bluuebunny/crossref_metadata_2025 huggingface dataset:
A Review of Factors Influencing the Cost Development of Electricity Generation Technologies
Authors: Samadi Sascha
Published: November 2016

This article reviews the literature on the past cost dynamics of various renewable, fossil fuel and nuclear electricity generation technologies. It identifies 10 different factors which have played key roles in influencing past cost developments according to the literature. These 10 factors are: deployment-induced learning, research, development and demonstration (RD&D)-induced learning, knowledge spillovers from other technologies, upsizing, economies of manufacturing scale, economies of project scale, changes in material and labour costs, changes in fuel costs, regulatory changes, and limits to the availability of suitable sites. The article summarises the relevant literature findings for each of these 10 factors and provides an overview indicating which factors have impacted on which generation technologies. The article also discusses the insights gained from the review for a better understanding of possible future cost developments of electricity generation technologies. Finally, future research needs, which may support a better understanding of past and future cost developments, are identified.
Multi-Objective Optimization of a Solar Chimney Power Plant with Inclined Collector Roof Using Genetic Algorithm
Authors: Gholamalizadeh Ehsan , Kim Man-Hoe
Published: November 2016

This paper presents an optimization of a solar chimney power plant with an inclined collector roof using genetic algorithms. Five design parameters that affect the system performance are the collector radius, collector inlet height, collector outlet height, chimney height and diameter. A multi-objective design to simultaneously optimize three conflicting objectives including system efficiency, power output and expenditure is used. Based on this approach, obtaining the best combination of the possible geometrical parameters, performance of two built pilot power plants in Kerman (Iran) and Manzanares (Spain) are optimized thermo-economically. The heights of the zero-slope collectors of the Kerman and Manzanares systems are 2 m and 1.85 m, respectively. The results show that in the Kerman pilot the optimal collector inlet and outlet heights are 1.5 m and 2.95 m, respectively, while those optimal heights in the Manzanares prototype are 1.5 m and 4.6 m, respectively. It is found that selecting the optimal collector roof configuration in addition to the other design parameters has a significant effect in the system optimization process.
The Impact of Rurality and Disadvantage on the Diagnostic Interval for Breast Cancer in a Large Population-Based Study of 3202 Women in Queensland, Australia
Authors: Youl Philippa , Aitken Joanne , Turrell Gavin , Chambers Suzanne , Dunn Jeffrey , Pyke Christopher , Baade Peter
Published: November 2016

Delays in diagnosing breast cancer (BC) can lead to poorer outcomes. We investigated factors related to the diagnostic interval in a population-based cohort of 3202 women diagnosed with BC in Queensland, Australia. Interviews ascertained method of detection and dates of medical/procedural appointments, and clinical information was obtained from medical records. Time intervals were calculated from self-recognition of symptoms (symptom-detected) or mammogram (screen-detected) to diagnosis (diagnostic interval (DI)). The cohort included 1560 women with symptom-detected and 1642 with screen-detected BC. Symptom-detected women had higher odds of DI of >60 days if they were Indigenous (OR = 3.12, 95% CI = 1.40, 6.98); lived in outer regional (OR = 1.50, 95% CI = 1.09, 2.06) or remote locations (OR = 2.46, 95% CI = 1.39, 4.38); or presented with a “non-lump” symptom (OR = 1.84, 95% CI = 1.43, 2.36). For screen-detected BC, women who were Indigenous (OR = 2.36, 95% CI = 1.03, 5.80); lived in remote locations (OR = 2.35, 95% CI = 1.24, 4.44); or disadvantaged areas (OR = 1.69, 95% CI = 1.17, 2.43) and attended a public screening facility (OR = 2.10, 95% CI = 1.40, 3.17) had higher odds of DI > 30 days. Our study indicates a disadvantage in terms of DI for rural, disadvantaged and Indigenous women. Difficulties in accessing primary care and diagnostic services are evident. There is a need to identify and implement an efficient and effective model of care to minimize avoidable longer diagnostic intervals.
Drivers’ Visual Search Patterns during Overtaking Maneuvers on Freeway
Authors: Zhang Wenhui , Dai Jing , Pei Yulong , Li Penghui , Yan Ying , Chen Xinqiang
Published: November 2016

Drivers gather traffic information primarily by means of their vision. Especially during complicated maneuvers, such as overtaking, they need to perceive a variety of characteristics including the lateral and longitudinal distances with other vehicles, the speed of others vehicles, lane occupancy, and so on, to avoid crashes. The primary object of this study is to examine the appropriate visual search patterns during overtaking maneuvers on freeways. We designed a series of driving simulating experiments in which the type and speed of the leading vehicle were considered as two influential factors. One hundred and forty participants took part in the study. The participants overtook the leading vehicles just like they would usually do so, and their eye movements were collected by use of the Eye Tracker. The results show that participants’ gaze durations and saccade durations followed normal distribution patterns and that saccade angles followed a log-normal distribution pattern. It was observed that the type of leading vehicle significantly impacted the drivers’ gaze duration and gaze frequency. As the speed of a leading vehicle increased, subjects’ saccade durations became longer and saccade angles became larger. In addition, the initial and destination lanes were found to be key areas with the highest visual allocating proportion, accounting for more than 65% of total visual allocation. Subjects tended to more frequently shift their viewpoints between the initial lane and destination lane in order to search for crucial traffic information. However, they seldom directly shifted their viewpoints between the two wing mirrors.
Antiviral Therapy by HIV-1 Broadly Neutralizing and Inhibitory Antibodies
Authors: Zhang Zhiqing , Li Shaowei , Gu Ying , Xia Ningshao
Published: November 2016

