bluuebunny/crossref_metadata_2025 huggingface dataset:
External cephalic version at term with tocolysis and vibroacoustic stimulation
Authors: Annapoorna V. , Arulkumaran S. , Anandakumar C. , Chua S. , Montan S. , Ratnam S.S.
Published: July 2002

Objective: This study compared the obstetric outcome in women who had external cephalic version (ECV) for breech presentation after 36 weeks gestation with those who did not, to see whether ECV reduces breech deliveries and cesarean section rates with reduced complications. Method: External cephalic version was attempted in 200 women (study group) with the use of tocolysis and vibroacoustic stimulation. The control group (ECV not attempted) comprised of 278 women with breech presentation after 36 weeks. Result: The cesarean section rate was 14.0% in the successful version group compared with 55.2% in the unsuccessful version group. The overall cesarean section rate in the study group was 32.5%. In the control group of 278, the fetus remained in the breech presentation in labor in 269 women with a cesarean section rate of 51.4% which was not different from the unsuccessful version group (55.2%). Conclusion: This study supports the randomized trials conducted earlier in that ECV after 36 weeks gestation reduced the number of breech deliveries and cesarean sections (32.5% in the study group compared with 51.4% in the control group) (P > 0.00001).
Color Doppler energy and related quantitative analysis of gestational trophoblastic tumors
Authors: Xie H. , Hata K. , Lu M. , Kong Q. , Miyazaki K.
Published: July 2002

Objective: To assess the reliability of color Doppler energy (CDE) and a related quantitative analysis for detection and follow‐up of uterine involvement in gestational trophoblastic tumor. Method: CDE was performed in 19 patients with trophoblastic tumor, in 25 women in early pregnancy and 25 non‐pregnant women. The blood flow area ratio (BFAR) in CDE was used as an index representing uterine involvement. In nine of the 19 patients, BFAR was measured before, during and at termination of chemotherapy. Result: The BFAR (mean±S.D.) of uterine profiles in 19 patients (39.9±1.3%) was significantly higher than that in 25 pregnant women (24.6±10.1%, P=0.002) and in 25 non‐pregnant women (14.8±5.7%, P=0.001). In the follow‐up of nine patients, when β‐hCG was less than 3.1 ng/ml during the treatment, the BFAR (38.7±11.9%) decreased below that (44.2±14.6%) seen prior to treatment (P=0.009) and was much lower at termination of treatment (27.5±12.3%, P=0.048). Conclusion: These data support the use of CDE and the related quantitative analysis as a new method for detecting and follow‐up of uterine involvement in patients with trophoblastic tumors.
Expression of glial cell line‐derived neurotrophic factor (GDNF) in the developing human fetal brain
Authors: Koo H. , Choi B.H.
Published: July 2002

GDNF expression was examined immunocytochemically in developing human fetal brains obtained from aborted fetuses ranging from 7 to 39 weeks in gestational age. At 7–8 weeks, strong immunoreactivity was noted within radial glial processes, glia limitans and choroid plexus of the telencephalic vesicle. By 10 weeks, ependymal cells, primitive matrix cells and early developing cortical plate neurons showed positive staining. By 15–16 weeks, migrating neurons in the subventricular and intermediate zones and in the cortical plate were strongly positive for GDNF. The glia limitans of the cerebral cortex and subependymal astrocytes remained positive at this time. As fetal age increased, GDNF expression shifted to neurons and glial cells in the deeper structures of the brain. The most prominent GDNF staining was observed in the cytoplasm and dendrites of Purkinje cells of the cerebellum by 25 weeks and thereafter. Pyramidal neurons of the CA1 region and granule cells of the dentate fascia of the hippocampus, neurons of the entorhinal cortex, and scattered neurons within the brain stem, medulla and spinal cord all showed strong GDNF staining by 25–35 weeks. Widespread GDNF expression in neuronal and non‐neuronal cells with distinct developmental shifts suggests that GDNF may play a critical role in the survival, differentiation and maintenance of neurons at different stages of development in the developing human fetal brain.
Scatter factor/hepatocyte growth factor (SF/HGF) content and function in human gliomas
Authors: Lamszus Katrin , Laterra John , Westphal Manfred , Rosen Eliot M.
Published: July 2002

Scatter factor/hepatocyte growth factor (SF/HGF) is a pleiotrophic cytokine that stimulates motility and invasion of several cancer cell types and induces angiogenesis. Its receptor MET is a transmembrane tyrosine kinase encoded by the C‐MET proto‐oncogene. To assess the potential relevance of SF/HGF in gliomas we performed functional studies in vivo and in vitro, expression analyses and correlative studies. We showed that both SF/HGF and MET are expressed in gliomas in vivo and are upregulated during transition from low grade to malignant glioma. When SF/HGF cDNA was transfected into glioma cells that expressed the MET receptor the cells formed considerably larger and more vascularized intracranial tumors in vivo than SF/HGF negative control clones. In other glioma cells, which constitutively expressed both SF/HGF and MET, we abolished SF/HGF expression by antisense ribozyme‐targeting, which led to a significant decrease in tumorigenicity and tumor growth. In vitro SF/HGF strongly stimulated glioma cell motility and to a lesser degree proliferation. SF/HGF also strongly increased endothelial cell motility in vitro and extracts of tumors derived from SF/HGF‐transfected glioma cells were more mitogenic for endothelial cells and more angiogenic in the rat cornea angiogenesis assay than extracts from control tumors. In a three‐dimensional in vitro angiogenesis assay basic fibroblast growth factor (bFGF) was found to synergize with either SF/HGF or vascular endothelial growth factor (VEGF) in inducing endothelial capillary‐like tubes, whereas neither SF/HGF nor VEGF alone or in combination were effective. Interestingly, while both VEGF and SF/HGF levels appeared to be increased in malignant gliomas compared with low grade ones, this was not the case for bFGF of which biologically relevant levels were already present in low grade gliomas. It thus seems that bFGF alone is insufficient to induce angiogenesis in gliomas but may act synergistically with either VEGF and/or SF/HGF when these become upregulated during malignant progression. In conclusion, we showed that SF/HGF may contribute to glioma progression by stimulating tumor invasiveness, proliferation and neovascularization.
The Nordic Study on schizophrenic patients living in the community. Subjective needs and perceived help
Authors: Middelboe T. , Mackeprang T. , Hansson L. , Werdelin G. , Karlsson H. , Bjarnason O. , Bengtsson-Tops A. , Dybbro J. , Nilsson L.L. , Sandlund M. , Sörgaard K.W.
Published: July 2002

