bluuebunny/crossref_metadata_2025 huggingface dataset:
Conformational Studies of Oligosaccharides
Authors: Yu Yang , Delbianco Martina
Published: April 2020

The conformation of a molecule strongly affects its function, as demonstrated for peptides and nucleic acids. This correlation is much less established for carbohydrates, the most abundant organic materials in nature. Recent advances in synthetic and analytical techniques have enabled the study of carbohydrates at the molecular level. Recurrent structural features were identified as responsible for particular biological activities or material properties. In this Minireview, recent achievements in the structural characterization of carbohydrates, enabled by systematic studies of chemically defined oligosaccharides, are discussed. These findings can guide the development of more potent glycomimetics. Synthetic carbohydrate materials by design can be envisioned.
Experimental Validation of a Multidimensional Model for an Indirect Temperature Swing Adsorption Unit
Authors: Ried Thomas , Salazar Duarte Gabriel , Hinrichsen Olaf
Published: April 2020

Conventional temperature swing adsorption (TSA) is mainly applied for the removal of trace contaminants. Indirectly heated and cooled adsorbers were developed to make bulk separation economically feasible. A quasi‐continuous TSA process to remove CO2 from an N2/CO2 mixture with a pilot plant is established. The experimentally determined data are taken to validate and to adjust a 2D simulation model. For the validation, the CO2 desorption, the N2 recovery rate as well as the axial temperature profile are compared. The successful model validation can be seen in the good agreement between simulation and experimental results. Moreover, this process is able to separate high amounts of CO2 and to produce a nearly CO2‐free product stream.
Experiences in porting mini‐applications to OpenACC and OpenMP on heterogeneous systems
Authors: Vergara Larrea Verónica G. , Budiardja Reuben D. , Gayatri Rahulkumar , Daley Christopher , Hernandez Oscar , Joubert Wayne
Published: April 2020

This article studies mini‐applications—Minisweep, GenASiS, GPP, and FF—that use computational methods commonly encountered in HPC. We have ported these applications to develop OpenACC and OpenMP versions, and evaluated their performance on Titan (Cray XK7 with K20x GPUs), Cori (Cray XC40 with Intel KNL), Summit (IBM AC922 with Volta GPUs), and Cori‐GPU (Cray CS‐Storm 500NX with Intel Skylake and Volta GPUs). Our goals are for these new ports to be useful to both application and compiler developers, to document and describe the lessons learned and the methodology to create optimized OpenMP and OpenACC versions, and to provide a description of possible migration paths between the two specifications. Cases where specific directives or code patterns result in improved performance for a given architecture are highlighted. We also include discussions of the functionality and maturity of the latest compilers available on the above platforms with respect to OpenACC or OpenMP implementations.
Correlation of Physicochemical and Antimicrobial Properties of Liposomes Loaded with (+)‐Usnic Acid
Authors: Battista Sara , Bellio Pierangelo , Celenza Giuseppe , Galantini Luciano , Franceschini Irene , Mancini Giovanna , Giansanti Luisa
Published: April 2020

(+)‐Usnic acid (UA) is a natural substance that displays pharmacological activity, but it is barely soluble in water, so it was included in liposomes in order to study its properties. First, the effects of phospholipid structure and loading methodology on UA entrapment efficacy were evaluated. Then, the physicochemical and biological properties (UA delivery efficacy to Staphylococcus aureus bacterial cells) of different liposome formulations containing structurally related amphiphiles derived from L‐prolinol were fully investigated. Entrapment efficiency of UA with passive loading by incubation was 80–100 molar percentage, which is related to lipophilicity of the drug and to the packing and fluidity of the bilayer. Some of the investigated formulations show the potential of UA in delivery systems (minimum inhibitory concentration of liposomal UA: 8 μg/mL) and even subtle variations of the molecular structure of lipids can significantly affect the liposomes’ physicochemical properties and efficiency of drug release.
Zinc and Cadmium Complexes of Pyridinemethanol Carboxylates: Metal Carboxylate Zwitterions and Metal–Organic Frameworks
Authors: Liu Yan , Lin Shi‐Xin , Niu Ru‐Jie , Liu Quan , Zhang Wen‐Hua , Young David J.
Published: April 2020

The heterofunctional lactone furo[3,4‐b]pyridin‐5(7H)‐one (L1) undergoes a coordination‐induced ring‐opening reaction with Zn(NO3)2 ⋅ 6H2O to yield the zwitterionic [Zn(L1′)2(H2O)2] (1, L1′=2‐(hydroxymethyl)nicotinate) with an uncoordinated carboxylate. The same reaction with Cd(NO3)2 ⋅ 4H2O provides a two‐dimensional (2D) network of [Cd(L1′)2]n (3) with the carboxylates coordinated to cadmium(II) propagating the assembly. The corresponding reactions of Zn(NO3)2 ⋅ 6H2O and Cd(NO3)2 ⋅ 4H2O with 2‐(hydroxymethyl)isonicotinic acid (HL2) generated zwitterionic [Zn(L2)2(H2O)2] (2) and a 2D network [Cd(L2)2]n⋅nDMF (4, DMF=N,N′‐dimethylformamide), respectively. Complexes 1–4 are weakly emissive, giving ligand‐centered emissions at 409 nm (1), 412/436 nm (2), 404 nm (3), and 412/436 nm (4) in CHCl3 solutions upon excitation at 330 nm. This work points to the potential of using ‘hidden’ functionalities widely found in small organic molecules and natural products for the construction of coordination complexes with new functionality and potential applications.
N‐Alkylated C‐Glycosyl Amino Acid Derivatives: Synthesis by a One‐Pot Four‐Component Ugi Reaction
Authors: Vlahoviček‐Kahlina Kristina , Štefanić Zoran , Vazdar Katarina , Jerić Ivanka
Published: April 2020

