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Structural geometry of orogenic gold deposits： Implications for exploration of world-class and giant deposits

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Geoscience Frontiers 2018年第4期9卷 1163-1177页

作者： david I.Groves m.Santosh Richard J.Goldfarb Liang Zhang Orebusters Pty Ltd Gwelup 6018 Western Australia Australia State Key Laboratory of Geological Processes and mineral Resources China University of Geosciences Beijing 100083 China Centre for Tectonics Resources and Exploration Dept. of Earth Sciences University of Adelaide SA 5005 Australia Division of Interdisciplinary Science Faculty of Science Kochi University Kochi 780-8520 Japan

With very few exceptions, orogenic gold deposits formed in subduction-related tectonic settings in accretionary to collisional orogenic belts from Archean to Tertiary times. Their genesis, including metal and fluid source, fluid pathways, depositional mechanisms, and timing relative to regional structural and metamorphic events, continues to be controversial. However, there is now general agreement that these deposits formed from metamorphic fluids, either from metamorphism of intra-basinal rock sequences or de-volatilization of a subducted sediment wedge, during a change from a compressional to transpressional, less commonly transtensional, stress regime, prior to orogenic collapse. In the case of Archean and Paleoproterozoic deposits, the formation of orogenic gold deposits was one of the last events prior to cratonization. The late timing of orogenic gold deposits within the structural evolution of the host orogen implies that any earlier structures may be mineralized and that the current structural geometry of the gold deposits is equivalent to that at the time of their formation provided that there has been no significant post-gold orogenic overprint. Within the host volcano-sedimentary sequences at the province scale, world-class orogenic gold deposits are most commonly located in second-order structures adjacent to crustal scale faults and shear zones, representing the first-order ore-forming fluid pathways, and whose deep lithospheric connection is marked by lamprophyre intrusions which, however, have no direct genetic association with gold deposition. more specifically, the gold deposits are located adjacent to ～10°-25° district-scale jogs in these crustal-scale faults. These jogs are commonly the site of arrays of ～70° cross faults that accommodate the bending of the more rigid components, for example volcanic rocks and intrusive sills, of the host belts. Rotation of blocks between these accommodation faults causes failure of more competent units and/or re

关键词： Structural geometry Tectonic history Fluid pathways Orogenic gold deposits Exploration criteria

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Synthetic polymers:A review of applications in drilling fluids

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Petroleum Science 2024年第1期21卷 475-518页

作者： Shadfar Davoodi mohammed Al-Shargabi david A.Wood Valeriy S.Rukavishnikov Konstantin m.minaev School of Earth Sciences&Engineering Tomsk Polytechnic UniversityLenin AvenueTomskRussia DWA Energy Limited LincolnUnited Kingdom

With the growth of deep drilling and the complexity of the well profile,the requirements for a more complete and efficient exploitation of productive formations increase,which increases the risk of various ***,reagents based on modified natural polymers(which are naturally occurring compounds)and synthetic polymers(SPs)which are polymeric compounds created industrially,are widely used to prevent emerging complications in the drilling ***,compared to modified natural polymers,SPs form a family of high-molecular-weight compounds that are fully synthesized by undergoing chemical polymerization *** provide substantial flexibility in their ***,their size and chemical composition can be adjusted to provide properties for nearly all the functional objectives of drilling *** can be classified based on chemical ingredients,type of reaction,and their responses to ***,some of SPs,due to their structural characteristics,have a high cost,a poor temperature and salt resistance in drilling fluids,and degradation begins when the temperature reaches 130℃.These drawbacks prevent SP use in some medium and deep ***,this review addresses the historical development,the characteristics,manufacturing methods,classification,and the applications of SPs in drilling *** contributions of SPs as additives to drilling fluids to enhance rheology,filtrate generation,carrying of cuttings,fluid lubricity,and clay/shale stability are explained in *** mechanisms,impacts,and advances achieved when SPs are added to drilling fluids are also *** typical challenges encountered by SPs when deployed in drilling fluids and their advantages and drawbacks are also *** issues also impact the applications of SPs in drilling ***,the cost of the most relevant SPs,and the monomers used in their synthesis,are *** impacts of SPs when deployed in drilling fluids,and t

