bluuebunny/crossref_metadata_2025 huggingface dataset:
Intestinal Helminth Infections, Compliance and Effectiveness of Albendazole Treatment among CDC Workers (18-45 Years) in Tiko, South-West Region, Cameroon
Authors: Ndamukong-Nyanga Judith Lum , Owah Dioh Njanakea , Yunga Nyanga Bernard , Nji Desdemona Njabi , Jacqueline Changsen
Published: May 2020

Intestinal helminthes infections are among the most prevalent of chronic human infections worldwide. These infections are common among people who work under very poor conditions most of the time without protective hand gloves, shoes and uniforms in the field. A cross-sectional study was done to determine the prevalence of intestinal helminthes among Cameroon Development Cooperation (CDC) workers and their compliance to anti-helminthic treatement form November 2017 to April 2018. It involved 102 workers aged18-45 years attending CDC cottage Hospital in Tiko. A cross-sectional study was done in which demographic data and data related to predisposing factors and preventive measures was collected using a simplified questionnaire, stool samples were collected pre and post treatement. Macroscopic and microscopic examination of stool samples was carried out in the hospital laboratory. Out of 102 people, a total of 81 (79.4%) people were infected with one or more species of intestitinal helminthes and there was significant difference in the infection with respect to various helminthes species (0.004). Among the 81 infected cases, 58(71.6%) were infected with single helminth species and 23 (28.4%) were infected with more than one species (coinfection). Intestinal helminths varied significantly among the participants with prevalences of 24.5% for T. trichuris, 6,9% for Hookworm, 0.9% for S. japanicum, 24.5% for S. haematobium, 34.3% for A. lumbricoides and 7.8% for S.  mansoni (P<0.004). Out of the 40 participants who took the drug (albendazole), 32 (80%) came for retesting and disappointedly, 8 (20.00%) of the treated participants did not come.  A majority of the 32 people retested were negative (28, 87.5%) for all species of intestinal helminth parasites, 4 (12.5%) still tested positive for the parasite presence in their stool among which 2 had schistosoma haematobium, one had schistosoma mansoni and one had Ascaris lumbricoides. Workers were recommended to wear protective hand gloves, and proper working shoes in line with their work description.
Effect of De-blossoming Treatments on Physical Characteristics of Different Mango Varieties during Off-season Fruit Production under South Gujarat Conditions
Authors: Chaudhary A. D. , Ahlawat T. R. , Bhandari D. R. , Patel Dharmishtha
Published: May 2020

An investigation was conducted during 2013-14 and 2014-15 seasons under South Gujarat conditions to study the impact of de-blossoming in six mango varieties during regular flowering season on off season fruiting characters. The investigation consisted of four de-blossoming treatments i.e. foliar sprays of Naphthalene Acetic Acid at 400 and 800 ppm, hand de-blossoming and untreated trees which were imposed on six mango varieties i.e. Amrapali, Baramasi, Neelphanso, Neelum, Ratna and Totapuri. The trial was evaluated in a Randomized Block Design with factorial concept. De-blossoming was done at full bloom stage for induction of off season flowering. Results indicated that in regular season cultivar ‘Totapuri’ recorded significantly higher fruit weight, fruit length, fruit width and fruit volume during 2013-14 and 2014-15. With regard to off-season fruiting, significantly maximum value of the above traits was observed in ‘Ratna’ cultivar. Fruit weight, volume, length and width were lowest in cv. ‘Neelphanso’ in regular as well as in off-season. Hand de-blossoming was found superior over control for fruit weight and fruit volume in all the varieties selected for this study in the coastal climate of South Gujarat.
Unregulated Social Work Practice in Botswana: A Risk to Professional Integrity and Clients’ Welfare
Authors: Jongman Kgomotso , Tshupeng More
Published: May 2020

Through professional regulation, the aspirational goals of the Code of Ethics is to become a legal obligation with enforceable accountability for public protection. The professional regulation does not only protect the public but also gives integrity and respect to the profession. Social workers are licensed and they always know that malpractice may lead to losing their registration and licenses. The above is a reality in many countries, while in Botswana, after 74 years since the first social welfare officer started to work in the welfare department, the country has not yet established any regulatory body. Even though the regulation might not be a guarantee for ethical practice, but it is better to have a framework that can be used to regulate in terms of monitoring and evaluating practice. The education and practice of social work is unregulated and has left a vacuum where, anybody who government deems to be eligible can be employed as social worker. The above statement is buttressed by the Children’s Act, 2009 section 2, which says, ‘a social worker is a person who holds a qualification in social work, or such other qualification as may be prescribed, and is employed as such by government or such other institution as maybe approved under this Act and any other law’. This has brought challenges in dealing with values, principles and standards of social work, teaching and practice in Botswana [1]. The complaint is that social workers are unprofessional and not adhering to their own code of conduct. From the complaints, the assumption is that social work has a code of conduct as a heling profession. The reality is there is no code of conduct and there is no licensure in Botswana. This paper is a narrative of examples of cases where social workers were deemed not adhering to their professional ethics and not providing service to the most vulnerable at the time of need. These stories are used as a yardstick to argue for the establishment of an ACT of parliament which will establish the council of social work. The council will be a regulatory body of social work.
Crystal structure of the Enterococcus faecalis α‐N‐acetylgalactosaminidase, a member of the glycoside hydrolase family 31
Authors: Miyazaki Takatsugu , Park Enoch Y.
Published: May 2020