C‐glycosides represent an important group of naturally occurring glycosylation derivatives but are also efficient mimetics of native O‐glycosides. Here, a one‐pot four‐component methodology is described toward a library of N‐alkylated C‐glycosyl amino acid derivatives comprising seven different isopropylidene‐protected carbohydrate units. The applied methodology tolerates different amines and isocyanides and provides access to Ugi products in yields up to 85 %. X‐ray analysis of selected products bearing three different carbohydrate motifs and comparison of their crystal structures with similar ones deposited in Cambridge Crystallographic Database revealed that four structures adopt different conformations, mostly not typical for peptide structures. This property opens the possibility to exploit here described N‐alkylated C‐glycosyl amino acid derivatives as templates to access different biotic and abiotic secondary structures.
Genotyping‐by‐sequencing and ecological niche modeling illuminate phylogeography, admixture, and Pleistocene range dynamics in quaking aspen (Populus tremuloides)
Authors: Bagley Justin C. , Heming Neander M. , Gutiérrez Eliécer E. , Devisetty Upendra K. , Mock Karen E. , Eckert Andrew J. , Strauss Steven H.
Published: April 2020

Populus tremuloides is the widest‐ranging tree species in North America and an ecologically important component of mesic forest ecosystems displaced by the Pleistocene glaciations. Using phylogeographic analyses of genome‐wide SNPs (34,796 SNPs, 183 individuals) and ecological niche modeling, we inferred population structure, ploidy levels, admixture, and Pleistocene range dynamics of P. tremuloides, and tested several historical biogeographical hypotheses. We found three genetic lineages located mainly in coastal–Cascades (cluster 1), east‐slope Cascades–Sierra Nevadas–Northern Rockies (cluster 2), and U.S. Rocky Mountains through southern Canadian (cluster 3) regions of the P. tremuloides range, with tree graph relationships of the form ((cluster 1, cluster 2), cluster 3). Populations consisted mainly of diploids (86%) but also small numbers of triploids (12%) and tetraploids (1%), and ploidy did not adversely affect our genetic inferences. The main vector of admixture was from cluster 3 into cluster 2, with the admixture zone trending northwest through the Rocky Mountains along a recognized phenotypic cline (Utah to Idaho). Clusters 1 and 2 provided strong support for the “stable‐edge hypothesis” that unglaciated southwestern populations persisted in situ since the last glaciation. By contrast, despite a lack of clinal genetic variation, cluster 3 exhibited “trailing‐edge” dynamics from niche suitability predictions signifying complete northward postglacial expansion. Results were also consistent with the “inland dispersal hypothesis” predicting postglacial assembly of Pacific Northwestern forest ecosystems, but rejected the hypothesis that Pacific‐coastal populations were colonized during outburst flooding from glacial Lake Missoula. Overall, congruent patterns between our phylogeographic and ecological niche modeling results and fossil pollen data demonstrate complex mixtures of stable‐edge, refugial locations, and postglacial expansion within P. tremuloides. These findings confirm and refine previous genetic studies, while strongly supporting a distinct Pacific‐coastal genetic lineage of quaking aspen.
Greater root phosphatase activity of tropical trees at low phosphorus despite strong variation among species
Authors: Guilbeault‐Mayers Xavier , Turner Benjamin L. , Laliberté Etienne
Published: April 2020

Soil phosphorus (P) availability in lowland tropical rainforests influences the distribution and growth of tropical tree species. Determining the P‐acquisition strategies of tropical tree species could therefore yield insight into patterns of tree β‐diversity across edaphic gradients. In particular, the synthesis of root phosphatases is likely to be of significance given that organic P represents a large pool of potentially available P in tropical forest soils. It has also been suggested that a high root phosphatase activity in putative nitrogen (N) ‐fixing legumes might explain their high abundance in lowland neotropical forests under low P supply. Here, we measured phosphomonoesterase (PME) activity on the first three root orders of co‐occurring tropical tree species differing in their N‐fixation capacity, growing on soils of contrasting P availability in Panama. Our results show that root PME activity was higher on average in P‐poor than in P‐rich soils, but that local variation in PME activity among co‐occurring species within a site was larger than that explained by differences in soil P across sites. Legumes expressed higher PME activity than nonlegumes, but nodulated legumes (i.e., actively fixing nitrogen) did not differ from legumes without nodules, indicating that PME activity is unrelated to N fixation. Finally, PME activity declined with increasing root order, but the magnitude of the decline varied markedly among species, highlighting the importance of classifying fine roots into functional groups prior to measuring root traits. Our results support the hypothesis that low‐P promotes a high root PME activity, although the high local variation in this trait among co‐occurring species points toward a high functional diversity in P‐acquisition strategies within an individual community.
Versatile Binding Modes of Chiral Macrocyclic Amine towards Rare Earth Ions
Authors: Wydra Karol , Kobyłka Michał J. , Lis Tadeusz , Ślepokura Katarzyna , Lisowski Jerzy
Published: April 2020