关键词： Synthetic versus natural polymers Nanopolymers Drilling fluid additives Lubricity Clay swelling Hole cleaning

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The βC1 Protein of Gem,n,v,rus--Betasatellite Complexes:A Target and Repressor of Host Defenses

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molecular Plant 2018年第12期11卷 1424-1426页

作者： Fangfang Li Xiuling Yang david m.Bisaro Xueping Zhou State Key Laboratory for Biology of Plant Diseases and Insect Pests Institute of Plant ProtectionChinese Academy of Agricultural SciencesBeijing 100193 China Department of molecular Genetics Center for Applied Plant SciencesCenter for RNA Biologyand Infectious Diseases InstituteOhio State University ColumbusOH 43210USA State Key Laboratory of Rice Biology Institute of BiotechnologyZhejiang UniversityHangzhou 310058China

Geminiviruses are a family of plant viruses that cause devastating diseases in many economically important crops worldwide. These pathogens encapsidate circular,single-stranded DNAs (ssDNAs)of 2.5-3.0 kb that replicate through double-stranded DNA (dsDNA)*** of the genus Begomovirus,which comprises by far the largest number of species in the family,are transmitted by whiteflies and have genomes consisting of one or two DNAs.

关键词： βC1 Protein Host Defenses

Role of polyethylene particles in peri-prosthetic osteolysis:A review

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World Journal of Orthopedics 2011年第10期2卷 93-101页

作者： Gerald J Atkins david R Haynes Donald W Howie david m Findlay Discipline of Orthopaedics and Trauma The University of AdelaideSouth Australia 5005Australia Discipline of Pathology The University of AdelaideSouth Australia 5005Australia

There is convincing evidence that particles produced by the wear of joint prostheses are causal in the periprosthetic loss of bone,or osteolysis,which,if it progresses,leads to the phenomenon of aseptic *** is important to fully understand the biology of this bone loss because it threatens prosthesis survival,and loosened implants can result in peri-prosthetic fracture,which is disastrous for the patient and presents a difficult surgical *** focus of this review is the bioactivity of polyethylene(PE)particles,since there is evidence that these are major players in the development and progression of osteolysis around prostheses which use PE as the bearing *** review describes the biological consequences of interaction of PE particles with macrophages,osteoclasts and cells of the osteoblast lineage,including *** explores the possible cellular mechanisms of action of PE and seeks to use the findings to date to propose potential nonsurgical treatments for *** particular,a nonsurgical approach is likely to be applicable to implants containing newer,highly cross-linked PEs(HXLPEs),for which osteolysis seems to occur with much reduced PE wear compared with conventional *** caveat here is that we know little as yet about the bioactivity of HXLPE particles and addressing this constitutes our next challenge.

关键词： Polyethylene Aseptic loosening Osteolysis Wear particle Peri-prosthetic

Vegetation change as related to terrain factors at two glacier forefronts, Glacier National Park, montana, U.S.A.

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Journal of mountain Science 2020年第1期17卷 1-15页

作者： Callie B.LAmBERT Lynn m・RESLER Yang SHAO david R.BUTLER Department of Geography Virginia Tech220 Stanger StreetBlacksburgVA24061USA Texas State University Department of GeographySan MarcosTX 78666USA