Glycoside hydrolases catalyze the hydrolysis of glycosidic linkages in carbohydrates. The glycoside hydrolase family 31 (GH31) contains α‐glucosidase, α‐xylosidase, α‐galactosidase, and α‐transglycosylase. Recent work has expanded the diversity of substrate specificity of GH31 enzymes, and α‐N‐acetylgalactosaminidases (αGalNAcases) belonging to GH31 have been identified in human gut bacteria. Here, we determined the first crystal structure of a truncated form of GH31 αGalNAcase from the human gut bacterium Enterococcus faecalis. The enzyme has a similar fold to other reported GH31 enzymes and an additional fibronectin type 3‐like domain. Additionally, the structure in complex with N‐acetylgalactosamine reveals that conformations of the active site residues, including its catalytic nucleophile, change to recognize the ligand. Our structural analysis provides insight into the substrate recognition and catalytic mechanism of GH31 αGalNAcases.
Evolution of white matter damage in amyotrophic lateral sclerosis
Authors: Gabel Matt C. , Broad Rebecca J. , Young Alexandra L. , Abrahams Sharon , Bastin Mark E. , Menke Ricarda A. L. , Al‐Chalabi Ammar , Goldstein Laura H. , Tsermentseli Stella , Alexander Daniel C. , Turner Martin R. , Leigh P. Nigel , Cercignani Mara
Published: May 2020

Objective

To characterize disease evolution in amyotrophic lateral sclerosis using an event‐based model designed to extract temporal information from cross‐sectional data. Conventional methods for understanding mechanisms of rapidly progressive neurodegenerative disorders are limited by the subjectivity inherent in the selection of a limited range of measurements, and the need to acquire longitudinal data.

Methods

The event‐based model characterizes a disease as a series of events, each comprising a significant change in subject state. The model was applied to data from 154 patients and 128 healthy controls selected from five independent diffusion MRI datasets acquired in four different imaging laboratories between 1999 and 2016. The biomarkers modeled were mean fractional anisotropy values of white matter tracts implicated in amyotrophic lateral sclerosis. The cerebral portion of the corticospinal tract was divided into three segments.

Results

Application of the model to the pooled datasets revealed that the corticospinal tracts were involved before other white matter tracts. Distal corticospinal tract segments were involved earlier than more proximal (i.e., cephalad) segments. In addition, the model revealed early ordering of fractional anisotropy change in the corpus callosum and subsequently in long association fibers.

Interpretation

These findings represent data‐driven evidence for early involvement of the corticospinal tracts and body of the corpus callosum in keeping with conventional approaches to image analysis, while providing new evidence to inform directional degeneration of the corticospinal tracts. This data‐driven model provides new insight into the dynamics of neuronal damage in amyotrophic lateral sclerosis.
Cationic Block Copolymer Nanoparticles with Tunable DNA Affinity for Treating Rheumatoid Arthritis
Authors: Wu Jingjiao , Liang Huiyi , Li Yuanchao , Shi Yi , Bottini Massimo , Chen Yongming , Liu Lixin
Published: May 2020

A high concentration of cell‐free DNA (cfDNA) in joints is considered a disease causative agent of rheumatoid arthritis (RA) and cfDNA scavenging has been regarded as an efficient therapeutic avenue. Cationic polymers can hamper progression of joint inflammation in a rat model of RA by scavenging cfDNA; however, they may cause systemic toxicity due to the strong positive charges. To reduce the toxicity, herein a library of cationic nanoparticles (cNPs) of block copolymer micelles is developed and the effects of structure and surface composition on cNP efficacy to bind nucleic acids, toxicity, and therapeutic activity on a collagen induced arthritis (CIA) rat model of RA are assessed. The library includes cNPs with a homoshell from poly(lactic‐co‐glycolic acid)‐block‐poly(2‐(dimethylamino)ethyl methacrylate) (PLGA‐b‐PDMA) block copolymers and cNPs with a mixed shell of poly(ethylene glycol) (PEG) and PDMA by coself‐assembling PLGA‐b‐PDMA and PLGA‐b‐PEG block copolymers. Relatively to the homoshell cNPs, introduction of PEG segments translates into a lower DNA binding efficacy while preserving ability to hamper joint inflammation. Moreover, they show a greater accumulation and longer retention at the inflamed joints, allowing a lower administration frequency. In conclusion, this work shows that the therapeutic index of cationic materials can be tuned by introducing surface neutral moieties.
Predicting prolonged length of stay after endoscopic transsphenoidal surgery for pituitary adenoma
Authors: Vimawala Swar , Chitguppi Chandala , Reilly Erin , Fastenberg Judd H. , Garzon‐Muvdi Tomas , Farrell Christopher , Rabinowitz Mindy R. , Rosen Marc R. , Evans James , Nyquist Gurston G.
Published: May 2020

Background

Endoscopic transsphenoidal surgery (ETS) for the resection of pituitary adenoma has become more common throughout the past decade. Although most patients have a short postoperative hospitalization, others require a more prolonged stay. We aimed to identify predictors for prolonged hospitalization in the setting of ETS for pituitary adenomas.

Methods

A retrospective chart review as performed on 658 patients undergoing ETS for pituitary adenoma at a single tertiary care academic center from 2005 to 2019. Length of stay (LoS) was defined as date of surgery to date of discharge. Patients with LoS in the top 10th percentile (prolonged LoS [PLS] >4 days, N = 72) were compared with the remainder (standard LoS [SLS], N = 586).