Depending on the reaction conditions, the enantiopure macrocycle H3L containing three phenolic units is able to form mono‐ and trinuclear coordination compounds with rare earth metal ions. In these complexes this macrocycle can act as protonated H4L+, neutral H3L, monodeprotonated H2L–, bis‐deprotonated HL2– or tris‐deprotonated L3– ligand. X‐ray crystal structure of the Y(III) derivative of the protonated macrocycle shows highly folded conformation of the ligand with N2O3 set of donor atoms, while the structure of the Y(III) complex of the monodeprotonated macrocycle shows more regular helically twisted conformation of the ligand. Under basic conditions trinuclear complexes of the type [M3L(OH)2] are formed with most of rare earth ions, where the macrocycle acts as N6O3 ligand. This type of complex is not formed for the La(III) and Ce(III) ions of the largest radii within the lanthanide(III) series, instead trinuclear complexes of the type [M3L2] are formed. The X‐ray crystal structures of La(III) complex with fully deprotonated or bis‐deprotonated macrocycles indicate that each macrocyclic unit binds only two metal ions, while one of them is shared by two macrocycles.
A Comparative Experimental and Computational Study of Heterometallic Fe‐M (M = Cu, Ag, Au) Carbonyl Clusters Containing N‐Heterocyclic Carbene Ligands
Authors: Berti Beatrice , Bortoluzzi Marco , Cesari Cristiana , Femoni Cristina , Iapalucci Maria Carmela , Mazzoni Rita , Zacchini Stefano
Published: April 2020

The [Fe(CO)4{M(NHC)}]– (M = Cu, NHC = IMes, 1; M = Cu, NHC = IPr, 2; M = Ag, NHC = IMes, 3; M = Ag, NHC = IPr, 4; IMes = C3N2H2(C6H2Me3)2; IPr = C3N2H2(C6H3iPr2)2) mono‐anions were obtained from the reaction of Na2[Fe(CO)4]·2thf with one equivalent of M(NHC)Cl (M = Cu, Ag; NHC = IMes, IPr) in dmso. Furthermore, the reaction of Na2[Fe(CO)4]·2thf with two equivalents of M(NHC)Cl in thf afforded the neutral compounds Fe(CO)4{M(NHC)}2 (M = Cu, NHC = IMes, 11; M = Cu, NHC = IPr, 12; M = Ag, NHC = IMes, 13; M = Ag, NHC = IPr, 14). 2 and 4 further reacted with one equivalent of M(IPr)Cl (M = Cu, Ag, Au) resulting in the trimetallic clusters Fe(CO)4{Cu(IPr)}{Ag(IPr)} (18), Fe(CO)4{Cu(IPr)}{Au(IPr)} (19), and Fe(CO)4{Ag(IPr)}{Au(IPr)} (20). 1–4, 11–14 and 18–20 have been spectroscopically characterized by IR, 1H and13C{1H} NMR techniques. The molecular structures of 2, 12, 18, 19 and 20 have been determined through single‐crystal X‐ray diffraction. The structure, bonding and stability of the copper and silver IMes derivatives were compared to the related Fe‐Au clusters previously reported on the basis of theoretical calculations. Stability of the Fe–M bonds decreases in the order Au > Cu > Ag, and the same trend was found for what concerns the M‐IMes interactions. The decomposition products of 1–4, 11–14 and 18–20 have been studied allowing, among the others, the structural characterization of the new species [Fe2(CO)8{Ag(IPr)}]– (10) and Fe(CO)4(CH2IMes) (21).
Enhanced Charge Separation and Transfer of Fe2O3@Nitrogen‐Rich Carbon Nitride Tubes for Photocatalytic Water Splitting
Authors: Zhao Chen , Zheng Mang , Wang Dan , Li Qi , Jiang Baojiang
Published: April 2020

Carbon nitride is widely used in photocatalytic hydrogen production, but it is still difficult to split water without any sacrificial reagent. Herein, nanosized Fe2O3 is combined with 3D nitrogen‐rich carbon nitride tubes (ACN), to form an Fe2O3@ACN Z‐scheme heterojunction, which accelerates the electrons’ transfer from Fe2O3 to ACN and improves the charge separation efficiency. Meanwhile, the bandgap of Fe2O3@ACN is about 2.01 eV, beneficial to the enhancement of visible light absorption capacity. As a result, without any sacrificial agent, the hydrogen evolution rate reaches 3.7 μmol h−1 (10 mg catalyst, AM1.5) through water splitting, which is three times that of ACN and 45 times that of bulk C3N4 (GCN). This work provides a new strategy to prompt pure water splitting based on carbon nitride catalysts.
Preparation and flame retardancy of flax fabric/polybenzoxazine laminates
Authors: Samyn Fabienne , Murariu Oltea , Bonnaud Leila , Duquesne Sophie
Published: April 2020

Driven by the need to reduce the carbon footprint of materials, natural fibres reinforced composites are increasingly used. Today, their level of maturity allows to consider their applications in fields where high performance such as flame retardancy are required. This article compares the fire retardant properties of flax laminates based on two thermosets resins, a bio‐based polybenzoxazine and a petroleum‐based epoxy, both considered for aeronautical applications. The effect of alkaline and silane surface modifications of the fibres on the properties of the composites was investigated. The treatments of the flax were proven to allow a better impregnation of the fibres by the matrices but at the same time more defects were observed. Regarding the fire behaviour of the composites, no difference of flammability was highlighted between the treated and untreated materials. The burnthrough resistance evaluation was performed using a small‐scale aeronautical test. The better performance of the epoxy‐based composite compare to the polybenzoxazine one was shown whereas charring is favoured for polybenzoxazine. The low deformability of the char formed when polybenzoxazine decomposes leads to the formation of cracks with the subsequent failure of the test.
Preparation and odor characteristics of nitriles derived from aldehydes
Authors: Lan Liyuan , Huang Shuai , Liu Yongguo , Sun Baoguo , Tian Hongyu
Published: April 2020