In a community sample of 418 persons diagnosed with schizophrenia, subjective needs and perceived help was measured by the Camberwell Assessment of Need (CAN). The mean number of reported needs was 6.2 and the mean number of unmet needs 2.6. The prevalence of needs varied substantially between the need areas from 3.6% (‘telephone’) to 84.0% (‘psychotic symptoms’). The rate of satisfaction estimated as the percentage of persons satisfied with the help provided within an area varied between 20.0% (‘telephone’) and 80.6% (‘food’).

The need areas concerning social and interpersonal functioning demonstrated the highest proportion of unmet to total needs.

In a majority of need areas the patients received more help from services than from relatives, but in the areas of social relations the informal network provided substantial help. In general the patients reported a need for help from services clearly exceeding the actual amount of help received.

In a linear regression model symptom load (BPRS) and impaired functioning (GAF) were significant predictors of the need status, explaining 30% of the variance in total needs and 20% of the variance in unmet needs.

It is concluded that the mental health system fails to detect and alleviate needs in several areas of major importance to schizophrenic patients. Enhanced collaboration between the care system and the informal network to systematically map the need profile of the patients seems necessary to minimise the gap between perceived needs and received help.
Dementia and depression: Co-distribution and risk factors in a geriatric in- and outpatient sample
Authors: Morawetz C , Stevens A , Wormstall H
Published: July 2002

The results of a cross-sectional study on N = 212 elderly in- and outpatients are presented including sociodemographic data, physical findings, CAT-scan and EEG, as well as psychological tests for cognitive performance and affective symptoms. Forty-one percent of the patients showed mild and 13% severe cognitive deficits. Depression was diagnosed in 23% of the severely impaired and in 16% of the cognitively mildly impaired or unimpaired patients. Statistical analysis revealed that increasing age, female sex and low premorbid intellectual level were significantly associated with loss of cognitive function. Dementia and depression were not significantly associated with each other. The only risk factor for depression was a history of affective illness, but not cognitive deficits or social situation. CAT-scan and EEG were abnormal in 50% of the patients; however, this did not correlate with cognitive impairment or the presence of depression. From this study it is concluded that depression and dementia coincide frequently in elderly patients, but that they are associated with different risk factors It is suggested that dementia and depression are treated as two distinct disease entities.
THE “PUSH” FOR EVIDENCE: MANAGEMENT OF THE SECOND STAGE
Authors: Roberts Joyce E.
Published: July 2002

Recognition that the available evidence does not support arbitrary time limits for the second stage of labor has led to reconsideration of the influence of maternal bearing down efforts on fetal/newborn status as well as on maternal pelvic structural integrity. The evidence that the duration of ‘active’ pushing is associated with fetal acidosis and denervation injury to maternal perineal musculature has contributed to the delineation of at least two phases during second stage, an early phase of continued fetal descent, and a phase of “active” pushing. The basis for the recommendation that the early phase of passive descent be prolonged and the phase of active pushing shortened by strategies to achieve effective, but non‐detrimental pushing efforts is reviewed. The rational includes an emphasis on the obstetric factors that are optimal for birth and conducive to efficient maternal bearing down. Explicit assessment of these obstetric factors and observation of maternal behavior, particularly evidence of an involuntary urge to push, should be coupled with the use of maternal positions that will promote fetal descent as well as reduce maternal pain. The use of epidural analgesia for pain relief can also be accompanied by these same principles, although further research is needed to verify the strategies of “delayed pushing” and maintenance of pain relief along with a reconceptualization of the second stage of labor.
Generation of High Quality, Uniform and Stable Plasmonic Colorants via Laser Direct Writing
Authors: Wang Yunxia , Ren Feng , Ding Tao
Published: April 2020

Brilliant plasmonic colors with long‐standing stability are generated via laser direct writing. This plasmonic coloring system is made of silver nanoparticles (Ag NPs) layer embedded in the quartz glass formed by ion implantation. The laser‐induced plasmonic heating merges the small Ag NPs into larger ones, which modifies the plasmon resonances. The plasmon resonances can be further tuned via changing the irradiation time and power, which shows scattering colors ranging from red to green and cyan. By scanning the laser across the Ag NPs layer, sophisticated plasmonic patterns and images with high resolution (≈105 DPI) can be obtained and preserved over long time (several months). This plasmonic coloring system via laser printing is facile, cost‐effective, accurate, and highly stable with rich hue, compared to other plasmonic color systems, which bears significant potentials for industrial applications such as optics, displays, decorations, data storage, and anti‐counterfeiting.
Sequentially Processed P3HT/CN6‐CP•−NBu4+ Films: Interfacial or Bulk Doping?
Authors: Karpov Yevhen , Kiriy Nataliya , Formanek Petr , Hoffmann Cedric , Beryozkina Tetyana , Hambsch Mike , Al‐Hussein Mahmoud , Mannsfeld Stefan C. B. , Büchner Bernd , Debnath Bipasha , Bretschneider Michael , Krupskaya Yulia , Lissel Franziska , Kiriy Anton
Published: April 2020