Human immunodeficiency virus type 1 (HIV-1) infection causes acquired immune deficiency syndrome (AIDS), a global epidemic for more than three decades. HIV-1 replication is primarily controlled through antiretroviral therapy (ART) but this treatment does not cure HIV-1 infection. Furthermore, there is increasing viral resistance to ART, and side effects associated with long-term therapy. Consequently, there is a need of alternative candidates for HIV-1 prevention and therapy. Recent advances have discovered multiple broadly neutralizing antibodies against HIV-1. In this review, we describe the key epitopes on the HIV-1 Env protein and the reciprocal broadly neutralizing antibodies, and discuss the ongoing clinical trials of broadly neutralizing and inhibitory antibody therapy as well as antibody combinations, bispecific antibodies, and methods that improve therapeutic efficacy by combining broadly neutralizing antibodies (bNAbs) with latency reversing agents. Compared with ART, HIV-1 therapeutics that incorporate these broadly neutralizing and inhibitory antibodies offer the advantage of decreasing virus load and clearing infected cells, which is a promising prospect in HIV-1 prevention and treatment.
Protective Effect of Tempol against Cisplatin-Induced Ototoxicity
Authors: Youn Cha , Kim Jun , Jo Eu-Ri , Oh Jeonghyun , Do Nam , Cho Sung
Published: November 2016

One of the major adverse effects of cisplatin chemotherapy is hearing loss. Cisplatin-induced ototoxicity hampers treatment because it often necessitates dose reduction, which decreases cisplatin efficacy. This study was performed to investigate the effect of Tempol on cisplatin-induced ototoxicity in an auditory cell line, House Ear Institute-Organ of Corti 1 (HEI-OC1). Cultured HEI-OC1 cells were exposed to 30 μM cisplatin for 24 h with or without a 2 h pre-treatment with Tempol. Cell viability was determined using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay and apoptotic cells were identified using terminal deoxynucleotidyl transferase dUTP nick end labeling of nuclei (TUNEL) assay and flow cytometry. The effects of Tempol on cisplatin-induced cleaved poly(ADP-ribose) polymerase, cleaved caspase, and mitochondrial inducible nitric oxide synthase expression were evaluated using western blot analysis. Levels of intracellular reactive oxygen species (ROS) were measured to assess the effects of Tempol on cisplatin-induced ROS accumulation. Mitochondria were evaluated by confocal microscopy, and the mitochondrial membrane potential was measured to investigate whether Tempol protected against cisplatin-induced mitochondrial dysfunction. Cisplatin treatment decreased cell viability, and increased apoptotic features and markers, ROS accumulation, and mitochondrial dysfunction. Tempol pre-treatment before cisplatin exposure significantly inhibited all these cisplatin-induced effects. These results demonstrate that Tempol inhibits cisplatin-induced cytotoxicity in HEI-OC1, and could play a preventive role against cisplatin-induced ototoxicity.
Isoliquiritigenin Attenuates Atherogenesis in Apolipoprotein E-Deficient Mice
Authors: Du Fen , Gesang Quzhen , Cao Jia , Qian Mei , Ma Li , Wu Dongfang , Yu Hong
Published: November 2016

Isoliquiritigenin (ISL) exhibits antioxidation and anti-inflammation activity. We sought to investigate the effects and mechanism of ISL on the development of atherosclerotic lesions in apolipoprotein E-deficient (apoE−/−) mice. Firstly, we determined that ISL reduced the mRNA levels of inflammatory factors interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), and monocyte chemotactic protein-1 (MCP-1), while it increased the expression of several lipoprotein-related genes in peritoneal macrophages treated with lipopolysaccharide (LPS). ISL also enhanced peroxisome proliferator-activated receptor gamma (PPARγ) protein levels and reversed the changes of ATP-binding cassette transporter A (ABCA1) and cluster of differentiation 36 (CD36) in macrophages treated with oxidative low-density lipoprotein (ox-LDL). Then, in an in vivo study, female apoE−/− mice were fed a Western diet with ISL (0, 20, 100 mg/kg/day) added for 12 weeks. We found that ISL decreased the plasma cholesterol levels of very low-density lipoprotein (VLDL)/LDL, promoted plasma superoxide dismutase (SOD) and paraoxonase-1 (PON1) activities, and decreased plasma IL-6, TNF-α, and MCP-1 levels. Moreover, ISL significantly reduced the atherosclerotic lesions and hepatic steatosis in apoE−/− mice. In the liver, ISL altered the expression of several key genes (such as SRBI, ABCA1, ABCG8, PPARγ, and FASN) involving cholesterol-selective uptake and excretion into bile, triglyceride (TG) biosynthesis, and inflammation. These results suggest that the atheroprotective effects of ISL are due to the improvement of lipid metabolism, antioxidation, and anti-inflammation, which involve PPARγ-dependent signaling.
Identification and Expression Analysis of Polygalacturonase Family Members during Peach Fruit Softening
Authors: Qian Ming , Zhang Yike , Yan Xiangyan , Han Mingyu , Li Jinjin , Li Fang , Li Furui , Zhang Dong , Zhao Caiping
Published: November 2016

