bluuebunny/crossref_metadata_2025 huggingface dataset:
Domino P‐µMB: A New Approach for the Sequential Immobilization of Enzymes Using Polydopamine/Polyethyleneimine Chemistry and Microfabrication
Authors: Changani Zinat , Razmjou Amir , Taheri‐Kafrani Asghar , Asadnia Mohsen
Published: April 2020

Developing a facile approach for the manipulation of the direction and order of the enzymatic reactions via sequential immobilization on inexpensive substrates is a continuous demand. Herein, a new methodology is introduced that allows making a desired enzymatic reaction pathway on a paper‐based microfluidic‐membrane based biosensor (P‐µMB). Although the method is universal, here, as a proof‐of‐concept, the sequential immobilization of α‐amylase, glucose oxidase (GOx) and horseradish peroxidase (HRP) is presented for fabricating a P‐µMB. To this end, hydrophilic polydopamine/polyethyleneimine patterns are created on the hydrophobic polypropylene membrane using 3D printing and a polydimethylsiloxane (PDMS) mold, and a coating layer of silver nanoparticles (AgNPs) is used to modify the patterns. The enzymes are then individually immobilized on the desired locations with another set of PDMS molds. It is observed that AgNPs P‐µMB in the sequential immobilization system has stable activity at various temperature and pH regimes, high selectivity toward starch, wide‐range linear sensitivity, and a limit of detection of 0.002% w/w starch. A smartphone camera is used for the quantitative analysis of the analyte with the mean gray intensity as the analytical parameter. This developed system provides a platform for further sequential immobilization of other types of biological elements.
Recent Progress on Interface Engineering for High‐Performance, Stable Perovskites Solar Cells
Authors: Zhu Yiyi , Poddar Swapnadeep , Shu Lei , Fu Yu , Fan Zhiyong
Published: April 2020

Rapid progress in the domain of perovskite solar cells (PSCs) has boosted the power conversion efficiency (PCE) of such cells to 25.2%. However, the long‐term stability of a high‐performance PSCs is still the foremost concern that hinders its practical application. The interfaces are considered as the key part that determines the overall device performance and longevity. These interfaces include the intralayer grain boundaries (GBs) inside the perovskites, the interface between perovskites with electron/hole transport layer (ETL/HTL), and the interface of ETL/HTL with top/down contacts. To acquire a deep and detailed understanding of the impacts of interfacial properties, herein, a concise overview of recent interfacial engineering strategies with the aim of minimizing traps, promoting carrier extraction, and improving stability are summarized.
Flexible Liquid‐Filled Fiber Adapter Enabled Wearable Optical Sensors
Authors: Pan Jing , Jiang Chengpeng , Zhang Zhang , Zhang Lei , Wang Xiaozhi , Tong Limin
Published: April 2020

Wearable optical sensors are attracting intensive research interests owing to their advantage of high sensitivity, fast response, and immunity to electromagnetic interferences. However, tunable optical properties and reconfigurable sensor structures remain great challenges for the wearable optical sensors. Herein, flexible liquid‐filled fiber adapters (FLFFAs), which are sensitive to mechanical stimuli, are demonstrated. The novel FLFFA consists of a soft liquid‐filled tubing and two silica optical fibers. The liquid core bestows the FLFFA both tunability and reconfigurability in sensing performance. Deformation of the tubing through bending or pressing results in wavelength‐insensitive changes in light transmission. By measuring the output intensity, the FLFFA based sensors achieve high angle resolution (0.18°) and low detection limit (0.7 mN) for bending and pressure sensing, respectively. The superior sensing properties together with mechanical flexibility and robustness enable real‐time monitoring of finger joint motion, respiration, and wrist pulse. Benefiting from an LED charge‐coupled device (CCD) signal recording system, a 4 × 3 keyboard is realized by simultaneously measuring the output signals of 12 FLFFAs. The FLFFA provides a promising method to detect subtle physiological signals and may find applications in healthcare devices, artificial skins, and sensor networks.
Unveiling the Axial Hydroxyl Ligand on FeN4C Electrocatalysts and Its Impact on the pH‐Dependent Oxygen Reduction Activities and Poisoning Kinetics
Authors: Yang Xin , Xia Dongsheng , Kang Yongqiang , Du Hongda , Kang Feiyu , Gan Lin , Li Jia
Published: April 2020

FeNC materials have shown a promising nonprecious oxygen reduction reaction (ORR) electrocatalyst yet their active site structure remains elusive. Several previous works suggest the existence of a mysterious axial ligand on the Fe center, which, however, is still unclarified. In this study, the mysterious axial ligand is identified as a hydroxyl ligand on the Fe centers and selectively promotes the ORR activities depending on different FeN4C configurations, on which the adsorption free energy of the hydroxyl ligand also differs greatly. The selective formation of hydroxyl ligand on specific FeNC configurations can resolve contradictories between previous theoretical and experimental results regarding the ORR activities and associated active configurations of FeNC catalysts. It also explains the pH‐dependent ORR activities and, moreover, a previously unreported pH‐dependent poisoning kinetics of the FeNC catalysts.
Lessons from a Career in Agricultural Development and Research Evaluation
Authors: Norton George W.
Published: April 2020

