bluuebunny/crossref_metadata_2025 huggingface dataset:
Kinetic Resolution of Tertiary 2‐Alkoxycarboxamido‐Substituted Allylic Alcohols by Chiral Phosphoric Acid Catalyzed Intramolecular Transesterification
Authors: Rajkumar Subramani , He Shunlong , Yang Xiaoyu
Published: May 2019

A highly enantioselective kinetic resolution of tertiary 2‐alkoxycarboxamido allylic alcohols has been achieved through a chiral phosphoric acid catalyzed intramolecular transesterification reaction. Both alkyl,aryl‐ and dialkyl‐substituted tertiary allylic alcohols were resolved with excellent efficiencies, affording both the recovered tertiary alcohols and the carbamate products with high enantioselectivities (with s factors up to 164.6). A gram‐scale reaction with 1 mol % catalyst loading and the facile conversion of the enantioenriched products into useful chiral building blocks, such as chiral oxazolidinones and β‐amino alcohols, demonstrate the value of this reaction.
Switching in Metal–Organic Frameworks
Authors: Bigdeli Fahime , Lollar Christina T. , Morsali Ali , Zhou Hong‐Cai
Published: May 2019

In recent years, metal–organic frameworks (MOFs) have become an area of intense research interest because of their adjustable pores and nearly limitless structural diversity deriving from the design of different organic linkers and metal structural building units (SBUs). Among the recent great challenges for scientists include switchable MOFs and their corresponding applications. Switchable MOFs are a type of smart material that undergo distinct, reversible, chemical changes in their structure upon exposure to external stimuli, yielding interesting technological applicability. Although the process of switching shares similarities with flexibility, very limited studies have been devoted specifically to switching, while a fairly large amount of research and a number of Reviews have covered flexibility in MOFs. This Review focuses on the properties and general design of switchable MOFs. The switching activity has been delineated based on the cause of the switching: light, spin crossover (SCO), redox, temperature, and wettability.
Plant‐supported silver nanoparticles: Efficient, economically viable and easily recoverable catalyst for the reduction of organic pollutants
Authors: Ismail Muhammad , Khan M.I. , Khan Murad Ali , Akhtar Kalsoom , Asiri Abdullah M. , Khan Sher Bahadar
Published: May 2019

Ginger rhizome powder was used for the synthesis of supported metallic nanoparticle catalysts. A simple and novel adsorption method was used for the synthesis of silver nanoparticles loaded on ginger powder (Ag/GP), copper on ginger powder (Cu/GP) and nickel on ginger powder (Ni/GP). Among these, Ag/GP showed selective reduction of methyl orange and was used for further reactions. The prepared nanomaterials were characterized through X‐ray diffraction, transmission electron microscopy, field emission scanning electron microscopy, fourier transform infrared spectroscopy and energy‐dispersive X‐ray spectroscopy. The prepared Ag/GP catalyst was employed in the catalytic reduction of 4‐nitrophenol (4‐NP), 2‐nitrophenol (2‐NP), rhodamine B, methyl red and congo red. Ag/GP showed excellent catalytic reduction activity, the rate constants being 1.26 × 10−3 and 2.38 × 10−3 s−1 for 2‐NP and 4‐NP, respectively. The turnover frequency reached 1.06 min−1 for 2‐NP and 1.16 min−1 for 4‐NP when using the Ag/GP catalyst. The prepared Ag/GP catalyst demonstrated outstanding activity for the degradation of a mixed solution of dyes. Also, stability and reusability of the prepared catalyst were investigated, which showed outstanding reusability up to five times and was stable up to five days.
Diphallia, Double Bladder, and Two Hemiscrotums: A Case Report
Authors: Dunn Debra , Fine Ronnie G.
Published: May 2019

Complete diphallia, a rare urogenital congenital anomaly in which a male is born with two fully formed phalluses, occurs in one out of every five to six million live births. The condition is characterized by two separate phalluses, each of which comprise a pair of corpora cavernosa and one corpus spongiosum with an orthotopic urethra. Approximately 100 cases have been reported worldwide, and it is thought that each case is unique. This article discusses diphallia, urethral duplication, and bladder duplication and concludes with a case study involving a three‐year‐old male born to consanguineous parents from a small, remote community in Ecuador who underwent surgery for correction of a complete coronal penile and bladder duplication. After consultation, the patient was scheduled for a right penectomy and cystoplasty.
Ascorbic Acid Promotes Procollagen C‐Proteinase Enhancer 1 Expression, Secretion, and Cell Membrane Localization
Authors: Gohar Ofra , Weiss Tali , Wineman Eitan , Kessler Efrat
Published: May 2019

Removal of the C‐propeptide from fibrillar procollagens is essential for collagen fibril assembly. The reaction is catalyzed by bone morphogenetic protein‐1/tolloid‐like proteinases and is accelerated by procollagen C‐proteinase enhancer 1 (PCPE‐1), an extracellular matrix glycoprotein that binds to the procollagen C‐propeptide and its expression overlaps that of collagen. Ascorbic acid (Asc) is vital for collagen hydroxylation, folding, and secretion. It also increases collagen gene expression. The role of Asc as a regulator of PCPE‐1 expression is debatable. To shed further light on this matter, herein, we studied the effects of Asc on PCPE‐1 expression, secretion, and cellular localization in Rat2 and/or mouse 3T3 fibroblasts. Asc increased PCPE‐1 expression at the translational and transcriptional levels about two‐fold. It also increased the rate of PCPE‐1 secretion approximately six‐fold. Endogenous PCPE‐1 was found to be cell associated, and Asc increased the amount of PCPE‐1 on the cell surface. In the absence of PCPE‐1 hydroxylation, we propose that the dependence of PCPE‐1 secretion on Asc may be related to its role in procollagen secretion. Localization of PCPE‐1 to the cell membrane favors the cell‐surface as a physiological site of PCPE‐1 action. Anat Rec, 2019. © 2019 Wiley Periodicals, Inc.
The relationship between implicit theories of intelligence, attainment and socio‐demographic factors in a UK sample of primary school children
Authors: Warren Frances , Mason‐Apps Emily , Hoskins Sherria , Devonshire Victoria , Chanvin Mathilde
Published: May 2019

