Review on the conversion of thermoacoustic power into electricity

Thermoacoustic engines convert heat energy into high amplitude acoustic waves and subsequently into electric power. This article provides a review of the four main methods to convert the (thermo)acoustic power into electricity. First, loudspeakers and linear alternators are discussed in a section on electromagnetic devices. This is followed by sections on piezoelectric transducers, magnetohydrodynamic generators, and bidirectional turbines. Each segment provides a literature review of the given technology for the field of thermoacoustics, focusing on possible configurations, operating characteristics, output performance, and analytical and numerical methods to study the devices. This information is used as an input to discuss the performance and feasibility of each method, and to identify challenges that should be overcome for a more successful implementation in thermoacoustic engines. The work is concluded by a comparison of the four technologies, concentrating on the possible areas of application, the conversion efficiency, maximum electrical power output and more generally the suggested focus for future work in the field.Comment: The following article appeared in J. Acoust. Soc. Am 143(2) and the final version in a proper two-column format may be found at: http://scitation.aip.org/content/asa/journal/jasa/143/2/10.1121/1.502339

Raman spectroscopy-based identification of nosocomial outbreaks of the clonal bacterium Escherichia coli

DNA-based techniques are frequently used to confirm the relatedness of putative outbreak isolates. These techniques often lack the discriminatory power when analyzing closely related microbes such as E. coli. Here the value of Raman spectroscopy as a typing tool for E. coli in a clinical setting was retrospectively evaluated

COSNET-a coherent optical subscriber network

A complete coherent multichannel system, designed for application in the local loop, is presented. The concept of a uni- and bidirectional system and its technical realization in a laboratory demonstrator are described. The network control, including frequency management of the bidirectional channels, and network security are discussed. Attention is paid to the scenario for evolution from a narrowband to a complete broadband system. All aspects are integrated in a demonstrator, which is capable of supporting a large number of narrowband and broadband distributive and communicative services. Novel technical solutions for frequency management, data induced polarization switching (DIPS), high-speed encryption, and network signaling are presented

Cardiometabolic Differences in People Living with HIV Receiving Integrase Strand Transfer Inhibitors Compared to Non-nucleoside Reverse Transcriptase Inhibitors:Implications for Current ART Strategies

In people living with HIV (PLHIV), integrase strand transfer inhibitors (INSTIs) are part of the first-line combination antiretroviral therapy (cART), while non-nucleoside reverse transcriptase inhibitor (NNRTI)-based regimens are alternatives. Distinct cART regimens may variably influence the risk for non-AIDS comorbidities. We aimed to compare the metabolome and lipidome of INSTI and NNRTI-based regimens. The 2000HIV study includes asymptomatic PLHIV (n = 1646) on long-term cART, separated into a discovery cohort with 730 INSTI and 617 NNRTI users, and a validation cohort encompassing 209 INSTI and 90 NNRTI users. Baseline plasma samples from INSTI and NNRTI users were compared using mass spectrometry-based untargeted metabolomic (n = 500) analysis. Perturbed metabolic pathways were identified using MetaboAnalyst software. Subsequently, nuclear magnetic resonance spectroscopy was used for targeted lipoprotein and lipid (n = 141) analysis. Metabolome homogeneity was observed between the different types of INSTI and NNRTI. In contrast, higher and lower levels of 59 and 45 metabolites, respectively, were found in the INSTI group compared to NNRTI users, of which 77.9% (81/104) had consistent directionality in the validation cohort. Annotated metabolites belonged mainly to ‘lipid and lipid-like molecules’, ‘organic acids and derivatives’ and ‘organoheterocyclic compounds’. In pathway analysis, perturbed ‘vitamin B1 (thiamin) metabolism’, ‘de novo fatty acid biosynthesis’, ‘bile acid biosynthesis’ and ‘pentose phosphate pathway’ were detected, among others. Lipoprotein and lipid levels in NNRTIs were heterogeneous and could not be compared as a group. INSTIs compared to individual NNRTI types showed that HDL cholesterol was lower in INSTIs compared to nevirapine but higher in INSTIs compared to doravirine. In addition, LDL size was lower in INSTIs and nevirapine compared to doravirine. NNRTIs show more heterogeneous cardiometabolic effects than INSTIs, which hampers the comparison between these two classes of drugs. Targeted lipoproteomic and lipid NMR spectroscopy showed that INSTI use was associated with a more unfavorable lipid profile compared to nevirapine, which was shifted to a more favorable profile for INSTI when substituting nevirapine for doravirine, with evidently higher fold changes. The cardiovascular disease risk profile seems more favorable in INSTIs compared to NNRTIs in untargeted metabolomic analysis using mass-spectrometry.</p