Lessons are presented from a career in evaluating impacts of agricultural technologies and institutions, with a major focus on pest management in developing countries. Agricultural productivity growth is fundamental to economic transformation and development, driven largely by technological and institutional changes. The latter are induced by changes in relative prices and are affected by transactions costs and collective action with implications for efficiency and poverty. Agricultural development leads to changes in farm structure and to many of the most educated existing rural communities. Institutional changes are needed to encourage rural investment and compensate those caught in place‐based poverty. Poverty is exacerbated by effects of climate change and pest problems with significant implications for the agenda of agricultural economists.
Co‐occurring medical conditions in adults with Down syndrome: A systematic review toward the development of health care guidelines. Part II
Authors: Capone George , Stephens Mary , Santoro Stephanie , Chicoine Brian , Bulova Peter , Peterson Moya , Jasien Joan , Smith Anna Jo ,   Down Syndrome Medical Interest Group (DSMIG‐USA) Adult Health Workgroup
Published: April 2020

Adults with Down syndrome (DS) represent a unique population who are in need of clinical guidelines to address their medical care. Many of these conditions are of public health importance with the potential to develop screening recommendations to improve clinical care for this population. Our workgroup previously identified and prioritized co‐occurring medical conditions in adults with DS. In this study, we again performed detailed literature searches on an additional six medical conditions of clinical importance. A series of key questions (KQ) were formulated a priori to guide the literature search strategy. Our KQs focused on disease prevalence, severity, risk‐factors, methodologies for screening/evaluation, impact on morbidity, and potential costs/benefits. The available evidence was extracted, evaluated and graded on quality. The number of participants and the design of clinical studies varied by condition and were often inadequate for answering most of the KQ. Based upon our review, we provide a summary of the findings on hip dysplasia, menopause, acquired cardiac valve disease, type 2 diabetes mellitus, hematologic disorders, and dysphagia. Minimal evidence demonstrates significant gaps in our clinical knowledge that compromises clinical decision‐making and management of these medically complex individuals. The creation of evidence‐based clinical guidance for this population will not be possible until these gaps are addressed.
Single‐Crystalline Optical Microcavities from Luminescent Dendrimers
Authors: Iwai Kohei , Yamagishi Hiroshi , Herzberger Colin , Sato Yuji , Tsuji Hayato , Albrecht Ken , Yamamoto Kimihisa , Sasaki Fumio , Sato Hiroyasu , Asaithambi Aswin , Lorke Axel , Yamamoto Yohei
Published: April 2020

Microcrystallites are promising minute mirrorless laser sources. A variety of luminescent organic compounds have been exploited along this line, but dendrimers have been inapplicable owing to their fragility and extremely poor crystallinity. Now, a dendrimer family that overcomes these difficulties is presented. First‐, second‐, and third‐generation carbazole (Cz) dendrimers with a carbon‐bridged oligo(phenylenevinylene) (COPV2) core (GnCOPV2, n=1–3) assemble to form microcrystals. The COPV2 cores align uni/bidirectionally in the crystals while the Cz units in G2‐ and G3COPV2 align omnidirectionally. The dendrons work as light‐harvesting antennas that absorb non‐polarized light and transfer it to the COPV2 core, from which a polarized luminescence radiates. Furthermore, these crystals act as laser resonators, where the lasing thresholds are strongly coupled with the crystal morphology and the orientation of COPV2, which is in contrast with the conventional amorphous dendrimers.
Not Guilty on Every Count: The “Non‐Innocent” Nitrosyl Ligand in the Framework of IUPAC′s Oxidation‐State Formalism
Authors: Ampßler Torsten , Monsch Georg , Popp Jens , Riggenmann Tobias , Salvador Pedro , Schröder Daniel , Klüfers Peter
Published: April 2020

Nitrosyl–metal bonding relies on the two interactions between the pair of N–O‐π* and two of the metal's d orbitals. These (back)bonds are largely covalent, which makes their allocation in the course of an oxidation‐state determination ambiguous. However, apart from M‐N‐O‐angle or net‐charge considerations, IUPAC′s “ionic approximation” is a useful tool to reliably classify nitrosyl metal complexes in an orbital‐centered approach.
The Interplay Between Lead Vacancy and Water Rationalizes the Puzzle of Charge Carrier Lifetimes in CH3NH3PbI3: Time‐Domain Ab Initio Analysis
Authors: Qiao Lu , Fang Wei‐Hai , Long Run
Published: April 2020

The perovskite CH3NH3PbI3 excited‐state lifetimes exhibit conflicting experimental results under humid environments. Using ab initio nonadiabatic (NA) molecular dynamics, we demonstrate that the interplay between lead vacancy and water can rationalize the puzzle. The lead vacancy reduces NA coupling by localizing holes, slowing electron–hole recombination. By creating a deep electron trap state, the coexistence of a neutral lead vacancy and water molecules enhances NA coupling, accelerating charge recombination by a factor of over 3. By eliminating the mid‐gap state by accepting two photoexcited electrons, the negatively charged lead vacancy interacting with water molecules increases the carrier lifetime over 2 times longer than in the pristine system. The simulations rationalize the positive and negative effects of water on the solar cell performance exposure to humidity.
Bis(thien‐2‐yl)‐2,1,3‐benzothiadiazole‐diketopyrrolopyrrole‐based acceptor–acceptor conjugated polymers: Design, synthesis, and the synergistic effect of the substituent on their solar cell properties
Authors: Du Junping , Feng Shanshan , Qin Pengju , Xu Liancai , Zhu Wenjing , Huang Jiang
Published: April 2020

