期刊文献+
共找到6,702篇文章
< 1 2 250 >
每页显示 20 50 100
Trace element and Nd isotope analyses of apatite in granitoids and metamorphosed granitoids from the eastern Central Asian Orogenic Belt:Implications for petrogenesis and post-magmatic alteration 被引量:1
1
作者 Xin-Yu Long Jie Tang +4 位作者 Wen-Liang Xu Chen-Yang Sun Jin-Peng Luan Shuai Xiong Xiao-Ming Zhang 《Geoscience Frontiers》 SCIE CAS CSCD 2023年第2期71-85,共15页
We present in situ trace element and Nd isotopic data of apatites from metamorphosed and metasomatized(i.e.,altered)and unaltered granitoids in the Songnen and Jiamusi massifs in the eastern Central Asian Orogenic Bel... We present in situ trace element and Nd isotopic data of apatites from metamorphosed and metasomatized(i.e.,altered)and unaltered granitoids in the Songnen and Jiamusi massifs in the eastern Central Asian Orogenic Belt,with the aim of fingerprinting granitoid petrogenesis,including both the magmatic and post-magmatic evolution processes.Apatites from altered granitoids(AG)and unaltered granitoids(UG)are characterized by distinct textures and geochemical compositions.Apatites from AG have irregular rim overgrowths and complex internal textures,along with low contents of rare earth elements(REEs),suggesting the re-precipitation of apatite during epidote crystallization and/or leaching of REEs from apatite by metasomatic fluids.eNd(t)values of the these apatites are decoupled from zircon eHf(t)values for most samples,which can be attributed to the higher mobility of Nd as compared to Sm in certain fluids.Apatites from UG are of igneous origin based on their homogeneous or concentric zoned textures and coupled Nd-Hf isotopic compositions.Trace element variations in igneous apatite are controlled primarily by the geochemical composition of the parental melt,fractional crystallization of other REEbearing minerals,and changes in partition coefficients.Sr contents and Eu/Eu^(*) values of apatites from UG correlate with whole-rock Sr and SiO2 contents,highlighting the effects of plagioclase fractionation during magma evolution.Apatites from UG can be subdivided into four groups based on REE contents.Group 1 apatites have REE patterns similar to the host granitoids,but are slightly enriched in middle REEs,reflecting the influence of the parental melt composition and REE partitioning.Group 2 apatites exhibit strong light REE depletions,whereas Group 3 apatites are depleted in middle and heavy REEs,indicative of the crystallization of epidote-group minerals and hornblende before and/or during apatite crystallization,respectively.Group 4 apatites are depleted in heavy REEs,but enriched in Sr,which are features of adakites.Some unusual geochemical features of the apatites,including the REE patterns,Sr contents,Eu anomalies,and Nd isotopic compositions,indicate that inherited apatites are likely to retain the geochemical features of their parental magmas,and thus provide a record of small-scale crustal assimilation during magma evolution that is not evident from the whole-rock geochemistry. 展开更多
关键词 Eastern CAOB Granitoid petrogenesis Apatite geochemistry Fluid-induced alteration Nd-Hf isotopic decoupling Crustal assimilation
原文传递
Risk stratification for radioactive iodine refractoriness using molecular alterations in distant metastatic differentiated thyroid cancer 被引量:1
2
作者 Zhuanzhuan Mu Xin Zhang +9 位作者 Dongquan Liang Jugao Fang Ge Chen Wenting Guo Di Sun Yuqing Sun Zhentian Kai Lisha Huang Jun Liang Yansong Lin 《Chinese Journal of Cancer Research》 SCIE CAS CSCD 2024年第1期25-35,共11页
Objective: Patients with radioactive iodine-refractory differentiated thyroid cancer(RAIR-DTC) are often diagnosed with delay and constrained to limited treatment options. The correlation between RAI refractoriness an... Objective: Patients with radioactive iodine-refractory differentiated thyroid cancer(RAIR-DTC) are often diagnosed with delay and constrained to limited treatment options. The correlation between RAI refractoriness and the underlying genetic characteristics has not been extensively studied.Methods: Adult patients with distant metastatic DTC were enrolled and assigned to undergo next-generation sequencing of a customized 26-gene panel(Thyro Lead). Patients were classified into RAIR-DTC or non-RAIR groups to determine the differences in clinicopathological