bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation analysis for tumor radiotherapy based on three‐component mathematical models
Authors: Hong Wen‐song , Zhang Gang‐qing
Published: March 2019

Objective

To setup a three‐component tumor growth mathematical model and discuss its basic application in tumor fractional radiotherapy with computer simulation.

Method

First, our three‐component tumor growth model extended from the classical Gompertz tumor model was formulated and applied to a fractional radiotherapy with a series of proper parameters. With the computer simulation of our model, the impact of some parameters such as fractional dose, amount of quiescent tumor cells, and α/β value to the effect of radiotherapy was also analyzed, respectively.

Results

With several optimal technologies, the model could run stably and output a series of convergent results. The simulation results showed that the fractional radiotherapy dose could impact the effect of radiotherapy significantly, while the amount of quiescent tumor cells and α/β value did that to a certain extent.

Conclusions

Supported with some proper parameters, our model can simulate and analyze the tumor radiotherapy program as well as give some theoretical instruction to radiotherapy personalized optimization.
Evaluation of mixed energy partial arcs for volumetric modulated arc therapy for prostate cancer
Authors: Momin Shadab , Gräfe James L. , Khan Rao F.
Published: March 2019

Purpose

The purpose of this work was to investigate the dosimetric impact of mixed energy (6‐MV, 15‐MV) partial arcs (MEPAs) technique on prostate cancer VMAT plans.

Methods

This work involved prostate only patients, planned with 79.2 Gy in 44 fractions to the planning target volume (PTV). Femoral heads, bladder, and rectum were considered organs at risk. This study was performed in two parts. For each of the 25 patients in Part 1, two single‐energy single‐arc plans, a 6 MV‐SA plan and a 15 MV‐SA plan, and a third MEPA plan involving composite of 6‐MV anterior–posterior partial arcs and a 15‐MV lateral partial arc weighted 1:2 were created. The dosimetric difference between MEPA(6/15 MV 1:2 weighted) and 6 MV‐SA plans, and MEPA(6/15 MV 1:2 weighted) and 15 MV‐SA plans were measured. In the Part 2 of this study, a second MEPAs plan (6 MV anterior–posterior arcs and 15 MV lateral arcs weighted 1:1), (MEPA 6/15 MV 1:1 weighted), was generated for 15 patients and compared only with two single‐energy partial arcs plans, a 6 and a 15 MV‐PA, to investigate the influence of the energy only. Dosimetric parameters of each structure, total monitor‐units (MUs), homogeneity index (HI), and conformity number (CN) were analyzed.

Results

In Part 1, no statistically significant differences were observed for mean dose to PTV and CN for MEPAs (6/15 MV 1:2 weighted) vs 6 and 15 MV‐SA. MEPAs (6/15 MV 1:2 weighted) increased HI compared to 6 and 15 MV‐SA (P < 0.0005; P < 0.0005). MEPAs (6/15 MV 1:2 weighted) produced significantly lower mean doses to rectum, bladder, and MUs/fraction, but higher mean doses to femoral heads, compared to 6 MV‐SA (P < 0.0005) and 15 MV‐SA (P < 0.0005). The results of Part 2 of this study showed that, in comparison to 6 and 15 MV‐PA, MEPAs (6/15 MV 1:1 weighted) plans significantly improved CNs (P < 0.0005; P < 0.0005) and produced significantly lower mean doses to the rectum and bladder (P < 0.0005; P < 0.0005). While mean doses to the PTV and femoral heads of MEPAs (6/15 MV 1:1 weighted) plans were statistically comparable to 6 MV‐PA (P > 0.05), MEPAs (6/15 MV 1:1 weighted) increased mean doses to left (P = 0.04) and right (P = 0.04) femoral heads compared to 15 MV‐PA. MEPAs (6/15 MV 1:1 weighted) resulted in significantly lower total MUs compared to 6 MV‐PA (P < 0.0005) and 15 MV‐PA (P = 0.04).

Conclusion

The study for prostate radiotherapy demonstrated that a choice of MEPAs for VMAT has the potential to minimize doses to OARs and improve dose conformity to PTV, at the expense of a moderate increase in mean dose to the femoral heads.
Nanosized Copper Selenide Functionalized Zeolitic Imidazolate Framework‐8 (CuSe/ZIF‐8) for Efficient Immobilization of Gas‐Phase Elemental Mercury
Authors: Yang Zequn , Li Hailong , Yang Jianping , Feng Shihao , Liu Xi , Zhao Jiexia , Qu Wenqi , Li Pu , Feng Yong , Lee Po‐Heng , Shih Kaimin
Published: March 2019

A key challenge in elemental mercury (Hg0) decontamination from flue gas lies in the design of a sorbent with abundant reactive adsorption sites that exhibit high affinity toward Hg0 to simultaneously achieve rapid capture and large capacity. Herein, zeolitic imidazolate framework‐8 (ZIF‐8) supported copper selenide (CuSe) nanocomposites are synthesized by a newly designed two‐step surfactant‐assisted method. The as‐prepared CuSe/ZIF‐8 with CuSe to ZIF‐8 mass ratio of 80% (0.8NC‐ZIF) exhibits unparalleled performance toward Hg0 adsorption with equilibrium capacity and average rate reaching 309.8 mg g−1 and 105.3 µg g−1 min−1, respectively, surpassing all reported metal sulfides and traditional activated‐carbon‐based sorbents. The impressive performance of 0.8NC‐ZIF for Hg0 immobilization is primarily attributed to the adequate exposure of the Se‐terminated sites with high affinity toward Hg0 resulted from the layered structure of CuSe. The adsorbed mercury selenide exhibits even higher stability than the most stable natural mercury ore—that is, mercury sulfide—hence minimizing its environmental impact when the CuSe/ZIF‐8 sorbent is dumped. This work provides a new mindset for future design of sorbents for efficient Hg0 capture from industrial flue gas. The results also justify the candidature of CuSe/ZIF to be applicable for mercury pollution remediation in real‐world conditions.
Hollow Loofah‐Like N, O‐Co‐Doped Carbon Tube for Electrocatalysis of Oxygen Reduction
Authors: Dong Yuanyuan , Zhou Mengwei , Tu Wenzhe , Zhu Enbo , Chen Ye , Zhao Yizhou , Liao Shijun , Huang Yu , Chen Qi , Li Yujing
Published: March 2019