Glacier recession is a globally occurring trend. Although a rich body of work has documented glacial response to climate warming, few studies have assessed vegetation cover change in recently deglaciated areas, especially using geospatial technologies. Here, vegetation change at two glacier forefronts in Glacier National Park, montana, *** quantified through remote sensing analysis,fieldwork validation, and statistical ***, we assessed the spatial and temporal patterns of landcover change at the two glacier forefronts in Glacier National Park and determined the role of selected biophysical terrain factors(elevation, slope, aspect, solar radiation, flow accumulation, topographic wetness index, and surficial geology) on vegetation change(from nonvegetated to vegetated cover) at the deglaciated *** imagery of the study locations in 1991, 2003,and 2015 were classified and validated using visual interpretation. model results revealed geographic differences in biophysical correlates of vegetation change between the study areas, suggesting that terrain variation is a key factor affecting spatialtemporal patterns of vegetation change. At Jackson Glacier forefront, increases in vegetation over some portion or all of the study period were negatively associated with elevation, slope angle, and consolidated bedrock. At Grinnell Glacier forefront,increases in vegetation associated negatively with elevation and positively with solar *** geospatial and field approaches to the study of vegetation change in recently deglaciated terrain are recommended to understand and monitor processes and patterns of ongoing habitat change in rapidly changing mountain environments.

关键词： Land cover change Physical geography Glacial forefronts Vegetation change Glacier National Park Terrain factors

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Late Ordovician mass Extinction: Earth, fire and ice

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National Science Review 2024年第1期11卷 51-65页

作者： david A.T.Harper Palaeoecosystems Group Department of Earth SciencesDurham University

The Late Ordovician mass Extinction was the earliest of the ‘big’ five extinction events and the earliest to affect the trajectory of metazoan life. Two phases have been identified near the start of the Hirnantian period and in the middle. It was a massive taxonomic extinction, a weak phylogenetic extinction and a relatively benign ecological extinction. A rapid cooling, triggering a major ice age that reduced the temperature of surface waters, prompted a drop in sea level of some 100 m and introduced toxic bottom waters onto the shelves. These symptoms of more fundamental planetary processes have been associated with a range of factors with an underlying driver identified as volcanicity. Volcanic eruptions, and other products, may have extended back in time to at least the Sandbian and early Katian, suggesting the extinctions were more protracted and influential than hitherto documented.

关键词： Ordovician LOmE paleoecology palaeobiogeography biotas

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World Journal of Orthopedics 2021年第11期12卷 891-898页

作者： mohammad m Alzahrani Saad m Alqahtani david Pichora Ryan Bicknell Department of Orthopaedics Imam Adulrahman Bin Faisal UniversityDammamKSA 34212Saudi Arabia Department of Orthopaedics Queens UniversityKingston K7L 3N6Canada

BACKGROUND Work-related injuries have gained recent attention,especially in the orthopaedic *** upper extremity orthopaedic surgical tasks require repetitive and constant maneuvers,these surgeons can be at increased risk of acquiring workrelated musculoskeletal(mSK)disorders during their years in *** To assess the prevalence,characteristics and impact of mSK disorders among upper extremity orthopaedic *** A modified version of the physical discomfort survey was sent to surgeons who were members of the American Shoulder and Elbow Surgeons and the Canadian shoulder and elbow society via *** collected data were analyzed using descriptive statistics,one-way analysis of variance,and Fisher's exact test.P values ofmales and the majority were younger than 55 years old(65.5%).A work-related mSK injury was reported by 89.4% of respondents,of which the most common diagnoses were low back pain(26.1%)and lateral elbow epicondylitis(18.3%).Among those that reported an injury,82.7%required treatment and 26% required time off work as a direct result of their *** need to undergo treatment due to the injury was associated with increased number of injuries(Pmoreover,surgeons were more likely to require time off work when they had been in practice for>21 years(PmSK injuries,with more than one quarter of surgeons reported requiring time off work due to an mSK *** high incidence of these disorders may place a financial and psychological burden on surgeons and affect their ability to provide patient *** of operative ergonomics,irrespective of surgical specialty may help to decrease or possibly prevent the occurrence of these disorders.