Three acceptor–acceptor conjugated copolymers (TBT‐DPP, FTBT‐DPP, and HFTBT‐DPP) with different substituent groups have been synthesized with palladium‐catalyzed Stille coupling condensation polymerization assisted with microwave. Polymer solar cells (PSCs) based on these copolymers as the electron donors and PC71BM as the acceptor have been fabricated. The synergistic effect of the substituent between two fluorine atoms and hexyl alkyl chains in bis(thien‐2‐yl)‐2,1,3‐benzothiadiazole fragment on their solar cell properties has been investigated. Both the fluorine atoms and the synergistic effect can improve the solubility of the polymers effectively while the excellent thermal stability properties are still retained. Two fluorine atoms (polymer FTBT‐DPP) increased the power conversion efficiency of the PSCs twice compared with TBT‐DPP (without substituent). The synergistic effect (polymer HFTBT‐DPP) decreased that seriously to zero. Density function theory calculations showed that the conjugation level of the polymer backbone is one of key factors. It demonstrates that the synergistic effect of fluorine atoms and alkyl chains in the same fragment does not always work well in improving the PSCs performance.
Low‐cost FloPump for regulated air sampling of volatile organic compounds
Authors: Saryan Preeti , Gowda Vinita
Published: April 2020

Premise

We present a low‐cost, battery‐operated, portable pump, “FloPump,” which allows regulated air sampling for the study of volatile organic compounds (VOCs). VOCs are routinely investigated in applications such as atmospheric chemistry, agriculture, and fragrance biology.

Methods and Results

We compared the performance of FloPump with the Supelco pump in collecting VOCs using two test samples: guava fruit (Psidium guajava) and a perfume. The sampling and identification of volatiles was carried out using a dynamic headspace sampling method followed by gas chromatography–mass spectrometry. We show that the sampling efficiency of FloPump is comparable to the commercial pump, and at an affordable cost of ~US$115 (~86% cheaper), it provides a viable option for researchers interested in sampling volatiles on a constrained budget.

Conclusions

Accurate air sampling is critical for the study of VOCs. We propose that FloPump will make air sampling more affordable, thus encouraging studies of VOCs.
Inoculation concentration modulating the secretion and accumulation pattern of exopolysaccharides in desert cyanobacterium Microcoleus vaginatus
Authors: Qian Long , Wu Li , Yang Lie , Zhang Zulin
Published: April 2020

Cyanobacterial exopolysaccharides (EPS) accumulated during microalgal cultivation have significant application potential in antioxidation, pharmaceutical products, and so on. Inoculation concentration strongly affects the cultivation cost, biomass, and EPS accumulation. In this study, a high‐EPS‐excreted desert cyanobacterium Microcoleus vaginatus was isolated, and the effects of inoculation concentration on biomass, photosynthetic activity, and EPS accumulation were explored. The results showed that the original fluorescence (Fo) provided a good indication to cyanobacterial biomass, when Chl‐a concentration was lower than 10 mg L−1. Inoculation concentration significantly affected cyanobacterial biomass and EPS concentration (P < 0.001), whereas did not affect photosynthetic activity (Fv/Fm; P > 0.05). The two fractions of EPS, capsular exopolysaccharides (CPS) and released exopolysaccharides (RPS) were strongly affect by inoculation concentration. Other than forming thick sheath (CPS) surrounded the filaments, M. vaginatus excreted higher proportions of RPS to culture medium, and the ratio of RPS to CPS ranged from 1.08 to 1.58 depending on the inoculation concentration. Additionally, although the biomass and EPS accumulation increased with inoculation concentration, the increasing inoculation concentration did not bring to the proportionate increase of the final biomass and EPS yield. Altogether, comprehensively considering the EPS yield and productivity, inoculation concentration of 0.04 mg Chl‐a L−1 is recommended for M. vaginatus to produce EPS, with an EPS yield of 94.32 mg L−1 and EPS productivity of 184.86 mg (mg Chl‐a)−1 L−1 d−1 at the end of experiment.
Overexpression of blue light receptor AaCRY1 improves artemisinin content in Artemisia annua L.
Authors: Fu Xueqing , He Yilong , Li Ling , Zhao Limei , Wang Yuting , Qian Hongmei , Sun Xiaofen , Tang Kexuan , Zhao Jingya
Published: April 2020

Artemisinin, an effective antimalarial compound, is isolated from the medicinal plant Artemisia annua L. However, because of the low content of artemisinin in A. annua, the demand of artemisinin exceeds supply. Previous studies show that the artemisinin biosynthesis is promoted by light in A. annua. Cryptochrome1 (CRY1) is involved in many processes in the light response. In this study, AaCRY1 was cloned from A. annua. Overexpressing AaCRY1 in Arabidopsis thaliana cry1 mutant resulted in blue‐light‐dependent short hypocotyl phenotype and short coleoptile under blue light. Yeast two‐hybrid and subcellular colocalization showed that AaCRY1 interacted with AtCOP1 (ubiquitin E3 ligase CONSTITUTIVE PHOTOMORPHOGENIC1). Overexpression of AaCRY1 in transgenic A. annua increased the artemisinin content. When AaCRY1 was overexpressed in A. annua driven by the CYP71AV1 (cytochrome P450 dependent amorpha‐4,11‐diene 12‐hydroxylase) promoter, the artemisinin content was 1.6 times higher than that of the control. Furthermore, we expressed the C terminal of AaCRY1(CCT) involved a GUS‐CCT fusion protein in A. annua. The results showed that the artemisinin content was increased to 1.7‐ to 2.4‐fold in GUS‐CCT transgenic A. annua plants. These results demonstrate that overexpression of GUS‐CCT is an effective strategy to increase artemisinin production in A. annua.
Nanoparticles containing constrained phospholipids deliver mRNA to liver immune cells in vivo without targeting ligands
Authors: Gan Zubao , Lokugamage Melissa P. , Hatit Marine Z. C. , Loughrey David , Paunovska Kalina , Sato Manaka , Cristian Ana , Dahlman James E.
Published: April 2020

