bluuebunny/crossref_metadata_2025 huggingface dataset:
Musings on Future Exploration Targets and Strategies in the Andes
Authors: Sillitoe Richard H.
Published: February 2020

A variety of metals and deposit types define the metallogeny of the Andes from Colombia through Ecuador, Peru, and Bolivia to Argentina and Chile, although porphyry copper and epithermal gold deposits undoubtedly predominate and will continue to do so. Discoveries over the last 30 yrs or so, predominantly in the central Andes and especially Chile, have been made using routine, field-based geologic and complementary geochemical methods, a situation that is considered unlikely to change radically in the foreseeable future. The only clearcut evolutionary change is the increased number of deposits being discovered beneath pre- and postmineral cover. The predictive capacity of conceptual geology has had minimal impact on the Andean discovery record but is thought to offer much promise for the future. This introductory article selects mineralization styles and relationships as well as some broader metallogenic parameters as simple examples of geologic concepts that may assist exploration. Emphasis is placed on porphyry copper ± molybdenum ± gold and high-, intermediate-, and lowsulfidation epithermal gold ± silver deposits, although reference is also made to several carbonate rock-hosted precious and base metal deposit types and styles as well as subvolcanic tin, volcanogenic massive sulfide, and slate-belt and intrusion-related gold deposits. Particular emphasis is placed on the potential for exceptionally high grade porphyry copper, porphyry gold, epithermal gold, and subvolcanic tin deposits. Deposits resulting from the oxidation, enrichment, and chemical transport of copper and zinc and mechanical transport of gold and silver during supergene weathering are also briefly highlighted.
Enargite-Gold Deposits at Marcapunta, Colquijirca Mining District, Central Peru
Authors: Vidal César E. , Ligarda Rolando
Published: February 2020

The Marcapunta enargite-Au deposits are located in the center of the Colquijirca mining district, 310 km northeast of Lima and 10 km south of the Cerro de Pasco mine. The regional geology comprises folded Permo-Triassic red-bed deposits of the Mitu Group succeeded by Pucará Group limestone and dolomite of Triassic to Jurassic age, which are overlain by carbonate breccia, conglomerate, and fresh-water limestone of the Eocene Calera Formation. These units are intruded and overlain by dacitic domes and pyroclastic rocks of the Marcapunta volcanic center. The north-trending Longitudinal fault controlled basin morphology during both the Pucará and Calera Formation sedimentation as well as emplacement of the Cerro de Pasco and Marcapunta Miocene volcanoes.

The Marcapunta Cu-As-Au deposits are zoned symmetrically northward into the Zn-Pb-Ag ores of Colquijirca and southwestward into the Zn-Pb-Ag San Gregorio deposit. The Miocene volcanic center at Marcapunta is intensely altered to advanced argillic alteration assemblages in the form of quartz-alunite ledges with argillic halos. Alunite mineral separates have been dated at 11.6 ± 0.1 Ma by K-Ar and 10.6 ± 0.1 Ma by 40Ar/39Ar methods. The main silicification and quartz-alunite alteration are controlled by several prominent east-west fractures and attain thicknesses from a few centimeters to ~50 m. Mineral assemblages are zoned outward from a central zone of vuggy quartz to quartz-alunite ± dickite, illite-kaolinite ± montmorillonite and external chlorite-calcite envelopes. Copper mineralization surrounds an interpreted subsurface diatreme vent and flares outward along the base of the dacitic domes comprising the Marcapunta volcanic center. Semimassive to massive quartz-pyrite bodies preferentially replaced limestone breccia and conglomerate of the Calera Formation and are sandwiched between the underlying Mitu Group sandstone and the overlying lava domes.

The northern, western, and southwestern flanks of the Marcapunta volcanic center are characterized by a recently determined and drill-tested, crescent-shaped gravimetric high. Ore zones attain thicknesses as much as 100 m adjacent to the steep diatreme walls and thin laterally into discrete strata-bound manto and breccia horizons. Ore mineralogy is dominated by enargite, covellite, native gold, and several precious metal-bearing telluride phases. Hypogene chalcocite and digenite occur in a discrete lower manto beneath the enargite zone of western Marcapunta. Gold appears to be concentrated in the southwestern parts of the replacement bodies. Cu/As ratios increase from a homogeneous value of 3/1 in the Smelter area, immediately north of the volcano, to variable values of 4 to 40/1 in the western Marcapunta enargite and digenite-chalcocite mantos.
Examinatorium Sozialrecht
Authors: Hebeler Timo , Buhr Laura
Published: February 2020

This „Examinatorium Sozialrecht“ gives an intense review of typical issues in social (security) law and makes effective exam preparation possible. The book contains advice on oral and written exams, as well as seminar papers. It contains numerous questions, cases and remedies and covers issues found in social (security) law exams. Furthermore, it gives ten examples of typical problems in seminar papers in this area of law and advice on how to handle them.
CORRELATION ANALYSIS OF OLYMPIC-STYLE WEIGHTLIFTING EXERCISES AND VERTICAL JUMPS
Authors: Králová Tereza , Gasior Jiří , Vanderka Marián , Cacek Jan , Vencúrik Tomáš , Bokůvka Dominik , Hammerová Tereza
Published: February 2020

