A PDF of the entire study is available on the webpage

Study of ABCB1 polymorphism (C3435T) in HIV-1-infected individuals from South India

Studies on P-glycoprotein expression and function have revealed that a single nucleotide polymorphism (SNP) in the human ABCB1 gene at 3435 (C > T) results in altered expression and function of P-glycoprotein [1, 2].There have been reports of lower nelfinavir and efavirenz (EFV) concentrations associated with TT genotypes (mutant) of ABCB1 C3435T polymorphism [3, 4].Frequency distribution of this polymorphism is known to vary across populations [3, 5, 6]. We report the genotype distribution of ABCB1 C3435T in 179 individuals (126 HIV-infected and 53 healthy) from South India. The polymorphism was correlated with plasma 12 h EFV and 2 h nevirapine (NVP) concentrations in 55 and 71 patients, respectively. Plasma EFV and NVP were estimated by HPLC [7, 8]. Genotyping was carried out by PCR-RFLP [9]

Author Correction:Transcriptional dysregulation of Interferome in experimental and human Multiple Sclerosis

The original version of this Article contained a typographical error in the spelling of the author Eliana M Coccia, which was incorrectly given as Eliana Coccia. This has now been corrected in the PDF and HTML versions of the Article, and in the accompanying Supplementary Material files

Efficacy and safety of once-daily nevirapine- or efavirenz-based antiretroviral therapy in HIV-associated tuberculosis: a randomized clinical trial

Background: Nevirapine (NVP) can be safely and effectively administered once-daily but has not been assessed in human immunodeficiency virus (HIV)–infected patients with tuberculosis (TB). We studied the safety and efficacy of once-daily NVP, compared with efavirenz (EFV; standard therapy); both drugs were administered in combination with 2 nucleoside reverse-transcriptase inhibitors. Methods: An open-label, noninferiority, randomized controlled clinical trial was conducted at 3 sites in southern India. HIV-infected patients with TB were treated with a standard short-course anti-TB regimen (2EHRZ3/4RH3; [2 months of Ethambutol, Isoniazid, Rifampicin, Pyrazinamide/4 months of Isoniazid and Rifampicin] thrice weekly) and randomized to receive once-daily EFV at a dose of 600 mg or NVP at a dose of 400 mg (after 14 days of 200 mg administered once daily) with didanosine 250/400 mg and lamivudine 300 mg after 2 months. Sputum smears and mycobacterial cultures were performed every month. CD4+ cell count, viral load, and liver function test results were monitored periodically. Primary outcome was a composite of death, virological failure, default, or serious adverse event (SAE) at 24 weeks. Both intent-to-treat and per protocol analyses were done, and planned interim analyses were performed. Results: A total of 116 patients (75% [87 patients] of whom had pulmonary TB), with a mean age of 36 years, a median CD4+ cell count of 84 cells/mm3, and a median viral load of 310?000 copies/mL, were randomized. At 24 weeks, 50 of 59 patients in the EFV group and 37 of 57 patients in the NVP group had virological suppression (P = .024). There were no deaths, 1 SAE, and 5 treatment failures in the EFV arm, compared with 5 deaths, 2 SAEs, and 10 treatment failures in the NVP arm. The trial was halted by the data and safety monitoring board at the second interim analysis. Favorable TB treatment outcomes were observed in 93% of the patients in the EFV arm and 84% of the patients in the NVP arm (P = .058). Conclusions: Compared with a regimen of didanosine, lamivudine, and EFV, a regimen of once-daily didanosine, lamivudine, and NVP was inferior and was associated with more frequent virologic failure and death