Once inside the cytoplasm of a cell, mRNA can be used to treat disease by upregulating the expression of any gene. Lipid nanoparticles (LNPs) can deliver mRNA to hepatocytes in humans, yet systemic non‐hepatocyte delivery at clinical doses remains difficult. We noted that LNPs have historically been formulated with phospholipids containing unconstrained alkyl tails. Based on evidence that constrained adamantyl groups have unique properties that can improve small molecule drug delivery, we hypothesized that a phospholipid containing an adamantyl group would facilitate mRNA delivery in vivo. We quantified how 109 LNPs containing “constrained phospholipids” delivered mRNA to 16 cell types in mice, then using a DNA barcoding‐based analytical pipeline, related phospholipid structure to in vivo delivery. By analyzing delivery mediated by constrained phospholipids, we identified a novel LNP that delivers mRNA to immune cells at 0.5 mg/kg. Unlike many previous LNPs, these (a) did not preferentially target hepatocytes and (b) delivered mRNA to immune cells without targeting ligands. These data suggest constrained phospholipids may be useful LNP components.
PRCC‐TFE3 regulates migration and invasion of translocation renal cell carcinomas via activation of Drp1‐dependent mitochondrial fission
Authors: Wang Bo , Gan Weidong , Han Xiaodong , Li Dongmei
Published: April 2020

PRCC‐TFE3 translocation renal cell carcinomas (tRCC) is a common subtype of TFE3 tRCCs in which TFE3 fusions are indicated as oncogenes to promote tumor development. PRCC‐TFE3 fusions are often accumulated in the nucleus and related to poorer outcomes and higher stages (III/IV). In this study, we found that PRCC‐TFE3 could positively regulate expression of both dynamin‐related protein 1 (Drp1) and fission protein 1, and alter distribution of mitochondria, which could promote cell migration and invasion independent of matrix metalloproteinase‐2 (MMP‐2) and MMP‐9. Together, our findings showed a new mechanism for PRCC‐TFE3 tRCC cell migration and invasion by alteration of mitochondrial dynamics. Thus, targeting dysregulated Drp1‐dependent mitochondrial fission may provide a novel strategy for suppressing the progression of PRCC‐TFE3 tRCC.
An unusual case of multibacillary leprosy mimicking prurigo nodularis
Authors: Noormohammadpour Pedram , Kamyab‐Hesari Kambiz , Razavi Zahra , Dolatyabi Nooshin , Taghizadeh Fazli Jafar , Daneshpazhooh Maryam , Nouri Zeinab
Published: April 2020

Leprosy is a chronic infectious disease with a wide range of clinical manifestations. The early diagnosis of leprosy is a worldwide challenge. We present a case of leprosy with unusual severe pruritus and generalized excoriated papules and nodules.
An unusual case of redo tricuspid valve replacement and repair of a previously unidentified anomalous pulmonary venous return in a patient with congenitally corrected transposition of the great arteries
Authors: Sadeghi Amir H. , Van de Woestijne Pieter , Taverne Yannick J.H.J. , Van Dijk Arie P. J. , Bogers Ad J. J. C.
Published: April 2020

Associated cardiovascular malformations in congenitally corrected transposition of the great arteries (CCTGA) should not be missed when a patient requires surgical correction. We present a case of an adult CCTGA patient who required redo surgery for recurrent tricuspid (left atrioventricular) valve regurgitation and previously unidentified partial anomalous pulmonary venous return.
Characteristics and Performances of Blended Polyethersulfone and Carbon‐Based Nanomaterial Membranes: Effect of Nanomaterial Types and Air Exposure
Authors: Suhartono Jono , Pertiwi Dyah Setyo , Noersalim Carlina , Yulianingsih Devi , Sofianti Falashiva , Saptoro Agus , Chafidz Achmad
Published: April 2020

Polyethersulfone (PES) is a widely used polymeric material for ultrafiltration or nanofiltration membranes. To enhance membrane permeability, rejection, and antifouling performance, the effect of four different types of carbon‐based nanomaterials and air exposures during PES/carbon‐based nanomaterial membrane fabrication was evaluated. The carbon‐based nanomaterials were pristine carbon nanotubes, oxidized CNTs (CNTs‐O), pristine graphene nanoplatelets (GNPs‐P), and oxidized graphene nanoplatelets (GNPs‐O). The characteristics and performances of pure and blended membranes were investigated based on their permeability, porosity, morphology, and hydrophobicity. Longer air contact time during membrane preparation resulted in lower membrane permeability, hydrophobicity, and porosity. All fabricated membranes tended to have channelled sponge‐like structure, and highest permeability was attributed to the PES/GNPs‐O membrane.
Afferent and efferent connections of the nucleus prethalamicus in the yellowfin goby Acanthogobius flavimanus
Authors: Hagio Hanako , Kawaguchi Masahumi , Abe Hideki , Yamamoto Naoyuki
Published: April 2020