Derivatives of the hexacyano‐[3]‐radialene anion radical (CN6‐CP•−) emerge as a promising new family of p‐dopants having a doping strength comparable to that of archetypical dopant 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyano‐quinodimethane (F4TCNQ). Here, mixed solution (MxS) and sequential processing (SqP) doping methods are compared by using a model semiconductor poly(3‐hexylthiophene) (P3HT) and the dopant CN6‐CP•−NBu4+ (NBu4+ = tetrabutylammonium). MxS films show a moderate yet thickness‐independent conductivity of ≈0.1 S cm−1. For the SqP case, the highest conductivity value of ≈6 S cm−1 is achieved for the thinnest (1.5–3 nm) films whereas conductivity drops two orders of magnitudes for 100 times thicker films. These results are explained in terms of an interfacial doping mechanism realized in the SqP films, where only layers close to the P3HT/dopant interface are doped efficiently, whereas internal P3HT layers remain essentially undoped. This structure is in agreement with transmission electron microscopy, atomic force microscopy, and Kelvin probe force microscopy results. The temperature‐dependent conductivity measurements reveal a lower activation energy for charge carriers in SqP samples than in MxS films (79 meV vs 110 meV), which could be a reason for their superior conductivity.
Significant Performance Improvement of Oxide Thin‐Film Transistors by a Self‐Assembled Monolayer Treatment
Authors: Cai Wensi , Zhang Jiawei , Wilson Joshua , Brownless Joseph , Park Seonghyun , Majewski Leszek , Song Aimin
Published: April 2020

Despite being a standard process in fabrication of organic thin‐film transistors (TFTs) to reduce interface trap density and decrease surface energy, self‐assembled monolayer (SAM) treatment of gate dielectrics is rarely used in oxide‐semiconductor‐based TFTs due to possible damage to the SAM during semiconductor deposition. Here, by studying the dependence of plasma damage to SAM on the deposition conditions of InGaZnO (IGZO) semiconductor thin films, the feasibility of enhancing the performance of oxide TFTs using octadecyltrichlorosilane (OTS)‐treated, ultra‐thin AlxOy gate dielectrics is explored. It is discovered that under optimized conditions, the TFTs can be significantly improved, showing a reduction of interface trap density by 50% and an increase of carrier mobility and current on/off ratio by a factor of 2.3 and 76, respectively. The effects on bias stress stability also show substantial improvement after the SAM interface treatment. Finally, such an optimized condition is found to also work for IGZO TFTs gated with OTS‐treated HfOx, showing an increase of mobility from 7.8 to 16 cm2 V−1 s−1 compared with the untreated devices. As a result, this simple and yet effective interface treatment method and the resulting devices may have potential applications in future low‐cost, low‐power electronics.
Network Structural CNTs Penetrate Porous Carbon Support for Phase‐Change Materials with Enhanced Electro‐Thermal Performance
Authors: Li Ang , Dong Cheng , Dong Wenjun , Yuan Fugen , Gao Hongyi , Chen Xiao , Chen Xiao‐Bo , Wang Ge
Published: April 2020

Electro‐thermal phase‐change materials (PCMs) enable continuous operation of heating‐related processes, which is urgently required for modern thermal‐management devices. Driven by the unmet needs to develop promising electro‐thermal PCMs with low operation voltage and high electro‐thermal storage efficiency simultaneously, unique ZIF@MOF‐derived carbon‐nanotube (CNT)‐penetrated porous carbon supports for electro‐thermal PCMs are introduced. The network structure of the support decreases the resistivity of the composite and ensures a low operation voltage. Furthermore, abundant CNT cores in porous carbon shells facilitate interfacial interaction between the PCMs and the support and realize a rapid heat transformation. It is noted that low thermal conductive porous carbon shells prevent convective heat dissipation at the CNT‐air interface to a great degree which leads to enhanced electro‐thermal storage efficiency. Consequently, the obtained electro‐thermal PCMs exhibit a low operation voltage of 1.1 V and a record‐high electro‐thermal storage efficiency of 94.5%, which shows great potential in thermal management of electronic devices.
Strong Anisotropy and Piezo‐Phototronic Effect in SnO2 Microwires
Authors: Li Ling , Gao Wei , Chen Hongyu , Zhao Kai , Wen Peiting , Yang Yujue , Wang Xingfu , Wei Zhongming , Huo Nengjie , Li Jingbo
Published: April 2020

1D microwires with low‐symmetric crystal structures are promising platforms to realize the anisotropy and piezotronics, enabling diverse novel device functions such as polarization sensitive photodetection, strain sensing, and energy conversion. Here, the highly anisotropy with polarized Raman spectra and angle‐resolved photocurrent as well as the remarkable piezoelectric characteristics in the 1D tin dioxide (SnO2) microwires is reported for the first time. The gauge factor can reach as high as 4100, implying the great strain “gating” effect on the current modulation. The cyclic stretching and releasing of the microwires has led to the significant oscillating piezoelectric current outputs of 750 pA. Moreover, the ultraviolent photoresponse is dramatically improved by one order of magnitude with fast speed of 2 ms benefitting from the excellent piezo‐phototronic effect. Both highly anisotropy and superior piezoelectricity in this work have opened up the new application scenarios of SnO2 microwires in unique angle‐dependent and stretchable electronics and optoelectronics.
Realizing the Capability of Negatively Charged Graphene Oxide in the Presence of Conducting Polyaniline for Performance Enhancement of Tribopositive Material of Triboelectric Nanogenerator
Authors: Ahmad Rafi u Shan , Haleem Abdul , Haider Zeeshan , Claver Uzabakiriho Pierre , Fareed Azam , Khan Irfan , Mbogba Momoh Karmah , Memon Kashan , Ali Wajahat , He Weidong , Hu Peng , Zhao Gang
Published: April 2020