Results

The average age was 54 years and 52.5% were male. The mean LoS was 2.1 days vs 7.5 days (SLS vs PLS). On univariate analysis, atrial fibrillation (p = 0.002), hypertension (p = 0.033), partial tumor resection (p < 0.001), apoplexy (p = 0.020), intraoperative cerebrospinal fluid (ioCSF) leak (p = 0.001), nasoseptal flap (p = 0.049), postoperative diabetes insipidus (DI) (p = 0.010), and readmission within 30 days (p = 0.025) were significantly associated with PLS. Preoperative continuous positive airway pressure (CPAP) (odds ratio, 15.144; 95% confidence interval, 2.596‐88.346; p = 0.003) and presence of an ioCSF leak (OR, 10.362; 95% CI, 2.143‐50.104; p = 0.004) remained significant on multivariable analysis.

Conclusion

For patients undergoing ETS for pituitary adenomas, an ioCSF leak or preoperative use of CPAP predicted PLS. Additional common reasons for PLS included postoperative CSF leak (10 of 72), management of DI or hypopituitarism (15 of 72), or reoperation due to surgical or medical complications (14 of 72).
Contributing factors for delayed postoperative cerebrospinal fluid leaks and suggested treatment algorithm
Authors: London Nyall R. , Mohyeldin Ahmed , Montaser Alla S. , Tanjararak Kangsadarn , Prevedello Daniel M. , Otto Bradley A. , Carrau Ricardo L.
Published: May 2020

Background

Delayed postoperative cerebrospinal fluid (CSF) leaks are uncommon and largely unstudied complications. In this study we aim to identify their etiology and understand the efficacy of various reconstruction strategies.

Methods

A retrospective chart analysis of 1017 endonasal skull base surgeries performed by a single neurosurgeon was completed identifying delayed CSF leaks (occurring >1 week after surgery).

Results

Seventeen cases of early (1‐2 weeks after surgery) or delayed (>2 weeks after surgery) postoperative CSF leak were identified. The most common reconstruction during the initial surgery consisted of an inlay or gasket seal collagen matrix (82.4% of patients) with an onlay pedicled flap (76.5% of patients). Presenting symptoms of delayed CSF leak included rhinorrhea (82.4%), headache (41.2%), and meningitis (23.5%). The most common causes included flap dehiscence (17.6%); provoking events such as emesis, sneezing, or fall (17.6%); flap necrosis (11.8%); flap displacement (11.8%); and inadequate apposition of the flap, that is, folded flap (11.8%). Reconstructive techniques of the delayed CSF leak included fortification of the initial reconstruction with free fat grafts (29.4% of patients), combined collagen matrix with a fat graft (23.5% of patients), repositioning of the previous flap (11.8% of patients), and repair with a new flap (11.8% of patients). CSF diversion (spinal/ventricular drain or shunt) was used in 17.6% of patients.

Conclusion

This study identifies the most common etiologic factors leading to a delayed CSF leak and its initial symptoms. Furthermore, it serves as the foundation for a reconstructive algorithm based on reinforcement of the initial repair with free abdominal fat graft with or without collagen matrix.
The Role of Surface Termination in Halide Perovskites for Efficient Photocatalytic Synthesis
Authors: Dong Yuanyuan , Li Kailin , Luo Wenjia , Zhu Cheng , Guan Haoliang , Wang Hao , Wang Lanning , Deng Kailin , Zhou Huanping , Xie Haipeng , Bai Yang , Li Yujing , Chen Qi
Published: May 2020

Halide perovskites have received attention in the field of photocatalysis owing to their excellent optoelectronic properties. However, the semiconductor properties of halide perovskite surfaces and the influence on photocatalytic performance have not been systematically clarified. Now, the conversion of triose (such as 1,3‐dihydroxyacetone (DHA)) is employed as a model reaction to explore the surface termination of MAPbI3. By rational design of the surface termination for MAPbI3, the production rate of butyl lactate is substantially improved to 7719 μg g−1 cat. h−1 under visible‐light illumination. The MAI‐terminated MAPbI3 surface governs the photocatalytic performance. Specially, MAI‐terminated surface is susceptible to iodide oxidation, which thus promotes the exposure of PbII as active sites for this photocatalysis process. Moreover, MAI‐termination induces a p‐doping effect near the surface for MAPbI3, which facilitates carrier transport and thus photosynthesis.
High molecular weight poly(butylene terephthalate‐co‐butylene 2,5‐furan dicarboxylate) copolyesters: From synthesis to thermomechanical and barrier properties
Authors: Zhang Xiaoqin , Ma Shugang , Shen Ang , Zhu Jin , Shen Zhisen , Wang Jinggang , Liu Xiaoqing
Published: May 2020

Poly(butylene terephthalate‐co‐butylene 2,5‐furandicarboxylate) copolyesters (PBTFs) were synthesized from 1,4‐butanediol, dimethyl terephthalate (DMT), and 2,5‐furandicarboxylic acid (FDCA) by a two‐step polymerization method. Their chemical structures were confirmed by Fourier‐transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and carbon nuclear magnetic resonance before thermal properties were explored with differential scanning calorimeter and thermogravimetric analyzer. Results showed that PBTFs changed from semi‐crystalline to completely amorphous when the content of FDCA unit was increased to 45 mol% at first, and then became crystallographic again with the further increment of FDCA unit to 75 mol%. For their mechanical properties, the tensile modulus and strength showed the similar trend, decreasing firstly and then increasing later. Their barrier to carbon dioxide and oxygen became better with the increasing of furan content due to the rigidity and higher polarity of furan ring. The performance of PBTFs copolyesters was investigated clearly, and the relative content of FDCA and DMT can be adjusted to satisfy different performance requirements.
Gas‐Sensing Transcriptional Regulators
Authors: Ganesh Irisappan , Gwon Da‐ae , Lee Jeong Wook
Published: May 2020