ABSTRACTPURPOSE Many types of vertical jumps (VJ) are commonly used to assess the development of the level of explosive strength of lower limbs achieved after a training period. This study is focused on comparing various parameters of different types of VJ with 1 RM in Olympic-style weightlifting, squat and deadlift with an Olympic bar.METHODS Twelve elite weightlifters (men=8; women=4; age 26±4 years, height = 173±8 cm; weight 93±23 kg; weight category from 64 kg to +109 kg) were tested for 1 RM in the following exercises: snatch, clean and jerk, deadlift, squat and variations of VJ on dynamometric plates (Kistler Force Plate). The variations of VJ were: squat jump with the arm swing (SJA) and non-arm swing (SJ), countermovement jump with the arm swing (CMJA) and non-arm swing (CMJ). The parameters compared for each type of VJ were: jump height (m), relative force (% of body weight), relative power (W/kg of body weight) and average power (W). For statistical analysis, the parametric Pearsons correlation coefficient with α=0.05 was used. RESULTS The results show a significant correlation between 1 RM in exercises with an Olympic bar (snatch, clean and jerk, back squat and deadlift) and the CMJ, CMJA, SJ and SJA only in the average power output (W) parameter (p<0.05). The significant correlation coefficients in the average power output (W) were for the CMJA and the snatch r=0.96 r2= 0.92, clean and jerk r=0.96 r2= 0.92, back squat r=0.97 r2= 0.94 and deadlift r=0.93 r2= 0.86; CMJ with hands on the hips and the snatch r=0.93 r2= 0.86, clean and jerk r= 0.93 r2= 0.86, back squat r= 0.95 r2= 0.90 and deadlift r= 0.94 r2= 0.88; for the SJA and the snatch r=0.8 r2= 0.64, clean and jerk r=0.81 r2= 0.65, back squat r=0.82 r2= 0.67 and deadlift r=0.78 r2= 0.60; for the SJ with hands on the hips and the snatch r= 0.76 r2= 0.57, clean and jerk r= 0.75 r2= 0.56, back squat r= 0.77 r2= 0.59 and deadlift r= 0.71 r2= 0.50. Significant correlation coefficients were not found for 1 RM in the snatch, clean and jerk, back squat and deadlift and the CMJ or SJ with and without arm swing in any of the following parameters: jump height (m), relative force (% of body weight), relative power output (W/kg of body weight).CONCLUSION The main finding is that the jump height (m) of the CMJ or SJ with or without arm swing did not correlate significantly with 1 RM in the snatch, clean and jerk, back squat and deadlift. Therefore, jump height measurement can be used as a motivation tool but not to predict maximum strength in Olympic bar exercises, or vice versa. We recommend using the average power output (W) parameter in the CMJ with using arms as a predictor of current performance level in exercises with an Olympic bar for men and women.Key words: snatch, clean and jerk, squat, deadlift, countermovement jump, squat jump
Trends in Body Mass Index among Children with Mild and Moderate Intellectual Disabilities
Authors: Králíková Jitka , Válková Hana
Published: February 2020

In recent years, worldwide obesity has increased both in the adult as well as childhood populations. Research shows that obesity nowadays is associated with still younger age. What is currently becoming the focal point of attention is the prevalence of obesity in people with intellectual disabilities whose physical and mental limitations affect, to a certain degree, their daily lives. Nevertheless, there is a lack of data for the childhood population with intellectual disabilities.This research seeks to compare trends in BMI indicators and eating habits among children with mild and moderate intellectual disabilities who live with their families as opposed to those who are provided for at Children’s home in region Zlín in the Czech Republic. The research method used was quantitative and comparative research approached deductively. BMI indicators were determined by means of InBody analyser. Eating habits data were collected through a questionnaire of our own design which is standardly used in the Special Olympics Healthy Athlete Project. The BMI trends were observed in twelve children from two primary schools.  We have concluded that children with mild ID who are provided for at the children’s home do not tend to be obesity, rather they have a proclivity to overweight or normal BMI and children with moderate ID have a proclivity to normal BMI or underweight. As emerged from case histories, only children with moderate ID living with their own families tend to have obesity or normal BMI but children with mild ID living with their own families tend to have overweight or normal BMI. Obesity and overweight are connected only with boys.Children’s weight remained the same within the existing BMI ranges. Summer holidays in children with mild ID and moderate ID living in children’s home had no verifiable effect on the BMI indicators. Children living in their own families had a subsequent weight rise before summer holiday (June 2017, June 2018) and a weight loss after holiday (September 2017, September 2018). Summer holiday influences the BMI indicators in children with mild ID and moderate ID living in their families. The research further shows that children with mild ID and moderate ID being cared for in the institutional environment have a healthier diet than children with mild ID and moderate ID living with their families.The conclusions of the research may serve as a recommendation for parents to pay more attention to their children’s diet as well as their physical activity.
Cancer-Related Stroke: An Emerging Subtype of Ischemic Stroke with Unique Pathomechanisms
Authors: Bang Oh Young , Chung Jong-Won , Lee Mi Ji , Seo Woo-Keun , Kim Gyeong-Moon , Ahn Myung-Ju ,   OASIS-Cancer Study Investigators
Published: February 2020