Research emerging from the USA suggests that holding an incremental theory of intelligence (growth mindset) has a positive impact on academic success. However, limited empirical work has explored this relationship in a UK sample, and there has been a lack of research into the antecedents which might influence the development of certain intelligence beliefs. This study aimed to explore these gaps in the existing literature. Data was collected from 710 9‐year‐old pupils (UK Year 5). Participants completed attainment tests in Maths and English, and a questionnaire to assess their implicit theories of intelligence (mindset). Socio‐demographic information—including gender, ethnicity, free school meal (FSM) status and special educational needs (SEN) status—was also collected. Results showed that pupils eligible for FSM or SEN endorsed more of an entity theory of intelligence than pupils not eligible for either. Analysis of the whole sample showed that attainment significantly correlated with implicit theories of intelligence, however, this relationship did not exist for children with FSM or SEN status. These findings help to elucidate the relationship between implicit theories of intelligence and attainment in the UK, but also suggest the importance of external support in potentially facilitating pupils’ belief systems. Results are discussed in relation to avenues for targeted intervention.
Recent developments in the synthesis of poly(hydroxybutyrate) based biocomposites
Authors: Raza Zulfiqar Ali , Noor Safa , Khalil Shanza
Published: May 2019

Poly(hydroxybutyrate) (PHB) has become an attractive biomaterial in research and development for past few years. It is natural bio‐based aliphatic polyester produced by many types of bacteria. Due to its biodegradable, biocompatible, and eco‐friendly nature, PHB can be used in line with bioactive species. However, high production cost, thermal instability, and poor mechanical properties limit its desirable applications. So there is need to incorporate PHB with other materials or biopolymers for the development of some novel PHB based biocomposites for value addition. Many attempts have been employed to incorporate PHB with other biomaterials (or biopolymers) to develop sustainable biocomposites. In this review, some recent developments in the synthesis of PHB based biocomposites and their biomedical, packaging and tissue engineering applications have been focused. The development of biodegradable PHB based biocomposites with improved mechanical properties could be used to overcome its native limitations hence to open new possibilities for industrial applications.
Virtual Screening Based on Ensemble Docking Targeting Wild‐Type p53 for Anticancer Drug Discovery
Authors: Li Xin , Zhang Xin‐Xin , Lin Yu‐Xi , Xu Xi‐Ming , Li Li , Yang Jin‐Bo
Published: May 2019

The tumor‐suppressor function of p53 makes it an attractive drug target. Efforts were mostly put on stabilization of the functional p53 or reactivation of mutated p53. Previous studies have shown that small molecules targeting Loop1/Sheet3 (L1/S3) can reactivate the R175H‐p53 and stabilize p53 in vitro. Since the L1/S3 pocket is shared by the mutate and the wild type (WT) p53, virtual screening is introduced to identify natural products targeting the L1/S3 of WT p53. Considering the high flexibility of Loop1, ensemble docking method is utilized for different clusters of the L1/S3. Seven conformations were chosen for docking. As one of the 181 selected candidates, torilin not only improved p53 activity, but also increased p21 protein expression level, which lies downstream of p53, therefore suppressing HCT116 cancer cell growth. Torilin may covalently bind to Cys124 of p53 by 2‐methyl‐2‐butenal (2M2B) group, as torilin derivatives, which do not contain the 2M2B group, were not able to increase the p53 transcription activity. In conclusion, this study demonstrated that L1/S3 of WT‐p53 is a druggable pocket, and torilin has a potential cytotoxicity through activating the p53 pathway.
Extracellular‐signal‐regulated kinase/mitogen‐activated protein kinase signaling as a target for cancer therapy: an updated review
Authors: Najafi Masoud , Ahmadi Amirhossein , Mortezaee Keywan
Published: May 2019

Mitogen‐activated protein kinase (MAPK) signaling pathway is activated in a wide spectrum of human tumors, exhibiting cardinal oncogenic roles and sustained inhibition of this pathway is considered as a primary goal in clinic. Within this pathway, receptor tyrosine kinases such as epithelial growth factor receptor, mesenchymal–epithelial transition, and AXL act as upstream regulators of RAS/RAF/MEK/extracellular‐signal‐regulated kinase. MAPK signaling is active in both early and advanced stages of tumorigenesis, and it promotes tumor proliferation, survival, and metastasis. MAPK regulatory effects on cellular constituent of the tumor microenvironment is for immunosuppressive purposes. Cross‐talking between MAPK with oncogenic signaling pathways including WNT, cyclooxygenase‐2, transforming growth factor‐β, NOTCH and (in particular) with phosphatidylinositol 3‐kinase is contributed to the multiplication of tumor progression and drug resistance. Developing resistance (intrinsic or acquired) to MAPK‐targeted therapy also occurs due to heterogeneity of tumors along with mutations and negative feedback loop of interactions exist between various kinases causing rebound activation of this signaling. Multidrug regimen is a preferred therapeutic avenue for targeting MAPK signaling. To enhance patient tolerance and to mitigate potential adversarial effects related to the combination therapy, determination of a desired dose and drug along with pre‐evaluation of cancer‐type‐specific kinase mutation and sensitivity, especially for patients receiving triplet therapy is an urgent need.
Properties of carbonized wheat kernels from the late Neolithic site of Donghuishan, Gansu Province, China
Authors: Wei Yimin , Guo Boli , Ren Mankuan
Published: May 2019

