bluuebunny/crossref_metadata_2025 huggingface dataset:
Migrating Semidiurnal Tide During the September Equinox Transition in the Northern Hemisphere
Authors: Pedatella N. M. , Liu H.‐L. , Conte J. F. , Chau J. L. , Hall C. , Jacobi C. , Mitchell N. , Tsutsumi M.
Published: December 2020

Specified Dynamics Whole Atmosphere Community Climate Model with thermosphere‐ionosphere eXtension simulations are used to investigate the solar migrating semidiurnal tide (SW2) around September equinox at middle to high latitudes in the Northern Hemisphere. A pronounced minimum in SW2 occurs around September equinox, and is characterized by a ∼50% reduction in tidal amplitudes for 20–30 days. Analysis of the simulation results indicates that the SW2 minimum occurs due to the seasonal transition of the zonal mean zonal winds, which alter the generation and propagation of different symmetric and antisymmetric modes of SW2. In particular, the antisymmetric modes notably decrease due to the more hemispherically symmetric zonal winds around equinox. It is further demonstrated that interannual variability in the timing of the SW2 minimum is related to the timing of the seasonal transition of the zonal mean zonal winds in the middle atmosphere. This leads to an earlier occurrence of the SW2 minimum during years when the seasonal transition occurs earlier, such as the recent 2019 September equinox which saw an earlier transition of the Southern Hemisphere zonal mean zonal winds following the occurrence of a sudden stratosphere warming. The connection between the timing of the SW2 minimum in the Northern Hemisphere and the timing of the seasonal transition in the middle atmosphere winds is confirmed by seasonal variability of 12‐h tides deduced from specular meteor radar observations at middle to high latitudes in the Northern Hemisphere.
Carbon Dioxide Fluxes of a Young Deciduous Afforestation Under the Influence of Seasonal Precipitation Patterns and Frequent Typhoon Occurrence
Authors: Maneke‐Fiegenbaum Falk , Santos Simone Heupel , Klemm Otto , Yu Jui‐Chu , Chiang Po‐Neng , Lai Yen‐Jen
Published: December 2020

Afforestation is considered a major tool for climate change mitigation with high potential particularly in the tropics. In this study we analyzed CO2 fluxes of an afforested former sugar cane plantation in southern Taiwan, as this forest had been planted with the goal of sequestering CO2 to help mitigate climate change. The plantation is exposed to a monsoon climate with dry but warm winter seasons, heavy precipitation during the summers and experiences a rather high frequency of typhoons (0.7 per year). The aim of this study is to quantify the net ecosystem exchange (NEE), ecosystem respiration (ER), gross primary production (GPP) and increment in above‐ground biomass (AGB) at the site. Specifically, we aim to analyze the influence of the distinct wet and dry seasonality and the frequent typhoon impact on these fluxes. We estimated the CO2 fluxes for two years using the eddy covariance approach. In 2010 and 2016 the forest sequestered carbon from the atmosphere with a NEE of −116 g C m−2 year−1 and −322 g C m−2 year−1, respectively. Between 2011 and 2014, the yearly increment in AGB increased with a mean increment of 509 ± 181 (SD) g C m−2 year−1. We observed high seasonal difference in CO2 fluxes particularly in ER and GPP, and conclude that high winter precipitation enhances CO2 uptake. Furthermore, frequent typhoons reduced the CO2 uptake and increment in AGB, such as in 2016, when a very strong typhoon passed the forest.
ProLB: A Lattice Boltzmann Solver of Large‐Eddy Simulation for Atmospheric Boundary Layer Flows
Authors: Feng Yongliang , Miranda‐Fuentes Johann , Guo Shaolong , Jacob Jérôme , Sagaut Pierre
Published: December 2020

A large‐eddy simulation tool is developed for simulating the dynamics of atmospheric boundary layers (ABLs) using lattice Boltzmann method (LBM), which is an alternative approach for computational fluid dynamics and proved to be very well suited for the simulation of low‐Mach flows. The equations of motion are coupled with the global complex physical models considering the coupling among several mechanisms, namely basic hydro‐thermodynamics and body forces related to stratification, Coriolis force, canopy effects, humidity transport, and condensation. Mass and momentum equations are recovered by an efficient streaming, collision, and forcing process within the framework of LBM while the governing equations of temperature, liquid, and vapor water fraction are solved using a finite volume method. The implementation of wall models for ABL, subgrid models, and interaction terms related to multiphysic phenomena (e.g., stratification, condensation) is described, implemented, and assessed in this study. An immersed boundary approach is used to handle flows in complex configurations, with application to flows in realistic urban areas. Applications to both wind engineering and atmospheric pollutant dispersion are illustrated.
Cold Pool Dynamics Shape the Response of Extreme Rainfall Events to Climate Change
Authors: Lochbihler Kai , Lenderink Geert , Siebesma A. Pier
Published: December 2020