Gas molecules are ubiquitous in the environment and are used as nutrient and energy sources for living organisms. Many organisms, therefore, have developed gas‐sensing systems to respond efficiently to changes in the atmospheric environment. In microorganisms and plants, two‐component systems (TCSs) and transcription factors (TFs) are two primary mechanisms to sense gas molecules. In this review, gas‐sensing transcriptional regulators, TCSs, and TFs, focusing on protein structures, mechanisms of gas molecule interaction, DNA binding regions of transcriptional regulators, signal transduction mechanisms, and gene expression regulation are discussed. At first, transcriptional regulators that directly sense gas molecules with the help of a prosthetic group is described and then gas‐sensing systems that indirectly recognize the presence of gas molecules is explained. Overall, this review provides a comprehensive understanding of gas‐sensing transcriptional regulators in microorganisms and plants, and proposes a future perspective on the use of gas‐sensing transcriptional regulators.
Computational Study of Pyrimidin‐2‐Aminopyrazol‐Hydroxamate‐based JAK2 Inhibitors for the Treatment of Myeloproliferative Neoplasms
Authors: Keretsu Seketoulie , Bhujbal Swapnil Pandurang , Cho Seung Joo
Published: May 2020

Janus Kinase 2 (JAK2) plays a vital role in the cytokine‐mediated signaling pathway. Several experimental studies have shown that myeloproliferative neoplasms (MPNs) are associated with the overexpression of JAK2. Hence, JAK2 inhibition is considered to be vital for MPNs therapy. We have performed computational studies on 29 pyrimidin‐2‐aminopyrazol‐hydroxamate‐based JAK2 inhibitors. A comparative molecular field analysis (CoMFA) model (q2 = 0.6 and r2 = 0.94) was developed. Contour maps from the CoMFA model suggested that electronegative groups at the carbonyl and electropositive groups at the hydroxyl were favored for JAK2 activity. Molecular docking and dynamics simulation revealed that the compound with highest activity (compound 13) formed electrostatic interactions with Leu932, Tyr934, Ser936, Asp939, and Tyr940 of JAK2. Binding free energy calculations showed that hydrophobic and H‐bond interactions were the key contributors to the total binding. Results of this study could provide useful insights into designing new JAK2 inhibitors.
Weighted word embeddings and clustering‐based identification of question topics in MOOC discussion forum posts
Authors: Onan Aytuğ , Toçoğlu Mansur Alp
Published: May 2020

Massive open online courses (MOOCs) are recent and widely studied distance learning approaches aimed at providing learning material to learners from geographically dispersed locations without age, gender, or race‐related constraints. MOOCs generally enriched by discussion forums to provide interactions among students, professors, and teaching assistants. MOOC discussion forum posts provide feedback regarding the students' learning processes, social interactions, and concerns. The purpose of our research is to present a document‐clustering model on MOOC discussion forum posts based on weighted word embeddings and clustering to identify question topics on discussion posts. In this study, four word‐embedding schemes (namely, word2vec, fastText, global vectors, and Doc2vec), four weighting functions (i.e., term frequency‐inverse document frequency [IDF], IDF, smoothed IDF, and subsampling function), and four clustering algorithms (i.e., K‐means, K‐means++, self‐organizing maps, and divisive analysis clustering algorithm) for document clustering and topic modeling on MOOC discussion forum posts have been evaluated. Twenty different feature representations obtained from word‐embedding schemes and weighting functions have been obtained. The feature representation schemes have been evaluated in conjunction with four clustering methods. For the evaluation task, the empirical results for the latent Dirichlet allocation have been also included. The empirical results in terms of adjusted rand index, normalized mutual information, and adjusted mutual information indicate that weighted word‐embedding schemes combined with clustering algorithms outperform the conventional schemes.
Sentiment analysis on massive open online course evaluations: A text mining and deep learning approach
Authors: ONAN Aytuğ
Published: May 2020

Massive open online courses (MOOCs) are recent innovative approaches in distance education, which provide learning content to participants without age‐, gender‐, race‐, or geography‐related barriers. The purpose of our research is to present an efficient sentiment classification scheme with high predictive performance in MOOC reviews, by pursuing the paradigms of ensemble learning and deep learning. In this contribution, we seek to answer several research questions on sentiment analysis on educational data. First, the predictive performance of conventional supervised learning methods, ensemble learning methods and deep learning methods has been evaluated. Besides, the efficiency of text representation schemes and word‐embedding schemes has been evaluated for sentiment analysis on MOOC evaluations. For the evaluation task, we have analyzed a corpus containing 66,000 MOOC reviews, with the use of machine learning, ensemble learning, and deep learning methods. The empirical analysis indicate that deep learning‐based architectures outperform ensemble learning methods and supervised learning methods for the task of sentiment analysis on educational data mining. For all the compared configurations, the highest predictive performance has been achieved by long short‐term memory networks in conjunction with GloVe word‐embedding scheme‐based representation, with a classification accuracy of 95.80%.
Robotic‐assisted balloon angioplasty and stent placement with distal embolic protection device for severe carotid artery stenosis in a high‐risk surgical patient
Authors: George Jon C. , Tabaza Luai , Janzer Sean
Published: May 2020