Background and objectives

The Dongshuishan ruins in Minle, Gansu, is a site of the late Neolithic (Siba culture) with crop cultivation history. A total of 105 carbonized wheat kernels (Triticum aestivum) were found at the ruins. The properties of carbonized kernels were analyzed and then compared with modern wheat kernels.

Findings

The single kernel weight of carbonized kernel was 9.52 mg on average, and the length and width of a kernel were 4.62 and 3.26 mm on average, respectively. The ratio of kernel width to length was 0.71 on average. The kernel length was shorter than that of modern wheat variety, but with a similar kernel width. The carbonized kernels were higher in 15N isotope content and high in the major minerals zinc (Zn), copper (Cu), lead (Pb), and strontium (Si). The carbonized kernels have existed since 3,463–3,361 cal BP.

Conclusions

It is estimated that the single kernel weight from Donghuishan was 45–47% of that of the modern wheat. Studying the properties of carbonized wheat affords us a significant reference that merits attention in the progress of improving and evolving varieties in the last hundred years in China.

Significance and novelty

Ascertaining the cultivation years of wheat in Donghuishan and analyzing the spread of wheat from West Asia to East Asia provided historic evidence for how the wheat spread from Donghuishan to middle China since 4,000 years ago.
Impact of Solute Properties and Water Matrix on Nanofiltration of Pesticides
Authors: Tan Lian See , Ahmad Abdul Latif , Shukor Syamsul Rizal Abd , Yeap Swee Pin
Published: May 2019

The application of different nanofiltration membranes for the separation of pesticides, i.e., atrazine and dimethoate, from aqueous solutions is described. The nanoflitration membranes DK, NF270, NF200, and NF90 were tested for the pesticide retention performance in a stirred dead‐end filtration system. NF90 demonstrated the best pesticide retention with over 95 % for atrazine and approximately 80 % for dimethoate. All membranes consistently showed better retention of atrazine than of dimethoate. Dissolving the pesticides in river or tap water amplified the overall pesticide retention performance, indicating that filtration in water treatment plants could render superior pesticide retention. However, a lower flux was obtained for the filtration of tap and river water.
Suppressing Charge Recombination and Ultraviolet Light Degradation of Perovskite Solar Cells Using Silicon Oxide Passivation
Authors: Ren Jing , Luo Qiang , Hou Qinzhi , Chen Hui , Liu Tao , He Hongcai , Wang Jinshu , Shao Qian , Dong Mengyao , Wu Shide , Wang Ning , Lin Jing , Guo Zhanhu
Published: May 2019

Organic‐metal lead halide perovskite solar cells (PSCs) featuring low‐cost and high efficiency have been recognized as promising photovoltaic devices, but their serious charge recombination and ultraviolet light irradiation instability limit their output efficiency and long‐term operation. In this work, we have introduced silicon oxide as an interfacial modifier of the electron transporting layer in TiO2‐based planar heterojunction PSCs. The incorporation of a silicon oxide modifier passivates the trap states of perovskite absorber and suppresses the charge recombination of PSCs. As a consequence, a competitive solar‐to‐electricity conversion efficiency of 18.0 % was achieved for the device fabricated with the silicon‐oxide‐modified TiO2 electron extraction layer, which is increased by 15 % compared with the PSC fabricated with pristine TiO2; this can be attributed to the significantly increased open‐circuit voltage and photocurrent density. Furthermore, the ultraviolet light irradiation stability of PSCs is greatly improved, resulting from the low photocatalytic activity of the silicon‐oxide‐modified TiO2 electron transporting layer, as revealed by the photoelectrochemical oxidation of CH3NH2. This work represents a feasible step through interfacial engineering toward the realization of ultraviolet‐light‐stable and scalable PSCs.
Sulfonylamide‐Based Ionic Liquids for High‐Voltage Potassium‐Ion Batteries with Honeycomb Layered Cathode Oxides
Authors: Yoshii Kazuki , Masese Titus , Kato Minami , Kubota Keigo , Senoh Hiroshi , Shikano Masahiro
Published: May 2019

The world is at the cusp of a new era where pivotal importance is being attached to the development of sustainable and high‐performance energy storage systems. Potassium‐ion batteries are deemed not only cheap battery candidates, but also as the penultimate high‐voltage energy storage systems within monovalent‐cation chemistries. However, their performance and sustainability are undermined by the lack of suitable electrolytes for high‐voltage operation, particularly owing to the limited availability of cathode materials. Here, the potential of ionic liquids based on potassium bis(trifluoromethanesulfonyl)amide (KTFSA) as high‐voltage electrolytes is presented by assessing their physicochemical properties along with the electrochemical properties upon coupling with new high‐voltage layered cathode materials. These ionic liquids demonstrate a wide electrochemical window (around 6.0 V), making them feasible and safe electrolytes for the high‐voltage potassium‐ion battery configuration. This is proven by matching this electrolyte with new high‐voltage layered cathode compositions, demonstrating stable electrochemical performance. The present findings of electrochemically stable ionic liquids based on potassium bis(trifluoromethanesulfonyl)amide will bolster further advancement of high‐performance cathode materials, whose performance at high‐voltage regimes were apparently restricted by the paucity of suitable and compatible electrolytes.
Impeller power draw during turbulent operation in solid‐liquid suspensions
Authors: Myers Kevin J. , Janz Eric E. , Bao Tianxin , Heigel M. Molly
Published: May 2019

