bluuebunny/crossref_metadata_2025_split huggingface dataset:
Calculations of Geochemical Baselines of Stream Waters in the Vicinity of Summitville, Colorado, Before Historic Underground Mining and Prior to Recent Open-Pit Mining
Authors: Miller W.R. , McHugh J.B. 
Published: February 2020

Abstract
The Summitville deposit, located in the San Juan Mountains of southwestern Colorado, was discovered in the 1870s and is an example of an acid-sulfate epithermal Au-Ag-Cu system associated with advanced argillic alteration (Gray and Coolbaugh, 1994; Plumlee et al., 1995). After early mining, the Reynolds adit was constructed in 1887 to dewater existing mines. Limited mining occurred between 1950 and 1984. In 1984, Summitville Consolidated Mining Company, Inc., a subsidiary of Galactic Resources, constructed an open pit heap leach operation to extract gold and ceased operations after declaring bankruptcy in late 1992.
Geologic Characteristics and Exploration Significance of Gold-Rich Porphyry Copper Deposits in the El Salvador Region, Northern Chile
Authors: Rivera Sergio L. , Vila Tomás , Osorio Jorge 
Published: February 2020

Abstract
The porphyry copper systems of the El Salvador region, represented mainly by El Salvador, Potrerillos, Exploradora, Sierra Jardín, and Coya, are located in the southern part of the middle Eocene to early Oligocene porphyry copper belt of northern Chile. They have distinctively higher gold grades (between 0.1 and 0.5 g/t) and slightly lower molybdenum grades (&lt;100 ppm) than the systems located in the northern parts of the belt. The El Salvador and Potrerillos deposits each contains resources of &gt;600 million metric tons (Mt) at &gt;0.6 percent Cu and 0.1 to 0.2 g/t Au. The Exploradora porphyry copper-gold prospect contains geologic resources of ~100 Mt at 0.3 percent Cu and 0.2 g/t Au, with an overlying leached capping enriched in gold, averaging ~0.5 g/t. The Sierra Jardín and Coya prospects show the lowest Cu contents (0.1–0.2 %), but the Au tenor is in the 0.1- to 0.5-g/t range.
The deposits are related to discrete magmatic pulses emplaced in different lithotectonic environments, including the borders of Paleocene volcanic structures (El Salvador, Sierra Jardín; 45–40 Ma) and dilational jogs and reverse and transfer faults (Exploradora, Potrerillos, and Coya; 37–31 Ma). Host rocks are mainly volcanic and marine sedimentary rocks of Jurassic to Cretaceous age. The most remarkable feature of the deposits is their relationship to multiphase, syntectonic tonalite to granodiorite intrusions. There is strong superimposition (telescoping) of intrusion and alteration-mineralization phases, including early, magnetite-rich, potassic alteration-mineralization, moderately to weakly developed sericitic alteration, and late-stage overprinted advanced argillic alteration. Postmineral phreatomagmatic activity is characterized by pebble dikes and/or diatreme breccias.
The appreciable number of gold-rich porphyries (as opposed to their gold-poor counterparts) discovered during the past ten years in the Chilean Andes (e.g., La Fortuna, Cerro Casale, Esperanza) implies that geologic conditions that favor their development are more widespread than previously considered. Several key characteristics of gold-rich porphyry copper deposits in the El Salvador region can be used for exploration purposes and open new ground to prospecting.
Hypogene Evolution of the Escondida Porphyry Copper Deposit, Chile
Authors: Padilla-Garza Rubén A. , Titley Spencer R. , Eastoe Christopher J. 
Published: February 2020

