1,921 research outputs found
Optimal design of multi-channel microreactor for uniform residence time distribution
Multi-channel microreactors can be used for various applications that require chemical or electrochemical reactions in either liquid, gaseous or multi phase. For an optimal control of the chemical reactions, one key parameter for the design of such microreactors is the residence time distribution of the fluid, which should be as uniform as possible in the series of microchannels that make up the core of the reactor. Based on simplifying assumptions, an analytical model is proposed for optimizing the design of the collecting and distributing channels which supply the series of rectangular microchannels of the reactor, in the case of liquid flows. The accuracy of this analytical approach is discussed after comparison with CFD simulations and hybrid analytical-CFD calculations that allow an improved refinement of the meshing in the most complex zones of the flow. The analytical model is then extended to the case of microchannels with other cross-sections (trapezoidal or circular segment) and to gaseous flows, in the continuum and slip flow regimes. In the latter case, the model is based on second-order slip flow boundary conditions, and takes into account the compressibility as well as the rarefaction of the gas flow
The impact of predation by marine mammals on Patagonian toothfish longline fisheries
Predatory interaction of marine mammals with longline fisheries is observed globally, leading to partial or complete loss of the catch and in some parts of the world to considerable financial loss. Depredation can also create additional unrecorded fishing mortality of a stock and has the potential to introduce bias to stock assessments. Here we aim to characterise depredation in the Patagonian toothfish (Dissostichus eleginoides) fishery around South Georgia focusing on the spatio-temporal component of these interactions. Antarctic fur seals (Arctocephalus gazella), sperm whales (Physeter macrocephalus), and orcas (Orcinus orca) frequently feed on fish hooked on longlines around South Georgia. A third of longlines encounter sperm whales, but loss of catch due to sperm whales is insignificant when compared to that due to orcas, which interact with only 5% of longlines but can take more than half of the catch in some cases. Orca depredation around South Georgia is spatially limited and focused in areas of putative migration routes, and the impact is compounded as a result of the fishery also concentrating in those areas at those times. Understanding the seasonal behaviour of orcas and the spatial and temporal distribution of “depredation hot spots” can reduce marine mammal interactions, will improve assessment and management of the stock and contribute to increased operational efficiency of the fishery. Such information is valuable in the effort to resolve the human-mammal conflict for resources
Noncommunicable disease and multimorbidity in young adults with cerebral palsy
Purpose: Individuals with cerebral palsy (CP) are at increased risk for frailty and chronic
disease due to factors experienced throughout the lifespan, such as excessive sedentary behaviors
and malnutrition. However, little is known about noncommunicable diseases (NCDs) and
multimorbidity profiles in young adults with CP. The study objective was to compare NCD and
multimorbidity profiles between young adults with and without CP.
Methods: A clinic-based sample of adults (18–30 years) with (n=452) and without (n=448) CP
was examined at the University of Michigan Medical Center. The prevalence and predictors of
13 NCDs were evaluated, including existing diagnoses or historical record of musculoskeletal,
cardiometabolic, and pulmonary morbidities. The level of motor impairment was determined
by the Gross Motor Function Classification System (GMFCS) and stratified by less vs more
severe motor impairment (GMFCS I–III vs IV–V). Logistic regression was used to determine
the odds of NCD morbidity and multimorbidity in adults with CP compared to adults without
CP, and for GMFCS IV–V compared to GMFCS I–III in those with CP, after adjusting for age,
sex, body mass index, and smoking.
Results: Adults with CP had a higher prevalence of osteopenia, osteoporosis, hypertension, myocardial
infarction, hyperlipidemia, asthma, and multimorbidity compared to adults without CP, and
higher odds of musculoskeletal (odds ratio [OR]: 6.97) and cardiometabolic morbidity (OR: 1.98),
and multimorbidity (OR: 2.67). Adults with CP with GMFCS levels IV–V had a higher prevalence
of osteopenia/osteoporosis, osteoarthritis, hypertension, other cardiovascular conditions, pulmonary
embolism, and multimorbidity, and higher odds of musculoskeletal (OR: 3.41), cardiometabolic (OR:
2.05), pulmonary morbidity (OR: 1.42), and multimorbidity (OR: 3.45) compared to GMFCS I–III.
Conclusion: Young adults with CP have a higher prevalence of chronic NCDs and multimorbidity
compared to young adults without CP, which is pronounced in those with more severe
motor impairment. These findings reiterate the importance of early screening for prevention
of NCDs in CPNational Institutes of Health (NIH) and the National Institute on Disability, Independent Living, and Rehabilitation Research (NIDILRR
Unstructured treatment interruption: an important risk factor for arterial stiffness in adult Malawian patients with antiretroviral treatment
OBJECTIVE: The aim of the study was to evaluate the impact of unstructured antiretroviral treatment (ART) interruption on arterial stiffness in adult Malawians who are on ART for at least 35 years.