In recent years, tremendous efforts have been made to investigate tribomaterials for triboelectric nanogenerators (TENGs), but due to their low performance there is still need of tribomaterials with new mechanisms for performance enhancement. Therefore, in this study, the potential of conducting polyaniline and tribonegative graphene oxide is exploited for performance enhancement of tribopositive material through a new mechanism of disturbing the equilibrium state inside the tribopositive material under an impact force. Thus, a TENG device made up of polymer with 700 µL polyaniline and 4 mg mL−1 graphene oxide as tribopositive and polydimethylsiloxane as a tribonegative layer with a dimension of 1 × 2 cm2 is able to produce an open‐circuit voltage of 314.92 V and a current density of 37.81 mA m−2 with a peak power density of 10.43 W m−2, which can directly power ON more than 175 white light‐emitting diodes. Amine group of polyaniline and its pathway to mobilize electrons inside the tribopositive material due to electron accepting ability of graphene oxide upon physical contact under external force are the main contributing factors toward performance enhancement. This work introduces a low cost, easy fabrication process with a new method for performance enhancement of tribopositive material to acquire a high performance TENGs.
Exploiting Flexible Memristors Based on Solution‐Processed Colloidal CuInSe2 Nanocrystals
Authors: Guo Ruiqi , Zhang Linxing , Meng Jie , Liu Aqiang , Yuan Jifeng , Zheng Kaibo , Tian Jianjun
Published: April 2020

Compared to analogous bulk materials, colloidal nanocrystals have presented a powerful platform for building up electronic devices on the nano/micrometer scale and flexible portable electronic apparatus with the benefits of solution‐based processing approach at room temperature. Herein, memristors based on CuInSe2 (CISe) colloidal nanocrystals prepared using a solution‐based process at room temperature are constructed. The memristors exhibit obvious bipolar resistive switching performance with a high–low resistance ratio larger than 5.7 and a steady retention time over 104 s. This is attributed to the copper ion redox reaction and the migration of these ions under an applied electric field. When the SET voltage is reached, the ions are separated from one of the electrodes, and the memristor changes from a low‐resistance state (LRS) to a high‐resistance state (HRS). Conversely, when the voltage reaches the RESET voltage, the memristor switches from a HRS to a LRS. In addition, the flexible memristor can be fabricated by spincoating nanocrystal solution onto polyethylene terephthalate (PET) at room temperature, showing excellent reproducibility of the performance including 100 times of continuous operation, 104 s of reproducible reading, 600 times of antifatigue testing, and thermal stability up to 95 °C. The flexible devices demonstrate promising applications for portable electronic devices.
Realizing Excellent n‐ and p‐Type Niobium‐Based Half‐Heusler Compounds Based on Thermoelectric Properties and High‐Temperature Stability
Authors: Silpawilawan Wanthana , Tanuslip Sora‐at , Chetty Raju , Ohta Michihiro , Ohishi Yuji , Muta Hiroaki , Kurosaki Ken
Published: April 2020

Half‐Heusler (HH) compounds are currently promising thermoelectric (TE) materials due to their outstanding performance. For reliable n‐ and p‐type HH compounds, the dimensionless figure of merit zT is reported as greater than unity. However, to develop a high‐performance TE module, zT, high‐temperature stability, and compatibility of n‐ and p‐type materials are key parameters. Here, the TE and thermomechanical properties and the high‐temperature stability of Nb‐based HH compounds: n‐type Nb0.75M0.1CoSb and p‐type FeNb0.9M0.1Sb (M = Ti, Zr, Hf) are investigated. The results reveal that the Ti‐doped system exhibits better TE and thermomechanical properties than the Zr‐ and Hf‐doped systems. Furthermore, the Ti‐doped samples show good high‐temperature stability in an inert atmosphere up to 773 K and in air up to 673 K. The performance of a 2π‐module based on the best n‐type Nb0.75Ti0.1CoSb and p‐type FeNb0.9Ti0.1Sb is simulated by using the 3D finite element method. The maximum output power density (ωmax) and conversion efficiency (ηmax) of 2.3 W cm−2 and 4.0%, respectively, are obtained when the cold‐ and hot‐side temperatures are 298 and 773 K, respectively.
Topological Hall Effect in Single Thick SrRuO3 Layers Induced by Defect Engineering
Authors: Wang Changan , Chang Ching‐Hao , Herklotz Andreas , Chen Chao , Ganss Fabian , Kentsch Ulrich , Chen Deyang , Gao Xingsen , Zeng Yu‐Jia , Hellwig Olav , Helm Manfred , Gemming Sibylle , Chu Ying‐Hao , Zhou Shengqiang
Published: April 2020