and molecular characteristics. Molecular risk stratification(MRS) was constructed based on the association between molecular alterations identified and RAI refractoriness, and the results were classified as high, intermediate or low MRS.Results: A total of 220 patients with distant metastases were included, 63.2% of whom were identified as RAIRDTC. Genetic alterations were identified in 90% of all the patients, with BRAF(59.7% vs. 17.3%), TERT promoter(43.9% vs. 7.4%), and TP53 mutations(11.5% vs. 3.7%) being more prevalent in the RAIR-DTC group than in the non-RAIR group, except for RET fusions(15.8% vs. 39.5%), which had the opposite pattern. BRAF and TERT promoter are independent predictors of RAIR-DTC, accounting for 67.6% of patients with RAIR-DTC. MRS was strongly associated with RAI refractoriness(P<0.001), with an odds ratio(OR) of high to low MRS of 7.52 [95%confidence interval(95% CI), 3.96-14.28;P<0.001] and an OR of intermediate to low MRS of 3.20(95% CI,1.01-10.14;P=0.041).Conclusions: Molecular alterations were associated with RAI refractoriness, with BRAF and TERT promoter mutations being the predominant contributors, followed by TP53 and DICER1 mutations. MRS might serve as a valuable tool for both prognosticating clinical outcomes and directing precision-based therapeutic interventions. 展开更多
关键词 Differentiated thyroid cancer distant metastases genetic alterations RAI refractoriness molecular risk stratification
下载PDF
Genomic alterations in oral multiple primary cancers
3
作者 Wen Wang Qian Wang +7 位作者 Shiying Sun Pengfei Zhang Yuyu Li Weimin Lin Qiwen Li Xiao Zhang Zhe Ma Haiyan Lu 《International Journal of Oral Science》 SCIE CAS CSCD 2024年第1期145-153,共9页
Oral squamous cell carcinoma (OSCC) is the predominant type of oral cancer, while some patients may develop oral multiple primary cancers (MPCs) with unclear etiology. This study aimed to investigate the clinicopathol... Oral squamous cell carcinoma (OSCC) is the predominant type of oral cancer, while some patients may develop oral multiple primary cancers (MPCs) with unclear etiology. This study aimed to investigate the clinicopathological characteristics and genomic alterations of oral MPCs. Clinicopathological data from patients with oral single primary carcinoma (SPC, n=202) and oral MPCs (n=34) were collected and compared. Copy number alteration (CNA) analysis was conducted to identify chromosomal-instability differences among oral MPCs, recurrent OSCC cases, and OSCC patients with lymph node metastasis. Whole-exome sequencing was employed to identify potential unique gene mutations in oral MPCs patients. Additionally, CNA and phylogenetic tree analyses were used to gain preliminary insights into the molecular characteristics of different primary tumors within individual patients. Our findings revealed that, in contrast to oral SPC, females predominated the oral MPCs (70.59%), while smoking and alcohol use were not frequent in MPCs.Moreover, long-term survival outcomes were poorer in oral MPCs. From a CNA perspective, no significant differences were observed between oral MPCs patients and those with recurrence and lymph node metastasis. In addition to commonly mutated genes such as CASP8, TP53 and MUC16, in oral MPCs we also detected relatively rare mutations, such as HS3ST6 and RFPL4A. Furthermore, this study also demonstrated that most MPCs patients exhibited similarities in certain genomic regions within individuals, and distinct differences of the similarity degree were observed between synchronous and metachronous oral MPCs. 展开更多
关键词 alterations METASTASIS ORAL
下载PDF
Sex-dependent alterations in extracellular vesicles linking chronic spinal cord injury to brain neuroinflammation and neurodegeneration
4
作者 Yun Li Junfang Wu 《Neural Regeneration Research》 SCIE CAS 2025年第2期483-484,共2页
Traumatic spinal cord injury(SCI)is a devastating exogenous injury with long-lasting consequences and a leading cause of death and disability worldwide.Advances in assistive technology,rehabilitative interventions,and... Traumatic spinal cord injury(SCI)is a devastating exogenous injury with long-lasting consequences and a leading cause of death and disability worldwide.Advances in assistive technology,rehabilitative interventions,and the ability to identify and intervene in secondary conditions have significantly increased the long-term survival rate of SCI patients,with some people even living well into their seventh or eighth decade.These survival changes have led neurotrauma researchers to examine how SCI interacts with brain aging.Public health and epidemiological data showed that patients with long-term SCI can have a lower life expectancy and quality of life,along with a higher risk of comorbidities and complications. 展开更多