Perineal wound closure using gluteal turnover flap or primary closure after abdominoperineal resection for rectal cancer: study protocol of a randomised controlled multicentre trial (BIOPEX-2 study)

BACKGROUND: Abdominoperineal resection (APR) for rectal cancer is associated with high morbidity of the perineal wound, and controversy exists about the optimal closure technique. Primary perineal wound closure is still the standard of care in the Netherlands. Biological mesh closure did not improve wound healing in our previous randomised controlled trial (BIOPEX-study). It is suggested, based on meta-analysis of cohort studies, that filling of the perineal defect with well-vascularised tissue improves perineal wound healing. A gluteal turnover flap seems to be a promising method for this purpose, and with the advantage of not having a donor site scar. The aim of this study is to investigate whether a gluteal turnover flap improves the uncomplicated perineal wound healing after APR for rectal cancer. METHODS: Patients with primary or recurrent rectal cancer who are planned for APR will be considered eligible in this multicentre randomised controlled trial. Exclusion criteria are total exenteration, sacral resection above S4/S5, intersphincteric APR, biological mesh closure of the pelvic floor, collagen disorders, and severe systemic diseases. A total of 160 patients will be randomised between gluteal turnover flap (experimental arm) and primary closure (control arm). The total follow-up duration is 12 months, and outcome assessors and patients will be blinded for type of perineal wound closure. The primary outcome is the percentage of uncomplicated perineal wound healing on day 30, defined as a Southampton wound score of less than two. Secondary outcomes include time to perineal wound closure, incidence of perineal hernia, the number, duration and nature of the complications, re-interventions, quality of life and urogenital function. DISCUSSION: The uncomplicated perineal wound healing rate is expected to increase from 65 to 85% by using the gluteal turnover flap. With proven effectiveness, a quick implementation of this relatively simple surgical technique is expected to take place. TRIAL REGISTRATION: The trial was retrospectively registered at Clinicaltrials.gov NCT04004650 on July 2, 2019

An original phylogenetic approach identified mitochondrial haplogroup T1a1 as inversely associated with breast cancer risk in BRCA2 mutation carriers

Introduction: Individuals carrying pathogenic mutations in the BRCA1 and BRCA2 genes have a high lifetime risk of breast cancer. BRCA1 and BRCA2 are involved in DNA double-strand break repair, DNA alterations that can be caused by exposure to reactive oxygen species, a main source of which are mitochondria. Mitochondrial genome variations affect electron transport chain efficiency and reactive oxygen species production. Individuals with different mitochondrial haplogroups differ in their metabolism and sensitivity to oxidative stress. Variability in mitochondrial genetic background can alter reactive oxygen species production, leading to cancer risk. In the present study, we tested the hypothesis that mitochondrial haplogroups modify breast cancer risk in BRCA1/2 mutation carriers. Methods: We genotyped 22,214 (11,421 affected, 10,793 unaffected) mutation carriers belonging to the Consortium of Investigators of Modifiers of BRCA1/2 for 129 mitochondrial polymorphisms using the iCOGS array. Haplogroup inference and association detection were performed using a phylogenetic approach. ALTree was applied to explore the reference mitochondrial evolutionary tree and detect subclades enriched in affected or unaffected individuals. Results: We discovered that subclade T1a1 was depleted in affected BRCA2 mutation carriers compared with the rest of clade T (hazard ratio (HR) = 0.55; 95% confidence interval (CI), 0.34 to 0.88; P = 0.01). Compared with the most frequent haplogroup in the general population (that is, H and T clades), the T1a1 haplogroup has a HR of 0.62 (95% CI, 0.40 to 0.95; P = 0.03). We also identified three potential susceptibility loci, including G13708A/rs28359178, which has demonstrated an inverse association with familial breast cancer risk. Conclusions: This study illustrates how original approaches such as the phylogeny-based method we used can empower classical molecular epidemiological studies aimed at identifying association or risk modification effects.Peer reviewe

Implementing a bidirectional impulse turbine into a thermoacoustic refrigerator

A thermoacoustic model is used to efficiently implement a bidirectional impulse turbine into a thermoacoustic refrigerator. Experiments are done for several gas types and mean pressures to identify its influence on the turbine efficiency. A scaling is investigated in an attempt to provide a unique function of the turbine efficiency for all operating conditions. Furthermore, the ratio of acoustic power absorbed by the turbine over to the total amount of available power is examined for varying conditions. Finally, the results are used to present a case study in which the turbine is used to drive the fluid pumps of the device. The remaining acoustic power is used for cooling, thus providing an off-grid thermoacoustic refrigerator that works purely with low-grade heat as an input

