bluuebunny/crossref_metadata_2025_split huggingface dataset:
Platinum‐group Element Geochemistry of Magnetite from Porphyry‐Cu‐Mo Deposits and their Host Rocks (Siberia, Russia)
Authors: BERZINA Anita 
Published: February 2012

Abstract:The concentrations of platinum‐group elements (PGE) have been analyzed in primary magmatic magnetite samples from the Zhireken, Shakhtama and Aksug porphyry Cu‐Mo deposits (Siberia, Russia) by laser ablation‐inductively coupled plasma mass spectrometry to determine the range of PGE contents in magnetites and to check whether magnetite from two main rock suites (barren plutonic suite and mineralized porphyry suite) has distinct PGE composition. The results presented here indicate that magnetites are enriched in PGE relative to whole‐rocks. Comparison of ore‐related porphyry and barren plutonic suites shows that magnetite exhibit relatively similar PGE distribution patterns in both suites. Variations in Rh and Ru contents were controlled by the oxygen fugacity during magma crystallization.
Zircon SHRIMP U‐Pb Dating of the Tourmalinites from Boron‐bearing Series of Borate Deposits in Eastern Liaoning and its Geological Implications
Authors: Jingdang LIU , Rongge XIAO , Yanfei ZHANG , Minghui FAN , Shengzhi WANG , Yuguo JIA , Gang WANG , Zhixue LIU 
Published: February 2012

Abstract:This paper focused on the zircon sensitive high resolution ion micro‐probeU‐Pb geochronology of the tourmalinites from boron‐bearing series of borate deposits in Eastern Liaoning. The zircons commonly have core‐rim structures, most cores show oscillatory zoning in cathodoluminescence and plane polarized light images, suggesting a magmatic detrital origin. Ages of the magmatic detrital zircons from the hyalotourmalite samples (N13) and (N14) are 2175 ± 5 Ma and 2171 ± 9 Ma, respectively. Moreover, metamorphic zircon from the sample (N13) shows an age of 1906 ± 4 Ma. Zircon core and rim from the hyalotourmalite sample (N02) record ages of 2171 ± 6 Ma and 1889 ± 62 Ma, which are explained as indicating the formation and metamorphic ages. Combined with the geological and geochemical studies, it can be concluded that the tourmalinites are formed during sedimentary exhalative mineralizations in the mid‐Paleoproterozoic (∼2170 Ma) and underwent the metamorphism in the late‐Paleoproterozoic (∼1900 Ma). The tourmalinites are the products of submarine acid volcanism in the extension rifting phase of the Liaoji Paleoproterozoic Rift, the rock‐forming materials of which are derived from the mantle sources with recycling crustal contamination. The emergence of tourmalinites not only indicates the mid‐Paleoproterozoic tectonic‐magmatic processes, but also provides impetus, heat and material sources for the mineralization of borate deposits in Eastern Liaoning.
Microbial Mats in Tibetan Hot Springs and their Contributions to the Cesium‐bearing Geyserite Ore Formation
Authors: Hailei WANG , Mianping ZHENG , Fanjing KONG 
Published: February 2012

Abstract:Microbial mats, mainly dominated by filamentous algae Calothrix and Oscillatoria, are well developed in Tibetan hot springs. A great number of fossil microorganisms, which existed as algae lamination in thermal depositional cesium‐bearing geyserite in this area, are identified as Calothrix and Oscillatoria through microexamination and culture experiments. These microbial mats show the ability to accumulate cesium from spring water to the extent of cesium concentration of 0.46–1.03% cell dry weight, 900 times higher than that in water, and capture large numbers of cesium‐bearing opal grain. Silicon dioxide colloid in spring water replaces and fills with the organism and deposits on it to form algae laminated geyserite after dehydration and congelation. Cesium in the microbial mats and opal grain is then reserved in the geyserite. Eventually, cesium‐bearing algae laminated geyserite is formed. Study on cesium distribution in geyserite also shows that cesium content in algae lamination, especially in heavily compacted algae lamination, is higher than in the opal layer. For geyserite with no algae lamination or other organism structure, which is generally formed in spring water with low silicon content, cesium accumulation and cesium‐bearing opal grain assembled by the microbial mats are also indispensable. After the microbial mats accumulating cesium from spring water, silicon dioxide colloid poorly replaces and fills with the organism to form opal grain‐bearing tremellose microbial mats. The shape and structure of the organisms are then destroyed, resulting in cesium‐bearing geyserite with no algae lamination structure after dehydration and congelation. It is then concluded that microbial mats in the spring area contribute to the enrichment of cesium in the formation of cesium‐bearing geyserite, and a biological genesis of the geyserite, besides of the physical and chemical genesis, is likely.
Provenance System Analysis of the Nantun Formation of the Huhehu Sag in Hailar Basin
Authors: Junhui LI , Qi'an MENG , Shuangfang LU , Defeng ZHU , Haibo WU , He LIU , Dazhi ZHANG 
Published: February 2012