关键词 alterations INFLAMMATION INJURY
下载PDF
Identifying Comprehensive Genomic Alterations and Potential Neoantigens for Cervical Cancer Immunotherapy in a Cohort of Chinese Squamous Cell Carcinoma of the Cervix
5
作者 Meng Wu Jialu Zhou +1 位作者 Zhe Zhang Yuanguang Meng 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2024年第6期565-580,共16页
Objective Genomic alterations and potential neoantigens for cervical cancer immunotherapy were identified in a cohort of Chinese patients with cervical squamous cell carcinoma(CSCC).Methods Whole-exome sequencing was ... Objective Genomic alterations and potential neoantigens for cervical cancer immunotherapy were identified in a cohort of Chinese patients with cervical squamous cell carcinoma(CSCC).Methods Whole-exome sequencing was used to identify genomic alterations and potential neoantigens for CSCC immunotherapy.RNA Sequencing was performed to analyze neoantigen expression.Results Systematic bioinformatics analysis showed that C>T/G>A transitions/transversions were dominant in CSCCs.Missense mutations were the most frequent types of somatic mutation in the coding sequence regions.Mutational signature analysis detected signature 2,signature 6,and signature 7 in CSCC samples.PIK3CA,FBXW7,and BICRA were identified as potential driver genes,with BICRA as a newly reported gene.Genomic variation profiling identified 4,960 potential neoantigens,of which 114 were listed in two neoantigen-related databases.Conclusion The present findings contribute to our understanding of the genomic characteristics of CSCC and provide a foundation for the development of new biotechnology methods for individualized immunotherapy in CSCC. 展开更多
关键词 Cervical squamous cell carcinoma Genome alteration Neoantigens IMMUNOTHERAPY
下载PDF
Application of Remote Sensing and GIS in Mineral Alteration Mapping and Lineament Extraction Case of Oudiane Elkharoub (Requibat Shield, Northern of Mauritania)
6
作者 Ould Mahmoud Hdeid Yousra Morsli +6 位作者 Mohamed Raji Zouhir Baroudi Malika Adjour Khaled Cheikh Nebagha Zein El Arby Vetah Mohamed El Moktar Isselmou Brahim Vall 《Open Journal of Geology》 CAS 2024年第9期823-854,共32页
The integration of remotely sensed data allowed the successful characterization of the mineral alteration zones of the Oudiane Elkharoub area in the Northeastern part of Reguibat Shield using image transformation tech... The integration of remotely sensed data allowed the successful characterization of the mineral alteration zones of the Oudiane Elkharoub area in the Northeastern part of Reguibat Shield using image transformation techniques. As both chemical and geochemical analyses showed significant Au, Ag, Cu, Pb, Mn, Cr, Ni, Th and Y anomalies, it’s very interesting to apply the remote sensing and GIS in mineral resources mapping. The remote sensing is a direct adjunct to the field, lithologic and structural mapping, and more recently, GIS has played an important role in the study of mineralization areas. The integration of several evidential maps highlighted the plausible areas with high concentrations of chlorite, epidote, kaolinite, calcite, alunite, hematite, illite and sulfur among other key mineral alterations that reflect the intensity of hydrothermal effects and the probable sites of ore bodies. The methodological approach integrates geological information acquired from Aster and Landsat 8 OLI/TIRS (Operational Land Imager/Thermal InfraRed Sensor) images and a multi-criteria GIS analysis. The superimposition of various lineament and hydrothermal alteration maps and the consideration of precious and base metal indicators allowed the zoning of sites likely to contain mineral concentrations. Remote sensing becomes an important tool for locating mineral deposits in its own right, when the primary and secondary processes of mineralization result in the formation of spectral anomalies. Reconnaissance lithological mapping is usually the first step of mineral resource mapping. This is complimented with structural mapping, as mineral deposits usually occur along or adjacent to geologic structures, and alteration mapping, as mineral deposits are commonly associated with hydrothermal alteration of the surrounding rocks. Ground truthing and laboratory studies including XRD analysis were utilized to verify the results. 展开更多