There is increasing evidence that local rainfall extremes can increase with warming at a higher rate than expected from the Clausius‐Clapeyron (CC) relation. The exact mechanisms behind this super‐CC scaling phenomenon are still unsolved. Recent studies highlight invigorated local dynamics as a contributor to enhanced precipitation rates with warming. Here, cold pools play an important role in the process of organization and deepening of convective clouds. Another known effect of cold pools is the amplification of low‐level moisture variability. Yet, how these processes respond to climatic warming and how they relate to enhanced precipitation rates remains largely unanswered. Unlike other studies which use rather simple approaches mimicking climate change, we present a much more comprehensive set of experiments using a high‐resolution large eddy simulation (LES) model. We use an idealized but realistically forced case setup, representative for conditions with extreme summer precipitation in midlatitudes. Based on that, we examine how a warmer atmosphere under the assumption of constant and varying relative humidity, lapse rate changes and enhanced large‐scale dynamics influence precipitation rates, cold pool dynamics, and the low‐level moisture field. Warmer conditions generally lead to larger and more intense events, accompanied by enhanced cold pool dynamics and a concurring moisture accumulation in confined regions. The latter are known as preferred locations for new convective events. Our results show that cold pool dynamics play an increasingly important role in shaping the response of local precipitation extremes to global warming, providing a potential mechanism for super‐CC behavior as subject for future research.
Coupling metal organic frameworks with molybdenum disulfide nanoflakes for targeted cancer theranostics
Authors: Yang Shuguang , Li Dejian , Chen Liang , Zhou Xiaojun , Fu Liwen , You Yanling , You Zhengwei , Kang Li , Li Maoquan , He Chuanglong
Published: December 2020

The construction of a multifunctional nanoplatform for the targeted delivery of antitumor drugs and photothermal therapy/chemotherapy of cancer.
Fast multipoint immobilization of lipase through chirall-proline on a MOF as a chiral bioreactor
Authors: Lirio Stephen , Shih Yung-Han , So Pamela Berilyn , Liu Li-Hao , Yen Yun-Ting , Furukawa Shuhei , Liu Wan-Ling , Huang Hsi-Ya , Lin Chia-Her
Published: December 2020

Successful co-immobilization of Pro and PPL on microporous MOF-1,4-NDC(Al) (PPL-Pro@MOF-1,4-NDC(Al)) has been demonstrated.
Metal–organic framework derived metal oxide/reduced graphene oxide nanocomposite, a new tool for the determination of dipyridamole
Authors: Salandari-Jolge Naeime , Ensafi Ali A. , Rezaei Behzad
Published: December 2020

NICo2O4/NIO@MOF-5 rGO can detect dipyridamole at trace levels with high selectivity and sensitivity.
Holistic quality evaluation of compound liquorice tablets using capillary electrophoresis fingerprinting combined with chemometric methods
Authors: Gong Dandan , Zheng Zijia , Chen Jinyu , Pang Ying , Sun Guoxiang
Published: December 2020

Integrated quality control of herbal medicine using eco-friendly capillary zone electrophoresis and equal weight ratio quantitative fingerprint method.
Mechanics of free-standing inorganic and molecular 2D materials
Authors: Zhang Xianghui , Beyer André
Published: December 2020

This review summarizes recent progress in the mechanical characterization of two-dimensional materials, as exemplified by an AFM-based analysis of 1 nm thick carbon nanomembranes (helium ion microscope image scale bar: 50 μm).
A high-energy-density supercapacitor with multi-shelled nickel–manganese selenide hollow spheres as cathode and double-shell nickel–iron selenide hollow spheres as anode electrodes
Authors: Mohammadi Zardkhoshoui Akbar , Ameri Bahareh , Hosseiny Davarani Saied Saeed
Published: December 2020

An effective approach is developed to construct multi-shelled nickel–manganese selenide hollow sphere and double-shell nickel–iron selenide hollow sphere electrode materials for supercapacitors.
Chemoselective Cu-catalyzed synthesis of diverse N-arylindole carboxamides, β-oxo amides and N-arylindole-3-carbonitriles using diaryliodonium salts
Authors: Kumar Mehra Manish , Malik Monika , Kumar Bintu , Kumar Dalip
Published: December 2020

Simple, efficient and chemoselective copper-catalyzed C–N bond formation strategies have been developed to achieve N-arylindole carboxamides, β-oxo amides and N-arylindole-3-carbonitriles in high yields.
Rh(iii)-Catalyzed sulfonylamination of α-indolyl alcohols via Csp2–Csp3 bond cleavage
Authors: Hu Xinwei , Tan Zheng , Liu Zhipeng , Chen Fengjuan , Jiang Huanfeng , Zeng Wei
Published: December 2020

A Rh(iii)-catalyzed beta-carbon amination of α-aryl alcohols with sulfonyl azides has been developed. This transformation features unstrained Csp2–Csp3 σ bond amination via C–C bond cleavage, and provides a direct approach to complex 2-aminoindoles.
Catalytic enantioselective synthesis of macrodiolides and their application in chiral recognition
Authors: Xiao Wanlong , Mo Yuhao , Guo Jing , Su Zhishan , Dong Shunxi , Feng Xiaoming
Published: December 2020

An asymmetric tandem Friedel–Crafts alkylation/intermolecular macrolactonization ofortho-quinone methides with C3-substituted indoles was achieved by using a chiralN,N′-dioxide-scandium(iii) complex.
Ruthenium catalyzed β-selective alkylation of vinylpyridines with aldehydes/ketonesviaN2H4mediated deoxygenative couplings
Authors: Lv Leiyang , Li Chao-Jun
Published: December 2020

Ruthenium-catalyzed β-selective alkylation of vinylpyridines with carbonyls (both aromatic and aliphatic ketones/aldehydes)viaN2H4mediated deoxygenative couplings was achieved.
Expecting Questions Modulates Cognitive Effort in a Syntactic Processing Task: Evidence From Pupillometry
Authors: Chapman Laura Roche , Hallowell Brooke
Published: December 2020

Purpose

Pupillary responses captured via pupillometry (measurement of pupillary dilation and constriction during the performance of a cognitive task) are psychophysiological indicators of cognitive effort, attention, arousal, and resource engagement. Pupillometry may be a promising tool for enhancing our understanding of the relationship between cognition and language in people with and without aphasia. Interpretation of pupillary responses is complex. This study was designed as a stepping-stone for future pupillometric studies involving people with aphasia. Asking comprehension questions is common in language processing research involving people with and without aphasia. However, the influence of comprehension questions on pupillometric indices of task engagement (tonic responses) and cognitive effort (task-evoked responses of the pupil [TERPs]) is unknown. We tested whether asking comprehension questions influenced pupillometric results of adults without aphasia during a syntactic processing task.