Twenty nitriles, including saturated and unsaturated aliphatic, araliphatic, and aromatic nitriles, were prepared from the corresponding aldehydes, commonly used as flavors or fragrances. The aldehydes were converted to aldoximes first, which then underwent dehydration by treatment with oxalyl chloride in the presence of a catalytic amount of dimethyl sulfoxide. The nitriles were obtained in high yields in most cases. The odor characteristics of the nitriles obtained were evaluated by GC‐O. The nitriles present varied characteristic odors, which are usually distinct from those of the corresponding aldehydes.
Antioxidative activities of volatile and non‐volatile extracts of Schisandra chinensis Baill fruit
Authors: Park Min‐Seon , Park Min‐Sun , Lee Kwang‐Geun
Published: April 2020

In this study, the antioxidative activity of volatile and non‐volatile extracts from Schisandra chinensis Baill fruit was evaluated. The antioxidative activity of the sample was measured via aldehyde/carboxylic acid assay, 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) assay, and lipid/malonaldehyde assay. The sample was steam distilled under reduced pressure for extracting out the volatile components. The volatile extract was fractionated into seven fractions. The non‐volatile compounds were extracted using methanol. The antioxidative activities of 500 μg/mL of non‐volatile extract were estimated to be 76.80% by DPPH assay and 85.55% by lipid/malonaldehyde assay. Aldehyde/carboxylic acid assay revealed that fractions ⅰ and ⅱ of the volatile extract exhibited the most potent and dose‐dependent antioxidative activity. Terpenes in the volatile extract including α‐ylangene (733.512 μg/g), β‐elemene (145.690 μg/g), and bornyl acetate (321.825 μg/g) were found to contribute to the antioxidative activity.
The impact of sex education mandates on teenage pregnancy: International evidence
Authors: Paton David , Bullivant Stephen , Soto Juan
Published: April 2020

To date most studies of the impact of school‐based sex education have focused either on specific, local interventions or experiences at a national level. In this paper, we use a new cross‐country dataset to explore the extent to which laws on sex education affect teenage pregnancy rates in developed countries. We find some evidence that laws mandating sex education in schools are associated with higher rates of teenage fertility. Parental opt out laws may minimise adverse effects of sex education mandates for younger teens. The estimated effects of mandatory sex education are robust to some but not all of our specifications designed to tease out causality. Taken together, changes in national laws relating to sexual health are unable to explain the significant declines in teenage pregnancy rates, which have been observed in many developed countries in recent years.
Ethical framework for head and neck cancer care impacted by COVID‐19
Authors: Shuman Andrew G. , Campbell Bruce H. ,   AHNS Ethics & Professionalism Service
Published: April 2020

The COVID‐19 pandemic has upended head and neck cancer care delivery in ways unforeseen and unprecedented. The impact of these changes parallels other fields in oncology, but is disproportionate due to protective measures and limitations on potentially aerosolizing procedures and related interventions specific to the upper aerodigestive tract. The moral and professional dimensions of providing ethically appropriate and consistent care for our patients in the COVID‐19 crisis are considered herein for head and neck oncology providers.
Should we wait or not? The preferable option for patients with stage IV oral cancer in COVID‐19 pandemic
Authors: Bhattacharjee Atanu , Patil Vijay M. , Dikshit Rajesh , Prabhash Kumar , Singh Arjun , Chaturvedi Pankaj
Published: April 2020

Background

The coronavirus infection is rapidly spreading, putting a strain on health care services across the globe. Patients with oral cancer are susceptible often immunosuppressed due to the disease and/or the treatment received.

Methods

We performed a simulation of the currently available data using a multistate and hazards model to provide an objective model for counseling and decision making for health care workers.

Results

Stage IV patients with oral cancer who did not receive treatment had progression of disease and an increased mortality rate compared to patients who receive treatment but did not contract COVID‐19. The patients who received treatment and got affected with COVID‐19 had a far worse impact and higher mortality rate than all other groups.

Conclusion

Isolation and deferring treatment for stage IV patients with oral cancer, so as to avoid hospital visits and contraction of COVID‐19, is an advisable strategy based on this model.
Drainage water reuse in the Nile Delta of Egypt: Fitting density functions and assessing temporal trends*
Authors: Shaban M.
Published: April 2020

This study attempts to investigate the variability in the current drainage water reuse pattern in terms of discharges (DWR (MCM) and their corresponding salinities (DWR (TDS mg l¯¹)) recorded since 1984 in the Nile Delta regions (Case I). In addition, the expected future DWR (DWR_E) patterns were simulated, taking into account the expected future reuse expansion projects (Case II). For Case I, basic descriptive statistics as well as non‐parametric assessment for monotonous trends were employed to characterize the structure of the DWR discharge and salinity data sets. Also, best probability density functions (PDFs) were fitted as smoothed adaptations to predict the occurrence probability in a certain interval. These analyses were repeated (excluding trend assessment) for aggregated discharge and salinity data simulating the possible future DWR patterns (Case II). The results indicate that DWR discharge and salinity series had increasing trends except the DWR salinity measured in the Western Nile Delta region that showed an insignificant decreasing trend. The results also show that there is a potential for increasing the mean DWR discharges up to 101, 32.6 and 282% for the Eastern, Middle and Western Delta regions, respectively. This will be accompanied with DWR salinity increases up to 39.5, 11.4 and 46.1%, respectively. © 2020 John Wiley & Sons, Ltd.
Improvement of digital PCR conditions for direct detection of KRAS mutations
Authors: Lee Jina , Kim Ji Hyun , Kang Sun Hyung , Yoo Hee Min
Published: April 2020

Background

In standard analytical conditions, an isolation step is essential for circulating tumor DNA (ctDNA) analysis. The necessity of this step becomes unclear with the development of highly sensitive detection methods. The aim of this study was to evaluate ctDNA mimetic nDNA detection as reference materials (RMs) using dPCR technologies either directly from serum or without serum.