关键词： Upper Extremity Surgeon Prevalence musculoskeletal Disorders

Prevalence and factors of work-related musculoskeletal disorders among hand surgeons

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World Journal of Orthopedics 2022年第5期13卷 465-471页

作者： Saad m Alqahtani mohammad m Alzahrani Ryan Bicknell david Pichora Department of Orthopaedics Imam Abdulrahman Bin Faisal UniversityDammam 34212Saudi Arabia Department of Orthopaedics Queens UniversityKingston K7L 3N6OntarioCanada

BACKGROUND The nature of tasks required by hand surgeons require both forceful and repetitive maneuvers,thus subjecting these surgeons to the risk of musculoskeletal(mSK)injuries during their years in *** To assess the prevalence,characteristics and impact of mSK disorders among hand *** A modified version of the physical discomfort survey was sent to surgeons who were members of the American Society for Surgery of the Hand via *** collected data were analyzed using descriptive statistics,one-way analysis of variance,and Fisher’s exact test.P values ofmSK injury,of which the most common diagnoses were lateral elbow epicondylitis(18.7%),low back pain(17.1%)and carpal tunnel syndrome(15.6%).Among those that reported an injury,73.1%required treatment and 29.2%needed time off work as a direct result of their *** number of work-related injuries incurred by a surgeon increased significantly with increasing age(PmSK injuries sustained by Hand surgeons with a high *** results should increase awareness on this aspect and fuel future studies directed at preventing these types of work-related injuries,thus minimizing the financial and psychological burden on these surgeons and the healthcare system.

关键词： Hand Surgeon Prevalence musculoskeletal disorders Occupational injuries

Stem cell treatment improves post stroke neurological outcomes:a comparative study in male and female rats

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Stroke & Vascular Neurology 2021年第4期6卷 519-527,I0005-I0010页

作者： Koteswara Rao Nalamolu Bharath Chelluboina Casimir A Fornal Siva Reddy Challa david m Pinson david Z Wang Jeffrey D Klopfenstein Krishna Kumar Veeravalli Cancer Biology and Pharmacology College of MedicineUniversity of IllinoisPeoriaIllinoisUSA Pharmaceutical and Biomedical Sciences California Health Sciences UniversityClovisCaliforniaUSA Neurological Surgery University of Wisconsin-MadisonMadisonWisconsinUSA Health Sciences Education College of MedicineUniversity of IllinoisPeoriaIllinoisUSA Neurology College of MedicineUniversity of IllinoisPeoriaIllinoisUSA Neurology Barrow Neurological InstitutePhoenixArizonaUSA Neurosurgery College of MedicineUniversity of IllinoisPeoriaIllinoisUSA OSF HealthCare Illinois Neurological Institute PeoriaIllinoisUSA Pediatrics College of MedicineUniversity of IllinoisPeoriaIllinoisUSA

Background and purpose The therapeutic potential of different stem cells for ischaemic stroke treatment is intriguing and somewhat *** results from our laboratory have demonstrated the potential benefits of human umbilical cord blood-derived mesenchymal stem cells(mSC)in a rodent stroke *** hypothesised that mSC treatment would effectively promote the recovery of sensory and motor function in both males and females,despite any apparent sex differences in post stroke brain *** Transient focal cerebral ischaemia was induced in adult Sprague-Dawley rats by occlusion of the middle cerebral *** the procedure,male and female rats of the untreated group were euthanised 1 day after reperfusion and their brains were used to estimate the resulting infarct volume and tissue *** groups of stroke-induced male and female rats were treated with mSC or vehicle and were subsequently subjected to a battery of standard neurological/neurobehavioral tests(modified Neurological Severity Score assessment,adhesive tape removal,beam walk and rotarod).The tests were administered at regular intervals(at days 1,3,5,7 and 14)after reperfusion to determine the time course of neurological and functional recovery after *** The infarct volume and extent of swelling of the ischaemic brain were similar in males and *** similar pathological stroke lesions,the clinical manifestations of stroke were more pronounced in males than females,as indicated by the neurological scores and other *** treatment significantly improved the recovery of sensory and motor function in both sexes,and it demonstrated efficacy in both moderate stroke(females)and severe stroke(males).Conclusions Despite sex differences in the severity of post stroke outcomes,mSC treatment promoted the recovery of sensory and motor function in male and female rats,suggesting that it may be a promising treatment for stroke.

关键词： neurological female rats