Method

Forty adults without aphasia listened to easy (canonical) and difficult (noncanonical) sentences in two conditions: one that contained an explicit comprehension task (question condition) and one that did not (no-question condition). The influence of condition and canonicity on pupillary responses was examined.

Results

The influence of canonicity was only significant in the question condition: TERPs for difficult sentences were larger than TERPs for easy sentences. Tonic responses did not differ between conditions.

Conclusions

Although participants had similar levels of attentiveness in both conditions, increases in indices of cognitive effort during syntactic processing were significant only when participants expected comprehension questions. Results contribute to a body of evidence indicating the importance of task design and careful linguistic stimulus control when using pupillometry to study language processing.

Supplemental Material

https://doi.org/10.23641/asha.13480368
Listening to a Dysphonic Speaker in Noise May Impede Children's Spoken Language Processing in a Realistic Classroom Setting
Authors: Schiller Isabel S. , Morsomme Dominique , Kob Malte , Remacle Angélique
Published: December 2020

Purpose

The aim of this study was to investigate children's processing of dysphonic speech in a realistic classroom setting, under the influence of added classroom noise.

Method

Typically developing 6-year-old primary school children performed two listening tasks in their regular classrooms: a phoneme discrimination task to assess speech perception and a sentence–picture matching task to assess listening comprehension. Speech stimuli were played back in either a typical or an impaired voice quality. Children performed the tasks in the presence of induced classroom noise at signal-to-noise ratios between +2 and +9 dB.

Results

Children's performance in the phoneme discrimination task decreased significantly when the speaker's voice was impaired. The effect of voice quality on sentence–picture matching depended on task demands: Easy sentences were processed more accurately in the impaired-voice condition than in the typical-voice condition. Signal-to-noise ratio effects are discussed in light of methodological constraints.

Conclusions

Listening to a dysphonic teacher in a noisy classroom may impede children's perception of speech, particularly when phonological discrimination is needed to disambiguate the speech input. Future research regarding the interaction of voice quality and task demands is necessary.
Hybrid grey wolf sunflower optimisation algorithm for energy‐efficient cluster head selection in wireless sensor networks for lifetime enhancement
Authors: Nagarajan Lavanya , Thangavelu Shankar
Published: December 2020

Wireless sensor networks (WSNs) are expected to find extensive applicability and accelerating deployment in the future. However, the main challenge faced in WSN is its perishing lifetime. The process of clustering a network is a popular mechanism employed for the purpose of extending the lifespan of WSNs and thereby making efficient data transmission. The main aim of a clustering algorithm is to elect an optimal cluster head (CH). The recent research trend suggests meta‐heuristic algorithms for the selection of optimal CHs. Meta‐heuristic algorithms possess the advantages of being simple, flexible, derivation‐free, and avoids local optima. This research proposes a novel hybrid grey wolf optimiser‐based sunflower optimisation (HGWSFO) algorithm for optimal CH selection (CHS) under certain factor constraints such as energy spent and separation distance, such that the network lifetime is enhanced. Sunflower optimisation (SFO) is employed for a broader search (exploration) where the variation of the step‐size parameter brings the plant closer to the sun in search of global refinement, thus increasing the exploration efficiency. Grey wolf optimisation (GWO) is employed for a narrow search (exploitation), where the parameter coefficient vectors are deliberately required to emphasise exploitation. This balances the exploration‐exploitation trade‐off, prolongs the network lifetime, increases the energy efficiency, and enhances the performance of the network with respect to overall throughput, residual energy of nodes, dead nodes, alive nodes, network survivability index, and convergence rate. The superior characteristic of the suggested HGWSFO is validated by comparing its performance with various other existing CHS algorithms. The overall performance of the proposed HGWSFO is 28.58%, 31.53%, 48.8%, 49.67%, 54.95%, 70.76%, and 87.10%, better than that of GWO, SFO, particle swarm optimisation (PSO), improved PSO, low‐energy adaptive clustering hierarchy (LEACH), LEACH‐centralised, and direct transmission, respectively.
Finite‐time dissipative control for time‐delay Markov jump systems with conic‐type non‐linearities under guaranteed cost controller and quantiser
Authors: Zhang Xiang , Yin Yanyan , Wang Hai , He Shuping
Published: December 2020