The nucleus prethalamicus (PTh) receives fibers from the optic tectum and then projects to the dorsal telencephalon in the yellowfin goby Acanthogobius flavimanus. However, it remained unclear whether the PTh is a visual relay nucleus, because the optic tectum receives not only visual but also other sensory modalities. Furthermore, precise telencephalic regions receiving prethalamic input remained unknown in the goby. We therefore investigated the full set of afferent and efferent connections of the PTh by direct tracer injections into the nucleus. Injections into the PTh labeled cells in the optic tectum, ventromedial thalamic nucleus, central and medial parts of the dorsal telencephalon, and caudal lobe of the cerebellum. We found that the somata of most tecto‐prethalamic neurons are present in the stratum periventriculare. Their dendrites ascend to reach the major retinorecipient layers of the tectum. The PTh is composed of two subnuclei (medial and lateral) and topographic organization was appreciated only for tectal projections to the lateral subnucleus (PTh‐l), which also receives sparse retinal projections. In contrast, the medial subnucleus receives fibers only from the medial tectum. We found that the PTh projects to nine subregions in the dorsal telencephalon and four in the ventral telencephalon. Furthermore, cerebellar injections revealed that cerebello‐prethalamic fibers cross the midline twice to innervate the PTh‐l on both sides. The present study is the first detailed report on the full set of the connections of PTh, which suggests that the PTh relays visual information from the optic tectum to the telencephalon.
Crystal Structure, Second Hyperpolarizability Measurements, and Theoretical Calculations of a New Coordination Polymer: Catena‐Poly[aqua‐Dichlorido‐bis(1H‐Imidazole)‐Manganese(ii)]
Authors: Li Tingbin , Hu Yali
Published: April 2020

The single crystals of a new coordination polymer catena‐poly[aqua‐dichlorido‐bis(1H‐imidazole)‐manganese(ii)] ([Mn(C3H4N2)2Cl2(H2O)]n) (CPADBIM) are obtained and characterized by X‐ray single crystal diffraction. It's second hyperpolarizability γ value is investigated by using a closed aperture Z‐scan technique with 20 ps pulses at wavelength 532 nm. Time‐dependent density‐functional theory with basis sets 6‐311++G(3d,3p) is used in computing the linear and non‐linear optical properties. The theoretical calculated γ value is in agreement with the experimental results.
Agronomic and physiological characteristics of a rice leaf early senescence mutant during its whole growth period
Authors: Xu Yunji , Li Ke , Shen Ying , Yu Qing , Zhang Weiyang , Zhang Hao , Wang Zhiqin
Published: April 2020

Diverse rice (Oryza sativa L.) leaf early senescence mutants have been identified and used for studies on senescence mechanisms. However, the reports are few about the agronomic and physiological characteristics of rice leaf early senescence mutants during the whole growth period. This study used a rice leaf early senescence mutant (osled) and its wild type (WT) to compare their main phenotypic and agronomic traits at different growth stages, as well as some physiological characteristics. The results showed the osled plants exhibited leaf early senescence initiating from the middle seedling stage to maturation, accompanied with dwarf phenotype, prolonged vegetative growth period, decreased green leaf area, reduced aboveground biomass, decreased crop growth rate and net assimilation rate, smaller panicle, an awn of 1.56‐ to 1.58‐cm length, and more panicles. Compared with WT, the osled plants had significantly reduced chlorophyll content, photosynthetic capacity, N content, and activities of nitrate reductase and glutamine synthase in leaves and enhanced activity of glutamate synthase and lowered pre‐anthesis nonstructural carbohydrate accumulation and remobilization in stems. The study revealed some physiological mechanisms underlying leaf senescence of the osled and provided new perspectives for understanding the growth characteristics of rice leaf early senescence mutants.
Low‐power compact tunable quenching configuration for minimizing afterpulsing in single‐photon avalanche diodes
Authors: Pahlavanzadeh Hadi , Karami Mohammad Azim
Published: April 2020

This paper unveils two efficient free running (FR) quenching circuits with the aim of reducing quenching time (QT) to minimize avalanche charge. Likewise, one circuit is compactly designed with low power consumption, suitable for single‐photon avalanche diode (SPAD) with hold‐off time below 10 ns. In second circuit, tunable hold‐off and reset‐time are provided within a wide range without decreasing QT, which are desirable in many applications. Proper operation and circuit uncertainty is assessed by Monte Carlo analysis in a standard 90‐nm complementary metal‐oxide semiconductor (CMOS) technology. In a bid to do a comparison between previously reported circuits and the proposed circuits, they are simulated with same SPAD model and parameters and results corroborate the proposed circuits guarantee active quenching time (AQT) of below 1 ns. Proposed circuits with current and area consumption of 0.74 μA, 32 μm2 for 7‐ns dead time and 16.2 μA, 93 μm2 for 21‐ns dead time are more efficient in terms of QT, area, and power consumption in comparison with other works.
Isolated word language identification system with hybrid features from a deep belief network
Authors: Sangwan Pardeep , Deshwal Deepti , Kumar Divya , Bhardwaj Saurabh
Published: April 2020