Designing a highly active doped‐carbon‐based oxygen reduction reaction (ORR) electrocatalyst with optimal stability is a must if large‐scale implementations of fuel cells are to be realized. Developing controllable doping strategies is essential for achieving highly active catalysts. Herein, a facile doping strategy is developed by designing a precursor material with unique core–shell nanostructure, whereby the Materials Institute Lavoisier (MIL) metal–organic framework (MOF) and polyaniline are core and shell components, and serving as oxygen and nitrogen precursors, respectively. A novel hollow loofah‐like carbon tube (HLCT) catalyst is derived from precursor material with controllable heteroatom‐doping concentrations through modulating the mass ratio of MOF/aniline. The optimal HLCT‐1/2 catalyst, with a MOF/aniline mass ratio of 1/2, exhibits excellent ORR activity and stability in an alkaline medium. Remarkably, the half‐wave potential (0.88 V) and the current density (4.35 mA cm−2) at 0.85 V of HLCT‐1/2 catalyst surpass that of commercial Pt/C. Such superior catalytic properties can be attributed to the high specific surface area and abundant active sites of loofah‐shape carbon tubes. Moreover, the O dopant modulates the content and distribution of N species, leading to the enhanced adsorption strength of oxygen molecules on catalyst surface, promoting the activation of oxygen, and thus achieving higher electrocatalytic activity.
A Facet‐Specific Quantum Dot Passivation Strategy for Colloid Management and Efficient Infrared Photovoltaics
Authors: Kim Younghoon , Che Fanglin , Jo Jea Woong , Choi Jongmin , García de Arquer F. Pelayo , Voznyy Oleksandr , Sun Bin , Kim Junghwan , Choi Min‐Jae , Quintero‐Bermudez Rafael , Fan Fengjia , Tan Chih Shan , Bladt Eva , Walters Grant , Proppe Andrew H. , Zou Chengqin , Yuan Haifeng , Bals Sara , Hofkens Johan , Roeffaers Maarten B. J. , Hoogland Sjoerd , Sargent Edward H.
Published: March 2019

Colloidal nanocrystals combine size‐ and facet‐dependent properties with solution processing. They offer thus a compelling suite of materials for technological applications. Their size‐ and facet‐tunable features are studied in synthesis; however, to exploit their features in optoelectronic devices, it will be essential to translate control over size and facets from the colloid all the way to the film. Larger‐diameter colloidal quantum dots (CQDs) offer the attractive possibility of harvesting infrared (IR) solar energy beyond absorption of silicon photovoltaics. These CQDs exhibit facets (nonpolar (100)) undisplayed in small‐diameter CQDs; and the materials chemistry of smaller nanocrystals fails consequently to translate to materials for the short‐wavelength IR regime. A new colloidal management strategy targeting the passivation of both (100) and (111) facets is demonstrated using distinct choices of cations and anions. The approach leads to narrow‐bandgap CQDs with impressive colloidal stability and photoluminescence quantum yield. Photophysical studies confirm a reduction both in Stokes shift (≈47 meV) and Urbach tail (≈29 meV). This approach provides a ≈50% increase in the power conversion efficiency of IR photovoltaics compared to controls, and a ≈70% external quantum efficiency at their excitonic peak.
Tuning Pore Heterogeneity in Covalent Organic Frameworks for Enhanced Enzyme Accessibility and Resistance against Denaturants
Authors: Sun Qi , Aguila Briana , Lan Pui Ching , Ma Shengqian
Published: March 2019

Achieving high‐performance biocomposites requires knowledge of the compatability between the immobilized enzyme and its host material. The modular nature of covalent organic frameworks (COFs), as a host, allows their pore geometries and chemical functionalities to be fine‐tuned independently, permitting comparative studies between the individual parameters and the performances of the resultant biocomposites. This research demonstrates that dual pores in COFs have profound consequences on the catalytic activity and denaturation of infiltrated enzymes. This approach enforces a constant pore environment by rational building‐block design, which enables it to be unequivocally determined that pore heterogeneity is responsible for rate enhancements of up to threefold per enzyme molecule. More so, the enzyme is more tolerant to detrimental by‐products when occupying the larger pore in a dual‐pore COF compared to a corresponding uniform porous COF. Kinetic studies highlight that pore heterogeneity facilitates mass transfer of both reagents and products. This unparalleled versatility of these materials allows many different aspects to be designed on demand, lending credence to their prospect as next‐generation host materials for various enzyme biocomposites catalysts.
NaNO2/K2S2O8‐mediated Selective Radical Nitration/Nitrosation of Indoles: Efficient Approach to 3‐Nitro‐ and 3‐Nitrosoindoles
Authors: Shoberu Adedamola , Li Cheng‐Kun , Tao Ze‐Kun , Zhang Guo‐Yu , Zou Jian‐Ping
Published: March 2019

A mild and selective radical nitration/nitrosation of indoles with NaNO2 using K2S2O8 as oxidant is developed. Free (NH)‐indoles and N‐methyl indoles furnished 3‐nitro‐ and 3‐nitrosoindoles respectively, in good yields. Contrary to existing protocols, pyrrole selectively afforded 3‐nitropyrrole. Mechanistic studies showed that the reaction proceeded via an initial formation of nitroso/oxime intermediate, which is further oxidized to the corresponding 3‐nitroindole depending on the substitution on the indole N‐atom. Furthermore, synthetic transformations were carried out on the synthesized products towards accessing other valuable compounds.