Abstract
At Escondida, the propylitic, potassic, and quartz-sericitic hydrothermal mineral assemblages are centered on a 38 Ma granodioritic stock composed of at least four phases. These early intrusive and related hydrothermal events were followed by rhyolitic intrusive and extrusive rocks and sulfide-rich veins of two advanced argillic alteration events at ~ 36 and ~34 Ma. The final hypogene copper grade of the deposit varies between 0.2 and 1.0 percent, reflecting varying degrees of overprinting by the successive copper mineralization stages.
The homogenization temperatures of primary fluid inclusions from quartz-orthoclase- (stage A), quartzsericite- (stage B), and quartz-alunite-bearing veins (stage C) vary between 500° and 560°, 280° and 380°, and 200° and 340°C, respectively, with estimated depths of trapping ranging from 1.5 to 3.0 km.
The δ34S values of sulfide minerals from the potassic assemblage range from −3.2 to −2.0 per mil, whereas values from the quartz-sericite assemblage vary between −1.1 and +0.6 per mil. These values suggest a common source of magmatic sulfur and indicate that sulfide minerals of stage B were not formed by leaching sulfide from stage A. The δ34S values of stage C sulfide minerals range from −2.5 to +2.7 per mil, which suggests that sulfide for the advanced argillic event may have been derived, in part, by leaching sulfide from the two earlier hydrothermal stages. Calculated values of δD and δ18O for water coexisting with igneous and hydrothermal minerals indicate a dominantly magmatic component in stages A and B and a mixture with meteoric water at the lower temperatures of stage B and during the advanced argillic event (stage C). Stage C may have formed by circulatión of surficial meteoric water heated by the 34 to 36 Ma subvolcanic rhyolitic rocks. It is also possible that some 2 m.y. after the emplacement, uplift, and denudatión of the main Escondida porphyry system, a new porphyry copper stock was emplaced in the same structural weakness zone, and that the subvolcanic rhyolite and advanced argillic alteration and associated mineralization represent the upper levels of this younger porphyry system.
A Reconstructed Cretaceous Depositional Setting for Giant Volcanogenic Massive Sulfide Deposits at Tambogrande, Northwestern Peru
Authors: Winter Lawrence S. , Tosdal Richard M. , Franklin James M. , Tegart Peter 
Published: February 2020

Abstract
The Cretaceous Tambogrande volcanogenic massive sulfide (VMS) deposits of northwestern Peru represent some of the largest Cu-Zn-Au-Ag bimodal-mafic VMS deposits in the world. There are currently three known deposits each with approximately 100 million metric tons (Mt) of massive pyrite-rich sulfide. The deposits are intimately associated with dacite lava dome complexes and were deposited within steep-sided basins on the sea floor. Reconstructed sea-floor paleogeomorphic models suggest that sulfide deposition was concentrated in the deepest parts of the basins. Sulfide deposition accompanied synvolcanic faulting and episodic dacitic and basaltic eruptions. A series of time-stratigraphic horizons are defined at the TG1 and TG3 deposits and mark stages in the development of the volcanic complex and massive sulfide bodies. There is only limited evidence for replacement of host rocks during formation of the Tambogrande deposits, in contrast to many other large massive sulfide deposits. The deposits at Tambogrande resulted from focused hydrothermal fluid flow along synvolcanic faults with deposition of sulfide minerals within deep and restricted basins. These depressions, the results of the structural and volcanologic setting, acted as efficient traps for sulfide deposition and were also important for the preservation of the sulfide masses as they acted to shield them from submarine oxidation and weathering. Steep basins and episodic bimodal lava eruptions are key geologic attributes of the depositional setting at Tambogrande and may be necessary for the formation of anomalously large VMS deposits in a volcanic-rock–dominated environment.
Masa hidup imago, progeni, dan kemampuan parasitisasi Anagyrus lopezi (De Santis) (Hymenoptera: Encyrtidae), parasitoid kutu putih singkong
Authors: Maharani Juwita Suri , Rauf Aunu , Maryana Nina 
Published: February 2020