Polygalacturonase (PG) is an important hydrolytic enzyme involved in pectin degradation during fruit softening. However, the roles of PG family members in fruit softening remain unclear. We identified 45 PpPG genes in the peach genome which are clustered into six subclasses. PpPGs consist of four to nine exons and three to eight introns, and the exon/intron structure is basically conserved in all but subclass E. Only 16 PpPG genes were expressed in ripening fruit, and their expression profiles were analyzed during storage in two peach cultivars with different softening characteristics. Eight PGs (PpPG1, -10, -12, -13, -15, -23, -21, and -22) in fast-softening “Qian Jian Bai” (QJB) fruit and three PGs (PpPG15, -21, and -22) in slow-softening “Qin Wang” (QW) fruit exhibited softening-associated patterns; which also were affected by ethylene treatment. Our results suggest that the different softening characters in QW and QJB fruit is related to the amount of PG members. While keeping relatively lower levels during QW fruit softening, the expression of six PGs (PpPG1, -10, -12, -11, -14, and -35) rapidly induced by ethylene. PpPG24, -25 and -38 may not be involved in softening of peach fruit.
PP-Rotation, P-Inversion and Metathesis in Diphosphines Studied by DFT Calculations: Comments on Some Literature Conflicts
Authors: Molloy Adam , Sánchez-Sanz Goar , Gilheany Declan
Published: November 2016

The potential energy surface for internal rotation about the phosphorus–phosphorus bond was calculated at the PCMDCM/B3LYP/6-311++G(d,p) computational level for a set of eight symmetrical, unsymmetrical and P-stereogenic diphosphines; H4P2, Me4P2, (CF3)4P2, Ph4P2, Me2P–P(CF3)2, Me2P–PPh2, and the meso- and dl-isomers of Me(CF3)P–PMe(CF3) and MePhP–PMePh. Certain trends in the data were elucidated and compared with conflicting data from the literature regarding the relative population of anti and gauche rotational isomers. The pyramidal inversion barriers (stereomutation barriers in P-stereogenic cases) for the same set of diphosphines was estimated through the inversion transition states and also compared to literature values. Finally, the Me4P2 + (CF3)4P2 → 2Me2(CF3)2P2 metathesis reaction was also explored to evaluate its feasibility versus inversion. The finding of larger barriers in the metathesis than in the inversion rules in favour of an inversion mechanism for the stereomutation of P-stereogenic diphosphines.
The Benefit of Conserving and Gaining Resources after Trauma: A Systematic Review
Authors: Hollifield Michael , Gory Andrea , Siedjak Jennifer , Nguyen Linda , Holmgreen Lucie , Hobfoll Stevan
Published: November 2016

Background: Traumatic events involve loss of resources, which has consistently been found to be associated with developing stress-related illness such as posttraumatic stress disorder (PTSD). Objective: The purpose of this systematic literature review was to determine if there is evidence for the salutatory effect of resource gain on PTSD, and if there are intervention models that utilize and assess gain in PTSD. Data Sources: All relevant online databases were systematically searched using key terms and a method, detailed in Figure 1. Results: Of 22 relevant articles, there were three intervention studies, one longitudinal naturalistic study, eleven non-intervention association studies focusing on PTSD, and eight non-intervention association studies not focusing on PTSD. The intervention and naturalistic studies showed a significant positive effect on PTSD by specifically targeting the gain of resources during an intervention. Other non-intervention research supports the notion that resource loss is pathogenic and resource gain is beneficial after traumatic exposure. Conclusions: Interventions that develop and assess effects of gain of various types of resources on stress-related illness should be encouraged. Interventions that already have proven efficacy for PTSD might include standardized assessment of resource loss and gain to further understand mechanisms of action.
The Duality of Knee Functional Axes and Foot Contact
Authors: Kim Wangdo , Choi Young , Lee Hong-Gi
Published: November 2016

Estimating the knee functional axis (KFA) is crucial to both correctly implanting a prosthesis and accessing joint kinematics. Researchers have reported on the KFA mainly with regard to manual management of flexion–extension movements performed passively without any voluntary movements. Active touch and movement refers to what is ordinarily called touching—variations in skin stimulation caused by surfaces are altered together by variations in motor activity. This fact is worth noting because it is often neglected that locomotion and its surfaces form an inseparable pair. The objective of this study was to confirm the distinction between touching and being touched. We were particularly interested in measuring the instantaneous axes of the knee (IAK) during locomotion. We propose the invariant structure of the knee as an attempt to distill a kind of higher-order simplification of a knee model relative to the enormous complexities of analytical anatomical objects.
Energy Storage Characteristics of BiFeO3/BaTiO3 Bi-Layers Integrated on Si
Authors: Liu Menglin , Zhu Hanfei , Zhang Yunxiang , Xue Caihong , Ouyang Jun
Published: November 2016

BiFeO3/BaTiO3 bi-layer thick films (~1 μm) were deposited on Pt/Ti/SiO2/(100) Si substrates with LaNiO3 buffer layers at 500 °C via a rf magnetron sputtering process. X-ray diffraction (XRD) analysis revealed that both BiFeO3 and BaTiO3 layers have a (00l) preferred orientation. The films showed a small remnant polarization (Pr ~ 7.8 μC/cm2) and a large saturated polarization (Ps ~ 65 μC/cm2), resulting in a slim polarization-electric field (P-E) hysteresis loop with improved energy storage characteristics (Wc = 71 J/cm3, η = 61%). The successful “slim-down” of the P-E loop from that of the pure BiFeO3 film can be attributed to the competing effects of space charges and the interlayer charge coupling on charge transport of the bi-layer film. The accompanying electrical properties of the bi-layer films were measured and the results confirmed their good quality.
Experimental Study on Reaction Characteristics of PTFE/Ti/W Energetic Materials under Explosive Loading
Authors: Li Yan , Jiang Chunlan , Wang Zaicheng , Luo Puguang
Published: November 2016