The use of robotic assistance in endovascular interventions may facilitate smoother procedures with fewer device manipulations, improve precision and accuracy of device deployment, and reduce exposure to fluoroscopic radiation. We used the CorPath GRX Robotic System for carotid balloon angioplasty and stent placement in a patient with limited surgical options.
Impact of coronavirus disease 2019 (COVID‐19) outbreak on outcome of myocardial infarction in Hong Kong, China
Authors: Tam Chor‐Cheung Frankie , Cheung Kent‐Shek , Lam Simon , Wong Anthony , Yung Arthur , Sze Michael , Fang Jonathan , Tse Hung‐Fat , Siu Chung‐Wah
Published: May 2020

Objective

To determine whether COVID‐19 may adversely affect outcome of myocardial infarction (MI) patients in Hong Kong, China.

Background

The COVID‐19 pandemic has infected thousands of people and placed enormous stress on healthcare system. Apart from being an infectious disease, it may affect human behavior and healthcare resource allocation which potentially cause treatment delay in MI.

Methods

This was a single center cross‐sectional observational study. From November 1, 2019 to March 31, 2020, we compared outcome of patients admitted for acute ST‐elevation MI (STEMI) and non‐ST elevation MI (NSTEMI) before (group 1) and after (group 2) January 25, 2020 which was the date when Hong Kong hospitals launched emergency response measures to combat COVID‐19.

Results

There was a reduction in daily emergency room attendance since January 25, 2020 (group 1,327/day vs. group 2,231/day) and 149 patients with diagnosis of MI were included into analysis (group 1 N = 85 vs. group 2 N = 64). For STEMI, patients in group 2 tended to have longer symptom‐to‐first medical contact time and more presented out of revascularization window (group 1 27.8 vs. group 2 33%). The primary composite outcome of in‐hospital death, cardiogenic shock, sustained ventricular tachycardia or fibrillation (VT/VF) and use of mechanical circulatory support (MCS) was significantly worse in group 2 (14.1 vs. 29.7%, p = .02).

Conclusions

More MI patients during COVID‐19 outbreak had complicated in‐hospital course and worse outcomes. Besides direct infectious complications, cardiology community has to acknowledge the indirect effect of communicable disease on our patients and system of care.
How Lanthanide Ions Affect the Addition–Elimination Step of Methanol Dehydrogenases
Authors: Prejanò Mario , Russo Nino , Marino Tiziana
Published: May 2020

The recently discovered methanol dehydrogenase, XoxF, is a widespread enzyme used by methylotrophic bacteria to oxidize methanol for carbon and energy, and requires lanthanide ions for its activity. This enzyme represents an essential component of methanol utilization by both methanol‐ and methane‐utilizing bacteria. The present investigation looks on the electronic, energetic and geometrical behavior of the methanol dehydrogenase from Methylacidiphilum fumariolicum SolV, which is strictly dependent on early lanthanide metals with +3 oxidation states, by examining enzyme‐substrate complexes of all the lanthanides. We focus on the catalytic reaction mechanism of two methanol dehydrogenases having as cofactor europium and ytterbium belonging to the mid‐ and later‐ series of lanthanides, in comparison with the methanol dehydrogenase containing the cerium, one early lanthanide. Our results provide evidence for the influence of the lanthanide contraction effect in all the elementary steps of the catalytic reaction mechanism. This indication may prove useful for developing new catalytic machineries of enzymes that adopt new‐to‐nature transformations.
Regioselective 3‐O‐Substitution of Unprotected Thiodigalactosides: Direct Route to Galectin Inhibitors
Authors: Vašíček Tomáš , Spiwok Vojtěch , Červený Jakub , Petrásková Lucie , Bumba Ladislav , Vrbata David , Pelantová Helena , Křen Vladimír , Bojarová Pavla
Published: May 2020

The synthesis of tailored bioactive carbohydrates usually comprises challenging (de)protection steps, which lowers synthetic yields and increases time demands. We present here a regioselective single‐step introduction of benzylic substituents at 3‐hydroxy groups of β‐d‐galactopyranosyl‐(1→1)‐thio‐β‐d‐galactopyranoside (TDG) employing dibutyltin oxide in good yields. These glycomimetics act as inhibitors of galectins—human lectins, which are biomedically attractive targets for therapeutic inhibition in, for example, cancerogenesis. The affinity of the prepared glycomimetics to galectin‐1 and galectin‐3 was studied in enzyme‐linked immunosorbent (ELISA)‐type assays and their potential to inhibit galectin binding on the cell surface was shown. We used our original in vivo biotinylated galectin constructs for easy detection by flow cytometry. The results of the biological experiments were compared with data from molecular modeling with both galectins. The present work reveals a facile and elegant synthetic route for the preparation of TDG‐derived glycomimetics that exhibit differing selectivity and affinity to galectins depending on the choice of 3‐O‐substitution.
Controllable Skeleton Rearrangement of 3‐Substituted Cyclobutanones under Basic Conditions†
Authors: Yan Peng , Zhou Qiang , Chen Jun , Lu Ping
Published: May 2020