For a class of conic‐type non‐linear time‐delay Markov jump systems, the asynchronous dissipative output feedback controller based on the guaranteed cost control and quantiser is designed in this study. In real applications, the system and the controller modes are always non‐synchronous, so we introduce the hidden Markov model to solve this problem. Furthermore, we define three novel auxiliary variables and use quantisers to accomplish the output feedback controller design. Then, the finite‐time boundedness and strict dissipativity of the closed‐loop systems are guaranteed by sufficient conditions, and the controller also meets the guaranteed cost‐control performance. By solving a set of linear matrix inequalities, we get the controller gains, the guaranteed cost control performance index J*, and the dissipative performance index α. Finally, the correctness and feasibility of this designed approach are demonstrated by a given example.
Pomegranate‐like high density LTO anode material for lithium‐ion batteries
Authors: Zhang Yawen , Bai Yilu , Ye Lanlan , Li Ting , Chen Rui , Jin Hong , Xia Hongyan , Xu Hui
Published: December 2020

In order to improve the rate performance and reduce the cost lithium ion anode, the Li4Ti5O12@TiO2 (LTO‐TO) was prepared by a facile hydrothermal reaction method with a micro‐scale TiO2 as the precursor. The morphologies and microstructures of the pomegranate‐like LTO‐TO were examined by scanning electron microscopy and transition electron microscopy. The results demonstrate that the nano‐LTO particles are located on the surface of the micro TiO2. The electrochemical properties of the LTO‐TO composites were characterized by galvanostatic charge/discharge. The as‐prepared composites present a high capacity of 157.3 mAh g−1 at 0.5 C. Even at a high current density of 10 C, it can still maintain a high capacity of 105.4 mAh g−1 and remains 92.8% (95 mA g−1) after 450 cycles. These results indicate that the as‐prepared LTO nano/micro‐sphere may be a potential anode material for lithium‐ion batteries.
Preparation of carbon dots with orange emission for Cr(Ш) detection and cellular imaging
Authors: Si Junying , Wang Hong , Wu Baoshuang , Wang Guangshuo , Yang Jiajia , Huo Zhongchao , Tian Tian , Zhao Xuelin , Han Shuai
Published: December 2020

A new type of orange emission carbon dots (OCDs) was prepared by hydrothermal method using 1,2,4‐triaminobenzene and p‐aminobenzenesulphonic acid as precursors. TEM characterization showed that the new OCDs were uniform in size with an average particle size of 4–7 nm. Infrared spectroscopy and XPS analysis showed that the surface of the OCDs were rich in hydrophilic functional groups. Fluorescence spectroscopy results showed that the obtained OCDs exhibited excellent fluorescence with an absolute quantum yield as high as 14.9%. The OCDs were further applied to the detection of metal ions. It was found that the fluorescence of OCDs could be effectively quenched by Cr(Ш) with a detection limit of 0.38 μm. Notably, the obtained OCDs have been successfully used for fluorescence detection of Cr3+ ions in cell level.
Surfactant‐free and controllable synthesis of hierarchically lithiated MoO3 microspheres
Authors: Shi Jiayuan , Zhang Hongmei , Chen Xiaotao , Shi Bin
Published: December 2020

The hierarchically lithiated MoO3 microspheres composed of primary crystallized particles have been prepared in the absence of surfactant. The surface morphologies of the lithiated MoO3 structures can be well regulated through adjusting the adding amounts of ethanol during their synthetic process. The results of XRD patterns and the elemental analysis indicated the decrease of lithium content with the increase of ethanol feeding amount. The obtained lithiated MoO3 samples showed the initial capacities of nearly 300 mAh/g at 30 mA/g and 41.8 mAh/g at 200 mA/g. Therefore, this work has showed a facile way to fabricate the lithiated MoO3 cathode materials with controllable surface morphology and lithium content.
Flavonolignans‐routed synthesis of selenium nanowires (SeNWs) and their cytotoxicity, cell migration potential against triple negative breast cancer cells
Authors: Kavithaa Krishnamoorthy , Paulpandi Manickam , Vadivalagan Chithravel , Asaikkutti Annamalai , Sumathi Sundaravadivelu
Published: December 2020

Recent evidences have demonstrated that bio‐macromolecule assisted nanomaterials syntheses have been widely used for cancer treatment. The aim of this study was to investigate the effects and cellular mechanisms of silymarin‐routed synthesis of selenium nanowires (SeNWs) on cytotoxic and cell migration inhibitory potential against triple negative breast cancer (MDA‐MB‐231) cells. Characterizations of SeNWs were detected by XRD, scanning electron microscopy, and Raman spectrum. Cell proliferation and migration of MDA‐MB‐231 cells were evaluated by MTT and wound assays respectively. The study revealed that SeNWs significantly suppressed the cell viability and cell migration potential compared with the control group. Moreover, SeNWs significantly induce the apoptotic induction in triple negative breast cancer cells. Overall, the current findings highlight the potential cancer therapeutic applications of SeNWs in in vitro condition.
Integrated boost‐forward‐flyback converter with high step‐up for green energy power‐conversion applications
Authors: Tseng Kuo‐Ching , Huang Hao‐Shiang , Cheng Chun‐An
Published: December 2020

An isolated high step‐up converter is proposed for renewable energy sources with low voltages, such as photovoltaic (PV) cells of solar energy and fuel cells of hydrogen energy, to achieve high voltage levels for series‐connection batteries and DC‐bus voltage sources. The proposed integrated boost‐forward‐flyback converter (IBFFC) is achieved by integrating a boost converter, a forward‐flyback converter and a voltage doubler. Moreover, an active‐clamp function is employed to recycle the energy of leakage inductance. An 800 W‐rated prototype has been implemented to verify the functionality of the presented converter; it offers an input voltage of 48 V and an output voltage of 400 V. In addition, the maximum efficiency is approximately 94%.
Cross interference suppression methodology by printed circuit board type metamaterial in multi‐frequency multi‐load magnetically coupled resonant wireless power transfer system
Authors: Liu Fuxin , Ding Ze
Published: December 2020