Parasitoid Anagyrus lopezi (De Santis) (Hymenoptera: Encyrtidae) diintroduksikan dari Thailand ke Indonesia pada tahun 2014 untuk mengendalikan hama asing invasif, kutu putih singkong Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae). Penelitian dilakukan di laboratorium dengan tujuan untuk mengetahui potensi reproduksi, pengaruh pemberian larutan madu terhadap masa hidup imago, mempelajari keperidian, progeni, dan respons A. lopezi terhadap peningkatan kerapatan inang. Penelitian dilaksanakan dengan memajankan nimfa instar-3 kutu putih pada parasitoid. Pengaruh perlakuan pakan madu terhadap masa hidup imago parasitoid dilakukan pada kondisi tanpa inang. Keperidian diukur berdasarkan banyaknya mumi yang terbentuk. Hasil penelitian menunjukkan betina hidup selama 3,7 hari dan jantan 3,2 hari bila hanya tersedia air. Masa hidup imago parasitoid berlangsung lebih lama bila tersedia madu. Parasitoid yang diberi larutan madu 50% mampu hidup 6–9 kali lipat lebih lama dibandingkan dengan yang hanya diberi air. Selama hidupnya imago betina A. lopezi memarasit 96–287 kutu putih, dengan rataan 203,7 atau tingkat parasitisasi 34,6%, serta 24,86% mengalami kematian karena kegiatan pengisapan inang. Masa perkembangan pradewasa dari telur hingga imago muncul berlangsung 17,97 dan 17,67 hari, berturut-turut untuk jantan dan betina. Rataan progeni per induk adalah 88,8 individu, dengan 56,9% berjenis kelamin betina. Pada kerapatan inang 2–100 individu, parasitoid A. lopezi memperlihatkan tanggap fungsional tipe III.
Glycyrrhizin suppresses epithelial-mesenchymal transition by inhibiting high-mobility group box1 via the TGF-β1/Smad2/3 pathway in lung epithelial cells
Authors: Gui Yanni , Sun Jian , You Wenjie , Wei Yuanhui , Tian Han , Jiang Shujuan 
Published: February 2020

Background
Epithelial-mesenchymal transition (EMT) plays an important role in fibrosis, chronic inflammation, tumor metastasis, etc. Glycyrrhizin, an active component extracted from licorice plant, has been reported to treat a variety of inflammatory reactions through inhibiting high-mobility group box1 (HMGB1), which has been suggested to be a significant mediator in EMT process. However, whether glycyrrhizin affects the EMT process or not remains unclear.

Methods
Human alveolar epithelial cell line A549 and normal human bronchial epithelial cell line BEAS-2B were treated with extrinsic TGF-β1 to induce EMT. Elisa was used to detect HMGB1 concentrations in cell supernatant. RNA interference and lentivirus infection experiments were performed to investigate the involvement of HMGB1 in EMT process. Cell Counting Kit-8 (CCK-8) was used to detect the viability of A549 and BEAS-2B cells treated with glycyrrhizin. Finally, the effects of glycyrrhizin on EMT changes, as well as the underlying mechanisms, were evaluated via Western blot, immunofluorescence and transwell assays.

Results
Our results showed that HMGB1 expression was increased by TGF-β1, and knockdown of HMGB1 expression reversed TGF-β1-induced EMT in A549 and BEAS-2B cells. Ectopic HMGB1 expression or TGF-β1 treatment caused a significant increase in HMGB1 release. Notably, we found that glycyrrhizin treatment effectively suppressed TGF-β1-induced EMT process by inhibiting HMGB1. Also, glycyrrhizin significantly inhibited the migration of both A549 and BEAS-2B cells promoted by TGF-β1. Mechanistically, HMGB1 overexpression could activate Smad2/3 signaling in A549 and BEAS-2B cells. Glycyrrhizin significantly blocked the phosphorylation of Smad2/3 stimulated either by TGF-β1 or by ectopic HMGB1 in A549 and BEAS-2B cells.