Methods

To determine an absolute count of both mutation and wild‐type bearing DNA molecules, genomic DNA (gDNA) and nucleosomal DNA (nDNA), which are similar in size to cell‐free DNA, were evaluated. We tested 3 KRAS mutations in colorectal cancer cell lines.

Results

We describe the recent progress in RMs. The short DNA fragments, such as sDNA and nDNA, exhibited higher quantitative values of dPCR compared to gDNA. The efficiency between Atlantis dsDNase (AD) and Micrococcal Nuclease (MN) affects DNA quantification. Moreover, there was a significant difference in dPCR output when spiking gDNA or nDNA containing KRAS mutations into FBS compared to the dPCR output under non‐FBS conditions.

Conclusion

The matrix effect crucially affects the accuracy of gDNA and nDNA level estimation in the direct detection of mimic of patient samples. The form of reference material we proposed should be optimized for various conditions to develop reference materials that can accurately measure copy number and verify the detection of KRAS mutations in the matrix.
Sociodemographic, sexual, and reproductive variables associated with pregnancy among adolescents from low socioeconomic background
Authors: Canavarro Maria Cristina , Silva Neuza , Diniz Eva , Pereira Marco , Koller Sílvia H. , Pires Raquel
Published: April 2020

Adolescent pregnancy remains a public health concern in both developed and developing countries. Portugal and Brazil represent some of the best examples of this phenomenon. The present study aimed to identify sociodemographic, sexual, and reproductive health‐related variables associated with adolescent pregnancy among students from low socioeconomic backgrounds in both countries. The sample included 984 female adolescents, among whom 215 became pregnant. Living with a partner and lack of information about sex and contraception from the family were the best explicative factors for pregnancy occurrence in both countries. Country‐specific variables were also identified. Our results may contribute to developing global preventive interventions, addressing the school as an ideal setting for primary intervention and considering culture‐specific characteristics of high‐risk populations.
l‐Serine transport in growing and maturing mouse oocytes
Authors: Zhang Han , McClatchie Taylor , Baltz Jay M.
Published: April 2020

Serine has roles in cell metabolism besides protein synthesis including providing one‐carbon units to the folate cycle. Since growing mouse oocytes undergo a burst of folate accumulation as they near full size, we have investigated whether oocytes transport serine. Substantial serine transport appeared in oocytes near the end of their growth. Serine transport continued when oocytes resumed meiosis but ceased partway through first meiotic metaphase, remaining quiescent in mature eggs in second meiotic metaphase. The serine transporter was sodium dependent and inhibited by alanine, cysteine, leucine, or histidine, and had a Michaelis–Menten constant (Km) for serine of 200 µM. Unexpectedly, exposing cumulus cell‐enclosed oocytes to the physiological mediator of meiotic arrest, natriuretic peptide precursor Type C, substantially stimulated serine transport by the enclosed oocyte. Finally, in addition to transport by the oocyte itself, cumulus cells also supply serine to the enclosed oocyte via gap junctions within intact cumulus–oocyte complexes.
SIRT3 deficiency is resistant to autophagy‐dependent ferroptosis by inhibiting the AMPK/mTOR pathway and promoting GPX4 levels
Authors: Han Dandan , Jiang Lili , Gu Xiaolong , Huang Shimeng , Pang Jiaman , Wu Yujun , Yin Jingdong , Wang Junjun
Published: April 2020

Ferroptosis, an autophagy‐dependent cell death, is characterized by lipid peroxidation and iron accumulation, closely associated with pathogenesis of gestational diabetes mellitus (GDM). Sirtuin 3 (SIRT3) has positive regulation on phosphorylation of activated protein kinase (AMPK), related to maintenance of cellular redox homeostasis. However, whether SIRT3 can confer autophagy by activating the AMPK‐mTOR pathway and consequently promote induction of ferroptosis is unknown. We used human trophoblastic cell line HTR8/SVneo and porcine trophoblastic cell line pTr2 to deterimine the mechanism of SIRT3 on autophagy and ferroptosis. The expression of SIRT3 protein was significantly elevated in trophoblastic cells exposed to high concentrations of glucose and ferroptosis‐inducing compounds. Increased SIRT3 expression contributed to classical ferroptotic events and autophagy activation, whereas SIRT3 silencing led to resistance against both ferroptosis and autophagy. In addition, autophagy inhibition impaired SIRT3‐enhanced ferroptosis. On the contrary, autophagy induction had a synergistic effect with SIRT3. Based on mechanistic investigations, SIRT3 depletion inhibited activation of the AMPK‐mTOR pathway and enhanced glutathione peroxidase 4 (GPX4) level, thereby suppressing autophagy and ferroptosis. Furthermore, depletion of AMPK blocked induction of ferroptosis in trophoblasts. We concluded that upregulated SIRT3‐enhanced autophagy activation by promoting AMPK‐mTOR pathway and decreasing GPX4 level to induce ferroptosis in trophoblastic cells. SIRT3 deficiency was resistant to high glucose‐ and erastin‐induced autophagy‐dependent ferroptosis and is, therefore, a potential therapeutic approach for treating GDM.
Do Microcredit Loans Do What They Are Intended To Do? A Case Study of the Credit Village Microcredit Programme in China
Authors: Jiang Meishan , Paudel Krishna P. , Zou Fan
Published: April 2020