Systemic cancer and ischemic stroke are common conditions and two of the most frequent causes of death among the elderly. The association between cancer and stroke has been reported worldwide. Stroke causes severe disability for cancer patients, while cancer increases the risk of stroke. Moreover, cancer-related stroke is expected to increase due to advances in cancer treatment and an aging population worldwide. Because cancer and stroke share risk factors (such as smoking and obesity) and treatment of cancer can increase the risk of stroke (e.g., accelerated atherosclerosis after radiation therapy), cancer may accelerate conventional stroke mechanisms (i.e., atherosclerosis, small vessel disease, and cardiac thrombus). In addition, active cancer and chemotherapy may enhance thrombin generation causing stroke related to coagulopathy. Patients with stroke due to cancer-related coagulopathy showed the characteristics findings of etiologic work ups, D-dimer levels, and infarct patterns. In this review, we summarized the frequency of cancer-related stroke among patients with ischemic stroke, mechanisms of stroke with in cancer patients, and evaluation and treatment of cancer-related stroke. We discussed the possibility of cancer-related stroke as a stroke subtype, and presented the most recent discoveries in the pathomechanisms and treatment of stroke due to cancer-related coagulopathy.
Maximum Likelihood and Bayesian Estimation of Repeatability Index: Application of Estimating Ratio of Variance Components
Authors: Al-Eid Maha , Shoukri Mohamed M.
Published: February 2020

An index of repeatability is constructed to evaluate the relative magnitude of measurement error. This index is constructed as a ratio of two variance components. Estimation of the index is derived under the one-way random effects model. We compare the well-known maximum likelihood estimator to the Bayesian estimation procedure using non-informative prior. Large sample variance of the of the maximum likelihood estimator are obtained using the inverse of Fisher’s information matrix and the delta method. Inference procedure using the. We also construct a test statistic on the equality of two repeatability indices using the Monte Carlo integration and sampling Importance re-sampling method. We illustrate the methodologies on the estimation of the index of repeatability of Gamma-glutamyl-transferase, an enzyme found in many organs all over the human body, with the highest concentrations found in the liver. This enzyme’s level is raised in the blood in most diseases that cause damage to the liver or bile ducts and is considered an essential serum marker for alcohol-related liver disease.
The Risk of Nanotechnology: A Challenge to the Insurance Industry
Authors: Sliwinski Adam , Lomott Marietta Janowicz-
Published: February 2020

Nanotechnology poses a challenge for the modern man. Aside from the many benefits that nanotechnological growth may bring, it exposes our civilization to an increasing number of new risks, creating hazards that are currently difficult to foresee. Nanotechnological developments may have a negative impact on the natural environment; some researchers claim that they may even jeopardize the very existence of humankind. Existence of defined threats opens up space for the functioning of insurance. Answering the need for nanotechnological risk management, the insurance sector should develop a strategy that would offer a reduction of risk aversion (especially among producers) and augment further development of nanotechnology-based production methods. However, this leads to questions whether nanotechnology-related risk is an insurable risk and whether it is technically feasible at this time to draft such an insurance offer. The present publication attempts to answer these questions.
Review of the Causes of 1907 Panic and Aftermath
Authors: Ramjerdi Maria Hamideh
Published: February 2020

The Panic of 1907 is often known as the Panic that initiated the development of the Federal Reserve System (Bordo, 1985). The Panic of 1907 was â€œThe beginning of the end of unregulated capital markets and banking system without the lender of the last resort in the United States.â€ (Fohlin, Gehrig and Haas, 2015, page 2). Numerous causes lead to the Panic of 1907 including: shadow banking, the San Francisco earthquake and fire, stock price manipulation, seasonal agriculture fluctuations, an outflow of gold, and higher interest rates. This paper reviews the primary literature on these causes, and how they led to the Panic of 1907 and the subsequent regulations culminating in the Federal Reserve Bank.
Josep M. Castellet, Josep Ferrater Mora, Joan Fuster, Joaquim Molas i Baltasar Porcel. Debat sobre [la] cultura catalana. Vallvidrera, estiu 1967
Authors: Amat Fust´ Jordi
Published: February 2020

Ressenya: Josep M. Castellet, Josep Ferrater Mora, Joan Fuster, Joaquim Molas i Baltasar Porcel. Debat sobre [la] cultura catalana. Vallvidrera, estiu 1967. Edició i pròleg de Jordi Cerdà Subirachs. Barcelona: L’Avenç, 168 p.
Soviet Foreign Policy from the Spanish Civil War to the Molotov-Ribbentrop Pact, 1936–1939
Authors: Kowalsky Daniel
Published: February 2020

Having consolidated his power in the late 1920s, Joseph Stalin long focused on internal affairs: the Five Year Plans, collectivization of agriculture, rapid industrialization, and modernization of the Red Army. Despite his penchant for domestic policy, from the summer of 1936 Stalin’s Soviet Union was increasingly drawn into foreign affairs. This article explores Stalin’s foreign policy on the eve of the Second World War. The Soviet Union’s multiple failures in forging an anti-Fascist alliance with Britain and France, most notably in the Spanish Civil War, will be explored as the prelude to Stalin’s eventual decision, in August 1939, to authorize the Molotov-Ribbentrop Pact.
The Local Festival of Kampos: A Fictional Narrative of Place, Space and Interiority
Authors: Vidali Maria
Published: February 2020