DESIGN: The number of treatment interruption events for at least 60 days during ART treatment was quantified in patients for at least 35 years using retrospective routinely collected clinic data. Treatment interruption data were linked to patient carotid-femoral pulse wave velocity (PWV); PWV more than 10 m/s was set as the threshold for clinically significant cardiovascular disease risk.
METHODS: PWV was measured in patients (on ART >= 18 months), during routine ART clinic visits in Blantyre, Malawi, between November 2014 and July 2015. Multivariable linear regression was used to estimate the change in PWV m/s associated with treatment interruption. Multivariable logistic regression was used to estimate risk of PWV more than 10 m/s. All models were controlled for demographic and cardiometabolic risk factors.
RESULTS: In 220 patients (median age 45 years, range 37–80 years), 86 (37.4%) patients had at least one treatment interruption event. Median length of treatment interruption events was 75 days (range 31 days to 8 years). Overall, 31 (14%) patients had a PWV more than 10 m/s. In multivariable analysis, we found a 0.2 increase in PWV m/s per treatment interruption event (0.2, 95% confidence interval 0.1–0.4) and a two-fold increased risk of PWV more than 10 m/s per treatment interruption event (adjusted odds ratio 2.2, 95% confidence interval 1.2–4.0).
CONCLUSIONS: Treatment interruption in patients with ART for at least 35 years is a common and important risk factor for arterial stiffness. Therefore, the link between treatment interruption and cardiovascular disease in this setting in which traditional risks factors are less prevalent needs to be explored further
Isolation and analysis of high quality nuclear DNA with reduced organellar DNA for plant genome sequencing and resequencing
<p>Abstract</p> <p>Background</p> <p>High throughput sequencing (HTS) technologies have revolutionized the field of genomics by drastically reducing the cost of sequencing, making it feasible for individual labs to sequence or resequence plant genomes. Obtaining high quality, high molecular weight DNA from plants poses significant challenges due to the high copy number of chloroplast and mitochondrial DNA, as well as high levels of phenolic compounds and polysaccharides. Multiple methods have been used to isolate DNA from plants; the CTAB method is commonly used to isolate total cellular DNA from plants that contain nuclear DNA, as well as chloroplast and mitochondrial DNA. Alternatively, DNA can be isolated from nuclei to minimize chloroplast and mitochondrial DNA contamination.</p> <p>Results</p> <p>We describe optimized protocols for isolation of nuclear DNA from eight different plant species encompassing both monocot and eudicot species. These protocols use nuclei isolation to minimize chloroplast and mitochondrial DNA contamination. We also developed a protocol to determine the number of chloroplast and mitochondrial DNA copies relative to the nuclear DNA using quantitative real time PCR (qPCR). We compared DNA isolated from nuclei to total cellular DNA isolated with the CTAB method. As expected, DNA isolated from nuclei consistently yielded nuclear DNA with fewer chloroplast and mitochondrial DNA copies, as compared to the total cellular DNA prepared with the CTAB method. This protocol will allow for analysis of the quality and quantity of nuclear DNA before starting a plant whole genome sequencing or resequencing experiment.</p> <p>Conclusions</p> <p>Extracting high quality, high molecular weight nuclear DNA in plants has the potential to be a bottleneck in the era of whole genome sequencing and resequencing. The methods that are described here provide a framework for researchers to extract and quantify nuclear DNA in multiple types of plants.</p
Combined autologous chondrocyte implantation (ACI) with supra-condylar femoral varus osteotomy, following lateral growth-plate damage in an adolescent knee: 8-year follow-up
We report the 8-year clinical and radiographic outcome of an adolescent patient with a large osteochondral defect of the lateral femoral condyle, and ipsilateral genu valgum secondary to an epiphyseal injury, managed with autologous chondrocyte implantation (ACI) and supracondylar re-alignment femoral osteotomy. Long-term clinical success was achieved using this method, illustrating the effective use of re-alignment osteotomy in correcting mal-alignment of the knee, protecting the ACI graft site and providing the optimum environment for cartilage repair and regeneration. This is the first report of the combined use of ACI and femoral osteotomy for such a case
Higher-order multipole amplitudes in charmonium radiative transitions
Using 24 million decays in CLEO-c, we have searched
for higher multipole admixtures in electric-dipole-dominated radiative
transitions in charmonia. We find good agreement between our data and
theoretical predictions for magnetic quadrupole (M2) amplitudes in the
transitions and ,
in striking contrast to some previous measurements. Let and
denote the normalized M2 amplitudes in the respective aforementioned decays,
where the superscript refers to the angular momentum of the . By
performing unbinned maximum likelihood fits to full five-parameter angular
distributions, we determine the ratios and , where
the theoretical predictions are independent of the charmed quark magnetic
moment and are and .Comment: 32 pages, 7 figures, acceptance updat
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