Metal/fluoropolymer composites represent a new category of energetic structural materials that release energy through exothermic chemical reactions initiated under shock loading conditions. This paper describes an experiment designed to study the reaction characteristics of energetic materials with low porosity under explosive loading. Three PTFE (polytetrafluoroethylene)/Ti/W mixtures with different W contents are processed through pressing and sintering. An inert PTFE/W mixture without reactive Ti particles is also prepared to serve as a reference. Shock-induced chemical reactions are recorded by high-speed video through a narrow observation window. Related shock parameters are calculated based on experimental data, and differences in energy release are discussed. The results show that the reaction propagation of PTFE/Ti/W energetic materials with low porosity under explosive loading is not self-sustained. As propagation distance increases, the energy release gradually decreases. In addition, reaction failure distance in PTFE/Ti/W composites is inversely proportional to the W content. Porosity increased the failure distance due to higher shock temperature.
The Role of Individual Disulfide Bonds of μ-Conotoxin GIIIA in the Inhibition of NaV1.4
Authors: Han Penggang , Wang Kang , Dai Xiandong , Cao Ying , Liu Shangyi , Jiang Hui , Fan Chongxu , Wu Wenjian , Chen Jisheng
Published: November 2016

μ-Conotoxin GIIIA, a peptide toxin isolated from Conus geographus, preferentially blocks the skeletal muscle sodium channel NaV1.4. GIIIA folds compactly to a pyramidal structure stabilized by three disulfide bonds. To assess the contributions of individual disulfide bonds of GIIIA to the blockade of NaV1.4, seven disulfide-deficient analogues were prepared and characterized, each with one, two, or three pairs of disulfide-bonded Cys residues replaced with Ala. The inhibitory potency of the analogues against NaV1.4 was assayed by whole cell patch-clamp on rNaV1.4, heterologously expressed in HEK293 cells. The corresponding IC50 values were 0.069 ± 0.005 μM for GIIIA, 2.1 ± 0.3 μM for GIIIA-1, 3.3 ± 0.2 μM for GIIIA-2, and 15.8 ± 0.8 μM for GIIIA-3 (-1, -2 and -3 represent the removal of disulfide bridges Cys3–Cys15, Cys4–Cys20 and Cys10–Cys21, respectively). Other analogues were not active enough for IC50 measurement. Our results indicate that all three disulfide bonds of GIIIA are required to produce effective inhibition of NaV1.4, and the removal of any one significantly lowers its sodium channel binding affinity. Cys10–Cys21 is the most important for the NaV1.4 potency.
An Analysis of the Weldability of Ductile Cast Iron Using Inconel 625 for the Root Weld and Electrodes Coated in 97.6% Nickel for the Filler Welds
Authors: Cárcel-Carrasco Francisco-Javier , Pérez-Puig Miguel-Angel , Pascual-Guillamón Manuel , Pascual-Martínez Rafael
Published: November 2016

This article examines the weldability of ductile cast iron when the root weld is applied with a tungsten inert gas (TIG) welding process employing an Inconel 625 source rod, and when the filler welds are applied with electrodes coated with 97.6% Ni. The welds were performed on ductile cast iron specimen test plates sized 300 mm × 90 mm × 10 mm with edges tapered at angles of 60°. The plates were subjected to two heat treatments. This article analyzes the influence on weldability of the various types of electrodes and the effect of preheat treatments. Finally, a microstructure analysis is made of the material next to the weld in the metal-weld interface and in the weld itself. The microstructure produced is correlated with the strength of the welds. We treat an alloy with 97.6% Ni, which prevents the formation of carbides. With a heat treatment at 900 °C and 97.6% Ni, there is a dissolution of all carbides, forming nodules in ferritic matrix graphite.
Effect of the Thermodynamic Behavior of Selective Laser Melting on the Formation of In situ Oxide Dispersion-Strengthened Aluminum-Based Composites
Authors: Wang Lianfeng , Jue Jiubin , Xia Mujian , Guo Lijie , Yan Biao , Gu Dongdong
Published: November 2016

This paper presents a comprehensive investigation of the phase and microstructure, the thermodynamic behavior within the molten pool, and the growth mechanism of in situ oxide dispersion-strengthened (ODS) aluminum-based composites processed by a selective laser melting (SLM) additive manufacturing/3D printing process. The phase and microstructure were characterized by X-ray diffraction (XRD) and a scanning electronic microscope (SEM) equipped with EDX, respectively. The thermodynamic behavior within the molten pool was investigated for a comprehensive understanding on the growth mechanism of the SLM-processed composite using a finite volume method (FVM). The results revealed that the in situ Al2Si4O10 ODS Al-based composites were successfully fabricated by SLM. Combined with the XRD spectrum and EDX analysis, the new silica-rich Al2Si4O10 reinforcing phase was identified, which was dispersed around the grain boundaries of the aluminum matrix under a reasonable laser power of 200 W. Combined with the activity of Marangoni convection and repulsion forces, the characteristic microstructure of SLM-processed Al2Si4O10 ODS Al-based composites tended to transfer from the irregular network structure to the nearly sphere-like network structure in regular form by increasing the laser power. The formation mechanism of the microstructure of SLM-processed Al2Si4O10 ODS Al-based composites is thoroughly discussed herein.
The Effect of Ultrafast Heating in Cold-Rolled Low Carbon Steel: Recrystallization and Texture Evolution
Authors: Castro Cerda Felipe , Kestens Leo , Monsalve Alberto , Petrov Roumen
Published: November 2016