Abstract:Huhehu Sag is a new battlefield for the future oil and gas exploration in the Hailar Basin. At present, exploration of this area stays at a low level and the understanding of the provenance system of the Nantun Formation is comparatively weak. So, to carry out the detailed depiction of the provenance system in the study area is significant for the sedimentary system reconstruction, for the prediction of reservoir distribution and favorable areas. Based on comprehensive analysis of paleogeomorphy, light‐heavy mineral and seismic reflection features, sandstone thickness and sandstone percentage, this paper analyzes in detail the provenance system of the Nantun Formation in Huhehu Sag from various angles and levels. It shows that provenances of the Huhehu Sag mainly originated from the eastern Xilinbeier Salient and western Bayan Mountain Uplift. The provenances surrounding the lake basin converged to the center of the basin, among which, the steep slope belt and the gentle slope belt are the main provenances, and the southern uplift is a secondary one. The distribution framework of the provenance fundamentally determines the distribution rules of the depositional system and its sand body developing during the Nantun period.
New Approaches and Markers for Identifying Secondary Biogenic Coalbed Gas
Authors: Mingxin TAO , Jing LI , Xiaobin LI , Yuzhen MA , Zhongping LI , Zuodong WANG , Zhongliang GAO , Xiaojun ZHANG , Yanlong WANG 
Published: February 2012

Abstract:According to the adsorption‐desorption characteristics of coalbed gas and analysis of various experimental data, this paper proposes that the generation of secondary biogenic gas (SBG) and its mixing of with the residual thermogenic gas at an early stage inevitably lead to secondary changes of the thermogenic gas and various geochemical additive effects. Experimental results also show that the fractionation of the carbon isotope of methane of coal core desorption gas changes very little; the δ13C1 value of the mixed gas of biogenic and thermogenic gases is between the δ13C1 values of the two “original” gases, and the value is determined by the carbon isotopic compositions and mixing proportions of the two “original” methanes. Therefore this paper proposes that the study on the secondary changes of the thermogenic gas and various additive effects is a new effective way to study and identify SBG. Herein, a systematic example of research on the coalbed gas (Huainan coalbed gas) is further conducted, revealing a series of secondary changes and additive effects, the main characteristics and markers of which are: (1) the contents of CO2 and heavy‐hydrocarbons decrease significantly; (2) the content of CH4 increases and the gas becomes drier; (3) the δ13C and δD values of methane decrease significantly and tend to have biogenetic characteristics; and (4) the values of δ13C2 and δ13Cco2 grow higher. These isotopic values also change with the degradation degrees by microbes and mixing proportions of the two kinds of gases in different locations. There exists a negative correlation between the δ13C1vsδ13Cco2 values. The Δδ13Cc2–c1 values obviously become higher. The distributions of the Δδ13Cco2–c1 values are within certain limits and show regularity. There exist a positive correlation between the N2 versus Ar contents, and a negative correlation between the N2 versus CH4 contents, indicating the down forward infiltration of the surface water containing air. These are important markers of the generation and existence of SBG.
Accumulation and Reformation of Silurian Reservoir in the Northern Tarim Basin
Authors: Guangyou ZHU , Jie CUI , Jin SU , Haijun YANG , Bin ZHANG , Jianfeng HU , Yongfeng ZHU 
Published: February 2012