关键词 Remote Sensing GIS ASTER Landsat 8 (OLI/TIRS) Structure Mineralization alteration MINERAL LINEAMENT Reguibat Shield Oudiane Elkharoub
下载PDF
Bilateral meibomian gland morphological alterations in unilateral herpes simplex keratitis based on artificial intelligence analysis
7
作者 Xin-Xin Yu Xue-Wen Chen +1 位作者 Qi Dai Shuang-Qing Wu 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2024年第12期2153-2157,共5页
AIM:To explore whether unilateral herpes simplex keratitis(HSK)can cause morphological changes of bilateral meibomian glands(MGs)based on artificial intelligence(AI)analytical system.METHODS:In the retrospective study... AIM:To explore whether unilateral herpes simplex keratitis(HSK)can cause morphological changes of bilateral meibomian glands(MGs)based on artificial intelligence(AI)analytical system.METHODS:In the retrospective study,29 patients with unilateral HSK and 29 participants matched in terms of age and sex were included as control group.Meibographic images of the upper eyelid using Keratograph 5M and assessed ocular surface parameters including tear meniscus height and tear break-up time.MG density and vagueness values were automatically analyzed and calculated using an AI analytical system.We compared the differences between the affected and the contralateral unaffected eyes in HSK patients,and the normal control eyes.We employed either the paired t-test or the Wilcoxon signed-rank test to compare significant difference between the affected and unaffected eyes in HSK patients or between the HSK group and control group.RESULTS:The MG density was 0.19±0.09 in the HSKaffected eye and 0.18±0.07 in contralateral unaffected eye,which had no significant difference(P=0.616).The MG density between the affected eye with HSK and the normal control group was statistically significant(P=0.028).There was a significant difference in MG density between the contralateral unaffected eye and the normal control group(P=0.012).However,no significant difference in vagueness value was observed between the eye with HSK and the control group or between HSK eye and contralateral eye.CONCLUSION:The MG density between the HSKaffected eye and the contralateral unaffected eye don’t significantly differ,whereas there is a significant decrease in the HSK group compared to that of the normal participants.Unilateral HSV keratitis may suffer from bilateral changes of MG morphology indicating bilateral dry eye.Therefore,the fellow eye of patients with unilateral HSK should be considered a potential case of MG dysfunction,necessitating early treatment for bilateral dry eye in the clinic. 展开更多
关键词 herpes simplex keratitis artificial intelligence meibomian gland morphology bilateral alterations
下载PDF
Clinicopathological alterations in wild mammals from the reservoir system of Trypanosoma cruzi:a scoping review
8
作者 Ricardo Sanchez Pérez JoséManuel Aranda-Coello +1 位作者 JoséAntonio De Fuentes Vicente Oscar Rico Chavez 《Animal Diseases》 CAS 2024年第1期48-58,共11页
Trypanosoma cruzi is the etiologic agent of Chagas disease.This flagellated protozoan is transmitted to humans as well as different species of domestic and wild animals via vectors from the Reduviidae family(known as&... Trypanosoma cruzi is the etiologic agent of Chagas disease.This flagellated protozoan is transmitted to humans as well as different species of domestic and wild animals via vectors from the Reduviidae family(known as"kissing bugs").Despite the fact that hundreds of species of wild mammals are part of the reservoir system,the morphologi-cal changes and clinical manifestations resulting from the pathogenesis of the infection have been largely neglected.The aim of this review is to systematically compile the available information regarding clinicopathological altera-tions in wild mammals due to natural infection by T.cruzi.Information was obtained from six online bibliographic data search platforms,resulting in the identification of 29 publications that met the inclusion criteria.Mortality was the most common clinical manifestation,cardiac damage was the main finding at necropsy,and lymphoplas-macytic inflammation was the most frequent microscopic injury.Thus,regardless of its role as a reservoir,T.cruzi has the potential to affect the health status of wild mammals,a situation that highlights the need for further research to analyze,measure,and compare its effects at both the individual and population levels. 展开更多