Conclusions
HMGB1 is a vital mediator of EMT changes induced by TGF-β1 in lung epithelial cells. Importantly, glycyrrhizin can effectively block Smad2/3 signaling pathway through inhibiting HMGB1, thereby suppressing the EMT progress.
Effect of Infant and Young Child Feeding Practices on the Nutritional Status of Children 0-24 Months of Age in Port Harcourt, Nigeria
Authors: S. Tobi N. , Alex-Hart B. A. , O. George I. 
Published: February 2020

Background: Childhood under-nutrition is prevalent in many developing countries including Nigeria, and is an underlying cause for more than half of all childhood deaths. Based on the recent Nigeria Demographic and Health Survey (NDHS), the prevalence of under-nutrition between 2008 and 2013 has risen, despite an increase in exclusive breastfeeding (EBF) rate over the same period.
This study was carried out to assess the effect of infant and young child feeding practices on , nutritional status of children 0 – 24 months in Port Harcourt, Nigeria.
Subjects and Methods: Data were collected between November and December 2016 from 307 mother-child (aged 0 – 24 months) pairs attending six health centres in Port Harcourt using a pretested self-administered questionnaire. Data collected included maternal and child socio-demographics, mother’s infant feeding practices, 24-hour dietary recall and anthropometric measurements. Data were analysed using SPSS version 20.0.
Results: The mean age of the children was 5.6±6.1 months, 207 (67.4%) were under 6 months of age and 100 (32.6%) between the ages of 6 to 24 months. Three hundred and three (98.7%) children were breastfed. The rate of exclusive breastfeeding was 51.7% among the children aged 0 – 5.9 months. The mean age at which breastfeeding was stopped was 9.3±5.5 months. The average age at which complementary foods were started was 4.4±1.8 months. All the children on complementary feeding met the minimum feeding frequency, but only 43 (33.6%) met the minimum dietary diversity of 4 or more food groups. Overall, 111 (36.2%) children were fed according to WHO recommendation. 10.1% of the children were overweight/obese, 5.5% were wasted, 6.2% were underweight and 8.8% were stunted. Lack of EBF was positively associated with stunting (p = 0.024).
Conclusion: Infant and Young Child Feeding practices among mothers in Port Harcourt fall short of the WHO recommendations, resulting in various types of malnutrition among the children. Therefore, more emphasis should be laid on growth monitoring and promotion services and age-specific nutritional counseling to parents and care-givers.
Microbiological and Probiotic Assessment of Yeast Isolated from Wholegrain Millet Sourdoughs
Authors: M. Adisa A. , O. T. Ifesan B. , Enujiugha V. N. , B. Adepeju A. 
Published: February 2020

Background: The term probiotics have been described as live microorganisms associated with fermented foods that confer health benefit to the host. For a long time, researches into the world of probiotics have extensively and predominantly centred upon species of lactic acid bacteria and until recently Saccharomyces cerevisiae, as the only well-defined and proven probiotic yeast strain. The purpose of this study was to isolate and characterise the yeast species associated with the fermentation of wholegrain millet sourdoughs and investigate in vitro the possible probiotic potential of the isolates.
Methodology: Wholegrain millet sourdoughs were prepared by spontaneous fermentation of the flours with tap water in the ratio 1:1 (w/v) for 48 h at 28 ± 2ºC through backslopping. A total of twenty five yeasts were identified based on their cultural, morphological and biochemical characteristics. The selected isolates were characterized to species level using API 20 C AUX test identification kit. Probiotic properties examined included bile salt and acid tolerance under conditions simulating the human gastrointestinal tract (GIT) and positive antagonistic activity against selected pathogens following well established procedures.
Results: The selected isolates investigated were characterized to belong to species of Saccharomyces and Kluveromyces. All of the isolates were discovered to exhibit sufficient survival under acidic pH of 2.0 with values ranging from 1.0log cfu ml-1 to 7.8log cfu ml-1 and showed high resistance to bile salt with values ranging from 63-99%. They also exhibited good antimicrobial activity against enteric pathogens of E. coli, Salmonella typhimurium, Staphylococcus aureus, Klebsiella pneumonia, Streptococcus pyogenes, Proteus vulgaris and Pseudomonas sp.
Conclusion: Millet sourdoughs can serve as an affordable nutritionally healthy substrate for delivery of probiotics to the gastro-intestinal tract, thereby proffering basic health functionality. This study allowed to isolate and to identify yeast species present in millet sourdoughs with technological potential for sourdough applications.
Activating Basal Planes of NiPS3 for Hydrogen Evolution by Nonmetal Heteroatom Doping
Authors: Wang Jun , Li Xinzhe , Wei Bin , Sun Rong , Yu Wei , Hoh Hui Ying , Xu Haomin , Li Jing , Ge Xingbo , Chen Zuxin , Su Chenliang , Wang Zhongchang 
Published: February 2020