This article is created out of the architectural space and narratives of village life. The narratives concern the interiority of life in Kampos, a farming village on the Greek Cycladic island of Tinos, on the day when the village celebrates the Holy Trinity, its patron saint. The village area on this festive day is depicted in the movement of the families from their houses to the church, the procession from the patron saint’s church to a smaller church through the main village street, and, finally, in the movement of the villagers back to speci!c houses. Through a series of spatial and social layers, the meaning of the communal table on the day of the festival, where food is shared, is reached. A series of negotiations create a different space, where the public, private and communal blend and reveal different layers of “interiority” through which this community is bounded and connected. In this article, I follow the revelation and discovery of truth through fiction, story or myth, as argued by the French philosopher Paul Ricoeur.
Reading Between the Lines: Revealing Interiority
Authors: Atmodiwirjo Paramita , Yatmo Yandi Andri
Published: February 2020

Words, texts and narratives have the potential to reveal the complexity of interiority; they can tell stories beyond the physical materiality of space to reveal spatial occupation, address social and cultural issues embedded in space and capture the trajectories of inhabitation over time. This issue of Interiority addresses writing and reading as a form of inquiry towards the idea of interiority being embedded within the represented forms of architecture and interior. The articles in this issue demonstrate various forms of inquiry concerning the idea of interiority through various media of ‘writing,’ then explore how their reading becomes a way of revealing interiority.
Reticulon proteins modulate autophagy of the endoplasmic reticulum in maize endosperm
Authors: Zhang Xiaoguo , Ding Xinxin , Marshall Richard Scott , Paez-Valencia Julio , Lacey Patrick , Vierstra Richard David , Otegui Marisa S
Published: February 2020

Reticulon (Rtn) proteins shape tubular domains of the endoplasmic reticulum (ER), and in some cases are autophagy receptors for selective ER turnover. We have found that maize Rtn1 and Rtn2 control ER homeostasis and autophagic flux in endosperm aleurone cells, where the ER accumulates lipid droplets and synthesizes storage protein accretions metabolized during germination. Maize Rtn1 and Rtn2 are expressed in the endosperm, localize to the ER, and re-model ER architecture in a dose-dependent manner. Rtn1 and Rtn2 interact with Atg8a using four Atg8-interacting motifs (AIMs) located at the C-terminus, cytoplasmic loop, and within the transmembrane segments. Binding between Rtn2 and Atg8 is elevated upon ER stress. Maize rtn2 mutants display increased autophagy and up-regulation of an ER stress-responsive chaperone. We propose that maize Rtn1 and Rtn2 act as receptors for autophagy-mediated ER turnover, and thus are critical for ER homeostasis and suppression of ER stress.
Epidemiological scenario of dengue in the state of Manipur during the last 3 years
Authors: Singh Leimapokpam Shivadutta , Singh Rajkumar Manojkumar , Singh Huidrom Lokhendro
Published: February 2020

Background

The study of disease transmission of dengue fever (DF) is perplexing in the Indian subcontinent as all the four serotypes are circling. Also, there is no efficient epidemiological examination done on dengue cases in Manipur, a north-eastern territory of India.

Method

We utilized the dengue information extricated from the lab register of Viral Research and Diagnostic Laboratory (VRDL) from 2016 to 2018. All presumed outpatient and inpatients dengue cases from open and private health-care facilities are incorporated into the VRDL database whose informed consent were gotten.

Results

A sum of 1689 instances of associated patients with dengue infection was tried for dengue ELISA test and 272 (16.10%) samples were seen as seropositive. The month-wise conveyance of dengue cases is very intriguing as the three years of study demonstrates a variation design in perception. In all the three years dengue seropositive cases were seen higher in the male populace. Be that as it may, there is no noteworthy incentive to the inspiration of dengue seropositive towards male than female.

Conclusion

Our examination exhibits a comparative epidemiological investigation on seroprevelance of dengue in the province of Manipur for three years. This is an endeavour to show epidemiological dengue seroprevelance in the territory of Manipur which in future would be a reference from general wellbeing worries for making up essential move intend to shorten the spread of dengue.
Reservoir Flow Unit Analysis of Akos Field in Niger Delta
Authors: Emujakporue G. O. , Enyenihi E. E.
Published: February 2020

In this study, the flow units of reservoirs of Akos field have been computed with the Stratigraphic Modified Lorenz plot. Cumulative flow capacity and cumulative storage capacity were used for constructing the Stratigraphic Modified Lorenz Plot (SMLP). The flow capacity and storage capacity are functions of calculated permeability and porosity values considering their sampling depth. The porosity and permeability were obtained from composite well logs of eight oil wells in the study area. Two reservoirs A and B were delineated from the well logs. The stratigraphic Modified Lorenz Plots (SMLP) revealed a total of one hundred and twelve (112) Flow units (FU) in the two observed reservoirs A and B. Reservoir A has a total of 53 FU (25 speed zones, 18 baffle zones and 10 barrier zones) and reservoir B has a total of 59 FU (29 speed zones, 16 baffle zones and 14 barrier zones) which cut across all the wells. The flow units in both reservoirs fall within the speed zones, baffles and barrier unit categories. The speed zone units with equal flow and storage capacities are the dominant flow units in both reservoirs. This is an indication that the sediments have good reservoir qualities. The baffle zones have more storage capacity than the speed zones. The barrier zones within the reservoirs are acting as a seal to the flow of fluid.
Comparative and evolutionary analyses of the divergence of plant oligosaccharyltransferase STT3 isoforms
Authors: Niu Guanting , Shao Zhuqing , Liu Chuanfa , Chen Tianshu , Jiao Qingsong , Hong Zhi
Published: February 2020