关键词 Trypanosoma cruzi Chagas disease American trypanosomiasis Clinicopathological alterations Natural infection Wild mammals
下载PDF
Hematological Alterations in an Eastern Sudanese Chronic Kidney Disease Patient Population
9
作者 Mohammed Omer Abaker Gibreel Sundus Kamal Ibrahim +4 位作者 Wijdan Abdel Aziz Hassan Manar Yahia Mahjoub Leyla Mohammed Kheir Hamid Hibatellah Majzoub Abbas Nuha Fouzi Mohammed 《Open Journal of Urology》 2024年第6期359-367,共9页
Background: Chronic Kidney Disease (CKD), associated with a slow and progressive loss of kidney function over a period of several years, is an important clinical disaster with an increasing rate of morbidity and morta... Background: Chronic Kidney Disease (CKD), associated with a slow and progressive loss of kidney function over a period of several years, is an important clinical disaster with an increasing rate of morbidity and mortality especially in the least developed countries. Many hematological parameters are thought to alter dramatically during the course of the disease. These include white blood cells, red blood cells, and platelets. Methods: We tried, retrospectively, to evaluate the peripheral blood hematological alterations in a group of patients undergoing hemodialysis in an eastern Sudan dialysis center to add local medical information. Results: Anemia (Low hemoglobin and hematocrit) was detected in 94% of the patients’ group. Mean Erythrocyte count (3.32vs.4.76 (×109/L)), Hemoglobin concentration (9.4vs.13 (g/dl)), Hematocrit (28.7vs.38.7 (L/L)) and platelet count (296 vs. 238 (×109/L)) were significantly lower in the patients’ group than in the control group (P-values Conclusion: Five out of eight studied parameters (Red cell count, hemoglobin, hematocrit, mean cell hemoglobin concentration, and platelets count) have shown a significant alteration in CKD patients. As the complete blood count (CBC) test is the most utilized test in clinical laboratory practice, these alterations may be considered as early indicators for CKD. Furthermore, all patients with CKD must be routinely checked for these alterations. 展开更多
关键词 Chronic Kidney Disease Chronic Renal Failure Hematological alterations CBC Eastern Sudan HEMODIALYSIS
下载PDF
Evaluation of the coupled impact of silicon oxide nanoparticles and low-salinity water on the wettability alteration of Berea sandstones 被引量:1
10
作者 ALOMAIR Osamah AL-DOUSARI Mabkhout +1 位作者 AZUBUIKE CNyeso GARROUCH Ali 《Petroleum Exploration and Development》 SCIE 2023年第4期934-943,共10页
This study investigated experimentally the coupled effects of hydrophilic SiO_(2) nanoparticles(NPs)and low-salinity water(LSW)on the wettability of synthetic clay-free Berea sandstone.Capillary pressure,interfacial t... This study investigated experimentally the coupled effects of hydrophilic SiO_(2) nanoparticles(NPs)and low-salinity water(LSW)on the wettability of synthetic clay-free Berea sandstone.Capillary pressure,interfacial tension(IFT),contact angle,Zeta potential,and dynamic displacement measurements were performed at various NP mass fractions and brine salinities.The U.S.Bureau of Mines(USBM)index was used to quantify the wettability alteration.Furthermore,the NP stability and retention and the effect of enhanced oil recovery by nanofluid were examined.The results showed that LSW immiscible displacement with NPs altered the wettability toward more water wet.With the decreasing brine salinity and increasing NP mass fraction,the IFT and contact angle decreased.The wettability alteration intensified most as the brine salinity decreased to 4000 mg/L and the NP mass fraction increased to 0.075%.Under these conditions,the resulting incremental oil recovery factor was approximately 13 percentage points.When the brine salinity was 4000 mg/L and the NP mass fraction was 0.025%,the retention of NPs caused the minimum damage to permeability. 展开更多