The prosperity of market in multi‐charging devices has made the researches on multi‐load magnetically coupled resonant (MCR) wireless power transfer (WPT) technique be an urgent issue nowadays. For the sake of load recognition and controllable power distribution, the concept of multi‐frequency excitation was introduced into multi‐load MCR WPT systems. However, the transferred power components at different frequencies inevitably suffer the cross interference at receivers, which negatively affects the accuracy of load recognition and power distribution. To suppress the cross interference, a methodology by using the metamaterial composed of a printed circuit board (PCB) spiral inductor and a lumped capacitor was proposed. The concept of equivalent mutual inductance (Meq) was presented to quantitatively describe the influence of metamaterials on the couplings between the transmitting (Tx) and receiving (Rx) coils. By magnetic field simulation, a series of Meq curves versus operating frequency under different metamaterial parameters were plotted and an optimal design was adopted to suppress the power components at non‐targeted frequencies. Moreover, a detailed circuit model was built to characterize the output power of multiple loads after introducing the metamaterial. Finally, the experiments from a prototype was carried out and the experimental results verified the effectiveness of proposed suppression methodology.
Thermal analysis of non‐isolated conventional PWM‐based DC–DC converters with reliability consideration
Authors: Tarzamni Hadi , Esmaeelnia Farhad Panahandeh , Tahami Farzad , Fotuhi‐Firuzabad Mahmud , Tohidi Sajjad , Dehghanian Payman , Lehtonen Matti
Published: December 2020

This paper proposes analytics for reliability assessment of non‐isolated conventional pulse width modulation DC‐DC (NIDC‐DC) converters. This class of converters consists of conventional Buck, Boost, Buck–Boost, Cuk, Sepic and Zeta topologies. The proposed analytics are founded based on the Markov process principles and can effectively capture the effects of duty cycle, input voltage, output power, voltage gain, components characteristics and aging on the overall reliability performance and mean time to failure of the NIDC‐DC converters. Furthermore, the suggested framework takes both continuous and discontinuous conduction modes of each converter into account, with which the open and short circuit faults in the components are analysed. As an important outcome, the most reliable operation region of the NIDC‐DC converters are obtained with respect to different operational parameters, which is useful in design procedure. Eventually, extensive thermal experiments with an appropriate reflection of reliability metric are conducted to measure the components’ temperatures and verify their performance in different operating conditions.
Improving reliability in electric drive systems during IGBT short‐circuit fault
Authors: Naghavi Maryam , Ghanbari Mahmood , Ebrahimi Reza , Jannati Mohammad
Published: December 2020

To improve the reliability of electric drive systems during the insulated‐gate bipolar transistor short‐circuit fault, a control method is proposed for Y‐connected 3‐phase induction motors. This method allows the operation of 3‐phase induction motor drives under the insulated‐gate bipolar transistor short‐circuit fault without the requirement of a specific inverter topology and control strategy. At first, a modified inverter topology that can rectify the problem produced by an insulated‐gate bipolar transistor short‐circuit fault is presented. Then, based on the introduced inverter topology, a developed model for Y‐connected 3‐phase induction motors is presented. According to this model, an indirect vector control system for the faulted drive system based on the calculation of forward and backward magneto‐motive force of the motor is proposed. The performance of the control system is validated using experimental tests for a 1HP Y‐connected 3‐phase induction motor drive system. This research also compares the performance of the proposed indirect vector control technique with conventional indirect vector control techniques during the insulated‐gate bipolar transistor short‐circuit fault.
Multilevel common‐ground inverter with voltage boosting for PV applications
Authors: Kumari Sangeeta , Verma Arun Kumar , N Sandeep , Yaragatti Udaykumar R. , Pota Hemanshu Roy
Published: December 2020

Nowadays, transformer‐less Photovoltaic‐based grid‐connected inverters are more popular in renewable energy application due to their reduced size, cost, and high efficiency. However, the absence of galvanic isolation leads to the flow of leakage current in such system hindering personal safety, and deteriorating power quality. Therefore, this paper presents a five‐level transformer‐less inverter topology for PV applications with less component count and reduced complexity. The proposed inverter topology completely eliminates the common mode leakage current. Besides, the proposed topology has an inherent capability to boost the voltage without using any magnetic component or boosting circuit, and is based on the principle of switched/auxiliary capacitor. The proposed topology do not have any limitation of modulation index since the auxiliary capacitors are naturally balanced, hence less complex or no dedicated control scheme is required for balancing/regulating the auxiliary capacitor voltages. In order to verify the performance of the proposed inverter topology, a laboratory prototype is developed which confirms the operation, and feasibility of the proposed inverter. Results depicting the output voltage, load current, and voltage across the auxiliary capacitor are presented for various operating conditions. Further, simulation results depicting the leakage current in the proposed, H5, and H6 topologies are included. Finally, a quantitative comparison study is done, highlighting the benefits of the proposed inverter topology regarding boosted voltage, elimination of leakage current, and reduced component count.
Lung Protective Ventilation in Brain-Injured Patients: Low Tidal Volumes or Airway Pressure Release Ventilation?
Authors: Garg Ravi
Published: December 2020