The representation of good audio features is the first and foremost requirement for improving the identification performance of any system. Most of the representation learning approaches are based on connectionist systems to learn and extract latent features from the speech data. This research work presents a hybrid feature extraction approach to integrate Mel‐Frequency Cepstral Coefficients (MFCC) features with Shifted Delta Cepstral (SDC) coefficients features, which are further stacked to Deep Belief Network (DBN), for yielding new feature representations of the speech signals. DBN is utilized for unsupervised feature learning on the extracted MFCC‐SDC acoustic features. A 3‐layer Back Propagation Neural Network (BPNN) classifier is initialized in terms of the learning outcomes of hidden layers of DBN for identifying language from the uttered speech. The efficiency of the proposed approach is evaluated by simulating several experimental algorithms on the user‐defined database of isolated words in four languages, namely, Tamil, Malayalam, Hindi, and English, in the working platform of MATLAB. The obtained results for the proposed hybrid approach MFCC‐SDC‐DBN are promising. The proposed approach is also compared with the baseline feature extraction approach MFCC‐SDC by utilizing traditional acoustic features and BPNN classifier. The accuracy obtained with our proposed approach is 98.1% whereas that of the baseline approach is 82%, thereby providing an overall improvement of 16.1%.
Congestion‐aware multiaccess edge computing collaboration model for 5G
Authors: Salama Gerges M. , Ismail Alshimaa H. , Soliman Tarek Abed , Hamed Hesham F.A. , El‐Bahnasawy Nirmeen A.
Published: April 2020

In 5G cloud computing, the most notable and considered design issues are the energy efficiency and delay. The majority of the recent studies were dedicated to optimizing the delay issue by leveraging the edge computing concept, while other studies directed its efforts towards realizing a green cloud by minimizing the energy consumption in the cloud. Active queue management‐based green cloud model (AGCM) as one of the recent green cloud models reduced the delay and energy consumption while maintaining a reliable throughput. Multiaccess edge computing (MEC) was established as a model for the edge computing concept and achieved remarkable enhancement to the delay issue. In this paper, we present a handoff scenario between the two cloud models, AGCM and MEC, to acquire the potential gain of such collaboration and investigate its impact on the cloud fundamental constraints; energy consumption, delay, and throughput. We examined our proposed model with simulation showing great enhancement for the delay, energy consumption, and throughput over either model when employed separately.
Advocate for accessibility in historic renovations
Authors: Enos Gary A.
Published: April 2020

Code problems had forced the closing of one of the most prominent buildings on the University of Massachusetts at Amherst campus, the Old Chapel. The university in 2014 hired Finegold Alexander Architects to transform the site, which once served as a library and place of assembly, into a vibrant student center. Finegold Alexander Principal Regan Shields Ives discussed a project that, according to reviewers honoring it with a Boston Society of Architects William D. Smith Memorial Award, “is proof that accessible design and historic buildings do not have to be at odds with each other.”
Share methods and practices of Universal Design for Learning with faculty
Authors: Bedrossian Louise
Published: April 2020

With increasingly diverse student bodies, including students with disabilities, higher education faculty members need solutions for better inclusivity and effective teaching methods for all students.
Offer faculty a handy guide to meeting online course accessibility requirements
Authors: Sutton Halley
Published: April 2020

With the spread of COVID‐19, many college and university campuses are moving previously in‐person courses online. While this presents a multitude of challenges even as it may help prevent the spread of the virus, it's important to make sure these courses that have rapidly shifted delivery mode remain accessible to students with disabilities. The Web Accessibility Initiative is an online database of resources for those wanting to ensure that materials presented online meet accessibility standards for those with disabilities. It includes guidelines for accessibility, Universal Design techniques, evaluations, and more.
Multi‐temporal assessment of grassland α‐ and β‐diversity using hyperspectral imaging
Authors: Gholizadeh Hamed , Gamon John A. , Helzer Christopher J. , Cavender‐Bares Jeannine
Published: April 2020

While more and more studies are exploring the application of remote sensing in assessing biodiversity for different ecosystems, most consider biodiversity at one point in time. Using several remote‐sensing‐based metrics, we asked how well remote sensing can detect biodiversity (both α‐ and β‐diversity) in a prairie grassland across time using airborne hyperspectral data collected in two successive years (2017 and 2018) and at different periods in the growing season (2018). The ability to detect biodiversity using “spectral diversity” and “spectral species” types indeed varied significantly over a 2‐yr timespan. Toward the end of the growing season in 2018, the relationship between field‐ and remote‐sensing‐based α‐ and β‐diversity weakened compared to data collected from the same season in the previous year. This contrasting pattern between the two years was likely influenced by prescribed fire, altered weather, and the resulting shifting species composition and phenology. These findings indicate that direct detection of α‐ and β‐diversity in grasslands should be multi‐temporal when possible and should consider the effect of disturbances, climate variables, and phenology. We demonstrate an essential role for airborne platforms in developing a global biodiversity monitoring system involving forthcoming space‐borne hyperspectral sensors.
A novel quantitative framework for riverscape genetics
Authors: White Shannon L. , Hanks Ephraim M. , Wagner Tyler
Published: April 2020