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Uniform Lithium Deposition Assisted by Single‐Atom Doping toward High‐Performance Lithium Metal Anodes
Authors: Zhai Pengbo , Wang Tianshuai , Yang Weiwei , Cui Shiqiang , Zhang Peng , Nie Anmin , Zhang Qianfan , Gong Yongji
Published: March 2019

For a long time lithium (Li) metal has been considered one of the most promising anodes for next‐generation rechargeable batteries. Despite decades of concentrated research, its practical application is still hindered by dendritic Li deposition and infinite volume change of Li metal anodes. Here, atomically dispersed metals doped graphene is synthesized to regulate Li metal nucleation and guide Li metal deposition. The single‐atom (SA) metals, supported on the nitrogen‐doped graphene can not only increase the Li adsorption energy of the localized area around the metal atomic sites with a moderate adsorption energy gradient but also improve the atomic structural stability of the overall materials by constructing a coordination mode of M‐Nx‐C (M, N, and C denoted as metal, nitrogen, and carbon atoms, respectively). As a result, the as‐obtained electrode exhibits an ultralow voltage hysteresis of 19 mV, a high average Coulombic efficiency of 98.45% over 250 cycles, and a stable Li plating/stripping performance even at a high current density of 4.0 mA cm−2. This work demonstrates the application of SA metal doping in the rational design of Li metal anodes and provides a new concept for further development of Li metal batteries.
Edge‐Exposed Molybdenum Disulfide with N‐Doped Carbon Hybridization: A Hierarchical Hollow Electrocatalyst for Carbon Dioxide Reduction
Authors: Li Haoyi , Liu Xiaozhi , Chen Shuangming , Yang Deren , Zhang Qi , Song Li , Xiao Hai , Zhang Qinghua , Gu Lin , Wang Xun
Published: March 2019

Electrochemical CO2 reduction (CO2RR) is a promising technology to produce value‐added fuels and weaken the greenhouse effect. Plenty of efforts are devoted to exploring high‐efficiency electrocatalysts to tackle the issues that show poor intrinsic activity, low selectivity for target products, and short‐lived durability. Herein, density functional theory calculations are firstly utilized to demonstrate guidelines for design principles of electrocatalyst, maximum exposure of catalytic active sites for MoS2 edges, and electron transfer from N‐doped carbon (NC) to MoS2 edges. Based on the guidelines, a hierarchical hollow electrocatalyst comprised of edge‐exposed 2H MoS2 hybridized with NC for CO2RR is constructed. In situ atomic‐scale observation for catalyst growth is performed by using a specialized Si/SiNx nanochip at a continuous temperature‐rise period, which reveals the growth mechanism. Abundant exposed edges of MoS2 provide a large quantity of active centers, which leads to a low onset potential of ≈40 mV and a remarkable CO production rate of 34.31 mA cm−2 with 92.68% of Faradaic efficiency at an overpotential of 590 mV. The long‐term stability shows negligible degradation for more than 24 h. This work provides fascinating insights into the construction of catalysts for efficient CO2RR.
Being in the right place at the right time? Parallel diversification bursts favored by the persistence of ancient epizoochorous traits and hidden factors in Cynoglossoideae
Authors: Otero Ana , Jiménez‐Mejías Pedro , Valcárcel Virginia , Vargas Pablo
Published: March 2019

Premise of the Study

Long‐distance dispersal (LDD) syndromes, especially endozoochory, facilitate plant colonization of new territories that trigger diversification. However, few studies have analyzed how epizoochorous fruits influence both range distribution and diversification rates. We examined the evolutionary history of a hyperdiverse clade of Boraginaceae (subfamily Cynoglossoideae, eight tribes, ~60 genera, ~1100 species) and the evolution of fruit traits. We evaluated the evolutionary history of diaspore syndromes correlated with geographic distribution and diversification rates over time.

Methods

Plastid DNA regions and morphological traits associated with dispersal syndromes were analyzed for 71 genera (226 species). We employed trait‐dependent diversification analysis (HiSSE) and biogeographic reconstruction (Lagrange) using a time‐calibrated phylogeny.

Key Results

Our results indicate that (1) the earliest divergence events in Cynoglossoideae occurred in the central‐northeastern Palearctic during the Paleogene (early to middle Eocene); (2) an epizoochorous trait (specialized hooks named glochids) is ancestral and has been maintained long term; and (3) glochids are correlated with increased diversification rates in two distantly related clades (Rochelieae and Cynoglossinae). Rapid speciation occurred for these two groups in the same area (central‐eastern Palearctic) and same period (Oligocene‐Miocene: Rochelieae, 30.82–13.69 mya; Cynoglossinae, 33.10–15.21 mya). Lower diversification rates were inferred for the remaining four glochid‐bearing clades.