The optimal mode of mechanical ventilation for lung protection is unknown in brain-injured patients as this population is excluded from large studies of lung protective mechanical ventilation. Survey results suggest that low tidal volume (LTV) ventilation is the favored mode likely due to the success of LTV in other patient populations. Airway pressure release ventilation (APRV) is an alternative mode of mechanical ventilation that may offer several benefits over LTV in this patient population. APRV is an inverse-ratio, pressure-controlled mode of mechanical ventilation that utilizes a higher mean airway pressure compared with LTV. This narrative review compares both modes of mechanical ventilation and their consequences in brain-injured patients. Fears that APRV may raise intracranial pressure by virtue of a higher mean airway pressure are not substantiated by the available evidence. Primarily by virtue of spontaneous breathing, APRV often results in improvement in systemic hemodynamics and thereby improvement in cerebral perfusion pressure. Compared with LTV, sedation requirements are lessened by APRV allowing for more accurate neuromonitoring. APRV also uses an open loop system supporting clearance of secretions throughout the respiratory cycle. Additionally, APRV avoids hypercapnic acidosis and oxygen toxicity that may be especially deleterious to the injured brain. Although high-level evidence is lacking that one mode of mechanical ventilation is superior to another in brain-injured patients, several aspects of APRV make it an appealing mode for select brain-injured patients.
Comparative Analysis of Erythrocyte Sedimentation Rate Measured by Automated and Manual Methods in Anaemic Patients
Authors: Narang Vikram , Grover Sumit , Kang Amandeep Kaur , Garg Avantika , Sood Neena
Published: December 2020

Purpose Erythrocyte sedimentation rate (ESR) is a widely used indicator of inflammation and a routinely done hematology investigation to monitor patients of autoimmune and infectious diseases. We aimed to compare the ESR results obtained by Roller 20LC automated instrument and standard reference Westergren method and analyzed the effect of anemia (hematocrit) on ESR measurements through the automated method.

Methods We analyzed 1377 random anemic OPD patients (hematocrit [HCT] < 35%) for ESR levels measured by Roller 20LC using EDTA blood and Westergren method using citrated blood for a one and half year period from January 1, 2018 to June 30, 2019. Fabry’s formula was used to correct the Westergren ESR.

Results The total number of samples after evaluation were divided into low (n = 232), intermediate (n = 417), high (n = 406), and very high range of ESR (≥100 mm/hr; n = 422). Mean difference between values of corrected and automated ESR for the low, intermediate, high and very high ESR range was 2.33 ± 5.03, 10.95 ± 8.04, 28.22 ± 19.11 and 43.3 ± 19.22 mm/hr, respectively. The 95% limit of agreement calculated by the Bland–Altmann analysis between the two methods for low-ESR range was −7.53 to 12.2 (highest correlation coefficient –0.65), while for very high ESR, range was −5.1 to 81.5 (least coefficient of 0.18) (p < 0.001).

Conclusion In laboratories with high-sample load and where manual measurement may be tedious, the automated method of ESR measurement can safely replace the Westergren method for low-ESR values in patients with low hematocrit. While for high-ESR values, validation by the standard Westergren method may be needed.
Hemoglobin Oxidation in Stored Blood Accelerates Hemolysis and Oxidative Injury to Red Blood Cells
Authors: Mustafa Ibrahim , Hadwan Tameem Ali Qaid
Published: December 2020

Introduction Maintaining blood supply is a challenge in blood banks. Red blood cells (RBCs) stored at 4°C experience issues of biochemical changes due to metabolism of cells, leading to changes collectively referred to as “storage lesions.” Oxidation of the red cell membrane, leading to lysis, contributes to these storage lesions.

Methods Blood bags with CPD-SAGM stored at 4°C for 28 days were withdrawn aseptically on days 1, 14, and 28. Hematology analyzer was used to investigate RBC indices. Hemoglobin oxidation was studied through spectrophotometric scan of spectral change. RBC lysis was studied with the help of Drabkin's assay, and morphological changes were observed by light and scan electron microscopy.

Results RBCs show progressive changes in morphology echinocytes and spherocytes on day 28. There was 0.85% RBC lysis, an approximately 20% decrease in percentage oxyhemoglobin, and a 14% increase in methemoglobin formation, which shows hemoglobin oxidation on day 28.

Conclusions Oxidative damage to RBC, with an increase in storage time was observed in the present study. The observed morphological changes to RBC during the course of increased time shows that there is progressive damage to RBC membrane and a decrease in hemoglobin concentration; percentage RBC lysis is probably due to free hemoglobin and iron.
Surgeon-Level Variation in Outcome following Esophageal Atresia Repair Is Not Explained by Volume
Authors: O'Connor Elizabeth , Jaffray Bruce
Published: December 2020

Introduction To assess whether there is a difference in operative outcome for esophageal atresia (EA) depending on a surgeon's seniority as defined by years in consultant practice or number of cases performed. In addition a Clavien–Dindo score was used to sequentially analyze the outcome of each surgeon's EA procedure.

Materials and Methods All repairs performed over 22 years in an English regional center were analyzed. Outcomes were: death, anastomotic leak, need for dilatation, need for more than three dilatations, need for fundoplication, and a Clavien–Dindo adverse outcome of ≥3b. Possible explanatory variables were: number of prior repairs by the surgeon, surgeon's years of consultant experience. We also examined the effect of variables intrinsic to the infant as possible confounding variables and as independent predictors of outcome.