The microstructure and texture evolution of cold-rolled low carbon steel after ultrafast heating and quenching is investigated. Experiments were carried out at heating rates of 150 °C/s and 1500 °C/s. The recrystallization of ferrite is studied by scanning electron microscopy and electron backscattered diffraction techniques. The texture evolution of cold rolled steel during ultrafast heating was studied, making it possible to estimate the precise effect of heating rate on the orientations of newly formed grains. The experimental results showed that the recrystallization of ferrite was not completed before the full transformation of austenite. The noticeable increase in the fraction of recrystallized grains of diameter less than 1 µm, when the heating rate is increased from 150 °C/s to 1500 °C/s suggests that the increase of the heating rate enhances the nucleation of ferrite. The crystallographic orientations in recrystallized ferrite are strongly influenced by the heating rates. The effect of heating rate in the releasing of stored energy, carbon diffusion and spheroidization of cementite might explain some differences in textures observed in recrystallized ferrite.
Wear Behavior of Mechanically Alloyed Ti-Based Bulk Metallic Glass Composites Containing Carbon Nanotubes
Authors: Lin Yung-Sheng , Hsu Chih-Feng , Chen Jyun-Yu , Cheng Yeh-Ming , Lee Pee-Yew
Published: November 2016

The present paper reports the preparation and wear behavior of mechanically alloyed Ti-based bulk metallic glass composites containing carbon nanotube (CNT) particles. The differential scanning calorimeter results show that the thermal stability of the amorphous matrix is affected by the presence of CNT particles. Changes in glass transition temperature (Tg) and crystallization temperature (Tx) suggest that deviations in the chemical composition of the amorphous matrix occurred because of a partial dissolution of the CNT species into the amorphous phase. Although the hardness of CNT/Ti50Cu28Ni15Sn7 bulk metallic glass composites is increased with the addition of CNT particles, the wear resistance of such composites is not directly proportional to their hardness, and does not follow the standard wear law. A worn surface under a high applied load shows that the 12 vol. % CNT/Ti50Cu28Ni15Sn7 bulk metallic glass composite suffers severe wear compared with monolithic Ti50Cu28Ni15Sn7 bulk metallic glass.
Genesis and Multi-Episodic Alteration of Zircon-Bearing Chromitites from the Ayios Stefanos Mine, Othris Massif, Greece: Assessment of an Unconventional Hypothesis on the Origin of Zircon in Ophiolitic Chromitites
Authors: Kapsiotis Argyrios , Ewing Rassios Annie , Antonelou Aspasia , Tzamos Evangelos
Published: November 2016

Several small chromium (Cr) ore bodies are hosted within a unit of tectonically thinned dunite in the retired Ayios Stefanos mine of the western Othris ophiolite complex in Greece. Chromium ores consist of tectonically imprinted bodies of semi-massive to massive, podiform and lenticular chromitites composed of chromian spinel [Cr-spinel] with high Cr# [Cr/(Cr + Al) = 0.51–0.66] and Mg# [Mg/(Mg + Fe2+) = 0.58–0.76], low Fe3+# [Fe3+/(Fe3+ + Fe2+) ≤ 0.43] and low TiO2 (≤0.21 wt %) content. This composition is characteristic of Cr-spinels in equilibrium with melts of intermediate affinity between island-arc tholeiites (IATs) and mid-ocean ridge basalts (MORBs). Several Cr-spinel crystals in these ores exhibit imperfect zones made up of spinel hosting oriented lamellae of Mg-silicates (mostly chlorite) locally overgrown by porous domains along grain boundaries and fractures. From the Cr-spinel core to the lamellae-rich rim Cr#, Mg# and Fe3+# generally increase (0.68–0.87, 0.78–0.88 and 0.55–0.80, respectively), whereas from the core or the spinel zones with oriented lamellae to the porous domains Mg# and Fe3+# generally decrease (0.45–0.74 and ≤0.51, correspondingly). The lamellae-rich rims formed at oxidizing conditions, whereas the porous rims resulted from a later reducing event. Several tiny (≤30 μm), subhedral to anhedral and elongated Zr-bearing silicate mineral grains were discovered mainly along open and healed fractures cutting Cr-spinel. Most of the Zr-bearing silicate minerals (30 out of 35 grains) were found in a chromitite boulder vastly intruded by a complex network of gabbroic dykes. The dominant Zr-bearing silicate phase is by far zircon displaying a homogeneous internal texture in cathodoluminescence (CL) images. Raman spectroscopy data indicate that zircons have experienced structural damage due to self-irradiation. Their trace-element contents suggest derivation from a plagioclase-bearing, low-SiO2 intermediate to mafic source. Combined micro-textural and minerochemical data repeat the possibility of zircon derivation from limited volumes of high-T fluids emanating from the gabbroic intrusions. Once zircon is precipitated in cracks, it may be altered to Ca-rich Zr-bearing silicate phases (i.e., armstrongite, calciocatapleiite). Almost all zircons in these samples show evidence of gains in solvent compounds (CaO, Al2O3 and FeO) possibly due to re-equilibration with late deuteric fluids.
Selenium Nanoparticles Attenuate Oxidative Stress and Testicular Damage in Streptozotocin-Induced Diabetic Rats
Authors: Dkhil Mohamed , Zrieq Rafat , Al-Quraishy Saleh , Abdel Moneim Ahmed
Published: November 2016