Conclusions

One more example of “biogeographic congruence” in angiosperms is supported by a shared geographic (central‐northeastern Palearctic) and temporal (28.60–21.59 mya, late Oligocene) opportunity window for two main clades’ diversification. Epizoochorous traits (fruit glochids) had an effect in higher diversification rates only with the joint effect of other unmeasured factors.
Social Cohesion, Neighborhood Collective Efficacy, and Adolescent Subjective Well‐being in Urban and Rural Taiwan
Authors: Wang Shu‐Chen , Fowler Patrick J.
Published: March 2019

This study investigates the association between neighborhood social cohesion, collective efficacy, and adolescent subjective well‐being in a nationally representative sample of Taiwanese youth. The study represents a first to adapt and test a developmental ecological model within a Chinese cultural context. Data came from the Taiwan Youth Project, which assessed representative samples of seventh graders (n = 2,690) and ninth graders (n = 2,851) from both urban and rural counties. The analytic sample included 4,988 adolescents (M age = 14.4, SD = 1.14; 50% female) in Taiwan. A path analysis estimated the direct and indirect effects of social cohesion on adolescent well‐being. The results suggest that neighbors can affect young people's well‐being by reinforcing their perception of safety and enhancing their self‐esteem. Comparisons between youth from urban and rural areas demonstrate a general similarity in the developmental processes, though the perception of safety is less of a concern in rural areas. Findings emphasize universal aspects of neighborhood collective efficacy and developmental–ecological models, as well as allude to culturally specific dimensions in a Chinese‐based context.
Acute leukemia in a patient with 15q overgrowth syndrome
Authors: Bodle Ethan E. , Gupta Ridhi , Cherry Athena M. , Muffly Lori , Manning Melanie A.
Published: March 2019

Overgrowth syndromes are rare genetic conditions which present as global or segmental hyperplasia and are sometimes associated with increased risk of malignancy. Trisomy of the terminal portion of 15q which includes the IGFR1 gene, produces a rare overgrowth phenotype that has been termed 15q overgrowth syndrome (15q OGS). Upregulation of IGF1R has long been implicated in oncogenesis of multiple cancer types, including acute leukemias, and has been shown to render cells more susceptible to other transforming events. To date, too few cases of 15q OGS have been reported to identify any cancer predisposition. We present a case of a 34‐year‐old female with intellectual disability, macrocephaly, and subtle dysmorphic features who was diagnosed with mixed phenotype acute leukemia (lymphoid and myeloid). Prior to initiation of therapy she was referred to medical genetics for further evaluation and was identified as having a chromosomal translocation resulting in a partial trisomy of chromosome 15q, consistent with 15q OGS. A review of the literature for cases of malignancy in individuals with increased copy number of 15q revealed only one other reported patient. Given the small number of reported individuals, we cannot rule out an increased risk of cancer associated with this chromosomal overgrowth syndrome. Although concerns have been raised regarding treatment feasibility in the setting of chromosomal disorders, the reported patient underwent successful treatment with allogeneic hematopoietic stem‐cell transplant.
Lgr5+ intestinal stem cell sorting and organoid culture
Authors: Liu Ruixue , Li Haifeng , Cai Juan , Wei Qiang , Han Xiaonan
Published: March 2019

Intestinal epithelial stem cells (IESCs) are one of the most rapidly self‐renewing and proliferating adult stem cells. The IESCs reside at the bottom of intestinal and colonic crypts, giving rise to all intestinal epithelial lineages and maintaining intestinal epithelial replenishment. The technique of three‐dimensional culture based upon intestinal stem cell biology has been recently developed to study gastrointestinal development and disease pathogenesis. Here, we summarize the techniques used to isolate Lgr5‐positive IESCs to form the enteroids from intestine or colonoids from colon, and present the means to examine these organoid functions. This study will provide a simple and practical way for producing intestinal tissues in the laboratory.
Association between physician‐staffed ambulances and patient prognoses after out‐of‐hospital cardiac arrests with respect to shockable and non‐shockable rhythms: a retrospective observational study in a southern area of Shiga Prefecture Japan
Authors: Kato Fumitaka , Fujino Kazunori , Shiomi Naoto , Eguchi Yutaka
Published: March 2019

Aim

Out‐of‐hospital cardiac arrests (OHCA) are a significant public health problem; to improve patients’ prognoses, various interventions, such as providing physician‐staffed ambulances, have been implemented. We aimed to examine whether physician‐staffed ambulances were associated with patients’ prognoses after OHCA with respect to first‐monitored rhythms.

Methods

This retrospective observational study was undertaken between 1 September 2011 and 31 December 2015, using data based on Utstein‐style guidelines. We extracted data on age, sex, first‐monitored rhythm (shockable or non‐shockable), presence of a witness, bystander cardiopulmonary resuscitation, time from call to arrival at the scene, out‐of‐hospital adrenaline administration, out‐of‐hospital intubation, return of spontaneous circulation before arrival at the hospital, and survival and neurological outcomes 30 days after OHCA, according to cerebral performance categories. We undertook logistic regression analyses to assess the association between physician‐staffed ambulances and patients’ prognoses.

Results

A total of 882 OHCA patients were eligible for this study. Physician‐staffed ambulances attended to 164 OHCA patients. Multivariable analysis found that in non‐shockable rhythm patients, physician‐staffed ambulances significantly improved good neurological outcome (odds ratio, 3.65; 95% confidence interval [CI], 1.28–10.50; P = 0.02), return of spontaneous circulation before arrival at the hospital (odds ratio, 2.68; 95% CI, 1.62–4.42; P < 0.001), and 30‐day survival (odds ratio, 2.90; 95% CI, 1.30–6.45; P = 0.009). However, physician‐staffed ambulances were not associated with patient prognoses in shockable rhythm patients.