The purpose of this study is to assess if the credit village is an effective way to develop a microcredit programme in China from the perspective of poverty reduction policy and risk monitoring. Cross‐sectional household survey data from three credit villages in the Yunan County of China are analysed using 3SLS and IV probit models. The major finding is that the credit village loosens credit restrictions to some extent. However, it has no impact on educational expenditures, medical expenditures, long‐term assets, short‐term assets and women's rights. It is our observation that the microcredit programme in China needs more innovation to become effective. © 2020 John Wiley & Sons, Ltd.
Editorial for “Non‐Gaussian Diffusion Models and T1rho Quantification in the Assessment of Hepatic Sinusoidal Obstruction Syndrome in Rats”
Authors: Li Weiguo
Published: April 2020

Level of Evidence

5

Technical Efficacy Stage

2 J. Magn. Reson. Imaging 2020;52:1122–1123.
Understanding epidemic data and statistics: A case study of COVID‐19
Authors: Hoseinpour Dehkordi Amirhoshang , Alizadeh Majid , Derakhshan Pegah , Babazadeh Peyman , Jahandideh Arash
Published: April 2020

The 2019 novel‐coronavirus (COVID‐19) has affected 181 countries with approximately 1197405 confirmed cases (by 5th April). Understanding the transmission dynamics of the infection in each country which got affected on a daily basis and evaluating the effectiveness of control policies are critical for our further actions. To date, the statistics of COVID‐19 reported cases show that more than 80% of infected are mild cases of disease, around 14% of infected have severe complications, and about 5% are categorized as critical disease victims. Today's report (5th April 2020; daily updates in the prepared website) shows that the confirmed cases of COVID‐19 in the United States, Spain, Italy, and Germany are 308850, 126168, 124632, and 96092, respectively. Calculating the total case fatality rate (CFR) of Italy (4th April 2020), about 13.3% of confirmed cases have passed away. Compared with South Korea's rate of 1.8% (seven times lower than Italy) and China's 4% (69% lower than Italy), the CFR of Italy is too high. Some effective policies that yielded significant changes in the trend of cases were the lockdown policy in China, Italy, and Spain (the effect observed after some days), the shutdown of all nonessential companies in Hubei (the effect observed after 5 days), combined policy in South Korea, and reducing working hours in Iran.
Asymptomatic COVID‐19 infection in late pregnancy indicated no vertical transmission
Authors: Lu Dawei , Sang Lin , Du Shihua , Li Tao , Chang Yange , Yang Xiu‐An
Published: April 2020

This study is to investigate the clinical characteristics of late pregnancy with asymptomatic 2019 novel coronavirus disease (COVID‐19) infection, evaluate the outcome of maternal and fetal prognosis, and identify the evidence of intrauterine vertical transmission. A 22‐years‐old pregnant woman with asymptomatic COVID‐19 infection who was admitted to our hospital on 11 February 2020 was enrolled in this study. Clinical data including laboratory test results and chest computed tomography (CT) scanning were collected and reviewed. Diagnosis of late pregnancy with asymptomatic COVID‐19 infection was made. Lumbar anesthesia for cesarean section was performed and a female baby was delivered uneventfully, with the Apgar score of 9 to 10 points. Three times of COVID‐19 nucleic acid test for the baby was negative after delivery. The puerpera returned to normal after the operation and two times of throat swab COVID‐19 nucleic acid test were all negative after antiviral therapy. We reported an asymptomatic COVID‐19 pregnant woman with detailed clinical information and our result indicated that for late pregnant women with asymptomatic COVID‐19 infection, there might be no intrauterine infection caused by vertical transmission.
Characteristics of patients with coronavirus disease (COVID‐19) confirmed using an IgM‐IgG antibody test
Authors: Xie Jiajia , Ding Chengchao , Li Jing , Wang Yulan , Guo Hui , Lu Zhaohui , Wang Jinquan , Zheng Changcheng , Jin Tengchuan , Gao Yong , He Hongliang
Published: April 2020

Coronavirus disease (COVID‐19), caused by a novel betacoronavirus, severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), has rapidly developed into a pandemic since it was first reported in December 2019. Nucleic acid testing is the standard method for the diagnosis of viral infections. However, this method reportedly has a low positivity rate. To increase the sensitivity of COVID‐19 diagnoses, we developed an IgM‐IgG combined assay and tested it in patients with suspected SARS‐CoV‐2 infection. In total, 56 patients were enrolled in this study and SARS‐CoV‐2 was detected by using both IgM‐IgG antibody and nucleic acid tests. Clinical and laboratory data were collected and analyzed. Our findings suggest that patients who develop severe illness might experience longer virus exposure times and develop a more severe inflammatory response. The IgM‐IgG test is an accurate and sensitive diagnostic method. A combination of nucleic acid and IgM‐IgG testing is a more sensitive and accurate approach for diagnosis and early treatment of COVID‐19.
Strong policies control the spread of COVID‐19 in China
Authors: Li Bao‐Zhu , Cao Nv‐Wei , Zhou Hao‐Yue , Chu Xiu‐Jie , Ye Dong‐Qing
Published: April 2020

The coronavirus disease 2019 (COVID‐19) outbroke in Wuhan, Hubei Province, China, affecting more than 200 countries and regions. This study aimed to predict the development of the epidemic with specific interventional policies applied in China and evaluate their effectiveness. COVID‐19 data of Hubei Province and the next five most affected provinces were collected from daily case reports of COVID‐19 on the Health Committee official website of these provinces. The number of current cases, defined as the number of confirmed cases minus the number of cured cases and those who have died, were examined in this study. A modified susceptible‐exposed‐infectious‐removed (SEIR) model was used to assess the effects of interventional policies on the epidemic. In this study, 28 January was day 0 of the model. The results of the modified SEIR model showed that the number of current cases in Hubei and Zhejiang provinces tended to be stabilized after 70 days and after 60 days in the four other provinces. The predicted number of current cases without policy intervention was shown to far exceed that with policy intervention. The estimated number of COVID‐19 cases in Hubei Province with policy intervention was predicted to peak at 51 222, whereas that without policy intervention was predicted to reach 157 721. Based on the results of the model, strong interventional policies were found to be vital components of epidemic control. Applying such policies is likely to shorten the duration of the epidemic and reduce the number of new cases.
Persistent viral RNA positivity during the recovery period of a patient with SARS‐CoV‐2 infection
Authors: Yang Jian‐Rong , Deng Dao‐Ting , Wu Nan , Yang Bin , Li Hong‐Juan , Pan Xiao‐Ben
Published: April 2020

