Hybrid Pressure Retarded Osmosis–Membrane Distillation System for Power Generation from Low-Grade Heat: Thermodynamic Analysis and Energy Efficiency

We present a novel hybrid membrane system that operates as a heat engine capable of utilizing low-grade thermal energy, which is not readily recoverable with existing technologies. The closed-loop system combines membrane distillation (MD), which generates concentrated and pure water streams by thermal separation, and pressure retarded osmosis (PRO), which converts the energy of mixing to electricity by a hydro-turbine. The PRO-MD system was modeled by coupling the mass and energy flows between the thermal separation (MD) and power generation (PRO) stages for heat source temperatures ranging from 40 to 80 °C and working concentrations of 1.0, 2.0, and 4.0 mol/kg NaCl. The factors controlling the energy efficiency of the heat engine were evaluated for both limited and unlimited mass and heat transfer kinetics in the thermal separation stage. In both cases, the relative flow rate between the MD permeate (distillate) and feed streams is identified as an important operation parameter. There is an optimal relative flow rate that maximizes the overall energy efficiency of the PRO-MD system for given working temperatures and concentration. In the case of unlimited mass and heat transfer kinetics, the energy efficiency of the system can be analytically determined based on thermodynamics. Our assessment indicates that the hybrid PRO-MD system can theoretically achieve an energy efficiency of 9.8% (81.6% of the Carnot efficiency) with hot and cold working temperatures of 60 and 20 °C, respectively, and a working solution of 1.0 M NaCl. When mass and heat transfer kinetics are limited, conditions that more closely represent actual operations, the practical energy efficiency will be lower than the theoretically achievable efficiency. In such practical operations, utilizing a higher working concentration will yield greater energy efficiency. Overall, our study demonstrates the theoretical viability of the PRO-MD system and identifies the key factors for performance optimization

Parametric Amplification of Nonlinear Response of Single Crystal Niobium

Giant enhancement of the nonlinear response of a single crystal Nb sample, placed in {\it a pumping ac magnetic field}, has been observed experimentally. The experimentally observed amplitude of the output signal is about three orders of magnitude higher than that seen without parametric pumping. The theoretical analysis based on the extended double well potential model provides a qualitative explanation of the experimental results as well as new predictions of two bifurcations for specific values of the pumping signal.Comment: 6 pages, 10 figure

COVID-19 Post-vaccination depression in older Israeli adults : the role of negative world assumptions

BACKGROUND: With the outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, the aging population has been shown to be highly vulnerable. As a result, policy makers and the media urged older adults to restrict social interactions, placing them at greater risk of mental health problems, such as depression. However, there has been a little previous attempt to examine coronavirus disease-2019 (COVID-19) vaccine-related risk factors and depressive symptoms amongst older adults. METHODS: Participants (938 older adults, Mage = 68.99, s.d. = 3.41, range 65–85) answered an online questionnaire at the start of the COVID-19 vaccination program in Israel. Participants completed measures of background characteristics, world assumptions, COVID-19 vaccine-related variables, and symptoms of depression. RESULTS: Univariate logistic regression revealed that more negative world assumptions were linked with clinical depression levels. CONCLUSIONS: Older adults in our sample were susceptible to unique factors associated with clinical depression influenced by their world assumptions during their COVID-19 vaccination. The high level of depression following vaccination indicates that it may take time to recover from depression associated with pandemic distress. Cognitive interventions that focus on world assumptions are recommended

Right ventricular outflow tract velocity time integral-to-pulmonary artery systolic pressure ratio: a non-invasive metric of pulmonary arterial compliance differs across the spectrum of pulmonary hypertension.