Conclusion

Despite our study's limitations, physician‐staffed ambulances might be associated with good neurological outcomes in non‐shockable rhythm patients. Our observations could provide more appropriate prehospital treatment options for OHCA patients.
Editorial: Wissenschaftsfreiheit mithilfe von Netzwerken sichern
Authors: Boele‐Woelki Katharina , Fisher Cathleen , Pape Hans‐Christian , Francisco Joseph S.
Published: March 2019

Wissenschaftsfreiheit existiert nicht um ihrer selbst willen. Ihr grundlegender Zweck besteht darin, eine von Offenheit geprägte Umgebung zu schaffen, in der das Streben nach Wahrheit voranschreiten kann. Wissenschaftsfreiheit soll die besten Köpfe unserer Zeit unterstützen, fördern und befähigen, sodass auch die nächste Generation junger Forscher ihre Aufgabe in der Gesellschaft erfüllen kann …” Lesen Sie mehr im Gast‐Editorial von Joseph S. Francisco et al.
Modulation of Higher‐order Behaviour in Model Protocell Communities by Artificial Phagocytosis
Authors: Rodríguez‐Arco Laura , Kumar B. V. V. S. Pavan , Li Mei , Patil Avinash J. , Mann Stephen
Published: March 2019

Collective behaviour in mixed populations of synthetic protocells is an unexplored area of bottom‐up synthetic biology. The dynamics of a model protocell community is exploited to modulate the function and higher‐order behaviour of mixed populations of bioinorganic protocells in response to a process of artificial phagocytosis. Enzyme‐loaded silica colloidosomes are spontaneously engulfed by magnetic Pickering emulsion (MPE) droplets containing complementary enzyme substrates to initiate a range of processes within the host/guest protocells. Specifically, catalase, lipase, or alkaline phosphatase‐filled colloidosomes are used to trigger phagocytosis‐induced buoyancy, membrane reconstruction, or hydrogelation, respectively, within the MPE droplets. The results highlight the potential for exploiting surface‐contact interactions between different membrane‐bounded droplets to transfer and co‐locate discrete chemical packages (artificial organelles) in communities of synthetic protocells.
A Polyaromatic Gemini Amphiphile That Assembles into a Well‐Defined Aromatic Micelle with Higher Stability and Host Functions
Authors: Nishioka Tomoya , Kuroda Kiyonori , Akita Munetaka , Yoshizawa Michito
Published: March 2019

A gemini‐type amphiphilic molecule, constituted of two V‐shaped polyaromatic amphiphiles linked by a linear acetylene spacer, was synthesized. The gemini amphiphile assembles into a well‐defined aromatic micelle (ca. 2 nm in core diameter), providing higher stability in water even at low concentration (0.09 mm) and high temperature (>130 °C). Unlike common gemini amphiphiles with aliphatic chains, the present amphiphile and its micellar assembly emit green and orange fluorescence (ΦF=33 and 9 %), respectively. Despite strong and multiple π‐stacks of the polyaromatic panels of the amphiphiles, the water‐soluble gemini aromatic micelle incorporates medium‐size to large hydrophobic compounds into the frameworks. Interestingly, the guest binding capability toward large planar molecules was enhanced by more than two times through the pre‐encapsulation of spherical molecules in the cavity.
Origin of Thermal and Hyperthermal CO2 from CO Oxidation on Pt Surfaces: The Role of Post‐Transition‐State Dynamics, Active Sites, and Chemisorbed CO2
Authors: Zhou Linsen , Kandratsenka Alexander , Campbell Charles T. , Wodtke Alec M. , Guo Hua
Published: March 2019

The post‐transition‐state dynamics in CO oxidation on Pt surfaces are investigated using DFT‐based ab initio molecular dynamics simulations. While the initial CO2 formed on a terrace site on Pt(111) desorbs directly, it is temporarily trapped in a chemisorption well on a Pt(332) step site. These two reaction channels thus produce CO2 with hyperthermal and thermal velocities with drastically different angular distributions, in agreement with recent experiments (Nature, 2018, 558, 280–283). The chemisorbed CO2 is formed by electron transfer from the metal to the adsorbate, resulting in a bent geometry. While chemisorbed CO2 on Pt(111) is unstable, it is stable by 0.2 eV on a Pt(332) step site. This helps explain why newly formed CO2 produced at step sites desorbs with far lower translational energies than those formed at terraces. This work shows that steps and other defects could be potentially important in finding optimal conditions for the chemical activation and dissociation of CO2.
Micellar Catalysis for Ruthenium(II)‐Catalyzed C−H Arylation: Weak‐Coordination‐Enabled C−H Activation in H2O
Authors: Yetra Santhivardhana Reddy , Rogge Torben , Warratz Svenja , Struwe Julia , Peng Wentao , Vana Philipp , Ackermann Lutz
Published: March 2019

Chemoselective C−H arylations were accomplished through micellar catalysis by a versatile single‐component ruthenium catalyst. The strategy provided expedient access to C−H‐arylated ferrocenes with wide functional‐group tolerance and ample scope through weak chelation assistance. The sustainability of the C−H arylation was demonstrated by outstanding atom‐economy and recycling studies. Detailed computational studies provided support for a facile C−H activation through thioketone assistance.
Spectroscopic investigation, DFT, fluorescence, molecular docking and biological studies of divalent and trivalent binuclear complexes prepared from benzoyl thiosemicarbazide derivative of 2‐benzylmalonohydrazide
Authors: El‐Morshedy Reham M. , El‐Gamil Mohammed M. , Abou‐Elzahab Mohamed Mahmoud , Abu El‐Reash Gaber M.
Published: March 2019