Experimental measurements with six impeller types in solid‐liquid suspensions indicate that impeller power draw in the turbulent regime is approximately proportional to the solid‐liquid suspension density when the solids are distributed throughout the liquid; however, the accuracy of this approach is limited and there are clear differences in the behaviours of the various impellers. In general, power draw increases are less than suspension density increases for impellers with large blade‐trailing vortices, while power draw increases are equal to or greater than suspension density increases for impellers with smaller blade‐trailing vortices. The power draw data is well‐described using linear relations between the impeller power number and the density difference correlating parameter proposed by Micheletti et al.,[9] with the slope of the relation being dependent on impeller type. More extensive testing with a pitched‐blade turbine, using a greater variety of solids, found that the relation between the impeller power number and the density difference correlating parameter is independent of particle size for particles as large as 1  mm (1000 microns). For particles larger than 1.7  mm (1700 microns), in addition to suspension density, the solid volume fraction affects the pitched‐blade turbine power number; however, it is difficult to determine if this effect exists at all scales or if it is a result of the large particle size relative to the impeller dimensions in the experimental system. For large particles, the power draw is increased by the addition of neutrally‐buoyant particles that do not change the suspension density, with the magnitude of the increase being dependent on impeller type.
Experimental methods in chemical engineering: Fluorescence emission spectroscopy
Authors: Gomes Anderson J. , Lunardi Claure N. , Rocha Fellipy S. , Patience Gregory S.
Published: May 2019

Fluorescence is a luminescence phenomenon in which a compound emits light after absorption of electromagnetic irradiation. Specialized terms such as photoluminescence, cathodoluminescence, anodoluminescence, radioluminescence, and x‐ray fluorescence sometimes are used to indicate the type of exciting radiation. Fluorescence spectroscopy provides reliable quantitative and qualitative data. It precisely tracks chemical reactions from fluorescent materials compounds with aromatic groups, or conjugated planar, or cyclic molecules. It is up to 1000 times more sensitive than UV‐vis or infrared spectroscopy. Fluorescence intensity depends on the fluorophore (compound that fluoresces), its concentration, excitation and emission wavelengths, temperature and contamination. We adjust the slit dimensions, photomultiplier tube voltage and bandpass filter cutoff to maximize the signal while avoiding saturating the detector. Together with x‐ray diffraction, it is the most common spectroscopic technique with applications in geology, chemistry, medicine, and astronomy. A bibliometric analysis of the top 10 000 cited papers identified 5 clusters based on keywords centered around: (1) cancer, cells, and proteins; (2) aggregation induced emission, LED, and complexes; (3) live cells, sensors, and probes; (4) quantum dots, DNA, and biosensors; and (5) nanoparticles, in vivo, and drug delivery. Chemical engineers have yet to fully embrace fluorescence spectroscopy as the category is ranked 16th among all scientific categories that exploit it.
Development of biocompatible NaGdF4: Er3+, Yb3+ upconversion nanoparticles used as contrast agents for bio‐imaging
Authors: Tse Wai Hei , Chen Longyi , McCurdy Colin M. , Tarapacki Christine M. , Chronik Blaine A. , Zhang Jin
Published: May 2019

Upconversion nanoparticles with special fluorescence and magnetic properties have been considered an alternative contrast agent for multiple bio‐imaging techniques. It is important to understand the effects of the surface properties and dosage of upconversion nanoparticles on both the magnetic resonance (MRI) image and the photoluminescence spectrum. Here, NaGdF4: Er3+, Yb3+ upconversion nanoparticles (UCNPs) modified with amine functional group were produced through a one‐pot thermal decomposition. The average length of the cubic UCNPs is estimated at 53 ±13 nm. The effect of the dosage of amine modified UCNPs on the MRI image is investigated. The T1 and T2 relaxivities of the amine modified UCNPs in agarose gel at 3 T are r1 = 6.79 ±0.14 and r2  = 17.0 ±0.18 (mmol/L)−1 s−1, which are comparable to the relaxivities of commercially available MRI contrast agents. In addition, the photoluminescence of the amine modified UCNPs at low concentrations < 150 µg/mL are further investigated with the excitation wavelength (λex) at 980 nm. The internalization of the amine modified UCNPs cultured with human umbilical vascular endothelial cells (HUVEC) is observed by the fluorescence imaging. Meanwhile, T1‐weighted MRI imaging of HUVEC cells treated with amine modified UCNPs at 10 µg/mL can be obtained. No significant toxic effect on cells is found when the concentration of the amine modified UCNPs is < 300 µg/mL. This study indicates that a low concentration of amine‐modified NaGdF4: Er3+, Yb3+ UCNPs can be used as the contrast agent for both fluorescence imaging and magnetic resonance imaging.
A large series of hyalinizing trabecular tumors: Cytomorphology and ancillary techniques on fine needle aspiration
Authors: Dell’Aquila Marco , Gravina Carmen , Cocomazzi Alessandra , Capodimonti Sara , Musarra Teresa , Sfregola Stefania , Fiorentino Vincenzo , Revelli Luca , Martini Maurizio , Fadda Guido , Pantanowitz Liron , Larocca Luigi Maria , Rossi Esther Diana
Published: May 2019