关键词 NANOPARTICLE low-salinity water wettability alteration interfacial tension contact angle USBM index
下载PDF
Integrating Aster Images Processing and Fieldwork for Identification of Hydrothermal Alteration Zones at the Oumjrane-Boukerzia District, Moroccan Anti-Atlas
11
作者 Lhoussayn Ouhoussa Abdessamade Ghafiri +1 位作者 Lakhlifa Ben Aissi Brahim Es-Sabbar 《Open Journal of Geology》 CAS 2023年第2期171-188,共18页
Mapping from remote sensing has become more effective in the field of geology, mainly in lithological discrimination and identification of hydrothermal alteration zones. The use of this technique consists in obtaining... Mapping from remote sensing has become more effective in the field of geology, mainly in lithological discrimination and identification of hydrothermal alteration zones. The use of this technique consists in obtaining information about the rock mass and the main ones existing in the inaccessible areas. Satellite data from the ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) sensor represent a favorable potential for detecting the spectral signatures of mineral zones and identifying their nature. These data are more reliable in places where the climate is arid with less abundant vegetation, as at the Oumjrane-Boukerzia mining district. This region which is part of the Eastern Anti-Atlas, is composed of several mineralized veins which still require detailed studies and exploration by the technique of remote sensing. In this work we applied several processing techniques on ASTER imagery such as Colored Composition, Principal Component Analysis and Ratio Bands. The use of the reports of the specialized Bands makes it possible to identify some hydrothermal alteration minerals within the mining district of Oumjrane Boukerzia. These minerals are represented mainly by iron oxides and hydroxides (Hematite, jarosite, limonite and goethite), carbonate minerals (dolomite, calcite), clay minerals (Illite, kaolinite and chlorite) and quartz minerals. This work allows us to produce a map of hydrothermal alteration zones which can be used as a valuable reference in the strategy of mining exploration for the base metals (Cu, Pb, Zn and Ba), in the mining district of Oumjrane-Boukerzia and in the entire Eastern Anti-Atlas. 展开更多
关键词 ANTI-ATLAS Oumjrane-Boukerzia alteration Mineral ASTER Remote Sensing
下载PDF
Insight into the evolution of breast cancer driven by genetic alterations
12
作者 Canbin Fang Xueqi Fan +1 位作者 Wanling Lin Guojun Zhang 《Cancer Biology & Medicine》 SCIE CAS CSCD 2023年第12期927-933,共7页
Breast cancer originates primarily from the epithelial cells of the mammary gland.Repeated mammary gland expansion and degeneration are accompanied by an increased risk of genetic alterations in the breast1.These muta... Breast cancer originates primarily from the epithelial cells of the mammary gland.Repeated mammary gland expansion and degeneration are accompanied by an increased risk of genetic alterations in the breast1.These mutations in breast epithelial cells dynamically occur in response to pregnancy,labor and delivery,breastfeeding,and the menstrual cycle,with a decline in mutation rates after menopause,which may be related to a decrease in estrogen levels.The breast epithelial cell mutations are also consistent with epidemiologic observations2. 展开更多
关键词 alterations BREAST CANCER
下载PDF
Synaptic alterations as a common phase in neurological and neurodevelopmental diseases: JNK is a key mediator in synaptic changes
13
作者 Clara Alice Musi Carlo Bonadonna Tiziana Borsello 《Neural Regeneration Research》 SCIE CAS CSCD 2023年第3期531-532,共2页
Brain synapses play a key role in neuronal communication:this“conversation”is at the basis of all brain activities and synaptic dysfunction leads to brain disorders.We study the modulators of this crucial synaptic f... Brain synapses play a key role in neuronal communication:this“conversation”is at the basis of all brain activities and synaptic dysfunction leads to brain disorders.We study the modulators of this crucial synaptic function and we here present the evidence supporting the c-Jun N-terminal kinase(JNK)pathway as a pivotal actor in this scenario. 展开更多
关键词 alterations diseases NEUROLOGICAL
下载PDF