Abstract:Silurian sandstone in Tarim Basin has good reservoir properties and active oil and gas shows, especially thick widely‐distributed bituminous sandstone. Currently, the Silurian was found containing both bitumen and conventional reservoirs, with petroleum originating from terrestrial and marine source rocks. The diversity of their distribution was the result of “three sources, three stages” accumulation and adjustment processes. “Three sources” refers to two sets of marine rocks in Cambrian and Middle‐Upper Ordovician, and a set of terrestrial rock formed in Triassic in the Kuqa depression. “Three stages” represents three stages of accumulation, adjustment and reformation occurring in Late Caledonian, Late Hercynian and Late Himalayan, respectively. The study suggests that the Silurian bitumen is remnants of oil generated from Cambrian and Ordovician source rocks and accumulated in the sandstone reservoir during Late Caledonian‐Early Hercynian and Late Hercynian stages, and then damaged by the subsequent two stages of tectonic uplift movements in Early Hercynian and Pre‐Triassic. The authors presumed that the primary paleo‐reservoirs formed during these two stages might be preserved in the Silurian in the southern deep part of the Tabei area. Except for the Yingmaili area where the Triassic terrestrial oil was from the Kuqa Depression during Late Himalayan Stage, all movable oil reservoirs originated from marine sources. They were secondary accumulations from underlying Ordovician after structure reverse during the Yanshan‐Himalayan stage. Oil/gas shows mixed‐source characteristics, and was mainly from Middle‐Upper Ordovician. The complexity and diversity of the Silurian marine primary properties were just defined by these three stages of oil‐gas charging and tectonic movements in the Tabei area.
Dealing with the Spatial Synthetic Heterogeneity of Aquifers in the North China Plain: A Case Study of Luancheng County in Hebei Province
Authors: Rong MA , Jiansheng SHI , Jichao LIU 
Published: February 2012

Abstract:The complexity of alluvial‐pluvial fan depositional systems makes the detailed characterization of their heterogeneity difficult, yet such a detailed characterization is commonly needed for construction of reliable groundwater models. Traditional models mainly focus on using a single aquifer property to qualitatively or semi‐quantitatively characterize the heterogeneity of aquifer, so that they are unable to quantitatively reflect the synthetic heterogeneity of all aquifer properties. In this paper, we propose the heterogeneity synthetic index (HSI) for quantitative characterization of synthetic heterogeneity of an aquifer. The proposed calculation process involves four steps: (1) estimation of the hydraulic conductivity of a sediment sample using the cloud‐Markov model, (2) establishment of the sedimentary microfacies distribution model through the Markov chain, (3) characterization of the distribution model of hydrogeological parameters using the improved sequential simulation method according to the “facies‐controlled modeling” technique, and (4) application of the entropy weight method to calculate the weight coefficient of the above aquifer properties. The HSI of an aquifer is calculated by superposition of these models according to the corresponding weight coefficient. This approach was applied to the Luancheng aquifer deposit in the southeast Hutuo River alluvial‐pluvial fan in the North China Plain (NCP). The results have demonstrated that aquifer 3 which was formed in the middle Pleistocene has the strongest heterogeneity, with an HSI of 0.25–0.75. Aquifer 4 formed in the early Pleistocene shows an intermediate heterogeneity, with the HSI ranging 0.35–0.75. The weakest heterogeneity was found in aquifers 1 and 2 formed in the Holocene and late Pleistocene, with HSI values of 0.40–0.75 and 0.40–0.80, respectively. The heterogeneity of all the four aquifers is relatively strong in the radial direction of the Huai River alluvial‐pluvial fan due to the abrupt change of microfacies. In contrast, in the radial direction of the Hutuo River alluvial‐pluvial fan, the microfacies change mildly, and the continuity of hydrogeological parameters is better, which has resulted in weaker heterogeneity of the four aquifers in this direction. Findings suggest that the sedimentary environment has significant effects on the aquifer heterogeneity. Considering that there arc many aquifer properties, HSI can quantitatively characterize the synthetic heterogeneity of the aquifer and describe the influence of each aquifer property on the synthetic heterogeneity of the aquifer according to its weight coefficient. Thus the HSI approach can be successfully used to deal with the spatial heterogeneity of aquifer and provide a foundation for studies on contaminant transport.
Middle‐Late Pleistocene Glacial Lakes in the Grand Canyon of the Tsangpo River, Tibet
Authors: Song ZHU , Zhenhan WU , Xitao ZHAO , Jianping LI , Hua WANG 
Published: February 2012