Summary of main observation and conclusion

Divergent skeleton rearrangements of cyclobutanones under simply basic conditions have been described. The reaction pathway is controlled by the nature of Z group on 3‐substituted cyclobutanones, leading to the formation of various lactones, lactams and acids. Preliminary results on enantioselective reaction were also reported.
Projections between visual cortex and pulvinar in the rat
Authors: Scholl Leo R. , Foik Andrzej T. , Lyon David C.
Published: May 2020

The extrageniculate visual pathway, which carries visual information from the retina through the superficial layers of the superior colliculus and the pulvinar, is poorly understood. The pulvinar is thought to modulate information flow between cortical areas, and has been implicated in cognitive tasks like directing visually guided actions. In order to better understand the underlying circuitry, we performed retrograde injections of modified rabies virus in the visual cortex and pulvinar of the Long‐Evans rat. We found a relatively small population of cells projecting to primary visual cortex (V1), compared to a much larger population projecting to higher visual cortex. Reciprocal corticothalamic projections showed a similar result, implying that pulvinar does not play as big a role in directly modulating rodent V1 activity as previously thought.
Perceptual rivalry across animal species
Authors: Carter Olivia , van Swinderen Bruno , Leopold David A. , Collin Shaun P. , Maier Alexander
Published: May 2020

This review in memoriam of Jack Pettigrew provides an overview of past and current research into the phenomenon of multistable perception across multiple animal species. Multistable perception is characterized by two or more perceptual interpretations spontaneously alternating, or rivaling, when animals are exposed to stimuli with inherent sensory ambiguity. There is a wide array of ambiguous stimuli across sensory modalities, ranging from the configural changes observed in simple line drawings, such as the famous Necker cube, to the alternating perception of entire visual scenes that can be instigated by interocular conflict. The latter phenomenon, called binocular rivalry, in particular caught the attention of the late Jack Pettigrew, who combined his interest in the neuronal basis of perception with a unique comparative biological approach that considered ambiguous sensation as a fundamental problem of sensory systems that has shaped the brain throughout evolution. Here, we examine the research findings on visual perceptual alternation and suppression in a wide variety of species including insects, fish, reptiles, and primates. We highlight several interesting commonalities across species and behavioral indicators of perceptual alternation. In addition, we show how the comparative approach provides new avenues for understanding how the brain suppresses opposing sensory signals and generates alternations in perceptual dominance.
Transportable Mononuclear Metal Atoms as Building Blocks for Bottom‐up Material Fabrication: Pt1(0) and Au1(0) Atoms in Stock Solutions
Authors: Li Huixiang , Liang Changhui , Gao Pan , Hou Guangjin , Liu Kairui , Liu Wei , Jiang Qike , Bai Shi , Zhang Z. Conrad
Published: May 2020

Premade and readily transportable mononuclear zero‐valent metal atoms in stock solvents offer the potential capability for bottom‐up designable metallic material fabrication. This work demonstrates a potentially universal and practical strategy to prepare weakly shielded mononuclear metal atoms in a volatile solvent, which also constitutes a strippable ligand to the metal atoms. Herein, M1(0) (M=Pt, Au) atoms are prepared by reducing H2PtCl6 and HAuCl4 with ethanol in ethylene glycol diethyl ether (EGDE) under mild temperatures. The diether oxygens of EGDE, H+, and Cl− coordinating to the M1(0) atoms, make the M1(0) atoms stable in the solvent under low pH. However, the M1(0) atoms can be released either by evaporation of HCl and EGDE or through neutralization of the HCl with a base. The premade M1(0) atoms can be used as primary building blocks to construct designable materials. To demonstrate a potential application, the M1(0) atoms are conveniently transported onto the surface of TiO2 through impregnation followed by mild heating. The atomic dispersion and reduced state of the metal atoms are well preserved, as verified by HAADF‐STEM images, XPS, and DRIFT spectroscopy.
Recent Advances in Activatable Organic Photosensitizers for Specific Photodynamic Therapy
Authors: Liu Ming , Li Changhua
Published: May 2020

Photodynamic therapy is an alternative modality for the therapy of diseases such as cancer in a minimally invasive manner. The essential photosensitizer, which acts as a catalyst when absorbing light, converts oxygen into cytotoxic reactive oxygen species that ablate malignant cells through apoptosis and/or necrosis, destroy tumor microvasculature, and stimulate immunity. An activatable photosensitizer whose photoactivity could be turned on by a specific disease biomarker is capable of distinguishing healthy cells from diseased cells, thereby reducing off‐target photodamage. In this Minireview, we highlight progress in activatable organic photosensitizers over the past five years, including: (i) biorthogonal activatable BODIPYs; (ii) activatable Se‐rhodamine with single‐cell resolution; (iii) silicon phthalocyanine targeting oxygen tension; (iv) general D‐π‐A scaffolds; and (v) AIEgens. The potential challenges and opportunities for developing new types of activatable organic photosensitizers to overcome the hypoxia dilemmas of photodynamic therapy are discussed.
Anthracene−Pentacene Dyads: Synthesis and OFET Characterization
Authors: Hauschild Miriam , Chen Lan , Etschel Sebastian H. , Ferguson Michael J. , Hampel Frank , Halik Marcus , Tykwinski Rik R.
Published: May 2020

