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The Chemistry of Niobium Mineralisation at Bayan Obo,Inner Mongolia,China:Constraints on the Hydrothermal Precipitation and Alteration of Nb-Minerals

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地质学报 2012年第5期86卷 700-722页

作者： Martin SMITH john spratt School of Environment and Technology University of BrightonBrightonBN41 2HQU.K. Department of Mineralogy The Natural History MuseumLondonSW7 5BDU.K.

As well as world class Fe and REE resources the Bayan Obo mineral deposits also hosts significant niobium resources(estimated as 2.2 Mt Nb with an average grade of 0.13 wt% Nb).Niobium in this study is primarily hosted in aeschynite-(Ce) and(Nd),but with subsidiary amounts of pyrochlore,fergusonite-(Ce),fersmite and *** we report on the paragenetic and textural setting of aeschynite,pyrochlore and fergusonite in the main ore bodies and in a carbonatite *** in a carbonatite sample is hosted in a phase tentatively(due to significant Ca,Mn and Ti contents) identified as fergusonite-(Ce).Aeschynite occurs overgrowing foliation in banded ores,in fractures and vugs in aegirine-rich rocks and in calcite *** composition in all settings is similar,but some examples in banded ores develop significant zonation in Y,Th and the REE,inferred to relate to buffering of halogen acid species to low levels by dissolution and fluoritisation of calcite,and the preferential precipitation of LREE from solution due to lower mineral solubility products compared to the *** lower in total concentration the ratios of REE in pyrochlore are similar to those of aeschynite and suggest the same metal *** crystallisation of pyrochlore probably relates to growth in paragenetic settings where carbonates had already been eliminated and hence the buffering of F-species activities in the hydrothermal fluid was *** aeschynite and pyrochlore show evidence of *** alteration of aeschynite resulted in leaching of A-site cations(Ca,REE,Th) and Nb,addition of Fe,and ultimately replacement by Ba-Ti phases(baotite and bafertisite).Secondary,metamictisation enhanced,possibly supergene alteration of pyrochlore resulted in hydration,leaching of A-site cations leading to the development of lattice vacancies and increases in *** presence of hydrothermal Nb resources at Bayan Obo suggests there may be potential for further Nb discoveries in the area,

关键词：地质学地层成矿 LREE

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Intracranial pressure is elevated at 24h post-stroke inmice

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Neuroprotection 2024年第1期2卷 60-64页

作者： Kirby E.Warren Rebecca J.Hood Fredrick R.Walker Neil J.spratt School of Biomedical Sciences and Pharmacy University of NewcastleCallaghanAustralia Hunter Medical Research Institute NewLambton HeightsAustralia School of Biomedicine Discipline of Anatomy and PathologyFaculty of Health and Medical SciencesThe University of AdelaideAdelaideAustralia Department of Neurology John Hunter HospitalNewLambton HeightsAustralia

Background:It has long been assumed that post-stroke intracranial pressure(ICP)elevation occurs because of large infarct and edema ***,we have repeatedly shown IcP elevation at 24 h post-stroke in the presence of little to no edema in *** processes are often conserved across species and types of ***,we aimed to determine if an ICP rise occurs at 24 h post-stroke in the presence of small infarct and edema volumes in ***:Mice were randomized by random number table to either photothrombotic stroke or sham surgery(n=15).Epidural ICP was recorded using a fiber optic catheter at 1 h post-stroke(baseline)and between 23 and ***:ICP was significantly higher at 24 h compared to baseline in stroke animals(n=6;10.71±6.45mmHg vs.3.74±2.20mmHg,respec-tively;p=0.03).ICP at 24 h was also significantly higher in stroke mice compared to sham(n=6;3.45±1.43mmHg;p=0.02).There was no change in ICP in sham mice(p=0.9).Edema volumes in stroke animals were small(0.04±0.04 mm3)and unlikely to have caused significant ICP ***:This study provides evidence of an edema-independent ICP elevation following small ischemic stroke in *** occurrence of this rise supports our findings in other species and suggests it is caused by a previously undescribed mechanism.

关键词： cerebraledema intracranial pressure ischemic stroke

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Tranexamic acid for intracerebral haemorrhage within 2 hours of onset: protocol of a phase Ⅱ randomised placebo-controlled double-blind multicentre trial

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Stroke & Vascular Neurology 2022年第2期7卷 158-165页