AbstractNiPS3, one of the most promising catalysts among transition metal trichalcogenidophosphates (MTPs) in hydrogen evolution reaction (HER) electrocatalysis, is still inhibited by its unsatisfactory activity originating from its semiconducting nature and inert basal plane. Here, it is proposed, for the first time, to engineer the basal surface activity of NiPS3 by nonmetal heteroatom doping, and predict that the degree to which the valance band of NiPS3 is filled dominates not only the electrical conductivity of the catalyst, but also the strength of hydrogen adsorption at its surface. Direct experimental evidence is offered that in all the single nonmetal doping samples, C‐doped NiPS3 exhibits the optimum activity owing to its moderate filled state of valance band and that C, N codoping even shows Pt‐like activity with an ultralow overpotential of 53.2 mV to afford 10 mA cm−2 current density and a high exchange current density of 0.7 mA cm−2 in 1 m KOH. The findings that less valance electrons of dopants than substitutional atoms are of pivotal importance for improving HER activity of NiPS3 catalyst pave the way for readily designing novel MTPs of ever high performance to replace the incumbent Pt‐based catalysts.
Local Defects in Colloidal Quantum Dot Thin Films Measured via Spatially Resolved Multi‐Modal Optoelectronic Spectroscopy
Authors: Lin Yida , Gao Tina , Pan Xiaoyun , Kamenetska Maria , Thon Susanna M. 
Published: February 2020

AbstractThe morphology, chemical composition, and electronic uniformity of thin‐film solution‐processed optoelectronics are believed to greatly affect device performance. Although scanning probe microscopies can address variations on the micrometer scale, the field of view is still limited to well under the typical device area, as well as the size of extrinsic defects introduced during fabrication. Herein, a micrometer‐resolution 2D characterization method with millimeter‐scale field of view is demonstrated, which simultaneously collects photoluminescence spectra, photocurrent transients, and photovoltage transients. This high‐resolution morphology mapping is used to quantify the distribution and strength of the local optoelectronic property variations in colloidal quantum dot solar cells due to film defects, physical damage, and contaminants across nearly the entire test device area, and the extent to which these variations account for overall performance losses. It is found that macroscopic defects have effects that are confined to their localized areas, rarely prove fatal for device performance, and are largely not responsible for device shunting. Moreover, quantitative analysis based on statistical partitioning methods of such data is used to show how defect identification can be automated while identifying variations in underlying properties such as mobilities and recombination strengths and the mechanisms by which they govern device behavior.
Bioinspired Fluffy Fabric with In Situ Grown Carbon Nanotubes for Ultrasensitive Wearable Airflow Sensor
Authors: Wang Haomin , Li Shuo , Wang Yiliang , Wang Huimin , Shen Xinyi , Zhang Mingchao , Lu Haojie , He Maoshuai , Zhang Yingying 
Published: February 2020