The binuclear Cr (III), Mn (II) and Fe (III) complexes of N,N′‐(2,2′‐(2‐benzylmalonyl)bis (hydrazine‐1‐carbonothioyl))dibenzamide (H4BPCD), which derived from the combination of 2‐benzylmalonohydrazide suspension with benzoyl‐isothiocyanate, have been isolated and investigated by the necessary analytical and spectroscopic techniques. The IR studies show that H4BPCD dispose as a mono‐negative hexadentate ligand (NOS)2 towards Mn (II) ion and tetra‐negative hexadentate (NOS)2 towards both Cr (III) and Fe (III) ions. The values of molar conductance in DMSO suggested the non‐electrolytic nature for all complexes. The magnetic measurements and the electronic transitions data confirmed the hexa‐coordinate geometry of complexes. The DFT geometry optimization of all compounds and IR comparative study of both theoretical and experimental of H4BPCD were carried out. Moreover, the H4BPCD and its Cr (III) complex displayed intra ligand (π → π*) fluorescence emission spectra which corroborate their photoactive nature. The coordinated and crystalline water molecules have been investigated by (TG/DTG) studies. The kinetic and thermodynamic parameters were computed using Horowitz‐ Metzger, Coats‐Redfern and Broido methods. Biological studies of DNA binding, minimum inhibitory concentration, in vitro determination of SOD‐like activity and MTT‐cytotoxicity assay as well as molecular docking studies were tested for the ligand and its complexes.
Synthesis of carbon quantum dots to fabricate ultraviolet‐shielding poly(vinylidene fluoride) films
Authors: Dong Li , Xiong Zhengrong , Liu Xiangdong , Sheng Dekun , Zhou Yan , Yang Yuming
Published: March 2019

The paper presents a simple and effective approach to fabricating a poly(vinylidene fluoride) (PVDF) film with excellent ultraviolet (UV) shielding performance. Carbon quantum dots (CQDs) with a highly UV absorbing property were made via a hydrothermal reaction and were then added to a poly(vinyl alcohol) (PVA) solution. The PVDF membrane pretreated with an alkaline solution was immersed in the prepared CQD/PVA solution to coat a UV‐shielding layer on the film surface. Fourier transform infrared spectroscopy, X‐ray photoelectron spectrometry, X‐ray diffraction, transmission electron microscopy, and UV–visible spectrophotometry were applied to study the structure, morphology, and optical performance of the CQD particles. The stability and UV‐shielding performance of the obtained PVDF‐OH@CQDs/PVA composite film were further investigated. The results showed that the CQD particles with diameter of 18 nm could be well dispersed in solution. Additionally, the CQDs had fairly high UV absorbance, and the PVDF‐OH@CQDs/PVA composite film could shield the UV light completely. The method described in this paper is a promising one for fabricating UV‐shielding composite films. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47555.
Design of polyurethane fibers: Relation between the spinning technique and the resulting fiber topology
Authors: Tan Chin Joo , Lee Jacky Jia Li , Ang Bee Chin , Andriyana Andri , Chagnon Grégory , Sukiman Muhamad Shafiq
Published: March 2019

Properties or characteristics of fibers are affected by their topology. In fact, these topologies are found to have significant impacts in the functionalities of many applications. Hence, in this study, the relations between the spinning techniques and the topology of the resulting fibers are studied with the aim to provide a guideline for future reference where fibers with certain topology can be fabricated to suit specific applications. For this purpose, polyurethane is chosen to be the raw material to fabricate the fibers due to its versatility to be applied in various fields. The surface morphology, structures, and alignments of the fibers are studied. It is found that the polymer solution properties largely influence the mechanisms in the spinning process and can significantly affect the topology of the fibers. For instance, viscous solutions enable the spinning of coiled and smooth fibers, whereas conductive solutions encourage the splaying of the solution jet which results in the spinning of straight fibers. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47706.
Functionalized graphene‐reinforced polysiloxane nanocomposite with improved mechanical performance and efficient healing properties
Authors: Zhao Liwei , Jiang Bo , Huang Yudong
Published: March 2019

It is a challenge to design nanofiller reinforced self‐healing nanocomposites with both improved mechanical properties and highly efficient self‐healing properties. In this work, we report a self‐healing polysiloxane nanocomposite using furan‐functionalized graphene (G‐FA) as reinforcement based on Diels−Alder (DA) chemistry. The formed interactions between G‐FA and polysiloxane chains were reversible DA bonds, which negligibly affected the nanocomposites healing efficiency. The self‐healing polysiloxane nanocomposite with 6% G‐FA has a tensile strength of 0.25 MPa that was improved by 140% when compared to an elastomer without G‐FA. The healable polysiloxane nanocomposite recovered more than 90% of its tensile strength and 98% of its elongation‐at‐break, demonstrating that the nanocomposite exhibited highly efficient self‐healing properties. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47725.
Sintered electrospun poly(ɛ‐caprolactone)–poly(ethylene terephthalate) for drug delivery
Authors: Chaparro Francisco J. , Presley Kayla F. , Coutinho da Silva Marco A. , Mandan Nayan , Colachis Matthew L. , Posner Michael , Arnold Ryan M. , Fan Fan , Moraes Christa R. , Lannutti John J.
Published: March 2019

Electrospinning has the inherent advantage of being able to achieve molecular mixing of polymers having substantially different melting points. Electrospun poly(ɛ‐caprolactone)–poly(ethylene terephthalate) (PCL:PET) capsules are densified by sintering to enable drug encapsulation. Proton and diffusive nuclear magnetic resonance, as well as a selective dissolution, suggest an absence of reaction between the two polymers. Sintering at 100 °C successfully densifies 88.89:11.11 and 75:25 PCL:PET blends. Following sintering, the otherwise dense 75:25 composition retains electrospun features and exhibits some “memory” of its previous state. Sintering increases UTS approximately eightfold versus as‐spun values for 88.89:11.11 and 75:25. Elongation increases sixfold and twofold and modulus 44‐ and 69‐fold for the 75:25 and 88.89:11.11 samples, respectively. Differential scanning calorimetry suggests a postsintering structure of nanoscale PET dispersed in PCL along the original fiber directions. Selective PCL removal from dense blends shows that fibrous characteristics remain. An internal shish–kebab‐like structure is also present in as‐spun 75:25 PCL:PET. Water absorption of hydrophobic oil‐containing capsules is approximately zero after 49 days. In contrast, hydrophilic (HPI) oils allow substantial water uptake. Unsurprisingly, there is no release of a model drug from the hydrophobic carrier. HPI oil provides linear (zero‐order) release inversely proportional to PET from the 88.89:11.11 and 75:25 ratios. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47731.
Open‐source data reveal how collections‐based fungal diversity is sensitive to global change
Authors: Andrew Carrie , Büntgen Ulf , Egli Simon , Senn‐Irlet Beatrice , Grytnes John‐Arvid , Heilmann‐Clausen Jacob , Boddy Lynne , Bässler Claus , Gange Alan C. , Heegaard Einar , Høiland Klaus , Kirk Paul M. , Krisai‐Greilhüber Irmgard , Kuyper Thomas W. , Kauserud Håvard
Published: March 2019