We investigated the protective and antioxidative effects of selenium nanoparticles (SeNPs) in streptozotocin STZ-induced diabetic rats. STZ-diabetic rats were exposed daily to treatments with SeNPs and/or insulin and then the effect of these treatments on the parameters correlated to oxidative damage of the rat testes were assessed. Biochemical analysis revealed that SeNPs are able to ameliorate the reduction in the serum testosterone caused by STZ-induced diabetes. Furthermore, SeNPs could significantly decrease testicular tissue oxidative stress markers, namely lipid peroxidation and nitric oxide. In contrast, treatment of the STZ-diabetic rats with SeNPs increased the glutathione content and antioxidant enzyme activities in testicular tissues. Moreover, microscopic analysis proved that SeNPs are able to prevent histological damage in the testes of STZ-diabetic rats. Molecular analysis revealed that the mRNA level of Bcl-2 (B-cell lymphoma 2) is significantly upregulated. On the contrary, the mRNA level of Bax (Bcl-2 Associated X Protein) was significantly downregulated. Furthermore, treatment of STZ-diabetic rats with SeNPs led to an elevation in the expression of PCNA (Proliferating Cell Nuclear Antigen Gene). Interestingly, the insulin treatment also exhibited a significant improvement in the testicular function in STZ-diabetic rats. Collectively, our results demonstrated the possible effects of SeNPs in attenuating diabetes-induced oxidative damage, in particular in testicular tissue.
Factors Affecting the Formation of 2:1 Host:Guest Inclusion Complexes of 2-[(R-Phenyl)amine]-1,4-naphthalenediones (PAN) in β- and γ-Cyclodextrins
Authors: Jankowski Christopher , Lamouroux Christine , Jiménez-Estrada Manuel , Arseneau Sebastien , Wagner Brian
Published: November 2016

The molecular hosts cyclodextrins form inclusion complexes with a wide variety of guests, resulting in complexes with various host:guest stoichiometries. In the case of a series of 19 1,4-naphthoquinolines as guests with either β- or γ-cyclodextrin studied using electrospray mass spectroscopy, in most cases only 1:1 complexes were observed, with 2:1 host:guest complexes observed in just 6 out of 38 host:guest combinations. It is shown that these higher-order complexes were observed only in the case of small (or no) electronically withdrawing substituents, and were much less likely in the case of the larger γ-cyclodextrin host. The size and electronic properties of the substituents involved shows that both steric and electronic factors must be taken into account in predicting which cyclodextrin host:guest stoichiometries will be stable enough to form (or once formed, be robust enough to be observed in the ESI-MS experiments). It is clear that the prediction of host-guest stoichiometry for a specific host-guest pair is complicated, and involves a subtle interplay of both electronic and steric factors. However, there are definite trends, which can be used to help predict host:guest stoichiometry for a given host-guest pair.
Ultrasound-Assisted Extraction May Not Be a Better Alternative Approach than Conventional Boiling for Extracting Polysaccharides from Herbal Medicines
Authors: Yip Ka-Man , Xu Jun , Tong Wing-Sum , Zhou Shan-Shan , Yi Tao , Zhao Zhong-Zhen , Chen Hu-Biao
Published: November 2016

In clinical practice polysaccharides from herbal medicines are conventionally prepared by boiling water extraction (BWE), while ultrasound-assisted extraction (UAE) has often been used instead employed in laboratory research due to its strong extraction ability and efficiency. However, if and how the polysaccharides obtained by UAE and BWE are comparable, and hence whether the UAE-based research is instructive for the actual usage of herbal polysaccharides still requires further evaluation. To address this issue, here we chemically analyzed and compared the UAE- and BWE-obtained polysaccharides from three herbal medicines, i.e., Ginseng Radix, Astragali Radix and Dendrobii Officinalis Caulis. Then, the spike recovery of two series of standard dextran and pullulan by UAE and BWE was tested. The results showed that the polysaccharides from the herbal medicines by UAE were quantitatively and qualitatively different with those by BWE. The powerful extraction ability and polysaccharide degradation caused by ultrasound collectively contributed to these differences. It was then revealed that not only the UAE conditions but also the polysaccharide structures could affect the extraction ability and polysaccharide degradation. Given these, we highly recommended that the effects of UAE on polysaccharides from herbal medicines should be first carefully considered before employing it in relevant chemical and pharmacological analysis.
Many Activities, One Structure: Functional Plasticity of Ribozyme Folds
Authors: Lau Matthew , Ferré-D’Amaré Adrian
Published: November 2016

Catalytic RNAs, or ribozymes, are involved in a number of essential biological processes, such as replication of RNA genomes and mobile genetic elements, RNA splicing, translation, and RNA degradation. The function of ribozymes requires the formation of active sites decorated with RNA functional groups within defined three-dimensional (3D) structures. The genotype (sequence) of RNAs ultimately determines what 3D structures they adopt (as a function of their environmental conditions). These 3D structures, in turn, give rise to biochemical activity, which can further elaborate them by catalytic rearrangements or association with other molecules. The fitness landscape of a non-periodic linear polymer, such as RNA, relates its primary structure to a phenotype. Two major challenges in the analysis of ribozymes is to map all possible genotypes to their corresponding catalytic activity (that is, to determine their fitness landscape experimentally), and to understand whether their genotypes and three-dimensional structures can support multiple different catalytic functions. Recently, the combined results of experiments that employ in vitro evolution methods, high-throughput sequencing and crystallographic structure determination have hinted at answers to these two questions: while the fitness landscape of ribozymes is rugged, meaning that their catalytic activity cannot be optimized by a smooth trajectory in sequence space, once an RNA achieves a stable three-dimensional fold, it can be endowed with distinctly different biochemical activities through small changes in genotype. This functional plasticity of highly structured RNAs may be particularly advantageous for the adaptation of organisms to drastic changes in selective pressure, or for the development of new biotechnological tools.
Molecular Docking Optimization in the Context of Multi-Drug Resistant and Sensitive EGFR Mutants
Authors: García-Godoy María , López-Camacho Esteban , García-Nieto José , Nebro Antonio , Aldana-Montes José
Published: November 2016