As an emerging infectious disease, the clinical course and virological course of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection remain to be further investigated. In this case report, we described a case of SARS‐CoV‐2 infection with the clinical course for more than 2 months. This patient had recovered from pneumonia after treatment. The viral RNA of throat swabs became negative and the viral‐specific antibodies were produced during the recovery period. However, the viral RNA reappeared and additionally persisted in throat swabs for more than 40 days. In addition, the viral RNA was detected in multiple types of specimens with extremely high titers in the saliva. In conclusion, these findings indicate that SARS‐CoV‐2 can cause a long clinical course. The coexistence of viral RNA and viral‐specific antibodies may imply an immune evasion of SARS‐CoV‐2 from the host's immune system.
Cognitive spectroscopy for evaluating Chinese black tea grades (Camellia sinensis): near‐infrared spectroscopy and evolutionary algorithms
Authors: Ren Guangxin , Sun Yemei , Li Menghui , Ning Jingming , Zhang Zhengzhu
Published: April 2020

BACKGROUND

Grading represents an essential criterion for the quality assurance of black tea. The main objectives of the study were to develop a highly robust model for Chinese black tea of seven grades based on cognitive spectroscopy.

RESULTS

Cognitive spectroscopy was proposed to combine near‐infrared spectroscopy (NIRS) with machine learning and evolutionary algorithms, selected feature information from complex spectral data and show the best results without human intervention. The NIRS measuring system was used to obtain the spectra of Chinese black tea samples of seven grades. The spectra acquired were preprocessed by standard normal variate transformation (SNV), multiplicative scatter correction (MSC) and minimum/maximum normalization (MIN/MAX), and the optimal pretreating method was implemented using principal component analysis combined with linear discriminant analysis algorithm. Three feature selection evolutionary algorithms, which were a genetic algorithm (GA), simulated annealing (SA) and particle swarm optimization (PSO), were compared to search the best preprocessed characteristic wavelengths. Cognitive models of Chinese black tea ranks were constructed using extreme learning machine (ELM), K‐nearest neighbor (KNN) and support vector machine (SVM) methods based on the selected characteristic variables. Experimental results revealed that the PSO–SVM model showed the best predictive performance with the correlation coefficients of prediction set (Rp) of 0.9838, the root mean square error of prediction (RMSEP) of 0.0246, and the correct discriminant rate (CDR) of 98.70%. The extracted feature wavelengths were only occupying 0.18% of the origin.

CONCLUSION

The overall results demonstrated that cognitive spectroscopy could be utilized as a rapid strategy to identify Chinese black tea grades. © 2020 Society of Chemical Industry
Hydrological evaluation of hourly merged satellite–station precipitation product in the mountainous basin of China using a distributed hydrological model
Authors: Zhu Dehua , Wang Gaoxu , Ren Qiwei , Ilyas Abro M.
Published: April 2020

Over the past two decades, various satellite‐based precipitation products have been released to provide uninterrupted time‐series precipitation with quasi‐global coverage. The latest Chinese merged satellite–gauge (CMS) rainfall product developed by the China Meteorological Administration (CMA) may reduce the errors in near real time by combining the Climate Prediction Centre's (CPC) morphing algorithm (CMORPH) rainfall estimates with over 30,000 weather station measurements, which therefore offer a potential alternative or supplement to ground‐based rainfall estimates for hydrometeorological applications in sparsely gauged or ungauged basins. In the present study, the characteristics of the CMS precipitation product were comprehensively evaluated for the period 2008–2012 over Danjiangkou basin, central China, and used to drive the Liuxihe (LXH)‐distributed hydrological model for detailed streamflow simulations. The results show that most of the small–median rainfall with an intensity < 25 mm·day–1 can be well captured by the CMS, and the simulated streamflow had relatively better agreement with observations for peak flow in the lower part of the basin. However, the total water amount was 15.7% less than the streamflow driven by rain gauges, on average. In addition, the depths of surface flow and groundwater forced by the CMS rainfall were 22.05% and 21.10% less than rain gauge, respectively. Overall, the study provides new insight into and experience of the hydrological applicability of the high spatiotemporal‐resolution satellite–gauge rainfall product for driving a distributed hydrological model at a daily resolution. This product has the potential to be an alternative data source for data‐sparse or ungauged basins for water resource management and hydrological simulation/prediction purposes.
Ensemble U‐net‐based method for fully automated detection and segmentation of renal masses on computed tomography images
Authors: Fatemeh Zabihollahy , Nicola Schieda , Satheesh Krishna , Eranga Ukwatta
Published: April 2020

Purpose

Detection and accurate localization of renal masses (RM) are important steps toward future potential classification of benign vs malignant RM. A fully automated algorithm for detection and localization of RM may eliminate the observer variability in the clinical workflow.