Background

Hyalinizing trabecular tumors (HTTs) are rare, essentially benign, follicular cell–derived thyroid neoplasms characterized by a trabecular growth pattern and nuclear pseudoinclusions. Their cytological findings are misleading, because these tumors are often misinterpreted on fine needle aspirate cytology as malignant lesions, such as papillary thyroid cancer and/or medullary thyroid cancer, leading to unnecessary total thyroidectomy. The aim of this study was to analyze the cytomorphological features and application of ancillary techniques in a series of HTTs.

Methods

Of 26 histological cases of HTT collected from September 2001 to December 2018, 18 cases had concomitant cytopathology. Cytological cases were processed with liquid‐based cytology (LBC). Immunocytochemistry for HBME‐1 and galectine‐3 as well as molecular testing for BRAFV600E mutation were performed on both LBC and histological specimens.

Results

The 18 lesions with fine needle aspirate cytology ranged in size from 5 to 45 mm. Cytological diagnoses included: 1 benign lesion favoring goiter (5.5%), 4 atypia of undetermined significance (22.2%), 6 follicular neoplasms (33.3%), 5 suspicious for malignancy favoring papillary thyroid cancer (28%), and 2 malignant (11%). Hence, 89% HTT had a negative concordant immunopanel, and they were 100% wild‐type BRAFV600E.

Conclusion

The majority of our HTTs (83.3%) were diagnosed in the indeterminate Bethesda categories, suggesting that their cytomorphological features pose issues for reaching a conclusive cytological diagnosis. The ancillary test results in our series support the fact that HTT is a benign neoplasm.
Blockchain for economically sustainable wireless mesh networks
Authors: Kabbinale Aniruddh Rao , Dimogerontakis Emmanouil , Selimi Mennan , Ali Anwaar , Navarro Leandro , Sathiaseelan Arjuna , Crowcroft Jon
Published: May 2019

Decentralization, in the form of mesh networking and blockchain, two promising technologies, is coming to the telecommunications industry. Mesh networking allows wider low‐cost Internet access with infrastructures built from routers contributed by diverse owners, whereas blockchain enables transparency and accountability for investments, revenue, or other forms of economic compensations from sharing of network traffic, content, and services. Crowdsourcing network coverage, combined with crowdfunding costs, can create economically sustainable yet decentralized Internet access. This means that every participant can invest in resources and pay or be paid for usage to recover the costs of network devices and maintenance. While mesh networks and mesh routing protocols enable self‐organized networks that expand organically, cryptocurrencies and smart contracts enable the economic coordination among network providers and consumers. We explore and evaluate two existing blockchain software stacks, Hyperledger Fabric (HLF) and Ethereum geth with Proof of Authority (PoA) intended as a local lightweight distributed ledger, deployed in a real city‐wide production mesh network and in laboratory network. We quantify the performance and bottlenecks and identify the current limitations and opportunities for improvement to serve locally the needs of wireless mesh networks, without the privacy and economic cost of relying on public blockchains.
Directionality of Halogen Bonds: An Interacting Quantum Atoms (IQA) and Relative Energy Gradient (REG) Study
Authors: Orangi Nasim , Eskandari Kiamars , Thacker Joseph C. R. , Popelier Paul L. A.
Published: May 2019

Interacting Quantum Atoms (IQA) and Interacting Quantum Fragments (IQF) analyses are used to study
(X=Cl and Br) model complexes in order to determine the origin of halogen bond directionality. IQA allows for the calculation of intra‐ and interatomic classical and exchange‐correlation energies, which can be used to determine the energetic nature of the changes that occur when deviating from the preferred halogen bond approach. The Relative Energy Gradient (REG) method is also applied to rank the IQA energies and reveal which energy contributions best describe the total behavior of the system. Indeed, all the pairwise interactions and atomic self‐energies are angularly dependent; some terms favor the linear structure and some tend toward nonlinear arrangements. For instance, when the C−X−N angle is altered, the halogen‐nitrogen interaction energy behaves like the total energy of the system while the carbon‐nitrogen interaction works against the total energy profile. Furthermore, the REG values reveal that the contribution of the halogen‐nitrogen interaction to the total behavior of the system is small. Instead, the secondary interactions (e. g., fluorine‐nitrogen and carbon‐hydrogen interactions) and atomic self‐energies are mainly responsible for the angular preference of these halogen bonds. Finally, IQF calculations followed by REG analysis reveal the importance of the self‐energy of the fragments.
Submarine channels ‘swept’ downstream after bend cutoff in salt basins
Authors: Covault Jacob A. , Sylvester Zoltán , Hudec Michael R. , Ceyhan Can , Dunlap Dallas
Published: May 2019