The topological Hall effect (THE) has been discovered in ultrathin SrRuO3 (SRO) films, where the interface between the SRO layer and another oxide layer breaks the inversion symmetry resulting in the appearance of THE. Thus, THE only occurs in ultrathin SRO films of several unit cells. In addition to employing a heterostructure, the inversion symmetry can be broken intrinsically in bulk SRO by introducing defects. In this study, THE is observed in 60‐nm‐thick SRO films, in which defects and lattice distortions are introduced by helium ion irradiation. The irradiated SRO films exhibit a pronounced THE in a wide temperature range from 5 to 80 K. These observations can be attributed to the emergence of Dzyaloshinskii–Moriya interaction as a result of artificial inversion symmetry breaking associated with the lattice defect engineering. The creation and control of the THE in oxide single layers can be realized by ex situ film processing. Therefore, this work provides new insights into the THE and illustrates a promising strategy to design novel spintronic devices.
The Journey toward Low Temperature, Low Pressure Catalytic Nitrogen Fixation
Authors: Shi Run , Zhang Xuerui , Waterhouse Geoffrey I. N. , Zhao Yunxuan , Zhang Tierui
Published: April 2020

Ammonia and its derived products are vital to modern societies. Artificial nitrogen fixation to ammonia via the Haber–Bosch process has been employed industrially for over 100 years. However, the Haber–Bosch process is energy intensive and not sustainable in its current form as it uses hydrogen sourced from steam methane reforming to reduce N2. The roadmap to sustainable NH3 production demands the discovery of novel approaches for nitrogen fixation under near ambient conditions that preferably use water as the reducing agent. Over the last decade, great efforts have been made to develop catalysts capable of N2 fixation under mild reaction conditions, using strategies such as low temperature thermal catalysis, nonthermal plasma catalysis, enzymatic catalysis, photocatalysis, and electrocatalysis to generate ammonia and other valuable nitrogen‐containing chemicals. In parallel with catalytic performance studies, researchers have also placed emphasis on the mechanistic understanding of natural and artificial nitrogen fixation catalysts. In this work, the various routes now being explored for nitrogen fixation are summarized. The different dinitrogen activation and hydrogenation pathways are described, whilst describing key advances made to date on the journey toward near ambient ammonia synthesis. Key obstacles that need to be overcome to attract industry interest are also discussed.
Recent Advances in Photoredox Methods for Ketone Synthesis
Authors: Chalotra Neha , Sultan Shaista , Shah Bhahwal Ali
Published: April 2020

Synthesis of ketones is one of the most addressed problems in organic chemistry owing to their presence in a diverse array of drugs, pharmaceuticals, natural products and photosensitizers. Many of the limitations associated with the traditional approaches enabling the synthesis of ketones like creation of high energy acylating reagents, poor functional group tolerance, pre‐activation of starting materials have been largely addressed with the advent of photoredox chemistry. This review summarizes the recent advances made in the photoredox catalyzed synthesis of ketones.
Hydrosulfonylation of Alkenes with Sulfonyl Chlorides under Visible Light Activation
Authors: Hell Sandrine M. , Meyer Claudio F. , Misale Antonio , Sap Jeroen B. I. , Christensen Kirsten E. , Willis Michael C. , Trabanco Andrés A. , Gouverneur Véronique
Published: April 2020

Sulfonyl chlorides are inexpensive reactants extensively explored for functionalization, but never considered for radical hydrosulfonylation of alkenes. Herein, we report that tris(trimethylsilyl)silane is an ideal hydrogen atom donor enabling highly effective photoredox‐catalyzed hydrosulfonylation of electron‐deficient alkenes with sulfonyl chlorides. To increase the generality of this transformation, polarity‐reversal catalysis (PRC) was successfully implemented for alkenes bearing alkyl substituents. This late‐stage functionalization method tolerates a remarkably wide range of functional groups, is operationally simple, scalable, and allows access to building blocks which are important for medicinal chemistry and drug discovery.
Oxidative Addition of Dihydrogen to Divanadium in Solid Ne: Multiple‐Bonded Triplet HVVH and Singlet V2(μ‐H)2
Authors: Hübner Olaf , Himmel Hans‐Jörg
Published: April 2020

Dinuclear compounds of early transition metals with a high metal–metal bond order are of fundamental interest due to their intriguing bonding situation and of practical interest because of their potential involvement in catalytic processes. In this work, two isomers of V2H2 have been generated in solid Ne by the reaction between V2 and H2 and detected by infrared spectroscopy: the linear HVVH molecule (3Σg− ground state), which is the product of the spin‐allowed reaction between V2 (3Σg− ground state) and H2, and a lower‐energy, folded V2(μ‐H)2 isomer (1A1 ground state) with two bridging hydrogen atoms. Both isomers are characterized by metal–metal bonding with a high bond order; the orbital occupations point to quadruple bonding. Irradiation with ultraviolet light induces the transformation of linear HVVH to folded V2(μ‐H)2, whereas irradiation with visible light initiates the reverse reaction.
Accumulation of 2‐tert‐Butyl‐1,4‐Benzoquinone in Frying Oil and Fried Food during Repeated Deep Fat Frying Processes
Authors: Ye Qin , Xia Chaosheng , Nie Xiaohua , Meng Xianghe
Published: April 2020

2‐tert‐Butyl‐1,4‐benzoquinone (TBBQ), the main oxidation product of tert‐butyl‐hydroquinone (TBHQ) during frying, is cytotoxic and its residual levels in frying oils and foods are unknown. In this study, TBBQ residues have been evaluated during the preparation of french fries. Results showed that frying at 140 °C resulted in the highest TBBQ peak concentration (48.42 mg kg−1) compared with frying at 190 or 170 °C. This unexpected finding can be attributed to more extensive hydrolytic reaction when frying at the lower temperature, generating more peroxyl radicals. TBBQ concentrations proved to be independent of the oil type among various unsaturated oils. However, higher TBBQ levels were observed in saturated palm oil and crude soybean oil than in unsaturated oil or refined oil. Continuous frying leads to the accumulation of a large amount of TBBQ in fried food. After frying 1–5 batches, TBBQ levels in both the frying oil and fries were above 10 mg kg−1, exceeding its critical cytotoxic concentration (IC50 value of 10.71 mg kg−1 for RAW 246.7 cells in our previous study), warranting concern with respect to the safety of fried food. FTIR has been utilized as an effective tool for visually monitoring the degree of oxidation in the frying medium with respect to its hydrogen peroxide level, which contributes to the increased level of TBBQ derived from TBHQ therein.
Constituent diversity of ethanol extracts from pitaya
Authors: Ma Jinghua , Mo Wei , Zhang Pangpan , Lai Yong , Li Ximei , Zhang Dangquan
Published: April 2020