Riverscape genetics, which applies concepts in landscape genetics to riverine ecosystems, lack appropriate quantitative methods that address the spatial autocorrelation structure of linear stream networks and account for bidirectional geneflow. To address these challenges, we present a general framework for the design and analysis of riverscape genetic studies. Our framework starts with the estimation of pairwise genetic distance at sample sites and the development of a spatially structured ecological network (SSEN) on which riverscape covariates are measured. We then introduce the novel bidirectional geneflow in riverscapes (BGR) model that uses principles of isolation‐by‐resistance to quantify the effects of environmental covariates on genetic connectivity, with spatial covariance defined using simultaneous autoregressive models on the SSEN and the generalized Wishart distribution to model pairwise distance matrices arising through a random walk model of geneflow. We highlight the utility of this framework in an analysis of riverscape genetics for brook trout (Salvelinus fontinalis) in north central Pennsylvania, USA. Using the fixation index (FST) as the measure of genetic distance, we estimated the effects of 12 riverscape covariates on geneflow by evaluating the relative support of eight competing BGR models. We then compared the performance of the top‐ranked BGR model to results obtained from comparable analyses using multiple regression on distance matrices (MRM) and the program STRUCTURE. We found that the BGR model had more power to detect covariate effects, particularly for variables that were only partial barriers to geneflow and/or uncommon in the riverscape, making it more informative for assessing patterns of population connectivity and identifying threats to species conservation. This case study highlights the utility of our modeling framework over other quantitative methods in riverscape genetics, particularly the ability to rigorously test hypotheses about factors that influence geneflow and probabilistically estimate the effect of riverscape covariates, including stream flow direction. This framework is flexible across taxa and riverine networks, is easily executable, and provides intuitive results that can be used to investigate the likely outcomes of current and future management scenarios.
Conservation and production responses vary by disturbance intensity in a long‐term forest management experiment
Authors: Kroll Andrew J. , Springford Aaron , Verschuyl Jake
Published: April 2020

Reductions in management intensity are often proposed to support a broader range of beneficial ecosystem responses than traditional management approaches.However, few studies evaluate ecosystem responses across approaches. Also, managers lack information about how species traits mediate responses across management approaches, a potentially substantial source of spatial and temporal variation in population and community responses that if ignored may hinder effectiveness of management programs. We used data collected over eight years from a manipulative experiment to test how four forest management strategies influenced avian community composition and wood production. After harvesting, we evaluated responses to three levels of plant cover suppression (Light, Moderate, and Intensive herbicide applications) in relation to a control without herbicide. We predicted the Moderate and Intensive treatments would exert strong negative effects on leaf‐gleaning insectivores, including species of conservation concern due to long‐term population declines. However, given high forest productivity, we expected temporal duration of effects to be short. Richness of leaf‐gleaning bird species was reduced by 20–50% during the first four years post‐harvest (when herbicide treatments were on‐going), but the effect size declined over the next four years once treatments were completed (13–20% reduction). Effect sizes were substantially smaller for the non‐leaf‐gleaner group during years 1–4 (19–27%) and disappeared during years 5–8 (2–3%). However, in our final year of observation, we did find an average of five fewer non‐leaf‐gleaner species on Light vs. Control units. In the last two years of observation, turnover probabilities for the leaf‐gleaner species remained higher on all treatments compared to the Control (0.11–0.21), indicating that new species continued to colonize treatments. Planted conifers were 40–44% taller and 74–81% larger in diameter in the Moderate and Intensive treatments compared to the Control, leading to substantial gains in wood biomass. Current practices provided more balance between two ecosystem responses, avian diversity and wood production, compared to less intensive alternatives. When short‐term negative effects occur, the spatial distribution of harvesting and regeneration regionally indicates that habitat is often available locally to support leaf‐gleaning and non‐leaf‐gleaning bird populations while releasing other portions of the region for high priority conservation objectives including late‐successional forest reserves.
Host plant genetic control of associated fungal and insect species in a Populus hybrid cross
Authors: Simon Sandra J. , Tschaplinski Timothy J. , M. LeBoldus Jared , Keefover‐Ring Ken , Azeem Muhammad , Chen Jin‐Gui , Macaya‐Sanz David , MacDonald William L. , Muchero Wellington , DiFazio Stephen P.
Published: April 2020

Plants employ a diverse set of defense mechanisms to mediate interactions with insects and fungi. These relationships can leave lasting impacts on host plant genome structure such as rapid expansion of gene families through tandem duplication. These genomic signatures provide important clues about the complexities of plant/biotic stress interactions and evolution. We used a pseudo‐backcross hybrid family to identify quantitative trait loci (QTL) controlling associations between Populus trees and several common Populus diseases and insects. Using whole‐genome sequences from each parent, we identified candidate genes that may mediate these interactions. Candidates were partially validated using mass spectrometry to identify corresponding QTL for defensive compounds. We detected significant QTL for two interacting fungal pathogens and three insects. The QTL intervals contained candidate genes potentially involved in physical and chemical mechanisms of host–plant resistance and susceptibility. In particular, we identified adjoining QTLs for a phenolic glycoside and Phyllocolpa sawfly abundance. There was also significant enrichment of recent tandem duplications in the genomic intervals of the native parent, but not the exotic parent. Tandem gene duplication may be an important mechanism for rapid response to biotic stressors, enabling trees with long juvenile periods to reach maturity despite many coevolving biotic stressors.
Are large frugivorous birds better seed dispersers than medium‐ and small‐sized ones? Effect of body mass on seed dispersal effectiveness
Authors: Godínez‐Alvarez Héctor , Ríos‐Casanova Leticia , Peco Begoña
Published: April 2020