Channel‐bend expansion and downstream translation, as well as vertical movements by aggradation and incision, set the stratigraphic architecture of channelized depositional systems. Early work on submarine‐channel evolution has suggested that downstream translation is rare. It is proposed here that downstream translation of bends might be common in deep‐water salt‐tectonic provinces, where complex topography can localize channel pathways that promote meander cutoffs and the generation of high‐curvature bends. Three‐dimensional seismic‐reflection data from a region with salt‐influenced topography in the Campos Basin, offshore Brazil, is used to characterize the structural geometry of a salt diapir and stratigraphic architecture of an adjacent submarine‐channel system that extends for 18 km. The combined structural and stratigraphic evolution is interpreted, including meander‐cutoff development near the salt diapir followed by ~10 km of downstream translation of a channel bend. The stratigraphic evolution is tested with a simple numerical model of channel meandering. This integrated subsurface characterization and stratigraphic modelling study sheds light on the processes and controls of submarine‐channel downstream translation, which might be common in rapidly deforming settings, such as salt basins, that promote localized subsidence, meander cutoffs, and rapidly translating, high‐curvature bends.
Convergent Synthesis of Oligosaccharides Structurally Related to Galactan I and Galactan II of Klebsiella Pneumoniae and their Use in Screening of Antibody Specificity
Authors: Argunov Dmitry A. , Trostianetskaia Anastasiia S. , Krylov Vadim B. , Kurbatova Ekaterina A. , Nifantiev Nikolay E.
Published: May 2019

Klebsiella pneumoniae Is a Gram‐negative pathogenic bacterium that emerges a challenge for modern medicine due to intensively rising multi‐drug resistance. Specific LPS O‐chains represent promising targets for development of vaccines for immunoprophylaxis or immunotherapy of K. pneumoniae‐caused diseases. Herein, the synthesis of di‐, tetra‐, and hexasaccharides which represent structural fragments of both galactan I and galactan II of K. pneumoniae LPS O‐chains is described. The galactofuranoside building block used for assembling the galactan I chains was prepared by pyranoside‐into‐furanoside (PIF) rearrangement of the corresponding galactopyranoside precursor bearing an acid‐labile temporary p‐methoxybenzyl protecting group at O(3). The synthesized set of K. pneumoniae antigenic oligosaccharides in the form of their biotinylated derivatives was used to create a glycoarray which was applied for the screening of antibodies to galactan I and galactan II in anti‐K. pneumoniae sera. The obtained results demonstrate the applicability of such a glycoarray‐based assay for typing antibodies to Klebsiella strains belonging to most frequent O1 serogroup.
Diastereoselective Synthesis of 2‐(1,3‐Dioxolanes‐4‐yl)‐4H‐pyran‐4‐ones from 2‐Diazo‐3,5‐dioxo‐6‐ynoates (sulfones) and Aldehydes Based on Tandem Cyclization‐Cycloaddition Strategy
Authors: Zhang Jianfang , Deng Guisheng , Wang Jianbo
Published: May 2019

In AgSbF6/Rh2(OAc)4/DCM system, two‐component reaction of 2‐diazo‐3,5‐dioxo‐6‐ynoates (sulfones) and two equivalent of aldehydes provided easy access to 2‐(1,3‐dioxolanes‐4‐yl)‐4H‐pyran‐4‐ones. This represents the first method for generating the novel heterocyclic compounds. A possible mechanism is proposed to explain this result. The most significant features of the tandem cyclization are simple procedure, mild conditions and high diastereoselectivity.
C‐Branched Imino Sugars: Synthesis and Biological Relevance
Authors: Dehoux‐Baudoin Cécile , Génisson Yves
Published: May 2019

Only few naturally occurring pyrrolizidine imino sugars possess a geminal‐hydroxyhydroxymethyl group. In search for more potent and selective inhibitors of carbohydrate processing enzymes, organic chemists took inspiration from this uncommon feature. The presence of such a group formally results from either i) a shift of the hydroxymethyl group of the imino sugar toward an adjacent hydroxylated position or ii) the addition of a second hydroxymethyl group on a tertiary alcohol. Five‐, six‐, seven‐membered ring imino sugars and bicyclic imino sugars embedding this structural feature were thus prepared by innovative synthetic strategies. Some of these derivatives are very potent and selective inhibitors of glycosidases. Moreover, several C‐branched imino sugars proved recently to act as corrector of F508del‐CTFR and open the way for the development of derivatives relevant in the context of cystic fibrosis.
Counter‐argument self‐efficacy predicts choice of belief‐defense strategies
Authors: Goldberg Matthew H. , Carmichael Cheryl L. , Hardin Curtis D.
Published: May 2019

Research has identified many strategies people use to defend against belief‐inconsistent information. However, little research has identified factors that predict which defense strategy people will use when more than one is available. Two experiments tested whether people choose to counter‐argue belief‐inconsistent information because they believe arguing will be successful, but resort to weaker defense strategies because they believe arguing will be unsuccessful. Exposure to strong versus weak belief‐inconsistent information caused a decrease in counter‐arguing and an increase in ignoring (Experiment 1) or claiming a belief to be a matter of opinion (untestable) rather than a matter of fact (testable; Experiment 2). Consistent with self‐efficacy theory, expectations of successful counter‐arguing was the mechanism responsible for both effects. When people feel less capable of successfully counter‐arguing because the information is too difficult to refute, they resort to epistemically weaker defense strategies in order to preserve their belief.
A performance comparison of serial and parallel solar‐assisted heat pump heating systems in Xi'an, China
Authors: Huan Chao , Wang Fenghao , Li Shengteng , Zhao Yujiao , Liu Lang , Wang Zhihua , Ji Changfa
Published: May 2019