The human Epidermal Growth Factor (EGFR) plays an important role in signaling pathways, such as cell proliferation and migration. Mutations like G719S, L858R, T790M, G719S/T790M or T790M/L858R can alter its conformation, and, therefore, drug responses from lung cancer patients. In this context, candidate drugs are being tested and in silico studies are necessary to know how these mutations affect the ligand binding site. This problem can be tackled by using a multi-objective approach applied to the molecular docking problem. According to the literature, few studies are related to the application of multi-objective approaches by minimizing two or more objectives in drug discovery. In this study, we have used four algorithms (NSGA-II, GDE3, SMPSO and MOEA/D) to minimize two objectives: the ligand–receptor intermolecular energy and the RMSD score. We have prepared a set of instances that includes the wild-type EGFR kinase domain and the same receptor with somatic mutations, and then we assessed the performance of the algorithms by applying a quality indicator to evaluate the convergence and diversity of the reference fronts. The MOEA/D algorithm yields the best solutions to these docking problems. The obtained solutions were analyzed, showing promising results to predict candidate EGFR inhibitors by using this multi-objective approach.
Phytochemical Profiling of Flavonoids, Phenolic Acids, Terpenoids, and Volatile Fraction of a Rosemary (Rosmarinus officinalis L.) Extract
Authors: Mena Pedro , Cirlini Martina , Tassotti Michele , Herrlinger Kelli , Dall’Asta Chiara , Del Rio Daniele
Published: November 2016

This paper presents a comprehensive analysis of the phytochemical profile of a proprietary rosemary (Rosmarinus officinalis L.) extract rich in carnosic acid. A characterization of the (poly)phenolic and volatile fractions of the extract was carried out using mass spectrometric techniques. The (poly)phenolic composition was assessed by ultra-high performance liquid chromatography-electrospray ionization-mass spectrometry (UHPLC-ESI-MSn) and a total of 57 compounds were tentatively identified and quantified, 14 of these being detected in rosemary extract for the first time. The rosemary extract contained 24 flavonoids (mainly flavones, although flavonols and flavanones were also detected), 5 phenolic acids, 24 diterpenoids (carnosic acid, carnosol, and rosmanol derivatives), 1 triterpenoid (betulinic acid), and 3 lignans (medioresinol derivatives). Carnosic acid was the predominant phenolic compound. The volatile profile of the rosemary extract was evaluated by head space solid-phase microextraction (HS-SPME) linked to gas chromatography-mass spectrometry (GC-MS). Sixty-three volatile molecules (mainly terpenes, alcohols, esters, aldehydes, and ketones) were identified. This characterization extends the current knowledge on the phytochemistry of Rosmarinus officinalis and is, to our knowledge, the broadest profiling of its secondary metabolites to date. It can assist in the authentication of rosemary extracts or rosemary-containing products or in testing its bioactivity. Moreover, this methodological approach could be applied to the study of other plant-based food ingredients.
Agarose and Its Derivatives as Supports for Enzyme Immobilization
Authors: Zucca Paolo , Fernandez-Lafuente Roberto , Sanjust Enrico
Published: November 2016

Agarose is a polysaccharide obtained from some seaweeds, with a quite particular structure that allows spontaneous gelation. Agarose-based beads are highly porous, mechanically resistant, chemically and physically inert, and sharply hydrophilic. These features—that could be further improved by means of covalent cross-linking—render them particularly suitable for enzyme immobilization with a wide range of derivatization methods taking advantage of chemical modification of a fraction of the polymer hydroxyls. The main properties of the polymer are described here, followed by a review of cross-linking and derivatization methods. Some recent, innovative procedures to optimize the catalytic activity and operational stability of the obtained preparations are also described, together with multi-enzyme immobilized systems and the main guidelines to exploit their performances.
Direct Separation of Pregabalin Enantiomers Using a Zwitterionic Chiral Selector by High Performance Liquid Chromatography Coupled to Mass Spectrometry and Ultraviolet Detection
Authors: Chennuru Lakshmi , Choppari Thirupathi , Nandula Ramakrishna , Zhang Tong , Franco Pilar
Published: November 2016

The chromatographic resolution of pregabalin enantiomers has been often achieved by derivatization of the molecule, in order to reach enough sensitivity at low concentrations of the minor enantiomer present in the active principle. In the present article, the development and optimization of two liquid chromatographic methods are presented for the direct resolution of pregabalin enantiomers on a chiral stationary phase (CSP) containing a zwitterionic selector derived from cinchona alkaloid and sulfonic acid (CHIRALPAK ZWIX). The key parameters for the separation as well as the compatibility of chromatographic conditions with different detection modes (ultraviolet and mass spectrometry) were investigated. The resulting methods were found to be selective, of high performance and low limits of detection (2 µg/mL by UV and 1 ng/mL by MS, respectively) and quantification (6 µg/mL by UV and 5 ng/mL by MS, respectively) for the minor enantiomer which is considered as a chiral impurity.
Semisynthetic and SAR Studies of Amide Derivatives of Neocrotocembraneic Acid as Potential Antitumor Agents
Authors: Shang Hai , Li Ling-Yu , Cheng Wei-Hua , Luo Jun , Zhang Hong-Wu , Zou Zhong-Mei
Published: November 2016