Abstract:Many moraines formed between Daduka and Chibai in the Tsangpo River valley since Middle Pleistocene. A prominent set of lacustrine and alluvial terraces on the valley margin along both the Tsangpo and Nyang Rivers formed during Quaternary glacial epoch demonstrate lakes were created by damming of the river. Research was conducted on the geological environment, contained sediments, spatial distribution, timing, and formation and destruction of these paleolakes. The lacustrine sediments 14C (10537±268 aBP at Linzhi Brick and Tile Factory, 22510±580 aBP and 13925±204 aBP at Bengga, 21096±1466 aBP at Yusong) and a series of ESR (electron spin resonance) ages at Linzhi town and previous data by other experts, paleolakes persisted for 691∼505 kaBP middle Pleistocene ice age, 75–40 kaBP the early stage of last glacier, 27–8 kaBP Last Glacier Maximum (LGM), existence time of lakes gradually shorten represents glacial scale and dam moraine supply potential gradually cut down, paleolakes and dam scale also gradually diminished. This article calculated the average lacustrine sedimentary rate of Gega paleolake in LGM was 12.5 mm/a, demonstrates Mount Namjagbarwa uplifted strongly at the same time, the sedimentary rate of Gega paleolake is more larger than that of enclosed lakes of plateau inland shows the climatic variation of Mount Namjagbarwa is more larger and plateau margin uplifted more quicker than plateau inland. This article analyzed formation and decay cause about the Zelunglung glacier on the west flank of Mount Namjagbarwa got into the Tsangpo River valley and blocked it for tectonic and climatic factors. There is a site of blocking the valley from Gega to Chibai. This article according to moraines and lacustrine sediments yielded paleolakes scale: the lowest lake base altitude 2850 m, the highest lake surface altitude 3585 m, 3240 m and 3180 m, area 2885 km2, 820 km2 and 810 km2, lake maximum depth of 735 m, 390 m and 330 m. We disclose the reason that previous experts discovered there were different age moraines dividing line of altitude 3180 m at the entrance of the Tsangpo Grand Canyon is dammed lake erosive decay under altitude 3180 m moraines in the last glacier era covering moraines in the early ice age of late Pleistocene, top 3180 m in the last glacier moraine remained because ancient dammed lakes didn't erode it under 3180 m moraines in the early ice age of late Pleistocene exposed. The reason of the top elevation 3585 m moraines in the middle Pleistocene ice age likes that of altitude 3180 m. There were three times dammed lakes by glacier blocking the Tsangpo River during Quaternary glacial period. During other glacial and interglacial period the Zelunglung glacier often extended the valley but moraine supplemental speed of the dam was smaller than that of fluvial erosion and moraine movement, dam quickly disappeared and didn't form stable lake.
Iron therapy alone or in combination with erythropoietin in surgical and medical cardiac patients
Authors: CLADELLAS MERCÈ , BRUGUERA JORDI , COMÍN‐COLET JOSEP 
Published: February 2012

SUMMARYAnemia has been associated to poor outcomes in the whole spectrum of patients with heart disease. The etiology of this comorbidity in cardiac patients is multifactorial but acute bleeding or chronic occult blood loss, iron deficiency and inflammation are common causes in these patients. Abnormal handling or availability of iron and inadequate response to endogenous erythropoietin have both raised the interest of researchers and clinicians to explore the therapeutic role of these agents either alone or in combination. In this review, we analyze the most recent research evaluating the role of iron alone or in combination with erythropoietin in the management of anemia of cardiac patients ranging from those patients that undergo cardiac surgery to those more advanced patients with chronic heart failure.
Contemporary medico‐legal dental radiology
Authors: Wright B 
Published: February 2012

AbstractThe advent of extraoral radiology in general dental practice has become more widespread since 2000, particularly with digital systems. With this comes a range of medico‐legal risks for dentists not adverted to previously.These risks include a higher than expected radiation dose for some surveys, and the risk of a ‘loss of a chance’ for a patient whereby the images may disclose pathology not diagnosed by general dental practitioners using OPG and CBVT radiology.Practitioners need to apply relevant legal principles in deciding which surveys to order and record, and also need to explain to patients the dosages of the radiation that they will likely receive. Practitioners also need to assess whether the resultant survey ought to be interpreted by a radiologist to diagnose any wider pathology with which a general practitioner may not be familiar. Extra caution needs to be used in ordering high dose radiology in paediatric patients.Dentists should not assume patients fully understand the nature of CBVT and MCT, and its risks and benefits. Consideration ought to be given to the volume of CBVT ordered dependent on factors such as patient age, symptoms, history and procedural intent.
Interpretation of panoramic radiographs
Authors: Perschbacher S 
Published: February 2012