Pitaya is rich in nutrition and unique in function and contains vegetable albumin, anthocyanins, rich vitamins, and water soluble dietary fiber, which are rare in fruits and vegetables. However, researches mostly focused on pitaya cultivation, biological characteristics, fresh‐keeping, and lacked analyses about chemical composition of pitaya. Therefore, ethanol extraction and GC/MS were used to extract and identify the bioactive components in pulp and pericarp of red pitaya and white pitaya. The extracting results showed that percentages of ethanol extracts from pulp and pericarp of red pitaya were 14.5% and 12%, whereas those of white pitaya were 16% and 12%. The GC/MS results showed that different kinds of bioactive constituents were identified in fresh pericarp and pulp of red pitaya and white pitaya. In the four ethanol extracts, there are rich polysiloxane plant organosilicon with total contents of 10.09%, 24.21%, 25.77%, and 23.25%. Meanwhile, there are many heterocyclic substances, and the content of pericarp is much higher than that of pulp. The four ethanol extracts also contain some other bioactive ingredients, such as esters, hydrocarbons, alcohols, amides, halides, and fatty acids, which can be used as raw materials for biomedicine, advanced cosmetics, and skin care products.
Sulfonamides incorporating ketene N,S‐acetal bioisosteres as potent carbonic anhydrase and acetylcholinesterase inhibitors
Authors: Istrefi Qëndresa , Türkeş Cüneyt , Arslan Mustafa , Demir Yeliz , Nixha Arleta R. , Beydemir Şükrü , Küfrevioğlu Ömer İ.
Published: April 2020

In this study, 15 novel compounds in a series of sulfonamide‐based ketenes (7a–o) were synthesized and characterized using Fourier‐transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and mass spectrometry. All compounds were tested for their ability to inhibit the human carbonic anhydrase (hCA) isoforms I and II, and acetylcholinesterase (AChE). The halogen‐appended compounds, 7g, 7o, and 7i, exhibited the highest hCA I/II and AChE inhibition, with the KI values in the low nanomolar range (KI = 9.01 ± 0.08, 7.41 ± 0.03, and 7.37 ± 0.31 nM, respectively), as compared with their corresponding parent 2‐[2,2‐dicyano‐1‐(phenylamino)vinylthio]‐N‐(4‐sulfamoylphenyl)acetamide analogs 7a–o. Besides, derivatives 7c and 7e selectively inhibited the isoform hCA I, whereas compounds 7m and 7n selectively inhibited isoform hCA II. These findings indicated that all compounds can inhibit metabolic dysfunctions, such as edema, epilepsy, glaucoma, and Alzheimer's disease, by specifically targeting both the hCA isoforms and AChE expression. Herein, also the interactions between ligands and receptors were highlighted through in silico molecular docking studies. The molecular mechanics–generalized Born surface area method was utilized to compute the binding free energy and the energy contribution of the critical residues in the active site was estimated. All these results would help us to perfectly understand the relationship between activity and structural characteristics of derivatives and to further improve newly and highly effective analogs targeting hCA and AChE.
Substituted adamantylphthalimides: Synthesis, antiviral and antiproliferative activity
Authors: Mandić Leo , Benčić Patricia , Mlinarić‐Majerski Kata , Liekens Sandra , Snoeck Robert , Andrei Graciela , Kralj Marijeta , Basarić Nikola
Published: April 2020

In this study, three groups of adamantylphthalimides, bearing different substituents at the phthalimide moiety, N‐(4′‐R2)phthalimidoadamantanes (1–7), 3‐[N‐(4′‐R2)phthalimido]‐1‐adamantanols (8–10), and 3‐[N‐(4′‐R2)phthalimido]adamantane‐1‐carboxylic acids (11–15), were synthesized and screened against tumor cells and viruses. The most potent compounds are not substituted at the adamantane and bear an OH or NH2 substituent at the phthalimide (compounds 3 and 5). The antiproliferative activities of compounds 3 and 5 are in the micromolar range, much higher than the one of thalidomide. A minor antiviral activity against cytomegalovirus and varicella‐zoster virus was found for compounds 3 and 5, but these compounds lacked selectivity. The results presented are important for the rational design of the next‐generation compounds with anticancer and antiviral activities.
Online Assessment of Applied Anatomy Knowledge: The Effect of Images on Medical Students' Performance
Authors: Sagoo Mandeep Gill , Vorstenbosch Marc A.T.M. , Bazira Peter J. , Ellis Harold , Kambouri Maria , Owen Charlie
Published: April 2020