A series of novel amide derivatives of cembranoid neocrotocembraneic acid were designed and synthesized. The antiproliferative activities of these derivatives were evaluated against three human tumor cell lines (the human cervical cancer cell line HeLa, chronic myeloid leukemia cell line K562 and leukemia multidrug-resistant cell line K562/A02). Some of the synthesized compounds exhibited moderate to good activity against all three cancer cell lines. Particularly, compound 8a exhibited more potent antiproliferative activity than the reference drug etoposide against drug-resistant cell line K562/A02, indicating that it possessed a great potential for further development as a multidrug resistance modulator by structural modification.
Temperature-Triggered Switchable Helix-Helix Inversion of Poly(phenylacetylene) Bearing l-Valine Ethyl Ester Pendants and Its Chiral Recognition Ability
Authors: Zhou Yanli , Zhang Chunhong , Qiu Yuan , Liu Lijia , Yang Taotao , Dong Hongxing , Satoh Toshifumi , Okamoto Yoshio
Published: November 2016

A phenylacetylene containing the l-valine ethyl ester pendant (PAA-Val) was synthesized and polymerized by an organorhodium catalyst (Rh(nbd)BPh4) to produce the corresponding one-handed helical cis-poly(phenylacetylene) (PPAA-Val). PPAA-Val showed a unique temperature-triggered switchable helix-sense in chloroform, while it was not observed in highly polar solvents, such as N,N′-dimethylformamide (DMF). By heating the solution of PPAA-Val in chloroform, the sign of the CD absorption became reversed, but recovered after cooling the solution to room temperature. Even after six cycles of the heating-cooling treatment, the helix sense of the PPAA-Val’s backbone was still switchable without loss of the CD intensity. The PPAA-Val was then coated on silica gel particles to produce novel chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC). These novel PPAA-Val based CSPs showed a high chiral recognition ability for racemic mandelonitrile (α = 2.18) and racemic trans-N,N′-diphenylcyclohexane-1,2-dicarboxamide (α = 2.60). Additionally, the one-handed helical cis-polyene backbone of PPAA-Val was irreversibly destroyed to afford PPAA-Val-H by heating in dimethyl sulfoxide (DMSO) accompanied by the complete disappearance of the Cotton effect. Although PPAA-Val-H had the same l-valine ethyl ester pendants as its cis-isomer PPAA-Val, it showed no chiral recognition. It was concluded that the one-handed helical cis-polyene backbone of PPAA-Val plays an important role in the chiral recognition ability.
Carbon-Based Materials for Photo-Triggered Theranostic Applications
Authors: Albert Karunya , Hsu Hsin-Yun
Published: November 2016

Carbon-based nanomaterials serve as a type of smart material for photo-triggered disease theranostics. The inherent physicochemical properties of these nanomaterials facilitate their use for less invasive treatments. This review summarizes the properties and applications of materials including fullerene, nanotubes, nanohorns, nanodots and nanographenes for photodynamic nanomedicine in cancer and antimicrobial therapies. Carbon nanomaterials themselves do not usually act as photodynamic therapy (PDT) agents owing to the high hydrophobicity, however, when the surface is passivated or functionalized, these materials become great vehicles for PDT. Moreover, conjugation of carbonaceous nanomaterials with the photosensitizer (PS) and relevant targeting ligands enhances properties such as selectivity, stability, and high quantum yield, making them readily available for versatile biomedical applications.
Bio-Guided Isolation of Methanol-Soluble Metabolites of Common Spruce (Picea abies) Bark by-Products and Investigation of Their Dermo-Cosmetic Properties
Authors: Angelis Apostolis , Hubert Jane , Aligiannis Nektarios , Michalea Rozalia , Abedini Amin , Nuzillard Jean-Marc , Gangloff Sophie , Skaltsounis Alexios-Leandros , Renault Jean-Hugues
Published: November 2016

Common spruce (Picea abies L.) is a fast-growing coniferous tree, widely used in several countries for the production of sawn wood, timber and pulp. During this industrial exploitation, large quantities of barks are generated as waste materials. The aim of this study was the bio-guided investigation and the effective recovery of methanol-soluble metabolites of common spruce bark for the development of new dermo-cosmetic agents. The active methanol extract was initially fractionated by Centrifugal Partition Chromatography (CPC) using a triphasic solvent system in a step-gradient elution mode. All resulting fractions were evaluated for their antibacterial activity, antioxidant activity and their capability to inhibit tyrosinase, elastase and collagenase activity. In parallel, the chemical composition of each fraction was established by combining a 13C-NMR dereplication approach and 2D-NMR analyses. As a result, fourteen secondary metabolites corresponding to stilbene, flavonoid and phenolic acid derivatives were directly identified in the CPC fractions. A high amount (0.93 g) of E-astringin was recovered from 3 g of crude extract in a single 125 min run. E-Astringin significantly induced the tyrosinase activity while E-piceid, taxifolin, and taxifolin-3′-O-glucopyranoside exhibited significant anti-tyrosinase activity. The above compounds showed important anti-collagenase and antimicrobial activities, thus providing new perspectives for potential applications as cosmetic ingredients.
Structural Investigation of Cell Wall Xylan Polysaccharides from the Leaves of Algerian Argania spinosa
Authors: Hachem Kadda , Faugeron Céline , Kaid-Harche Meriem , Gloaguen Vincent
Published: November 2016

Xylan-type polysaccharides were isolated from the leaves of Argania spinosa (L.) Skeels collected in the Tindouf area (southwestern Algeria). Xylan fractions were obtained by sequential alkaline extractions and purified on Sepharose CL-4B. The xylan structure was investigated by enzymatic hydrolysis with an endo-β(1→4)-xylanase followed by chromatography of the resulting fragments on Biogel P2, characterization by sugar analysis and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS ). The results show that the A. spinosa xylan is composed of a β-(1→4)-d-xylopyranose backbone substituted with 4-O-methyl-d-glucuronic acid and L-arabinose residues.