The synthesis of a series of unsymmetrical derivatives of pentacene appended with functionalized anthracene moieties is reported. These anthracene−pentacene dyads have been characterized by UV‐vis spectroscopy and cyclic voltammetry to examine their electronic properties. X‐ray crystallographic analysis was used to examine the solid‐state features of anthracene−pentacene dyads 1 a–d with H−, F−, Cl−, and Br− substituents on the 9‐position of anthracene, and shows that the packing arrangement of anthracene−pentacene derivatives 1 b,d,e are remarkably similar irrespective of the presence of fluoride, bromide or methyl substituents. The pentacene−anthracene dyads have been incorporated into OTFTs to evaluate their semiconducting properties. The pentacene derivative 1 b shows ambipolar behavior using AlOx C14PA as the gate dielectric (electron and hole mobilities of 7.6 ⋅ 10−3 and 1.6 ⋅ 10−1 cm2 V−1 s−1), while performance of all derivatives was poor using p‐doped Silicon as the substrate. These studies highlight the importance of thin‐film formation over molecular structure.
Robustness of close‐kin mark–recapture estimators to dispersal limitation and spatially varying sampling probabilities
Authors: Conn Paul B. , Bravington Mark V. , Baylis Shane , Ver Hoef Jay M.
Published: May 2020

Close‐kin mark–recapture (CKMR) is a method for estimating abundance and vital rates from kinship relationships observed in genetic samples. CKMR inference only requires animals to be sampled once (e.g., lethally), potentially widening the scope of population‐level inference relative to traditional monitoring programs.

One assumption of CKMR is that, conditional on individual covariates like age, all animals have an equal probability of being sampled. However, if genetic data are collected opportunistically (e.g., via hunters or fishers), there is potential for spatial variation in sampling probability that can bias CKMR estimators, particularly when genetically related individuals stay in close proximity.

We used individual‐based simulation to investigate consequences of dispersal limitation and spatially biased sampling on performance of naive (nonspatial) CKMR estimators of abundance, fecundity, and adult survival. Population dynamics approximated that of a long‐lived mammal species subject to lethal sampling.

Naive CKMR abundance estimators were relatively unbiased when dispersal was unconstrained (i.e., complete mixing) or when sampling was random or subject to moderate levels of spatial variation. When dispersal was limited, extreme variation in spatial sampling probabilities negatively biased abundance estimates. Reproductive schedules and survival were well estimated, except for survival when adults could emigrate out of the sampled area. Incomplete mixing was readily detected using Kolmogorov–Smirnov tests.

Although CKMR appears promising for estimating abundance and vital rates with opportunistically collected genetic data, care is needed when dispersal limitation is coupled with spatially biased sampling. Fortunately, incomplete mixing is easily detected with adequate sample sizes. In principle, it is possible to devise and fit spatially explicit CKMR models to avoid bias under dispersal limitation, but development of such models necessitates additional complexity (and possibly additional data). We suggest using simulation studies to examine potential bias and precision of proposed modeling approaches prior to implementing a CKMR program.
Ringed seal (Pusa hispida) seasonal movements, diving, and haul‐out behavior in the Beaufort, Chukchi, and Bering Seas (2011–2017)
Authors: Von Duyke Andrew L. , Douglas David C. , Herreman Jason K. , Crawford Justin A.
Published: May 2020

Continued Arctic warming and sea‐ice loss will have important implications for the conservation of ringed seals, a highly ice‐dependent species. A better understanding of their spatial ecology will help characterize emerging ecological trends and inform management decisions. We deployed satellite transmitters on ringed seals in the summers of 2011, 2014, and 2016 near Utqiaġvik (formerly Barrow), Alaska, to monitor their movements, diving, and haul‐out behavior. We present analyses of tracking and dive data provided by 17 seals that were tracked until at least January of the following year. Seals mostly ranged north of Utqiaġvik in the Beaufort and Chukchi Seas during summer before moving into the southern Chukchi and Bering Seas during winter. In all seasons, ringed seals occupied a diversity of habitats and spatial distributions, from near shore and localized, to far offshore and wide‐ranging in drifting sea ice. Continental shelf waters were occupied for >96% of tracking days, during which repetitive diving (suggestive of foraging) primarily to the seafloor was the most frequent activity. From mid‐summer to early fall, 12 seals made ~1‐week forays off‐shelf to the deep Arctic Basin, most reaching the retreating pack‐ice, where they spent most of their time hauled out. Diel activity patterns suggested greater allocation of foraging efforts to midday hours. Haul‐out patterns were complementary, occurring mostly at night until April‐May when midday hours were preferred. Ringed seals captured in 2011—concurrent with an unusual mortality event that affected all ice‐seal species—differed morphologically and behaviorally from seals captured in other years. Speculations about the physiology of molting and its role in energetics, habitat use, and behavior are discussed; along with possible evidence of purported ringed seal ecotypes.
Experiencing Community in a Covid Surge
Authors: Mukherjee Debjani
Published: May 2020

As I organize a pile of ethics consult chart notes in New York City in mid‐April 2020, I look at the ten cases that I have co‐consulted on recently. Nine of the patients were found to be Covid positive. The reasons for the consults are mostly familiar—surrogate decision‐making, informed refusal of treatment, goals of care, defining futility. But the context is unfamiliar and unsettling. Bioethicists are in pandemic mode, dusting off and revising triage plans. Patients and potential patients are fearful—of the disease itself and of the amplification of health disparities and inequities. There is much to contemplate, but as I go through my cases, I worry about disability, about biases and racist stereotypes. In this pandemic, historically marginalized communities are at risk of further disenfranchisement.
Do southern Appalachian Mountain summer stream temperatures respond to removal of understory rhododendron thickets?
Authors: Raulerson Scott , Jackson C. Rhett , Melear Nathan D. , Younger Seth E. , Dudley Maura , Elliott Katherine J.
Published: May 2020