Anatomical examinations have been designed to assess topographical and/or applied knowledge of anatomy with or without the inclusion of visual resources such as cadaveric specimens or images, radiological images, and/or clinical photographs. Multimedia learning theories have advanced the understanding of how words and images are processed during learning. However, the evidence of the impact of including anatomical and radiological images within written assessments is sparse. This study investigates the impact of including images within clinically oriented single‐best‐answer questions on students' scores in a tailored online tool. Second‐year medical students (n = 174) from six schools in the United Kingdom participated voluntarily in the examination, and 55 students provided free‐text comments which were thematically analyzed. All questions were categorized as to whether their stimulus format was purely textual or included an associated image. The type (anatomical and radiological image) and deep structure of images (question referring to a bone or soft tissue on the image) were taken into consideration. Students scored significantly better on questions with images compared to questions without images (P < 0.001), and on questions referring to bones than to soft tissue (P < 0.001), but no difference was found in their performance on anatomical and radiological image questions. The coding highlighted areas of “test applicability” and “challenges faced by the students.” In conclusion, images are critical in medical practice for investigating a patient's anatomy, and this study sets out a way to understand the effects of images on students' performance and their views in commonly employed written assessments.
Validity and accuracy of the Adult Attention‐Deficit/Hyperactivity Disorder (ADHD) Self‐Report Scale (ASRS) and the Wender Utah Rating Scale (WURS) symptom checklists in discriminating between adults with and without ADHD
Authors: Brevik Erlend Joramo , Lundervold Astri J. , Haavik Jan , Posserud Maj‐Britt
Published: April 2020

Objective

To validate the Adult ADHD Self‐Report Scale (ASRS) and the Wender Utah Rating Scale (WURS) in a well‐characterized sample of adult attention‐deficit/hyperactivity disorder (ADHD) patients and population controls.

Methods

Both the ASRS and the WURS were administered to clinically diagnosed adult ADHD patients (n = 646) and to population controls (n = 908). We performed principal component analyses (PCA) and calculated receiver operating curves (ROC) including area under the curve (AUC) for the full WURS and ASRS, as well as for the PCA generated factors and the ASRS short screener.

Results

We found an AUC of 0.956 (95% CI: 0.946–0.965) for the WURS, and 0.904 (95% CI: 0.888–0.921) for the ASRS. The ASRS short screener had an AUC of 0.903 (95%CI: 0.886–0.920). Combining the two full scales gave an AUC of 0.964 (95% CI: 0.955–0.973). We replicated the two‐factor structure of the ASRS and found a three‐factor model for the WURS.

Conclusion

The WURS and the ASRS both have high diagnostic accuracy. The short ASRS screener performed equally well as the full ASRS, whereas the WURS had the best discriminatory properties. The increased diagnostic accuracy may be due to the wider symptom range of the WURS and/or the retrospective childhood frame of symptoms.
Corporate carbon risk exposure, voluntary disclosure, and financial reporting quality
Authors: Lemma Tesfaye T. , Shabestari Mehrzad Azmi , Freedman Martin , Mlilo Mthokozisi
Published: April 2020

The study examines whether corporate carbon risk exposure is associated with financial reporting quality and whether voluntary carbon disclosure mediates the relationship. We analyze data drawn from firms traded on the Johannesburg Stock Exchange (JSE), for the period 2011 to 2015. We document robust evidence that firms with higher carbon risk exposure tend to provide financial statements of poorer quality (i.e., direct effect) and this association is partially mediated through voluntary carbon disclosure (i.e., indirect effect). The overall negative association between corporate carbon risk exposure and the firm's financial reporting quality is partly explained by the quality of voluntary carbon disclosure.
Feasibility study on machine‐learning‐based hybrid renewable energy applications for engineering education
Authors: Chandrasekaran Shilaja
Published: April 2020

In addition to the conventional natural resources such as petroleum extracts, natural gas and charcoal, and particularly with the current worldwide condition of economy of the energy sector, renewable energy sources are increasingly gaining attention. On the basis of recent researches, experts and environmentalists suggest that the renewable energy sources contribute for the major energy consumption. Rapid development of the renewable energy and energy‐efficient technologies results in significant energy security and economic benefits, which lead to reduction in capital investment for electricity systems. Therefore, through power system planning, we can augment the quality and efficiency of the power supply. The challenges in meeting the power requirements can be addressed by machine learning (ML) technique, an interdisciplinary field that allows using the statistical techniques to solve the energy‐related problems using pattern recognition, artificial neural network, and fuzzy and hybrid combinations. The recent innovations in web‐based and mobile technologies led to the application of ML in energy sector.
Association between cancer‐specific adverse event triggers and mortality: A validation study
Authors: Weingart Saul N. , Nelson Jason , Koethe Benjamin , Yaghi Omar , Dunning Stephan , Feldman Albert , Kent David , Lipitz‐Snyderman Allison
Published: April 2020

Background

As there are few validated measures of patient safety in clinical oncology, creating an efficient measurement instrument would create significant value. Accordingly, we sought to assess the validity of a novel patient safety measure by examining the association of oncology‐specific triggers and mortality using administrative claims data.

Methods

We examined a retrospective cohort of 322 887 adult cancer patients enrolled in commercial or Medicare Advantage products for one year after an initial diagnosis of breast, colorectal, lung, or prostate cancer in 2008‐2014. We used diagnosis and procedure codes to calculate the prevalence of 16 cancer‐specific "triggers"–events that signify a potential adverse event. We compared one‐year mortality rates among patients with and without triggers by cancer type and metastatic status using logistic regression models.

Results

Trigger events affected 19% of patients and were most common among patients with metastatic colorectal (41%) and lung (50%) cancers. There was increased one‐year mortality among patients with triggers compared to patients without triggers across all cancer types in unadjusted and multivariate analyses. The increased mortality rate among patients with trigger events was particularly striking for nonmetastatic prostate cancer (1.3% vs 7.5%, adjusted odds ratio 1.96 [95% CI 1.49‐2.57]) and nonmetastatic colorectal cancer (4.1% vs 11.7%, 1.44 [1.19‐1.75]).