Results A total of 190 repairs were performed or supervised by 12 consultants. There was no significant association between consultant experience and any objective outcome. However, sequential analysis suggests there is variation between surgeons in the incidence of Clavien–Dindo events of ≥3b. Performance showed deterioration in one case. Mortality was explicable by cardiac and renal anomalies.

Conclusion There are surgeon-level variations in outcomes for the procedure of EA repair, but they are not explained by volume. Surgeon performance can deteriorate. Our study would not support the concept that patient outcomes could be improved by concentrating the provision of this surgery to fewer hospitals or surgeons.
Implementation and Evaluation of an Electronic Maternal Early Warning Trigger Tool to Reduce Maternal Morbidity
Authors: Blumenthal Elizabeth A. , Hooshvar Nina , Tancioco Virginia , Newman Rachel , Senderoff Dana , McNulty Jennifer
Published: December 2020

Objective We compare maternal morbidity and clinical care metrics before and after the electronic implementation of a maternal early warning trigger (MEWT) tool.

Study Design This is a study of maternal morbidity and clinical care within three linked hospitals comparing 1 year before and after electronic MEWT implementation. We compare severe maternal morbidity overall as well as within the subcategories of hemorrhage, hypertension, cardiopulmonary, and sepsis in addition to relevant process metrics in each category. We describe the MEWT trigger rate in addition to MEWT sensitivity and specificity for morbidity overall and by morbidity type.

Results The morbidity rate ratio increased from 1.6 per 100 deliveries in the pre-MEWT period to 2.06 per 100 deliveries in the post-MEWT period (incidence rate ratio = 1.28, p = 0.018); however, in cases of septic morbidity, time to appropriate antibiotics decreased (pre-MEWT: 1.87 hours [1.11–2.63] vs. post-MEWT: 0.75 hours [0.31–1.19], p = 0.036) and in cases of hypertensive morbidity, the proportion of cases treated with appropriate antihypertensive medication within 60 minutes improved (pre-MEWT: 62% vs. post-MEWT: 83%, p = 0.040). The MEWT trigger rate was 2.3%, ranging from 0.8% in the less acute centers to 2.9% in our tertiary center. The MEWT sensitivity for morbidity overall was 50%; detection of hemorrhage morbidity was lowest (30%); however, it ranged between 69% for septic morbidity, 74% for cardiopulmonary morbidity, and 82% for cases of hypertensive morbidity.

Conclusion Overall, maternal morbidity did not decrease after implementation of the MEWT system; however, important clinical metrics such as time to antibiotics and antihypertensive care improved. We suspect increased morbidity was related to annual variation and unexpected lower morbidity in the pre-MEWT comparison year. Because MEWT sensitivity for hemorrhage was low, and because hemorrhage dominates administrative metrics of morbidity, process metrics around sepsis, hypertension, and cardiopulmonary morbidity are important to track as markers of MEWT efficacy.

Key Points
The Potential and the Limitations of Esophageal Robotic Surgery in Children
Authors: Ferrero Pierre Alexandre , Blanc Thomas , Binet Aurélien , Arnaud Alexis , Abbo Olivier , Vatta Fabrizio , Bonnard Arnaud , Spampinato Grazia , Lardy Hubert , Fourcade Laurent , Ballouhey Quentin
Published: December 2020

Introduction There have been numerous reports of robotic pediatric surgery in the literature, particularly regarding urological procedures for school-aged children. Thoracic procedures appear to be less common, despite the fact that encouraging results were reported more than 10 years. Our aim was to report a national experience of esophageal robotic-assisted thoracoscopic surgery (ERATS) and to discuss the most appropriate indications.

Materials and Methods A retrospective multicenter study was conducted to compile the ERATS performed at five French surgical centers that have been involved in spearheading robotic pediatric surgery over the past 15 years. The data were supplemented by a review of the literature.

Results Over the study period, 68 cases of robotic thoracic surgery were performed at the five pediatric centers in question. ERATS was performed for 18 patients (mean age 7.1 years [ ± 5.6]) in four of the centers. These comprised seven esophageal duplications, four esophageal atresias, five Heller's myotomies, and two cases of esophagoplasty. A conversion was needed for two neonates (11%) due to exposure difficulties. Four other procedures for patients who weighed less than 15 kg were successfully completed without causing postoperative complications. In the past 12 years, 22 other cases of ERATS were published worldwide. The indications were the same, except for esophagoplasty, which was not found.

Conclusion Aside from accessibility issues with the robotic platform, the main limitation is still very much that the low body weight of children results in incompatibility between the size of the trocars and the size of the intercostal space. ERATS is clearly a feasible procedure with technical advantages for most pediatric cases with body weights more than 15 kg. A transdiaphragmatic abdominal approach should be considered for lower esophagus surgery.
Impact of “Lateralizing” the Sigmoid Colostomy on Port Ergonomics in Laparoscopic Anorectoplasty for High Anorectal Malformations
Authors: Agrawal Vikesh , Sulya Deepak , Acharya Himanshu , Tiwari Abhishek , Sharma Dhananjaya
Published: December 2020

Introduction The high-type anorectal malformations (ARM) are conventionally managed by an initial left iliac fossa sigmoid colostomy, followed by laparoscopic anorectoplasty (LARP). Such a stoma occupies left half of the infraumbilical region and hinders the LARP ergonomics, leading to the surgeon's discomfort. We studied the outcome and impact of “lateralizing” (shifting laterally in the abdominal wall) the colostomy on port ergonomics.