Pulmonary arterial compliance (PAC), invasively assessed by the ratio of stroke volume to pulmonary arterial (PA) pulse pressure, is a sensitive marker of right ventricular (RV)-PA coupling that differs across the spectrum of pulmonary hypertension (PH) and is predictive of outcomes. We assessed whether the echocardiographically derived ratio of RV outflow tract velocity time integral to PA systolic pressure (RVOT-VTI/PASP) (a) correlates with invasive PAC, (b) discriminates heart failure with preserved ejection-associated PH (HFpEF-PH) from pulmonary arterial hypertension (PAH), and (c) is associated with functional capacity. We performed a retrospective cohort study of patients with PAH (n = 70) and HFpEF-PH (n = 86), which was further dichotomized by diastolic pressure gradient (DPG) into isolated post-capillary PH (DPG \u3c 7 mmHg; Ipc-PH, n = 54), and combined post- and pre-capillary PH (DPG ≥ 7 mm Hg; Cpc-PH, n = 32). Of the 156 patients, 146 had measurable RVOT-VTI or PASP and were included in further analysis. RVOT-VTI/PASP correlated with invasive PAC overall (ρ = 0.61, P \u3c 0.001) and for the PAH (ρ = 0.38, P = 0.002) and HFpEF-PH (ρ = 0.63, P \u3c 0.001) groups individually. RVOT-VTI/PASP differed significantly across the PH spectrum (PAH: 0.13 [0.010-0.25] vs. Cpc-PH: 0.20 [0.12-0.25] vs. Ipc-PH: 0.35 [0.22-0.44]; P \u3c 0.001), distinguished HFpEF-PH from PAH (AUC = 0.72, 95% CI = 0.63-0.81) and Cpc-PH from Ipc-PH (AUC = 0.78, 95% CI = 0.68-0.88), and remained independently predictive of 6-min walk distance after multivariate analysis (standardized β-coefficient = 27.7, 95% CI = 9.2-46.3; P = 0.004). Echocardiographic RVOT-VTI/PASP is a novel non-invasive metric of PAC that differs across the spectrum of PH. It distinguishes the degree of pre-capillary disease within HFpEF-PH and is predictive of functional capacity

Evaluating amplified rDNA restriction analysis assay for identification of bacterial communities

Amplified ribosomal DNA restriction analysis (ARDRA) and restriction fragment length polymorphism were originally used for strain typing and for screening clone libraries to identify phylogenetic clusters within a microbial community. Here we used ARDRA as a model to examine the capacity of restriction-based techniques for clone identification, and the possibility of deriving phylogenetic information from ARDRA-based dendrograms. ARDRA was performed in silico on 48,759 sequences from the Ribosomal Database Project, and it was found that the fragmentation profiles were not necessarily unique for each sequence in the database, resulting in different species sharing fragmentation profiles. Although ARDRA-based clusters separated clones into different genera, these phylogenetic clusters did not overlap with trees constructed according to sequence alignment, calling into question the intra-genus ARDRA-based phylogeny. It is thus suggested that the prediction power of ARDRA clusters in identifying clone phylogeny be regarded with caution

Influence of Natural Organic Matter Fouling and Osmotic Backwash on Pressure Retarded Osmosis Energy Production from Natural Salinity Gradients

Pressure retarded osmosis (PRO) has the potential to produce clean, renewable energy from natural salinity gradients. However, membrane fouling can lead to diminished water flux productivity, thus reducing the extractable energy. This study investigates organic fouling and osmotic backwash cleaning in PRO and the resulting impact on projected power generation. Fabricated thin-film composite membranes were fouled with model river water containing natural organic matter. The water permeation carried foulants from the feed river water into the membrane porous support layer and caused severe water flux decline of ∼46%. Analysis of the water flux behavior revealed three phases in membrane support layer fouling. Initial foulants of the first fouling phase quickly adsorbed at the active-support layer interface and caused a significantly greater increase in hydraulic resistance than the subsequent second and third phase foulants. The water permeability of the fouled membranes was lowered by ∼39%, causing ∼26% decrease in projected power density. A brief, chemical-free osmotic backwash was demonstrated to be effective in removing foulants from the porous support layer, achieving ∼44% recovery in projected power density. The substantial performance recovery after cleaning was attributed to the partial restoration of the membrane water permeability. This study shows that membrane fouling detrimentally impacts energy production, and highlights the potential strategies to mitigate fouling in PRO power generation with natural salinity gradients