AbstractPanoramic radiography has become a commonly used imaging modality in dental practice and can be a valuable diagnostic tool in the dentist’s armamentarium. However, the panoramic image is a complex projection of the jaws with multiple superimpositions and distortions which may be exacerbated by technical errors in image acquisition. Furthermore, the panoramic radiograph depicts numerous anatomic structures outside of the jaws which may create additional interpretation challenges. Successful interpretation of panoramic radiographs begins with an understanding of the normal anatomy of the head and neck and how it is depicted in this image type. This article will describe how osseous structures, soft tissues, air spaces and ghost shadows contribute to the final panoramic image. A systematic and repeated approach to examining panoramic radiographs, which is recommended to ensure that critical findings are not overlooked, is also outlined. Examples of challenging interpretations, including variations of anatomy, artefacts and disease, are presented to illustrate these concepts.
The impact of computer display performance on the quality of digital radiographs: a review
Authors: Butt A , Mahoney M , Savage NW 
Published: February 2012

AbstractRadiography makes an essential contribution to the processes of examination, diagnosis and treatment planning in dentistry. While the use of film‐based imaging still predominates in dentistry, digital imaging is gaining wider acceptance and the use of this modality is anticipated to expand in the future. Two concerns associated with this transition have been raised in the literature. The first of these is the dissatisfaction experienced by many dental professionals with quality of digital radiographs when compared to plain film. In addition, there are indications that practitioners feel limited in their understanding of those factors impacting on digital image quality.One key area highlighted in the literature as having a significant influence on digital radiographic quality and interpretation concerns the performance of the display device. Within the last decade, research derived from the fields of medical radiology and physics have demonstrated that suboptimally performing displays degrade image quality, thereby increasing the potential for compromised diagnostic outcomes. In the field of medicine, this has resulted in the establishment of standards applicable to computer displays used in diagnostic radiology. Conversely, limited guidelines exist in the field of dentistry. The aim of this review is to provide an outline of these standards and highlight the important relationship between computer display performance and digital image quality.
Cone beam computed tomography use in orthodontics
Authors: Nervina JM 
Published: February 2012

AbstractCone beam computed tomography (CBCT) is widely used by orthodontists to obtain three‐dimensional (3‐D) images of their patients. This is of value as malocclusion results from discrepancies in three planes of space. This review tracks the use of CBCT in orthodontics, from its validation as an accurate and reliable tool, to its use in diagnosing and treatment planning, and in assessing treatment outcomes in orthodontics.
Cone beam computed tomography and obstructive sleep apnoea
Authors: Strauss RA , Wang N 
Published: February 2012

AbstractSleep apnoea is characterized by an intermittent cessation or diminution of airflow during sleep that may result in significant pulmonary and cardiac consequences, and is associated with significant morbidity and mortality. It is a common disease that affects approximately 20% of patients who snore, equating to a total prevalence in the population of about 4% of all middle aged men and 2% of women. In reality, due to lack of recognition and the difficulty with obtaining an accurate diagnosis, the actual incidence is likely much higher.
Update on the biological effects of ionizing radiation, relative dose factors and radiation hygiene
Authors: White SC , Mallya SM 
Published: February 2012

AbstractDiagnostic imaging is an indispensable part of contemporary medical and dental practice. Over the last few decades there has been a dramatic increase in the use of ionizing radiation for diagnostic imaging. The carcinogenic effects of high‐dose exposure are well known. Does diagnostic radiation rarely cause cancer? We don’t know but we should act as if it does. Accordingly, dentists should select patients wisely – only make radiographs when there is patient‐specific reason to believe there is a reasonable expectation the radiograph will offer unique information influencing diagnosis or treatment. Low‐dose examinations should be made: intraoral imaging – use fast film or digital sensors, thyroid collars, rectangular collimation; panoramic and lateral cephalometric imaging – use digital systems or rare‐earth film screen combinations; and cone beam computed tomography – use low‐dose machines, restrict field size to region of interest, reduce mA and length of exposure arc as appropriate.