作者： Nawaf Yassi Henry Zhao Leonid Churilov Bruce C V Campbell Teddy Wu Henry Ma Andrew Cheung Timothy Kleinig Helen Brown Philip Choi Jiann-Shing Jeng Annemarei Ranta Hao-Kuang Wang Geoffrey C Cloud Rohan Grimley Darshan Shah Neil spratt Der-Yang Cho Karim Mahawish Lauren Sanders john Worthington Ben Clissold Atte Meretoja Vignan Yogendrakumar Mai Duy Ton Duc Phuc Dang Nguyen Thai My Phuong Huy-Thang Nguyen Chung Y Hsu Gagan Sharma Peter J Mitchell Bernard Yan Mark W Parsons Christopher Levi Geoffrey A Donnan Stephen M Davis Department of Medicine and Neurology Melbourne Brain Centre at The Royal Melbourne HospitalThe University of MelbourneParkvilleVictoriaAustralia Population Health and Immunity Division Walter and Eliza Hall Institute of Medical ResearchParkvilleVictoriaAustralia Ambulance Victoria MelbourneVictoriaAustralia Melbourne Medical School The University of MelbourneMelbourneVictoriaAustralia Stroke Division The Florey Institute of Neuroscience and Mental HealthParkvilleVictoriaAustralia Department of Neurology Christchurch HospitalChristchurchNew Zealand Department of Neurology Monash Medical CentreMonash UniversityClaytonVictoriaAustralia Department of Interventional Neuroradiology Liverpool HospitalLiverpoolNew South WalesAustralia Department of Neurology Royal Adelaide HospitalAdelaideSouth AustraliaAustralia Department of Neurology Princess Alexandra HospitalWoolloongabbaQueenslandAustralia Department of Neurology Box Hill HospitalEastern HealthBox HillVictoriaAustralia Stroke Centre and Department of Neurology National Taiwan University HospitalTaipeiTaiwan Department of Medicine Dunedin School of MedicineUniversity of OtagoWellingtonNew Zealand Department of Neurosurgery E-Da HospitalYanchaoKaohsiungTaiwan Department of Neurology Alfred HospitalMelbourneVictoriaAustralia Department of Clinical Neuroscience Monash University Central Clinical SchoolMelbourneVictoriaAustralia Department of Medicine Sunshine Coast University HospitalNambourQueenslandAustralia Department of Neurology Gold Coast University HospitalSouthportQueenslandAustralia Department of Neurology John Hunter HospitalThe University of NewcastleNewcastleNew South WalesAustralia Department of Neurosurgery China Medical University HospitalTaichungTaiwan Department of Internal Medicine Palmerston North HospitalPalmerston NorthNew Zealand Department of Neurology St Vincent's HospitalFitzroyVictoriaAustralia Department of Neurology Royal Prince Alfred HospitalCamperdownNew South WalesAustra

Rationale Haematoma growth is common early after intracerebral haemorrhage(ICH),and is a key determinant of *** acid,a widely available antifibrinolytic agent with an excellent safety profile,may reduce haematoma *** and design Stopping intracerebral haemorrhage with tranexamic acid for hyperacute onset presentation including mobile stroke units(STOP-MSU)is a phase Ⅱ double-blind,randomised,placebo-controlled,multicentre,international investigator-led clinical trial,conducted within the estimand statistical *** In patients with spontaneous ICH,treatment with tranexamic acid within 2 hours of onset will reduce haematoma expansion compared with *** size estimates A sample size of 180 patients(90 in each arm)would be required to detect an absolute difference in the primary outcome of 20%(placebo 39%vs treatment 19%)under a two-tailed significance level of *** adaptive sample size re-estimation based on the outcomes of 144 patients will allow a possible increase to a prespecified maximum of 326 *** Participants will receive 1 g intravenous tranexamic acid over 10 min,followed by 1 g intravenous tranexamic acid over 8 hours;or matching *** efficacy measure The primary efficacy measure is the proportion of patients with haematoma growth by 24±6 hours,defined as either≥33%relative increase or≥6 mL absolute increase in haematoma volume between baseline and follow-up CT *** We describe the rationale and protocol of STOP-MSU,a phase Ⅱ trial of tranexamic acid in patients with ICH within 2 hours from onset,based in participating mobile stroke units and emergency departments.

关键词： placebo centre absolute

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流行病学和临床研究中数据缺失的多重填补：机会和陷阱

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英国医学杂志中文版 2009年第6期12卷 371-375页

作者： Jonathan A C Sterne Ian R White john B Carlin Michael spratt Patrick Royston Michael G Kenward Angela M Wood James R Carpenter 张清(译) 张孔来(校) Department ofSocial Medicine University of BristolBristol BS8 2PR MRC BiostatisticsUnit Institute of PublicHealth CambridgeCB2 0SR Clinical Epidemiologyand BiostatisticsUnit MurdochChildren's ResearchInstitute andUniversityof MelbourneParkville Victoria3052 Australia Cancer andStatistical MethodologyGroups MRCClinical Trials UnitLondon NW1 2DA Medical StatisticsUnit kondon Schoolof Hygiene andTropical Medicinelondon WC1E 7HT Depamnent ofPublic Health andPrimary Care Instituteof Public HealthCambridge 北京协和医科大学流行病学教研室

许多研究都存在缺失数据。Jonathan

关键词：多重填补数据缺失临床研究流行病学缺失数据填补方法

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