STT3 is a catalytic subunit of hetero‐oligomeric oligosaccharyltransferase (OST), which is important for asparagine‐linked glycosylation. In mammals and plants, OSTs with different STT3 isoforms exhibit distinct levels of enzymatic efficiency or different responses to stressors. Although two different STT3 isoforms have been identified in both plants and animals, it remains unclear whether these isoforms result from gene duplication in an ancestral eukaryote. Furthermore, the molecular mechanisms underlying the functional divergences between the two STT3 isoforms in plant have not been well elucidated. Here, we conducted phylogenetic analysis of the major evolutionary node species and suggested that gene duplications of STT3 may have occurred independently in animals and plants. Across land plants, the exon–intron structure differed between the two STT3 isoforms, but was highly conserved for each isoform. Most angiosperm STT3a genes had 23 exons with intron phase 0, while STT3b genes had 6 exons with intron phase 2. Characteristic motifs (motif 18 and 19) of STT3s were mapped to different structure domains in the plant STT3 proteins. These two motifs overlap with regions of high nonsynonymous‐to‐synonymous substitution rates, suggesting the regions may be related to functional difference between STT3a and STT3b. In addition, promoter elements and gene expression profiles were different between the two isoforms, indicating expression pattern divergence of the two genes. Collectively, the identified differences may result in the functional divergence of plant STT3s.
Serum Protein Analysis of Nurse Sharks
Authors: AtallahBenson Leila , Merly Liza , Cray Carolyn , Hammerschlag Neil
Published: February 2020

Serum protein electrophoresis (EPH) is used to assess relative concentrations of blood proteins in clinical and biological studies. Serum EPH fractions have been determined for elasmobranchs using mammalian albumin, alpha 1-, alpha 2-, beta-, and gamma-globulin fractions, and have been deemed fractions 1 through 5, respectively. However, serum EPH fraction concentration reference intervals (RIs) have not been widely established for different elasmobranch species. In this study, RIs for fractions 1 through 5 were determined from 45 wild-caught Nurse Sharks Ginglymostoma cirratum (27 females and 23 males) in South Florida. Serum samples were isolated from whole blood following caudal venipuncture. Body condition was also measured in the field to assess the relative health of the individuals sampled. There was no relationship between body condition and serum EPH fraction concentrations. In addition, there was no difference in body condition or serum EPH fraction concentrations between females and males. Total solids and total protein values were significantly different (P <0.001). Nurse Shark serum EPH fraction 1 was found within the mammalian albumin migrating band distance and was negligible. Fraction 2 showed no peak in the mammalian alpha 1-globulin range. A thin, medium peak in the mammalian alpha 2-globulin range represented fraction 3. In the mammalian beta-globulin range, fraction 4 consisted of the majority of protein observed. It was represented by a smooth, broad peak. A short, medium broad peak in the mammalian gamma-globulin range represented fraction 5. The Nurse Shark serum EPH fraction RIs provided in this study may be utilized to clinically evaluate the health of Nurse Sharks in captivity and in the wild, and to compare the health of their populations around the world experiencing various anthropogenic stressors and other environmental impacts.
Zeolitic Imidazole Framework: Metal–Organic Framework Subfamily Members for Triboelectric Nanogenerators
Authors: Khandelwal Gaurav , Maria Joseph Raj Nirmal Prashanth , Kim Sang‐Jae
Published: February 2020

Zeolitic imidazole framework (ZIF), a subfamily of metal–organic framework (MOF), offers excellent chemical and thermal stability in addition to other MOF advantages. The triboelectric series predominantly consist of few metals and mainly polymers that are not suitable for the development of sensors with high selectivity and specificity. The development of multifunctional, tunable materials is of utmost importance for extending the applications of a triboelectric nanogenerator (TENG). The TENG based on the ZIF subfamily materials (ZIF‐7, ZIF‐9, ZIF‐11, and ZIF‐12) is reported here. The surface roughness, structural, morphological, and surface potential analysis reveals the detailed characteristics of the ZIF family members. The ZIFs and Kapton are used as triboelectric layers for the ZIF‐TENG fabrication. The device is analyzed in detail for its electrical performance (voltage, current, charge, stability, load matching analysis, and capacitor charging). The ZIF‐7 TENG generates the highest output of 60 V and 1.1 µA in vertical contact‐separation mode. Finally, various low‐power electronics are successfully driven with the capacitor charged by the output of the ZIF‐7 TENG.
Alternating Current Photovoltaic Effect
Authors: Zou Haiyang , Dai Guozhang , Wang Aurelia Chi , Li Xiaogan , Zhang Steven L. , Ding Wenbo , Zhang Lei , Zhang Ying , Wang Zhong Lin
Published: February 2020