Premise of the Study

Fungal diversity (richness) trends at large scales are in urgent need of investigation, especially through novel situations that combine long‐term observational with environmental and remotely sensed open‐source data.

Methods

We modeled fungal richness, with collections‐based records of saprotrophic (decaying) and ectomycorrhizal (plant mutualistic) fungi, using an array of environmental variables across geographical gradients from northern to central Europe. Temporal differences in covariables granted insight into the impacts of the shorter‐ versus longer‐term environment on fungal richness.

Results

Fungal richness varied significantly across different land‐use types, with highest richness in forests and lowest in urban areas. Latitudinal trends supported a unimodal pattern in diversity across Europe. Temperature, both annual mean and range, was positively correlated with richness, indicating the importance of seasonality in increasing richness amounts. Precipitation seasonality notably affected saprotrophic fungal diversity (a unimodal relationship), as did daily precipitation of the collection day (negatively correlated). Ectomycorrhizal fungal richness differed from that of saprotrophs by being positively associated with tree species richness.

Discussion

Our results demonstrate that fungal richness is strongly correlated with land use and climate conditions, especially concerning seasonality, and that ongoing global change processes will affect fungal richness patterns at large scales.
Historical changes in bivalve growth rates indicate ecological consequences of human occupation in estuaries
Authors: Wells Susan R. , Wing Lucy C. , Smith Abigail M. , Smith Ian W.G.
Published: March 2019

Only 800 years ago, New Zealand became the last major land mass to be settled by humans, leading to environmental degradation and precipitating a decline in indigenous fauna. Such ecological downgrading can alter ecosystem processes and drive down the capacity for remnant ecosystems to withstand the anthropogenic pressures of today.

In New Zealand, these impacts are chronicled in a concise and remarkably complete archaeological record and are distinguishable from natural changes due to changing climate.

Estuaries are subject to strong environmental gradients that drive productivity and contain critical habitats for key life‐history phases for marine and terrestrial species. Linking land to sea, they host abundant, accessible human resources and are sensitive to anthropogenic environmental modification.

Austrovenus stutchburyi is a common filter feeding bivalve in New Zealand estuaries. An important food source for Māori, their shells are abundant in middens. Growth rates of A. stutchburyi are affected by multiple environmental factors, including temperature, salinity, nutrients, and sediment, and are recorded through time as easily measurable annual shell bands. Measuring spatial and temporal variation in growth rate of A. stutchburyi can be used to identify the timing of changes in estuarine conditions.

Growth bands were measured in archaeological and modern (AD 1300–present) A. stutchburyi shells from six sites around New Zealand with varying occupational histories. There were no increases in growth rate, and rates declined measurably over time at three sites (up to a 50% reduction in growth per year). This decline was greater at estuaries that had experienced greater catchment modification, indicating that sediment loading due to land clearance was a likely driver of this change.

New Zealand's coastline and marine resources are often perceived as wild and pristine. We propose that fundamental changes have occurred in the functioning of coastal marine ecosystems, which constrain its future.
A Prospective Study of the Development of Inflammatory Arthritis in the Family Members of Indigenous North American People With Rheumatoid Arthritis
Authors: Tanner Stacy , Dufault Brenden , Smolik Irene , Meng Xiaobo , Anaparti Vidyanand , Hitchon Carol , Robinson David B. , Robinson William , Sokolove Jeremy , Lahey Lauren , Ferucci Elizabeth D. , El‐Gabalawy Hani
Published: March 2019

Objective

To determine the incidence of inflammatory arthritis and autoantibody prevalence in Indigenous North American people.

Methods

Unaffected relatives of Indigenous North Americans with rheumatoid arthritis (RA) from central Canada and Alaska were systematically monitored from 2005 to 2017. Rheumatoid factor (RF) and anti–citrullinated protein antibodies (ACPAs) were tested at every visit, and a subset was tested for ACPA fine specificity using a custom multiplex assay. Multistate models based on all available study visits were developed to determine the likelihood of transitioning between autoantibody states, or to inflammatory arthritis.

Results

Eighteen of 374 relatives (4.8%) developed inflammatory arthritis during follow‐up (after a mean ± SD of 4.7 ± 2.4 years), yielding a transition rate of 9.2 cases/1,000 person‐years. Thirty percent of those who developed inflammatory arthritis were seronegative at baseline, but all were seropositive at inflammatory arthritis onset. Although 30% of ACPA/RF double‐seropositive individuals developed inflammatory arthritis (after 3.2 ± 2.2 years), the majority of these individuals did not develop inflammatory arthritis. Multistate modeling indicated a 71% and 68% likelihood of ACPA and RF seropositive states, respectively, reverting to a seronegative state after 5 years, and a 39% likelihood of an ACPA/RF double‐seropositive state becoming seronegative. Fine specificity testing demonstrated an expansion of the ACPA repertoire prior to the development of inflammatory arthritis.