International Veterinary Epilepsy Task Force Consensus Proposal: Outcome of therapeutic interventions in canine and feline epilepsy

Common criteria for the diagnosis of drug resistance and the assessment of outcome are needed urgently as a prerequisite for standardized evaluation and reporting of individual therapeutic responses in canine epilepsy. Thus, we provide a proposal for the definition of drug resistance and partial therapeutic success in canine patients with epilepsy. This consensus statement also suggests a list of factors and aspects of outcome, which should be considered in addition to the impact on seizures. Moreover, these expert recommendations discuss criteria which determine the validity and informative value of a therapeutic trial in an individual patient and also suggest the application of individual outcome criteria. Agreement on common guidelines does not only render a basis for future optimization of individual patient management, but is also a presupposition for the design and implementation of clinical studies with highly standardized inclusion and exclusion criteria. Respective standardization will improve the comparability of findings from different studies and renders an improved basis for multicenter studies. Therefore, this proposal provides an in-depth discussion of the implications of outcome criteria for clinical studies. In particular ethical aspects and the different options for study design and application of individual patient-centered outcome criteria are considered

Evaluation of arterial anatomy in congenital clubfoot with color doppler ultrasound

OBJECTIVE: This investigation intended to evaluate anterior and posterior tibial arteries at the ankle joint level in congenital clubfoot, by using color Doppler ultrasound (CDU). MATERIAL AND METHOD: Twenty patients with idiopathic clubfoot were selected, from which 18 had unilateral involvement and two had bilateral involvement. Of the 18 patients with unilateral clubfoot, 16 went through surgical treatment and the other two were submitted to conservative treatment with serial casting. Of the bilateral cases, one patient was treated surgically and the other was treated with serial casting. All patients were clinically and radiographically assessed. We used the functional rating as described by Lehman. Then, CDU was applied bilaterally at the ankle joint level, trying to identify both posterior and anterior tibial arteries. RESULTS: In our present series of 20 cases with idiopathic clubfoot, in just one patient we could not identify the anterior tibial artery at the ankle joint level. In 12 patients who have had their arterial flow speeds and diameters measured by UDC, a positive correlation was found between functional level and anterior tibial artery diameter. No statistically significant differences were found between both flow speed and diameter of anterior tibial artery of the normal side, when compared to the affected side (in patients with unilateral disease). CONCLUSION: In our sample, we could not find any significant differences in arterial morphology and flow speed between the normal and the affected side. Furthermore, we noticed that the better the clinical result of clubfoot correction, the larger the diameter of anterior tibial artery in affected feet.OBJETIVO: Avaliação ultrassonográfica das artérias tibial anterior e posterior no pé torto congênito (PTC). MATERIAL E MÉTODO: Foram incluídos 20 pacientes portadores de PTC idiopático compreendendo 18 casos unilaterais e dois bilaterais, sendo que 17 pacientes foram submetidos a tratamento cirúrgico e três a tratamento conservador. Todos os pacientes apresentavam pés plantígrados e foram submetidos à avaliação clínica e radiográfica, seguido pelo exame de ultrassom Doppler colorido (UDC), visando a identificação das artérias tibiais anterior e posterior na altura do tornozelo. O nível funcional foi classificado pelos critérios de Lehman. RESULTADOS: Nesta série de 20 pacientes, somente em um não foi identificada a artéria tibial anterior. Nos 12 pacientes submetidos à mensuração de fluxo e calibre pelo UDC, foi encontrada uma correlação positiva entre o grau funcional do PTC e o calibre da artéria tibial anterior. Não houve redução estatisticamente significante entre o fluxo e calibre da artéria tibial anterior do lado normal em comparação com o lado alterado (nos casos de doença unilateral). CONCLUSÕES: Não houve alteração significativa da morfologia e fluxo arterial quando comparamos os lados afetado e normal. Além disso, quanto melhor o resultado clínico da correção do PTC, maior foi o calibre da artéria tibial anterior.UNIFESP Departamento de Ortopedia e TraumatologiaUNIFESP, Depto. de Ortopedia e TraumatologiaSciEL