It is well known that the photovoltaic effect produces a direct current (DC) under solar illumination owing to the directional separation of light‐excited charge carriers at the p–n junction, with holes flowing to the p‐side and electrons flowing to the n‐side. Here, it is found that apart from the DC generated by the conventional p–n photovoltaic effect, there is another new type of photovoltaic effect that generates alternating current (AC) in the nonequilibrium states when the illumination light periodically shines at the junction/interface of materials. The peak current of AC at high switching frequency can be much higher than that from DC. The AC cannot be explained by the established mechanisms for conventional photovoltaics; instead, it is suggested to be a result of the relative shift and realignment between the quasi‐Fermi levels of the semiconductors adjacent to the junction/interface under the nonequilibrium conditions, which results in electron flow in the external circuit back and forth to balance the potential difference between two electrodes. By virtue of this effect, the device can work as a high‐performance broadband photodetector with extremely high sensitivity under zero bias; it can also work as a remote power source providing extra power output in addition to the conventional photovoltaic effect.
Engineering the Architecture of Elastin‐Like Polypeptides: From Unimers to Hierarchical Self‐Assembly
Authors: Saha Soumen , Banskota Samagya , Roberts Stefan , Kirmani Nadia , Chilkoti Ashutosh
Published: February 2020

Well‐defined tunable nanostructures formed through the hierarchical self‐assembly of peptide building blocks have drawn significant attention due to their potential applications in biomedical science. Artificial protein polymers derived from elastin‐like polypeptides (ELPs), which are based on the repeating sequence of tropoelastin (the water‐soluble precursor to elastin), provide a promising platform for creating nanostructures due to their biocompatibility, ease of synthesis, and customizable architecture. By designing the sequence and composition of ELPs at the gene level, their physicochemical properties can be controlled to a degree that is unmatched by synthetic polymers. A variety of ELP‐based nanostructures are designed, inspired by the self‐assembly of elastin and other proteins in biological systems. The choice of building blocks determines not only the physical properties of the nanostructures, but also their self‐assembly into architectures ranging from spherical micelles to elongated nanofibers. This review focuses on the molecular determinants of ELP and ELP‐hybrid self‐assembly and formation of spherical, rod‐like, worm‐like, fibrillar, and vesicle architectures. A brief discussion of the potential biomedical applications of these supramolecular assemblies is also included.
Tunable Electronic Properties and Potential Applications of 2D GeP/Graphene van der Waals Heterostructure
Authors: Zeng Hui , Chen Ru‐Shan , Yao Ge
Published: February 2020

Heterostructure of various 2D semiconductors have attracted extensive attention due to their tunable electronic properties and tremendous application potential. Using first‐principles calculations, the electronic properties of a GeP/graphene van der Waals heterostructure are studied and the physical mechanism of its properties modulated by strain and electric field are examined. The calculations reveal that not only the electronic properties of the GeP/Graphene heterostructure, but also the position of the graphene's Dirac cone, can be modulated by uniaxial strain. Interestingly, uniaxial strain can induce p‐type to n‐type Schottky contact transition and its band alignment allows photocatalytic water splitting. The band edges of the GeP relative to that of graphene are effectively modulated by transverse electric field. These findings provide comprehensive understanding of fundamental properties of the GeP/graphene heterostructure and its tunable electronic properties through strain engineering and electric fields, which will be helpful to the application of 2D GeP‐based nanodevices.
Thermoelectric Characterization Platform for Electrochemically Deposited Materials
Authors: Barati Vida , Garcia Fernandez Javier , Geishendorf Kevin , Schnatmann Lauritz Ule , Lammel Michaela , Kunzmann Alexander , Pérez Nicolás , Li Guodong , Schierning Gabi , Nielsch Kornelius , Reith Heiko
Published: February 2020

Successful optimization of the thermoelectric (TE) performance of materials, described by the figure of merit zT, is a key enabler for its application in energy harvesting or Peltier cooling devices. While the zT value of bulk materials is accessible by a variety of commercial measurement setups, precise determination of the zT value for thin and thick films remains a great challenge. This is particularly relevant for films synthesized by electrochemical deposition, where the TE material is deposited onto an electrically conductive seed layer causing an in‐plane short circuit. Therefore, a platform for full in‐plane zT characterization of electrochemically deposited TE materials is developed, eliminating the impact of the electrically conducting seed layer. The characterization is done using a suspended TE material within a transport device which was prepared by photolithography in combination with chemical etching steps. An analytical model to determine the thermal conductivity is developed and the results verified using finite element simulations. Taken together, the full in‐plane zT characterization provides an inevitable milestone for material optimization under realistic conditions in TE devices.
Electron‐Beam‐Related Studies of Halide Perovskites: Challenges and Opportunities
Authors: Ran Junhui , Dyck Ondrej , Wang Xiaozheng , Yang Bin , Geohegan David B. , Xiao Kai
Published: February 2020

Electron beam microscopy and related characterization techniques play an important role in revealing the microstructural, morphological, physical, and chemical information of halide perovskites and their impact on associated optoelectronic devices. However, electron beam irradiation usually causes damage to these beam‐sensitive materials, negatively impacting their device performance, and complicating this interpretation. In this article, the electron microscopy and spectroscopy techniques are reviewed that are crucial for the understanding of the crystallization and microstructure of halide perovskites. In addition, special attention is paid to assessing and mitigating the electron beam‐induced damage caused by these techniques. Since the halide perovskites are fragile, a protocol involving delicate control of both electron beam dose and dose rate, coupled with careful data analysis, is key to enable the acquisition of reliable structural and compositional information such as atomic‐resolution images, chemical elemental mapping and electron diffraction patterns. Limiting the electron beam dose is critical parameter enabling the characterization of various halide perovskites. Novel methods to unveil the mechanisms of device operation, including charge carrier generation, diffusion, and extraction are presented in scanning electron microscopy studies combined with electron‐beam‐induced current and cathodoluminescence mapping. Future opportunities for electron‐beam‐related characterizations of halide perovskites are also discussed.
Effect of Fluorination on Lithium Transport and Short‐Range Order in Disordered‐Rocksalt‐Type Lithium‐Ion Battery Cathodes
Authors: Ouyang Bin , Artrith Nongnuch , Lun Zhengyan , Jadidi Zinab , Kitchaev Daniil A. , Ji Huiwen , Urban Alexander , Ceder Gerbrand
Published: February 2020