Conclusion

Despite a high incidence of inflammatory arthritis in this cohort of at‐risk relatives of Indigenous North Americans with RA, a large proportion of autoantibody‐positive individuals do not develop inflammatory arthritis and revert back to an autoantibody‐negative state.
Techno‐economic performance of a bio‐refinery for the production of fuel‐grade biofuel using a green catalyst
Authors: Gebremariam Shemelis N. , Marchetti Jorge M.
Published: March 2019

The main challenge to the wider use of biodiesel as a transport fuel has been its high cost of production. Studies have been performed to obtain the cheapest methods for biodiesel production. The calcium oxide catalyzed transesterification reaction has shown better performance for fuel‐grade biodiesel from cheaper feedstock. In this study, a calcium oxide catalyzed biodiesel production process is designed in four different scenarios based on different possible arrangements of the downstream processes.

The process flow diagrams of the different scenarios were designed using Aspen Plus and Super Pro software. These process simulations were used to evaluate the techno‐economic performance of the process scenarios. Technical performance was been evaluated based on the quantity and quality of the biodiesel and glycerol produced, the amount of biodiesel produced per amount of feedstock consumed, and the amount of other valuable byproducts. Similarly, the economic performance of the process scenarios has also been assessed using parameters such as total investment cost, unit production cost, net present value, internal rate of return, payback time, and return on investment.

Each of these four scenarios was divided into two production capacity levels to investigate the effect of change in production capacity on the economic feasibility of the process scenarios.

The scenario with consecutive centrifugations for glycerol and soap separation, and distillation for biodiesel purification, evidenced poor technical performance, whereas the double reactor scenario provided more, and better quality, product, and the economic feasibility of this scenario was good when the oil supply rate was above 4600 kg h−1. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd
Identification of metabolites of novel Anti‐MRSA fluoroquinolone WCK 771 in mouse, rat, rabbit, dog, monkey and human urine using liquid chromatography tandem mass spectrometry
Authors: Yeole Ravindra D. , Rane Vipul P. , Ahirrao Vinod K. , Chavan Rajesh P. , Patel Anasuya M. , Deshpande Prasad K. , Patel Mahesh V. , Patil Kiran R.
Published: March 2019

WCK 771 is an l‐arginine salt of levonadifloxacin (LND) being developed in intravenous dosage form and has recently completed a phase III trial in India. The pharmacokinetics of WCK 771, a novel anti‐MRSA fluoroquinolone, were examined in mice, rats, rabbits, dogs, monkeys and humans after systemic administration during pre‐clinical and clinical investigations. Urine and serum were evaluated for identification of metabolites. It was observed that LND mainly follows phase II biotransformation pathways. All of the species showed a different array of metabolites. In mice, rabbit and dog, the drug was mainly excreted in the form of O‐glucuronide (M7) and acyl glucuronide (M8) conjugates, whereas in rat and human major metabolite was sulfate conjugate (M6). Monkeys exhibited equal distribution of sulfate (M6) and glucuronide conjugates (M7, M8). In addition to these three major phase II metabolites; five phase I oxidative metabolites (M1, M2, M3, M4 and M5) were identified using liquid chromatography tandem mass spectrometry. Out of these eight metabolites M2, M3, M5, M7 and M8 are reported for the first time.
Clinical characteristics and risk score for poor clinical outcome of acute ischemic stroke patients treated with intravenous thrombolysis therapy
Authors: Yue Yun‐hua , Li Zhi‐zhang , Hu Liang , Zhu Xiao‐qiong , Xu Xu‐shen , Sun Hong‐xian , Wan Zhi‐wen , Xue Jie , Yu De‐hua
Published: March 2019

Background

Tissue plasminogen activator (t‐PA) is an effective therapy for acute ischemic stroke, but some patients still have poor clinical outcome. In this study, we investigated clinical characteristics of stroke patients and determined predictors for poor clinical outcome in response to t‐PA treatment.

Methods

Clinical data from 247 patients were retrospectively reviewed. Clinical parameters that were associated with survival of patients were analyzed. Areas under receiver operating characteristic curves (ROC) were used to determine the feasibility of using various combinations of the clinical parameters to predict poor clinical response. The clinical outcome was defined according to the changes in Modified Rankin Scale.

Results

Overall, 145 patients had improved/complete recovery, 73 had no change, and 29 had worsening conditions or died during the in‐clinic period. A univariate analysis showed that baseline characteristics including age, CRP, blood glucose level, systolic blood pressure, and admission NIHSS were significantly different (p < 0.05) among patients with different clinical outcome. A further multivariate analysis was then performed. Variables associated with poor clinical outcome (worsening/death) (p < 0.1) were included in the logistic regression model. Four parameters were retained in the model: Age, CRP, Blood glucose level, and Systolic blood pressure (ACBS). To allow a convenient usage of the ACBS classifier, the parameters were put into a scoring system, and the score at 7.7 was chosen as a cut‐off. The ROC curve of this ACBS classifier has an area under the curve (AUC) of 0.7788, higher than other individual parameters. The ACBS classifier provided enhanced sensitivity of 69.2% and specificity of 74.3%.

Conclusion

The ACBS classifier provided a satisfactory power in estimating the patients’ clinical outcome. After further validating, the classifier may provide important information to clinicians for making clinical decisions.
Hope for the best, prepare for the worst: How to manage coronary perforations
Authors: Claessen Bimmer E. , Mehran Roxana
Published: March 2019

Key Points

The incidence of coronary perforation in a contemporary cohort of 13,339 PCI procedures was 0.51%. The majority (75%) were large‐vessel perforations

Although only 1 patient required emergency cardiac surgery, in‐hospital mortality was high (10%)

Given the infrequent occurrence of coronary perforations, uniform recommendations for its management are lacking. Nonetheless, the present study suggests that avoiding oversized balloons or stents might potentially reduce the incidence of perforations