Conclusions

The association between adverse event triggers and poor survival among a cohort of cancer patients supports the validity of a cancer‐specific, administrative claims‐based trigger tool.
A Sweet Galactose Transfer: Metabolic Oligosaccharide Engineering as a Tool To Study Glycans in Plasmodium Infection
Authors: Kitowski Annabel , Bernardes Gonçalo J. L.
Published: April 2020

The introduction of chemical reporter groups into glycan structures through metabolic oligosaccharide engineering (MOE) followed by bio‐orthogonal ligation is an important tool to study glycosylation. We show the incorporation of synthetic galactose derivatives that bear terminal alkene groups in hepatic cells, with and without infection by Plasmodium berghei parasites, the causative agent of malaria. Additionally, we demonstrated the contribution of GLUT1 to the transport of these galactose derivatives, and observed a consistent increase in the uptake of these compounds going from naïve to P. berghei‐infected cells. Finally, we used MOE to study the interplay between Plasmodium parasites and their mosquito hosts, to reveal a possible transfer of galactose building blocks from the latter to the former. This strategy has the potential to provide new insights into Plasmodium glycobiology as well as for the identification and characterization of key glycan structures for further vaccine development.
Three cases in which drug‐induced hyponatremia was improved by replacing carbamazepine with lacosamide
Authors: Morimoto Masahito , Suzaki Ichiro , Shimakawa Seishi , Hashimoto Toshiaki , Nakatsu Tadanori , Hamada Shigeaki , Kyotani Shojiro
Published: April 2020

Carbamazepine often causes drug‐induced hyponatremia. Hyponatremia due to carbamazepine may be improved by changing to the same mechanism of action, lacosamide.
On the Resistances of a Slurry Electrode Vanadium Redox Flow Battery
Authors: Percin Korcan , van der Zee Bart , Wessling Matthias
Published: April 2020

We studied the half‐cell performance of a slurry‐based vanadium redox flow battery via the polarization and electrochemical impedance spectroscopy methods. First, the conductive static mixers are examined and lower ohmic and diffusion resistances are shown. Further analyses of the slurry electrodes for the catholyte (VO2+−VO2+) and anolyte (V3+−V2+) are presented for the graphite powder slurry containing up to 15.0 wt.% particle content. Overall, the anolyte persists as the more resistive half‐cell, while ohmic and diffusion‐related limitations are the dominating resistances for both electrolytes. The battery is further improved by the addition of Ketjen black nanoparticles, which results in lower cell resistances. The best results are achieved when 0.5 wt.% Ketjen black nanoparticles are dispersed with graphite powder since the addition of nanoparticles reduces ohmic, charge transfer and mass diffusion resistances by improving particle‐particle dynamics. The results prove the importance of understanding resistances in a slurry electrode system.
Flexible heteroatom‐doped porous carbon nanofiber cages for electrode scaffolds
Authors: Cai Weiping , Zhang Yuanyuan , Jia Yongtang , Yan Jianhua
Published: April 2020

Porous carbon nanofibers (PCNFs) with rich functionalities and high surface areas are important electrode scaffolds to load active materials, but increasing their pore volumes and strength simultaneously is a challenge. Here, we report a scalable method to fabricate B‐F‐N triply doped PCNF cages with high porosity of greater than 92.8% and small bending stiffness of 10 mN by electrospinning the mixed sol of poly(tetrafluoroethylene), poly(vinyl alcohol), boric acid, and carbon nanotubes (CNTs) followed by pyrolysis. The macro‐micro dual‐phase separation creates well‐controlled macropores (>60 nm) and meso‐micropores with large pore volumes (0.55 cm3/g) on carbon nanofibers, while the interior CNTs can cushion the applied stress and render the PCNF films with superior flexibility. Fabricated symmetrical supercapacitors with the PCNF cages exhibit high gravimetric capacitance of 164 F/g at 20 mV/s and 92.5% capacity retention after 20 000 cycles at 2 A/g. The reported approach allows the green synthesis of a new PCNF scaffold material with properties appealing for applications.
Light‐Activated Protein Conjugation and 89Zr‐Radiolabelling with Water‐Soluble Desferrioxamine Derivatives
Authors: Guillou Amaury , Earley Daniel F. , Holland Jason P.
Published: April 2020

Protein‐conjugates are vital tools in biomedical research, drug discovery and imaging science. For example, functionalised monoclonal antibodies (mAbs) coupled to the desferrioxamine B (DFO) chelate and radiolabelled with 89Zr4+ ions are used as radiopharmaceuticals for diagnostic positron emission tomography (PET). In this context, protein functionalisation requires the formation of a covalent bond that must be achieved without compromising the biological properties of the mAb. Photochemistry offers new synthetic routes toward protein conjugates like 89Zr‐mAbs but to harness the potential of light‐induced conjugation reactions new photoactivatable reagents are required. Herein, we introduce two photoactivatable DFO‐derivatives functionalised with an aryl azide (ArN3) for use in light‐activated conjugation and radiosynthesis of 89Zr‐mAbs. Incorporation of a tris‐polyethylene glycol (PEG)3 linker between DFO and the ArN3 group furnished water‐soluble chelates that were used in the one‐pot, photoradiosynthesis of different 89Zr‐radiolabelled protein conjugates with radiochemical yields up to 72.9±1.9 %. Notably, the DFO‐PEG3 chelates can be readily synthesised in accordance with Good Laboratory Practice (GLP), which will facilitate clinical trials with photoradiolabelled 89Zr‐mAbs.