Fluorine substitution is a critical enabler for improving the cycle life and energy density of disordered rocksalt (DRX) Li‐ion battery cathode materials which offer prospects for high energy density cathodes, without the reliance on limited mineral resources. Due to the strong Li–F interaction, fluorine also is expected to modify the short‐range cation order in these materials which is critical for Li‐ion transport. In this work, density functional theory and Monte Carlo simulations are combined to investigate the impact of Li–F short‐range ordering on the formation of Li percolation and diffusion in DRX materials. The modeling reveals that F substitution is always beneficial at sufficiently high concentrations and can, surprisingly, even facilitate percolation in compounds without Li excess, giving them the ability to incorporate more transition metal redox capacity and thereby higher energy density. It is found that for F levels below 15%, its effect can be beneficial or disadvantageous depending on the intrinsic short‐range order in the unfluorinated oxide, while for high fluorination levels the effects are always beneficial. Using extensive simulations, a map is also presented showing the trade‐off between transition‐metal capacity, Li‐transport, and synthetic accessibility, and two of the more extreme predictions are experimentally confirmed.
Hydrodynamic analysis of an axial impeller in a non‐Newtonian fluid through particle image velocimetry
Authors: Fernandes del Pozo David , Liné Alain , Van Geem Kevin M. , Le Men Claude , Nopens Ingmar
Published: February 2020

The rheology of non‐Newtonian fluids in agitated vessels is complex making equipment sizing more an art than a science. To increase our understanding and to resolve the data gap for computational fluid dynamics validation, we present a detailed particle image velocimetry study of the hydrodynamics of Carbopol encountered in a 70 L mechanically mixed (A310) tank at three different rotational speeds (100, 250, 500 rpm). Bulk flow visualizations show that the flow field below the impeller is highly influenced by the rheological behavior of the fluid. Moreover, an analysis of the shear rate and viscosity revealed important spatial heterogeneities. An estimation of the Reynolds number classified the rotational speeds as the onset of the transitional regime (100), in the transitional regime (250) and turbulent conditions (500 rpm). This data set consists of local mean and fluctuating velocities at different locations below the impeller, which are available for validation and further study.
Does relative deprivation induce migration? Evidence from Sub‐Saharan Africa
Authors: Kafle Kashi , Benfica Rui , Winters Paul
Published: February 2020

This analysis revisits the decades‐old relative deprivation theory of migration. In contrast to the traditional view that migration is driven by absolute income maximization, we test whether relative deprivation induces migration in the context of sub‐Saharan Africa. Taking advantage of the internationally comparable longitudinal data from integrated household and agriculture surveys from Tanzania, Ethiopia, Malawi, Nigeria, and Uganda, we use panel fixed effects to estimate the effects of relative deprivation on migration decisions. Using per capita consumption expenditure and multidimensional wealth index as well‐being measures, we find that a household's migration decision is based not only on its absolute well‐being level but also on the relative position of the household in the well‐being distribution of the community in which it resides. We also discover that the effect of relative deprivation on migration is amplified in rural, agricultural, and male‐headed households. Results are robust to alternative specifications including the use of Hausman Taylor Instrumental Variable (HTIV) estimator and pooled data across the five countries. Results confirm that the “migration‐relative deprivation” relationship also holds in the context of sub‐Saharan Africa. We argue that policies designed to check rural–urban migration through rural transformation and poverty reduction programs should use caution because such programs can increase economic inequality, which further increases migration flow.
The Price of Biodiesel RINs and Economic Fundamentals
Authors: Irwin Scott H. , McCormack Kristen , Stock James H.
Published: February 2020

The D4 RIN is the tradable compliance certificate for the biomass‐based diesel (BBD) mandate in the renewable fuel standard (RFS). Understanding the price dynamics of the D4 RIN is important for understanding the RFS because its price sets a ceiling on the ethanol RIN (D6) and because some observers have suggested that RIN price fluctuations are too large to be explained by economic theory. We use option pricing theory to develop a model of the D4 RIN in terms of its economic fundamentals: the spread between the price of biodiesel and petroleum diesel and the status of the biodiesel blenders’ tax credit. The resulting D4 fundamental price closely tracks actual D4 prices. We conclude that RIN price volatility arises because of the design of the RFS and intrinsic features of the U.S. fuel supply system.
Catalytic and antibacterial properties of 3‐dentate carboxamide Pd/Pt complexes obtained via a benign route
Authors: Kiani Mahsa , Bagherzadeh Mojtaba , Meghdadi Soraya , Fadaei‐Tirani Farzaneh , Schenk‐Joß Kurt , Rabiee Navid
Published: February 2020