Cardiometabolic Differences in People Living with HIV Receiving Integrase Strand Transfer Inhibitors Compared to Non-nucleoside Reverse Transcriptase Inhibitors:Implications for Current ART Strategies

In people living with HIV (PLHIV), integrase strand transfer inhibitors (INSTIs) are part of the first-line combination antiretroviral therapy (cART), while non-nucleoside reverse transcriptase inhibitor (NNRTI)-based regimens are alternatives. Distinct cART regimens may variably influence the risk for non-AIDS comorbidities. We aimed to compare the metabolome and lipidome of INSTI and NNRTI-based regimens. The 2000HIV study includes asymptomatic PLHIV (n = 1646) on long-term cART, separated into a discovery cohort with 730 INSTI and 617 NNRTI users, and a validation cohort encompassing 209 INSTI and 90 NNRTI users. Baseline plasma samples from INSTI and NNRTI users were compared using mass spectrometry-based untargeted metabolomic (n = 500) analysis. Perturbed metabolic pathways were identified using MetaboAnalyst software. Subsequently, nuclear magnetic resonance spectroscopy was used for targeted lipoprotein and lipid (n = 141) analysis. Metabolome homogeneity was observed between the different types of INSTI and NNRTI. In contrast, higher and lower levels of 59 and 45 metabolites, respectively, were found in the INSTI group compared to NNRTI users, of which 77.9% (81/104) had consistent directionality in the validation cohort. Annotated metabolites belonged mainly to ‘lipid and lipid-like molecules’, ‘organic acids and derivatives’ and ‘organoheterocyclic compounds’. In pathway analysis, perturbed ‘vitamin B1 (thiamin) metabolism’, ‘de novo fatty acid biosynthesis’, ‘bile acid biosynthesis’ and ‘pentose phosphate pathway’ were detected, among others. Lipoprotein and lipid levels in NNRTIs were heterogeneous and could not be compared as a group. INSTIs compared to individual NNRTI types showed that HDL cholesterol was lower in INSTIs compared to nevirapine but higher in INSTIs compared to doravirine. In addition, LDL size was lower in INSTIs and nevirapine compared to doravirine. NNRTIs show more heterogeneous cardiometabolic effects than INSTIs, which hampers the comparison between these two classes of drugs. Targeted lipoproteomic and lipid NMR spectroscopy showed that INSTI use was associated with a more unfavorable lipid profile compared to nevirapine, which was shifted to a more favorable profile for INSTI when substituting nevirapine for doravirine, with evidently higher fold changes. The cardiovascular disease risk profile seems more favorable in INSTIs compared to NNRTIs in untargeted metabolomic analysis using mass-spectrometry.</p

Topographic distribution of first landing sites of lymphatic metastases from patients with renal cancer

Introduction and Objective: Adjuvant studies with checkpoint inhibitors have attracted new interest in accurate pathological lymph node (LN) staging in renal cell carcinoma. Sentinel lymph node (SN) studies in cN0 patients revealed the pattern of lymphatic radiotracer drainage from renal tumors. The aim of this study was to describe the location of single- or oligometastatic LN and analyze if the topography of these first landing sites matches the drainage pattern observed in SN studies of renal tumors. Materials and Methods: We collected data from 8 referral centers from 1990 to 2018 of all patients with pT1-4 cN0 or cN1 M0 renal cell carcinoma with pathologically confirmed single- or oligometastases in locoregional LN. The location of LN metastases, number, size of metastatic LN, and survival were analyzed using descriptive statistics with SPSS version 22 (IBM, Chicago, IL). Results: From 3,794 patients with histologically confirmed pN1, a total of 76 patients (2%) with single- or oligometastatic pN1 were identified, of whom 24 (31.6%) and 52 (68.4%) were cN0 and cN1, respectively. On the left side, LN metastases were predominantly located in the para-aortal (48.0%; 95% confidence interval [CI] 29.22–63.12%) and hilar (31.42%; 95% CI 17.4–49.4%) area. On the right side, metastases located in retrocaval (26.82%; 95% CI 14.7–43.2%), hilar (26.82%; 95% CI 14.7–43.2%), interaortocaval (26.82%; 95% CI 14.7–43.2%), and paracaval (17.07%; 95% CI 7.6–32.6%) LNs. These landing sites exactly matched the lymphatic drainage pattern of intratumorally injected radiotracer reported in SN studies for both sides. Conclusions: Single- or oligometastatic LNs in renal cancer are mainly located in the hilar, retro-, para, and interaortocaval region on the right side and para-aortal region on the left side. These first landing sites match the drainage pattern reported in SN trials