In this study, a TRNSYS model for a solar‐assisted heat pump (SAHP) water heating system for a university bathroom in Xi'an was developed and validated through experimental measurements. Under the typical meteorological conditions in Xi'an, a comparative analysis of the performance of the serial indirect expansion SAHP (IDX‐SAHP) system and the parallel IDX‐SAHP system during different seasons was conducted using the validated model. The results demonstrated that for annual operation, the parallel IDX‐SAHP system showed better performance in the Xi'an district compared to the serial system. Under the same heating load, the average coefficient of performance (COP) of the serial IDX‐SAHP system was 3.23 and that of the parallel IDX‐SAHP system was 4.34. In particular, during summer and the transition season, the parallel IDX‐SAHP system showed large advantages, mainly owing to a larger part of the heating load being provided by the solar collector. However, the serial IDX‐SAHP system showed a higher efficiency than that of the parallel IDX‐SAHP system during winter conditions.
Techno‐economic assessment of solar photovoltaic integration into national grids: A case study of Burkina Faso
Authors: Ouedraogo Bachir Ismael , Yamegueu Daniel
Published: May 2019

To promote a low‐carbon society, it is urgent to better integrate renewable energies into energy supply systems. This paper examines the impact of solar photovoltaic (PV) integration into the national electrical grid in Burkina Faso on the electricity production cost. The analysis is based on the levelized cost of electricity (LCOE) technique. Several levels of PV integration have been considered namely 20%, 40%, 60%, and 80% of the total installed capacity. First, the results revealed all the configurations with PV integration are more attractive and cost‐effective compared with the conventional diesel standalone electricity system. The sensitivity analysis shows that the configuration with 80% PV is the most attractive when compared to the other ones as it has the lowest LCOE and CO2 emissions compared with the other scenarios. This paper also shows that in the context of rising fuel prices and environmental concern, the electricity production based on diesel standalone system is not a viable solution for Burkina Faso at the moment. Finally, the results revealed that subsidies offered by the government of Burkina Faso to support the electricity production cost will be more effective for a system with PV integration. This paper gives detail highlights of solution for policymakers to make useful investment in solar energy and widen the access to electricity in Burkina Faso.
Transition Cycles during Operation of a Reversible Solid Oxide Electrolyzer/Fuel Cell (rSOC) System
Authors: Aicart J. , Di Iorio S. , Petitjean M. , Giroud P. , Palcoux G. , Mougin J.
Published: May 2019

Reversible high temperature solid oxide cells (rSOC) can be operated both in the fuel cell (SOFC) and the electrolysis mode (SOEC). This specificity is a promising way to either store intermittent renewable energy surpluses by producing H2, or generate electricity from H2 or any other fuel locally available (CH4, biogas) when demand overtakes the local production. Therefore, rSOC technology could reinforce autonomy and flexibility in buildings, eco‐districts, up to industrial sites and local energy grids powered by intermittent renewable energies. Such a storage solution complements batteries, displays flexible energy storage durations, from a few hours up to seasonal cycles, and allows decorrelating power and storage capacity. Nonetheless, experiments are needed to assess whether rSOC systems can accommodate the surrounding environment and switch rapidly between various power levels and operating modes.

An rSOC system has been built and its ability to operate in both electrolysis and fuel cell modes has been demonstrated. The present work is focused on transitioning between 3 operating modes (SOEC, SOFC operated in H2, SOFC operated in CH4), each displaying 3 power levels. The results show that all transition cycles could be done in 3 to 10 min without negatively affecting short term stack performances.
Molecular characteristics of poorly differentiated chordoma
Authors: Shih Angela R. , Chebib Ivan , Deshpande Vikram , Dickson Brendan C. , Iafrate A. John , Nielsen G. Petur
Published: May 2019

Pediatric poorly differentiated chordoma is a subtype of chordoma with a much more aggressive clinical course and has been characterized by loss of SMARCB1. This study characterizes the molecular features of these tumors in comparison to conventional chordoma. A search of records between 1990 and 2017 at Massachusetts General Hospital identified two patients with sufficient excess tissue for molecular analysis and a third patient diagnosed with a highly cellular conventional chordoma. The three tumors were sent for array comparative genomic hybridization for genome‐wide copy number variants; multiplex PCR for single‐nucleotide variants; and RNA‐sequencing for fusions. Poorly differentiated chordoma showed chromosome 22q loss, including SMARCB1, with no identifiable mutations on multiplex PCR. The cellular conventional chordoma showed a complex pattern of chromosomal gains and losses involving 12 chromosomes, and an RB1 mutation at low allelic frequency. RNA‐Seq identified no disease‐defining gene fusion events. Poorly differentiated chordoma appears to represent a distinct type of tumor that is genetically unrelated to conventional chordoma. Recognition of this subtype is important because these malignancies should be treated aggressively with multimodality therapy, and possibly targeted therapy.
Mammalian Target of Rapamycin Complex 1 Signaling Is Required for the Dedifferentiation From Biliary Cell to Bipotential Progenitor Cell in Zebrafish Liver Regeneration
Authors: He Jianbo , Chen Jingying , Wei Xiangyong , Leng Hui , Mu Hongliang , Cai Pengcheng , Luo Lingfei
Published: May 2019