Frugivorous birds vary in seed dispersal effectiveness (SDE) depending on their body mass. It has been suggested that large birds are more effective dispersers than small ones because they consume a large number of fruits, disperse seeds of distinct sizes, and transport seeds over long distances. Yet, few studies have evaluated the impact of body mass on SDE of birds. In this study, we compiled one database for the quantity (i.e., frequency of visits to plants and number of seeds removed per visit) and quality (i.e., germination of seeds after gut passage and gut retention time of seeds) of seed dispersal by frugivorous birds to evaluate the impact of body mass on SDE. In addition, we compiled data on plant characteristics such as life‐form, fruit type, number of seeds per fruit, and size of seed to evaluate their influence on the quantity and quality of seed dispersal. Data were analyzed with linear mixed effects models and quantile regressions to evaluate the relationship between body mass of birds and quantity, quality, and SDE, in addition to the influence of plant characteristics on SDE. The body mass of birds was negatively related to the frequency of visits to plants. Furthermore, it was positively related to the number of seeds removed per visit, although negatively related to seed size. The life‐form of plants was the only factor explaining the germination of seeds after gut passage. Yet, the body mass of birds was positively related to the gut retention time of seeds. Small and medium birds have a relatively higher SDE than large birds. These results differ from the assertion that large birds are more effective dispersers of plants. Small and medium birds are also effective dispersers of plants that should be preserved and protected from the impact of human activities.
Provide leadership to address economic impact of pandemic
Authors: Hope Joan
Published: April 2020

“What should I be doing when I really don't know what will happen next? What can I learn?” Those are questions higher education leaders should be asking over the next few months about the impacts of the COVID‐19 pandemic, said Larenda Mielke, Vice President, Higher Education, at Kaufman Hall.
A platform for cloudification of network and applications in the Internet of Vehicles
Authors: da Silva Barbosa Francisco Edigleison , de Mendonça Júnior Francisco Ferreira , Dias Kelvin Lopes
Published: April 2020

Vehicular networks have evolved from traditional vehicle‐to‐vehicle (V2V) and vehicle‐to‐infrastructure (V2I) communications to the so‐called Internet of Vehicles (IoV), which encompasses cloud computing and the Internet of Things. Thus, IoV creates novel scenarios and applications such as autonomous driving, as well as research challenges regarding the requirements for connected cars such as ultra‐reliable low‐latency, communications and the need for high processing power closer to vehicles. In order to address the above issues for IoV, this article proposes integrating state‐of‐the‐art technology pillars that are well accepted by both industry and academia as building blocks for future 5G networks. We propose a flexible, hierarchical, and scalable IoV architecture that integrates software‐defined networking, edge/fog computing, network function virtualization, and containers. We evaluate the proposal in both infrastructure‐based and peer‐to‐peer content distribution scenarios. The results are promising and point out that the architecture can cope with the stringent requirements that need to be met in terms of latency for 5G‐based IoV applications.
An innovative cell model revealed the inhibitory effect of flavanone structure on peroxynitrite production through interaction with the IKKβ kinase domain at ATP binding site
Authors: Charoensin Supochana , Huang Tzou‐Chi , Hsu Jue‐Liang
Published: April 2020

It is hypothesized that the oxidative/nitrosative stress inhibitory effect of a flavanone is governed by its chemical structure. However, the existing cell‐based antioxidant assays primarily focus on single chemical to initiate toxic species production. In this study, a novel cell model using macrophage treated with a combination of PMA and LPS leading to generation of peroxynitrite was proposed to provide a more real physiological condition. Three flavanones (eriodictyol, naringenin, and pinocembrin) with different number of ortho‐dihydroxyl groups on B‐ring were used to provide a more comprehensive evaluation of the role of chemical structure in the new model. Dihydrorhodamine123 assay, protein immunoblotting, immunofluorescence assay, and in silico analysis by molecular docking between the flavanones and IKKβ catalytic kinase domain at the ATP binding site were employed. Results indicated that the generation of peroxynitrite was decreased at 10 µM of flavanones; eriodictyol was the most effective inhibitor. Western blot analysis and confocal fluorescence image also showed that eriodictyol could inhibit iNOS and p47 protein expressions through the inhibition of NF‐kB translocation and performed the maximal inhibition compared to that of the other groups. In addition, the highest CDOCKER energy values of eriodictyol (38.6703 kcal/mol) confirmed that the 3′,4′‐ortho‐dihydroxylation on the B‐ring played a crucial role in binding with IKKβ kinase domain at ATP binding site. Finally, we propose that the ortho‐dihydroxyl groups on B‐ring of flavanone may influence directly the occupation of the ATP binding site of IKKβ kinase domain leading to the abrogation of peroxynitrite formation in the innovative cell model.
Major head and neck reconstruction during the COVID‐19 pandemic: The University of Pittsburgh approach
Authors: Ranasinghe Viran , Mady Leila J. , Kim Seungwon , Ferris Robert L. , Duvvuri Umamaheswar , Johnson Jonas T. , Solari Mario G. , Sridharan Shaum , Kubik Mark
Published: April 2020

The 2019 novel coronavirus (COVID‐19) pandemic has created significant challenges to the delivery of care for patients with advanced head and neck cancer requiring multimodality therapy. Performing major head and neck ablative surgery and reconstruction is a particular concern given the extended duration and aerosolizing nature of these cases. In this manuscript, we describe our surgical approach to provide timely reconstructive care and minimize infectious risk to the providers, patients, and families.