The complexes PdII(qcq)(OAc) and PtII(qcq)Cl have been synthesized using environmentally benign synthesized ligands and characterized by elemental analyses: Fourier transform infrared spectroscopy, UV–visible spectroscopy, 1H NMR spectroscopy, and X‐ray diffraction. The catalytic activity of the complex was assessed, in different media, for the Mizoroki–Heck coupling reaction for typical aryl halides and terminal olefins under aerobic conditions. Since the base and the solvent were found to influence the efficiency of the reaction, reaction conditions, temperature, time, and the amount of K3PO4 and a mixture of H2O/PEG, were optimized. We found, for the Mizoroki–Heck reaction coupling less reactive aryl chloride derivatives with olefins, promising activity for palladium catalysts. The electrochemical behavior of Hqcq and the Pd(II) complex was investigated by cyclic voltammetry and irreversible PdII/I reductions were observed. Hqcq and the Pd(II) and Pt(II) complexes were also screened for their in vitro antibacterial activity. They showed promising antibacterial activity comparable to that of the antibiotic penicillin.
CuI‐catalyzed tandem synthesis of thioethers using aryl halides, electron‐deficient alkenes, and sodium iso‐propyl xanthogenate
Authors: Abbasi Mohammad , Nowrouzi Najmeh , Khezri Rahimeh
Published: February 2020

A ligand‐free, CuI‐catalyzed protocol was developed for the one‐step preparation of Michael adducts of aromatic thiols in high yields by reacting a mixture of an aryl halide and an electron‐deficient alkene with sodium iso‐propyl xanthogenate.
Immobilization of a Pd(II) complex on hydrophilic graphite oxide and its catalytic investigation in the Heck coupling reaction
Authors: Mastalir Ágnes , Hancsárik Martin , Szabó Tamás
Published: February 2020

Tetraamminepalladium(II) chloride monohydrate was heterogenized on hydrophilic graphite oxide (GO), synthesized by Brodie's method. Two samples, with Pd contents of 2% and 5%, referred to as Pd2 and Pd5, respectively, were prepared by a simple and scalable impregnation method and tested as catalysts in the Heck coupling reaction of styrene and bromobenzene. The reactions were carried out at 423 K for 3 hr by applying Na2CO3 as a base and N‐methylpirrolidone or dimethylformamide (DMF) as a solvent. The Pd complexes heterogenized on graphene oxide platelets proved to be highly active and selective catalysts, and Pd2 was more efficient than Pd5. The effect of quaternary ammonium salts (tetrabutylammonium bromide and tetrabutylammonium chloride, TBAC) as modifiers and that of an ionic liquid (1‐butyl‐3‐methylimidazolium bromide, bmim) was studied and the highest conversions were obtained when TBAC was employed. The selectivity for the formation of the main product, E‐stilbene, was in the range 91–96%. Catalyst recycling was investigated and the extent of leaching was found to depend on the solvent. DMF proved to be a highly feasible reaction medium because both catalysts could be recycled five times in this solvent without any significant loss of activity. A hot filtration test was performed and gave evidence that leaching of the active Pd species did not take place under the above reaction conditions. These results substantiate the fact that simple cationic Pd species can be efficiently immobilized on pristine GO surfaces without the requirement of the functionalization of GO with nitrogen‐containing mono or multidentate ligands as binding sites.
Effect of filler functional groups on the mechanical properties and relevant mechanisms of polydicyclopentadiene nanocomposites
Authors: He Zhi‐Long , Chen Li‐Na , Zhang Li , Ren Hui‐Yan , Xu Meng‐Di , Lou Ye‐Wei
Published: February 2020

Filler functionlizetion is an important strategy to enhance the mechanical properties of polymer composites via the realization of polymer/filler coexists compatibly, interfacial bonding and efficacious load transfer between matrix and filler. In this study, to realize the tailored mechanical properties of polydicyclopentadiene (PDCPD) and to gain insight into the effect of functional groups on their properties, functionalized silica (f‐SiO2) with different functional groups is prepared and combined with PDCPD to produce composites. Compared with neat PDCPD, the yield strength of the composite with 0.20 wt% vinyl‐SiO2 decreases and the impact toughness enhances limitedly, whereas the tensile ductility improves by 16 times. For the case with 0.20 wt% phenyl‐SiO2, it is interestingly observed that the yield strength reinforces by 45.3% and the impact toughness increases remarkably by 222.8%. For the case containing 0.20 wt% ethyl‐SiO2, simultaneous promotion in terms of strength and toughness is achieved. More importantly, the reinforcing/toughening and reaction mechanisms of f‐SiO2/PDCPD composites are explored.
Electrocatalysis of N2to NH3by HKUST‐1 with High NH3Yield
Authors: Cao Yueming , Li Peipei , Wu Tengteng , Liu Meiling , Zhang Youyu
Published: February 2020

Electrolytic ammonia synthesis from nitrogen at ambient conditions is appearing as a promising alternative to the Haber‐Bosch process which is consuming high energy and emitting CO2. Here, a typical MOF material, HKUST‐1 (Cu−BTC, BTC=benzene‐1,3,5‐tricarboxylate), was selected as an electrocatalyst for the reaction of converting N2to NH3under ambient conditions. At −0.75 V vs. reversible hydrogen electrode, it achieves excellent catalytic performance in the electrochemical synthesis of ammonia with high NH3yield (46.63 μg h−1 mg−1 cat.or 4.66 μg h−1 cm−2) and good Faraday efficiency (2.45%). It is indicated that the good performance of the HKUST‐1 catalyst may originate from the formation of Cu(I). In addition, the catalyst also has good selectivity for N2to NH3.