Method

In this paper, we describe a fully automated methodology for accurate detection and segmentation of RM from contrast‐enhanced computed tomography (CECT) images. We first determine the boundaries of the kidneys on the CECT images utilizing a convolutional neural network‐based method to be used as a region of interest to search for RM. We then employ a homogenous U‐Net‐based ensemble learning model to identify and delineate RM. We used an institutional dataset comprised of CECT images in 315 patients to train and evaluate the proposed method. We compared results of our method to those of three‐dimensional (3D) U‐Net for RM localization and further evaluated our algorithm using the kidney tumor segmentation (KiTS19) challenge dataset.

Results

The developed algorithm reported a Dice similarity coefficient (DSC) of 95.79% ± 5.16% and 96.25 ± 3.37 (mean ± standard deviation) for segmentation accuracy of kidney boundary from 125 and 60 test images from institutional and KiTS19 datasets, respectively. Using our method, RM were detected in 125 and 52 test cases, which corresponds to 100% and 86.67% sensitivity at patient level in institutional and KiTS19 test images. Our ensemble method for RM localization yielded a mean DSC of 88.65% ± 7.31% and 87.91% ± 6.82% on the institutional and KiTS19 test datasets, respectively. The mean DSC for RM delineation from CECT institutional test images using 3D U‐Net was 85.95% ± 1.46%.

Conclusion

We describe a method for automated localization of RM using CECT images. Our results are important in terms of clinical perspective as fully automated detection of RM is a fundamental step for further diagnosis of cystic vs solid RM and eventually benign vs malignant solid RM, that has not been reported previously.
3D isotropic resolution diffusion‐prepared magnitude‐stabilized bSSFP imaging with high geometric fidelity at 1.5 Tesla
Authors: Gao Yu , Zhou Ziwu , Han Fei , Zhong Xiaodong , Yang Yingli , Hu Peng
Published: April 2020

Introduction

MRI has been increasingly used in radiation therapy to facilitate tumor and organ delineation and assess treatment response. Diffusion MRI can provide cellularity information and may enable functional‐based treatment planning and adaptation. However, strong distortion associated with the conventional diffusion‐weighted single‐shot echo‐planar imaging (DW‐ssEPI) sequence is problematic for accurate target delineation. The goal of this work is to propose a 3D diffusion sequence with minimal distortion for radiation therapy applications.

Methods

A 3D diffusion‐prepared magnitude‐stabilized balanced steady‐state free precession sequence (DP‐MS‐bSSFP) was developed. A 2D navigator was acquired during the linear catalyzation stage of the bSSFP readout to estimate the phase, which was then used in a plane‐by‐plane low‐rank constrained reconstruction to correct the shot‐to‐shot k‐space inconsistency. A diffusion phantom was scanned to evaluate and compare the geometric reliability and apparent diffusion coefficient (ADC) accuracy with the conventional DW‐ssEPI. Eight landmarks were selected on each slice of the images to calculate the target registration error (TRE), which was used as a surrogate for geometric fidelity. The phantom was scanned under both 0℃ and room temperature. Brain scans were performed on five healthy volunteers. In the first volunteer, protocols of 1, 2, and 4 shots per Kz plane were compared. In vivo geometric fidelity and ADC accuracy were evaluated on the remaining four volunteers using the protocol of four shots per Kz plane. In the geometric fidelity study, 8–10 landmarks were picked on each slice to calculate the TRE. Regions of interest were placed on the white matter, the cerebellum, and the cerebrospinal fluid region to evaluate the ADC agreement between DW‐ssEPI and DP‐MS using the Bland‐Altman plot. All scans were performed at 1.5 mm isotropic resolution to meet the high‐resolution requirement of many radiotherapy applications.

Results

The DP‐MS had drastically improved geometric accuracy compared with DW‐ssEPI on the phantom. The mean TRE decreased from 2.09 mm to 0.70 mm. The percentage difference of the ADC values between the two diffusion sequences were less than 5.5% and 7% for the 0℃ and room temperature study, respectively. The DW‐ssEPI had strong distortion and susceptibility‐related artifacts at tissue air boundary, whereas distortion was minimal in DP‐MS images. Overall, the mean/max TRE was over 2 mm/7 mm in the volunteers for DW‐ssEPI, whereas less than 0.8 mm/2 mm for DP‐MS. Good ADC agreement was observed for the white matter, the cerebellum, and the CSF based on the Bland‐Altman plots.

Conclusion

A 3D diffusion sequence was developed and validated. It provided high‐resolution diffusion imaging with mean distortion less than 1 mm at 1.5 T, and is a promising imaging technique for treatment planning and adaptive radiotherapy.
Cadmium‐induced toxicity increases prolyl endopeptidase (PREP) expression in the rat testis
Authors: Venditti Massimo , Chemek Marouane , Minucci Sergio , Messaoudi Imed
Published: April 2020

During the differentiation of the male gamete, there is a massive remodeling in the shape and architecture of all the cells of the seminiferous epithelium. The cytoskeleton, as well as many associated proteins with it, plays a pivotal role in this process. The testis is particularly susceptible to environmental pollutant, which can lead to injury and impairment of normal spermatozoa production. Cadmium (Cd) is one of the major chemical environmental toxicants in economically developed countries. Food and cigarettes are the main sources of exposure to this element. Here, the protective role of zinc (Zn) to prevent the testicular toxicity in male adult rats after prenatal and during lactation exposure to Cd has been assessed. Altered testicular histology at the interstitial and germinal levels was found, whereas Zn supply completely corrected Cd toxicity. Moreover, the effects of these metals on the testicular expression and localization of the protease prolyl endopeptidase (PREP) were evaluated. Interestingly, the results showed an increase of PREP messenger RNA and protein. Data were corroborated by immunofluorescence. This study raises the possibility of using PREP as a new fertility marker.