Dense understory thickets of the native evergreen shrubRhododendron maximumexpanded initially following elimination of American chestnut by the chestnut blight, and later in response to loss of the eastern hemlock due to hemlock woolly adelgid invasion. Rhododendron thickets often blanket streams and their riparian zones, creating cool, low‐light microclimates. To determine the effect of such understory thickets on summer stream temperatures, we removed riparian rhododendron understory on 300 m reaches of two southern Appalachian Mountain headwater streams, while leaving two 300 m reference reaches undisturbed. Overhead canopy was left intact in all four streams, but all streams were selected to have a significant component of dead or dying eastern hemlock in the overstory, creating time‐varying canopy gaps throughout the reach. We continuously monitored temperatures upstream, within and downstream of treatment and reference reaches. Temperatures were monitored in all four streams in the summer before treatments were imposed (2014), and for two summers following treatment (2015, 2016). Temperatures varied significantly across and within streams prior to treatment and across years for the reference streams. After rhododendron removal, increases in summer stream temperatures were observed at some locations within the treatment reaches, but these increases did not persist downstream and varied by watershed, sensor, and year. Significant increases in daily maxima in treatment reaches ranged from 0.9 to 2.6°C. Overhead canopy provided enough shade to prevent rhododendron removal from increasing summer temperatures to levels deleterious to native cold‐water fauna (average summer temperatures remained below 16°C), and local temperature effects were not persistent.
Transpiration and evaporation of grassland using land surface modelling
Authors: Ma Wenchao , Wei Zhongwang , Wang Pei , Asanuma Jun
Published: May 2020

Partitioning transpiration (T) from evapotranspiration (ET) is a key process for understanding the interaction between land surfaces and the atmosphere. This paper reports daily partitioning results for a grassland over a 10‐year period, obtained using the Community Land Model 3.5 (CLM3.5) land surface model. Hourly forcing data were collected from a long‐term observation system located in the northeast of Japan (http://doi.org/10.24575/0001.198108). To test the model behavior, total ET was validated using eddy correlation measurements combined with the energy balance method. The results were compared with previous research using an isotope approach for partitioning. The results demonstrate that our model can capture the dynamics of ET and its components at this location. Evaporation (E), originating from the ground and canopy, varied inter‐annually, and from 2006 to 2015, average annual E was approximately 285 mm/year from the ground and 45 mm/year from the canopy. Average, T, was approximately 302 mm/year, accounting for approximately 48% of the total ET. Inter‐annual results demonstrate that the water flux transported by vegetation ranges from 17 to 83% during the April–October period. A sensitivity test conducted with forcing data indicates air temperature, incident solar radiation, and longwave radiation exhibited a notable effect on all ET components. Relative humidity exhibited the only negative feedback to both evaporation and transpiration, contrary to the other forcing parameters. Our study reemphasized the effectiveness of CLM3.5 in partitioning T from ET and in understanding the complex interaction between land surfaces and the atmosphere.
Supertetragonal Phases of Perovskite Oxides: Insights from Electronic Structure Calculations
Authors: Cohen Netanela , Diéguez Oswaldo
Published: May 2020

We review some of the insights that electronic‐structure calculations has brought about the properties of the materials with the largest electric polarization known – supertetragonal perovskite oxides. These are materials whose structure corresponds to a perovskite that has been substantially strechted along one of its pseudocubic axes. They grow in different forms: bulk crystals (such as BiCoO3), epitaxial films (such as BiFeO3), nanowires whose inside is under negative pressure (such as PbTiO3), and others. Electronic structure calculations based on density‐functional theory have revealed that supertetragonality potentially exist for many perovskite oxides under the right conditions, and they have helped explain why some of those conditions are easy to reach for some of the materials of the family, but not for others.
Effectiveness of a COVID‐19 screening questionnaire for pregnant women at admission to an obstetric unit in Milan
Authors: Tassis Beatrice , Lunghi Giovanna , Frattaruolo Maria P. , Ruggiero Marta , Somigliana Edgardo , Ferrazzi Enrico
Published: May 2020

Screening for SARS‐Cov‐2 at hospital admission using a specific questionnaire is less effective than nasopharyngeal swab but more sustainable, hence it can be considered in contexts with low incidence of the virus.
Numerical modelling of contracted sharp‐crested weirs and combined weir and gate systems
Authors: Altan‐Sakarya A. Burcu , Kokpinar M. Ali , Duru Aysel
Published: May 2020

Discharge measurement and control structures are widely employed in hydraulic engineering applications. The objective of this study is to numerically investigate the modelling of two different structures, namely sharp‐crested weirs as Problem 1 and combined weir and gate systems as Problem 2. The research methodology herein is based on the comparison of results of numerical simulations with experimental data for both problems separately. For the purpose of performing numerical simulations, the Reynolds‐averaged Navier–Stokes (RANS) equations are solved by finite volume formulation using commercially available Flow‐3D software. Assessment of empirical data and numerical findings for both problems reveals that discharge rates agree reasonably well. In addition, using the capabilities of numerical modelling, weir and gate discharge coefficients in the combined system are calculated separately which were not easy to obtain in experimental studies. It is seen that gate and weir discharge coefficients of the combined system are different and higher than the corresponding coefficients of the individual systems. © 2020 John Wiley & Sons, Ltd.