Materials and Methods This prospective study was conducted in the pediatric surgery unit of a medical college in central India between March 2014 and June 2017 in two parts. In the first part of the study, neonates with high ARM were block randomized in two groups: conventional colostomy (CC) in left iliac fossa and lateral colostomy (LC, laterally placed abdominal colostomy). Outcomes of colostomy were compared among these two groups. In the second part of the study, 40 consecutive infants from both types of colostomy groups underwent ergonomic comparison and assessment of the surgeon's discomfort during LARP (CC-LARP and LC-LARP). Standard statistical tests were used for comparison.

Results In the first part of the study, 203 ARM cases were included in this study; 100 underwent CC and 103 underwent LC. Colostomy prolapse, excoriation, reversed stoma, and short distal limb were significantly higher in the CC group. In the second part of the study, the LC-LARP group showed many significant advantages over the CC-LARP group, including less peri-stomal adhesions, better vision, shorter operative time, and better ergonomics (better manipulation, elevation, and azimuth angles). The LC-LARP also significantly reduced the surgeon's discomfort.

Conclusion Lateralization of high-sigmoid colostomy should be preferred over left iliac fossa sigmoid colostomy for ARM, as it improves the port ergonomics and reduces the surgeon's discomfort for second stage LARP.
Morquio Syndrome Presenting with Dural Band Pathology: A Case Report
Authors: Gupta Saloni , Sengar Kangana , Subramanian Arulselvi , Satyarthee Gurudatta
Published: December 2020

Morquio syndrome is caused by the deficiency of N-acetylgalactosamine-6-sulfate sulfatase (GALNS) enzyme, which is required for the catabolism of glycosaminoglycans (namely, chondroitin-6-sulfate and keratan sulfate). Pathogenic accumulation of these glycosaminoglycans occurs throughout the body. The various organs and tissues affected are bones, cartilage, tendon, teeth, trachea and lungs, heart, cornea, skin and connective tissues.

Here, we present a case of Morquio syndrome. A 16-year-old boy presented with multiple skeletal abnormalities, including cervicomedullary compression by dorsal dural band in foramen magnum. The dural band was resected during the surgery to relieve compression and sent for histopathological examination. This case report not only reviews the clinical features and shows rare dural band histopathological findings but also mentions a note on the future therapies of this syndrome.
Stability of SARS-CoV-2 RNA in Viral Lysis Buffer Stored at Different Temperatures
Authors: Perumal Nagaraj , Jain Rajeev Kumar , Shrivastava Rakesh , Lalwani Jaya , Chaurasia Deepti
Published: December 2020

Objectives The present COVID-19 pandemic resulted in an increased need for molecular diagnostic testing. Delay in the specimen processing and suboptimal storage of suspected samples in laboratories leads to degradation of SARS-CoV-2 viral RNA. Viral lysis buﬀers from RNA extraction kits have the potential to stabilize RNA. Hence, this study aimed to investigate the stability of SARS-CoV-2 RNA in viral lysis buffer at different temperatures and time periods.

Materials and Methods Aliquots of samples with known SARS-CoV-2 RNA were processed in viral lysis buﬀers simultaneously, stored separately at 2 to 8°C and 22 to 28°C for 24 hours, 48 hours and 72 hours. SARS-CoV-2 viral RNA was extracted from each aliquot and analyzed using multiplex real-time PCR.

Results SARS-CoV-2 RNA in samples placed in viral lysis buffer was stable for 48 hours at both 2 to 8°C and 22 to 28°C temperatures. Slight decline in the viral RNA quantity was found on aliquots tested after 48 hours of both the temperatures.

Conclusions Viral lysis buffer maintains the integrity of SARS-CoV-2 RNA for up to 48 hours even at room temperature and supports delayed diagnosis with an overwhelming sample load in testing laboratories.
Issues in growing Heusler compounds in thin films for spintronic applications
Authors: Guillemard C. , Petit-Watelot S. , Devolder T. , Pasquier L. , Boulet P. , Migot S. , Ghanbaja J. , Bertran F. , Andrieu S.
Published: December 2020

Heusler magnetic alloys offer a wide variety of electronic properties very promising for spintronics and magnonics. Some alloys exhibit a spin gap in their band structure at the Fermi energy, the so-called half-metal magnetic (HMM) behavior. This particular property leads to two very interesting properties for spintronics, i.e., fully polarized current together with ultra-low magnetic damping, two key points for spin-transfer-torque based devices. This Tutorial gives experimental details to grow and characterize Heusler Co2MnZ compounds in thin films (Z = Al, Si, Ga, Ge, Sn, Sb) by using molecular beam epitaxy in order to get the proper predicted electronic properties. A first part of this Tutorial is dedicated to control the stoichiometry as best as possible with some methods to test it. The chemical ordering within the lattice was examined by using electron diffraction during growth, regular x-ray diffraction, and scanning transmission electron microscopy. In particular, standard x-ray diffraction is carefully analyzed depending on the chemical ordering in the cubic cell and shown to be inefficient to distinguish several possible phases, on the contrary to electron microscopy. The electronic properties, i.e., magnetic moment, spin polarization, and magnetic damping were reviewed and discussed according to the stoichiometry of the films and also theoretical predictions. Polycrystalline films were also analyzed, and we show that the peculiar HMM properties are not destroyed, a good news for applications. A clear correlation between the spin polarization and the magnetic damping is experimentally demonstrated. At least, our study highlights the major role of stoichiometry on the expected properties.