AbstractRecently, electronic skin and smart textiles have attracted considerable attention. Flexible sensors, as a kind of indispensable components of flexible electronics, have been extensively studied. However, wearable airflow sensors capable of monitoring the environment airflow in real time are rarely reported. Herein, by mimicking the spider's fluff, an ultrasensitive and flexible all‐textile airflow sensor based on fabric with in situ grown carbon nanotubes (CNTs) is developed. The fabric decorated with fluffy‐like CNTs possesses exceptionally large contact area, endowing the airflow sensor with superior properties including ultralow detection limit (≈0.05 m s−1), multiangle airflow differential response (0°–90°), and fast response time (≈1.3 s). Besides, the fluffy fabric airflow sensor can be combined with a pristine fabric airflow sensor to realize highly sensitive detection in a wide airflow range (0.05–7.0 m s−1). Its potential applications including transmitting information according to Morse code by blowing the sensors, monitoring increasing and decreasing airflow velocity, and alerting blind people walking outside about potential hazard induced by nearby fast‐moving objects are demonstrated. Furthermore, the airflow sensor can be directly integrated into clothing as stylish designs without sacrificing comfortness. It is believed that the ultrasensitive all‐textile airflow sensor holds great promise for applications in smart textiles and wearable electronics.
Bicyclo[1.1.1]pentyl Sulfoximines: Synthesis and Functionalizations
Authors: Bär Robin M. , Langer Lukas , Nieger Martin , Bräse Stefan 
Published: February 2020

AbstractHerein we present the first synthesis of bicyclo[1.1.1]pentyl (BCP) sulfoximines from the corresponding sulfides. Both BCPs and sulfoximines are bioisosteres used in medicinal chemistry and therefore desirable motifs. The access to BCP sulfides was enabled by the thiol addition to [1.1.1]propellane as published before. A broad scope with specific limitations was discovered for the sulfoximination. To diversify the sulfoximines, N‐acylations and N‐arylations were performed. As the N‐arylation was low yielding we optimized the copper(I) catalyzed reaction. A wide range of aryl iodides could be deployed and competitive reactions showed that aryl bromides react equally fast. In a scale‐up we prepared a suitable precursor for a BCP drug analogue. In this work several molecular structures could be determined by single‐crystal X‐ray diffraction.magnified image
Copper‐Catalyzed Selective Pyrrole Functionalization by Carbene Transfer Reaction
Authors: Rodríguez Anabel M. , Molina Francisco , Díaz‐Requejo M. Mar , Pérez Pedro J. 
Published: February 2020

Abstract1H‐Pyrroles can be directly functionalized by means of the incorporation of carbene groups from diazo compounds, in a process catalyzed by TpxCu complexes (Tpx=hydrotrispyrazolylborate ligand). The reactions take place with a complete selectivity toward the formal insertion of the carbene into the Cα−H bond, leading to alkylated pyrroles, with no modification of the Cβ−H, N−H or C=C bonds of the pyrrole unit. Alkyl substituents at C‐ring as well as alkyl, aryl, allyl or alkyne substitution at N atom are tolerated, the strategy affording 20 new pyrrole derivatives. The observance of partial deuteration at the methylene group when the reaction is carried out with added D2O serves to discard the direct insertion of the carbene group into the Csp2−H bond, the alternative electrophilic attack to the pyrrole ring being feasible.magnified image
Iodine Mediated Base‐Controlled Regio‐Selective Annulation of 2‐(Pyridin‐2‐yl)acetate Derivatives with Acrylic Esters for the Synthesis of Indolizines
Authors: Fang Youlai , Li Fei , Yang Yuzhu , Liu Xiaolan , Pan Weidong 
Published: February 2020

AbstractAn iodine mediated base‐controlled reaction between 2‐(pyridin‐2‐yl)acetate derivatives and acrylic esters has been developed for the selective synthesis of 1,3‐disubstituted indolizines and 1,2‐disubstituted indolizines. A single‐pot reaction of 2‐(pyridin‐2‐yl)acetate derivatives and acrylic esters in the presence of CsOAc delivers 1,3‐disubstitued indolizines, while KHCO3 promotes the formation of C3‐iodo indolizines, which could be further de‐iodinated in the presence of copper powder, affording 1,2‐disubstituted indolizines via a sequential stepwise fashion. A plausible reaction mechanism involving radical process has been proposed for this reaction. Pd‐catalzyed reaction of C3‐iodo indolizines with aryl boronic acids has been described.magnified image