The liver has a high regenerative capacity. Upon two‐thirds partial hepatectomy, the hepatocytes proliferate and contribute to liver regeneration. After severe liver injury, when the proliferation of residual hepatocytes is blocked, the biliary epithelial cells (BECs) lose their morphology and express hepatoblast and endoderm markers, dedifferentiate into bipotential progenitor cells (BP‐PCs), then proliferate and redifferentiate into mature hepatocytes. Little is known about the mechanisms involved in the formation of BP‐PCs after extreme liver injury. Using a zebrafish liver extreme injury model, we found that mammalian target of rapamycin complex 1 (mTORC1) signaling regulated dedifferentiation of BECs and proliferation of BP‐PCs. mTORC1 signaling was up‐regulated in BECs during extreme hepatocyte ablation and continuously expressed in later liver regeneration. Inhibition of mTORC1 by early chemical treatment before hepatocyte ablation blocked the dedifferentiation from BECs into BP‐PCs. Late mTORC1 inhibition after liver injury reduced the proliferation of BP‐PC‐derived hepatocytes and BECs but did not affect BP‐PC redifferentiation. mTOR and raptor mutants exhibited defects in BEC transdifferentiation including dedifferentiation, BP‐PC proliferation, and redifferentiation, similar to the chemical inhibition. Conclusion: mTORC1 signaling governs BEC‐driven liver regeneration by regulating the dedifferentiation of BECs and the proliferation of BP‐PC‐derived hepatocytes and BECs.
Quantum Dots for Hybrid Energy Harvesting: From Integration to Piezo‐Phototronics
Authors: Cho Yuljae , Pak Sangyeon , An Geon‐Hyoung , Hou Bo , Cha SeungNam
Published: May 2019

Energy harvesting, which converts wasted environmental energy into electricity by utilizing various physical effects, hasattracted tremendous research interests as is one of the key technologies to realize advanced electronics in the future. In this review, we introduce recent progress in the field of hybrid energy harvesting technology. In particular, we focus on a quantum dots (QD)‐based hybrid energy harvesting device. Attributed to fascinating material properties that QD possess, employment of QDs into hybrid energy harvesting has shown great potential for independent and sustainable energy supply.First, an integration of a QD solar cell into a mechanical energy harvester is discussed to harness different types of environmental energy sources simultaneously. Second, a comprehensive explanation of a piezotronic and piezo‐phototronic effect is provided, which is followed by QD‐based piezo‐phototronic applications. Finally, we summarize recent progress that has been made in energy harvesting technology involving a photovoltaic and piezo/triboelectric effect
Penile‐preserving surgery for male distal urethral carcinoma followed by buccal mucosa urethroplasty
Authors: Kitamura Yosuke , Horiguchi Akio , Ojima Kenichiro , Kawamura Kazuki , Shinchi Masayuki , Asano Tomohiko , Ito Keichi , Azuma Ryuichi
Published: May 2019

Introduction

We report a case of distal urethral carcinoma treated with segmental urethral excision and reconstruction by staged buccal mucosa urethroplasty.

Case presentation

A 60‐year‐old man presented with difficulty urinating and a palpable mass on the ventral side of his penis. He was diagnosed as having localized distal urethral carcinoma (cT2N0M0) and underwent penile‐preserving surgery with staged urethroplasty using buccal mucosa as substitute tissue. The pathological diagnosis was squamous cell carcinoma of the urethra (T2) with negative surgical margin. At 2 years of follow‐up, there was no recurrence or metastasis, he could void in a standing position with an acceptable urinary stream, and he found the appearance of his external genitalia acceptable.

Conclusion

In cases of distal primary urethral carcinoma, urethroplasty using buccal mucosa graft could be alternative treatment option providing a better postoperative quality of life.
Regulation of tRNA‐dependent translational quality control
Authors: Steiner Rebecca E. , Ibba Michael
Published: May 2019

Translation is the most error‐prone process in protein synthesis; however, it is important that accuracy is maintained because erroneous translation has been shown to affect all domains of life. Translational quality control is maintained by both proteins and RNA through intricate processes. The aminoacyl‐tRNA synthetases help maintain high levels of translational accuracy through the esterification of tRNA and proofreading mechanisms. tRNA is often recognized by an aminoacyl‐tRNA synthetase in a sequence and structurally dependent manner, sometimes involving modified nucleotides. Additionally, some proofreading mechanisms of aminoacyl‐tRNA synthetases require tRNA elements for hydrolysis of a noncognate aminoacyl‐tRNA. Finally, tRNA is also important for proper decoding of the mRNA message by codon and anticodon pairing. Here, recent developments regarding the importance of tRNA in maintenance of translational accuracy are reviewed. © 2019 IUBMB Life, 2019 © 2019 IUBMB Life, 71(8):1150–1157, 2019
Unveiling the nonlinear optical response of Trictenotoma childreni longhorn beetle
Authors: Mouchet Sébastien R. , Verstraete Charlotte , Kaczmarek Anna M. , Mara Dimitrije , van Cleuvenbergen Stijn , Van Deun Rik , Verbiest Thierry , Maes Bjorn , Vukusic Pete , Kolaric Branko
Published: May 2019

The wings of some insect species are known to fluoresce under illumination by ultraviolet light. Their fluorescence properties are however, not comprehensively documented. In this article, the optical properties of one specific insect, the Trictenotoma childreni yellow longhorn beetle, were investigated using both linear and nonlinear optical (NLO) methods, including one‐ and two‐photon fluorescence and second harmonic generation (SHG). These three distinct optical signals discovered in this beetle are attributed to the presence of fluorophores embedded within the scales covering their elytra. Experimental evidence collected in this study indicates that the fluorophores are non‐centrosymmetric, a fundamental requirement for SHG. This study is the first reported optical behavior of this type in insects. We described how NLO techniques can complement other more convenient approaches to achieve a more comprehensive understanding of insect scales and integument properties.