Wettability alteration of organo-vermiculites induced by layer charge and tailored bis-N-heterocyclic quaternary ammonium salts
14
作者 Fan Ding Xin Jin +3 位作者 Tao Shen Shan-Shan Mao Qing Zhao Mang-Lai Gao 《Petroleum Science》 SCIE EI CAS CSCD 2023年第4期2596-2603,共8页
Wettability is an important surface property that deserves to further explore the factors on its alteration.Series of bis-N-heterocyclic quaternary ammonium salts with different spacer length and N-heterocyclic headgr... Wettability is an important surface property that deserves to further explore the factors on its alteration.Series of bis-N-heterocyclic quaternary ammonium salts with different spacer length and N-heterocyclic headgroups(morpholinium(BMMB,BMMD and BMMH),piperidinium(BPMH)and piperazinium(BMPMH))have been synthesized and employed for altering the wettability of vermiculite and its derivates(Vts)treated by Li^(+)-saturated heating method.The results of X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),thermogravimetric analysis(TG-DTG),scanning electron microscopy(SEM)and N_(2)adsorption/desorption isotherms indicate that all of the bis-N-heterocyclic quaternary ammonium salts have been successfully inserted into the vermiculite layers,leading to the organic monolayer.The results of capillary rise tests combined with Lipophilic to Hydrophilic Ratio(LHR)values unveil the wettability alteration of the organo-Vts.As the layer charge decreases,the hydrophilicity of the organo-Vts gradually increases,which is probably caused by the decline in binding sites.As the result of the change in spacer length of modifier,the wetting properties of morpholinium-based organo-Vts change in order of BMMD-Vts>BMMH-Vts>BMMB-Vts,and difference in N-heterocyclic headgroups leads to the sequence of wettability:BMPMH-Vts>BPMH-Vts>BMMH-Vts.Layer charge of Vt,spacer length and the type of the N-heterocyclic headgroup of modifier have the synergistic effect on the regulation of the wettability. 展开更多
关键词 VERMICULITE bis-N-heterocyclic quaternary ammonium SALTS Organo-vermiculite Layer charge Wettability alteration
下载PDF
Alteration Typology and Geochemical Signatures of the Napélépéra Gold-Bearing Granodiorite in South-West Burkina Faso (West Africa)
15
作者 Théophile Ouédraogo Sâga Sawadogo +1 位作者 Hermann Ilboudo Séta Naba 《Open Journal of Geology》 2023年第10期1162-1175,共14页
The characterization of the relationships between mineralization and hydrothermal alteration is an essential element in understanding gold deposits. In south-west Burkina Faso, the Napélépéra mineralisa... The characterization of the relationships between mineralization and hydrothermal alteration is an essential element in understanding gold deposits. In south-west Burkina Faso, the Napélépéra mineralisation, the mobility of chemical elements and alteration-mineralization relationships were studied by means of selected core drilling and geochemical analyses using ICP-MS (Inductively Coupled Plasma Mass Spectrometry) and ICP-AES (Inductively coupled plasma atomic emission spectroscopy). The mineralised granodiorite is grey porphyroid with quartz, plagioclase, biotite and amphibole. It is metaluminous and located in the tholeiitic series. The Na<sub>2</sub>O + CaO versus Fe<sub>2</sub>O<sub>3</sub> + MgO alteration diagram divides the samples according to alteration dominance. Chloritisation and carbonation are the main alterations. There is a relationship between gold mineralisation at Napélépéra and alteration, and the paragenesis of gold + pyrite ± carbonate ± silica ± sericite is the main characteristic. Carbonation is the result of fluid input in the shear corridor of the mineralised zone. The mass balance of comparative metals in the proximal and distal zones of the mineralisation shows the absence of metals, while As, Hg, Ag and Bi are strongly enriched from the distal zone to the mineralised zone. The oxides associated with the mineralisation are mainly NaO, SrO and CaO. 展开更多
关键词 Gold Mineralization alteration Mass Balance Granodiorite
下载PDF
ASTER Data Processing by Discrete Wavelets Transform and Band Ratio Techniques for the Identification of Lineaments and Hydrothermal Alteration Zones in Poli, North Cameroon
16
作者 Mohamadou Ahamadou May Nome Stella Meying Arsène 《Journal of Geoscience and Environment Protection》 2023年第9期216-232,共17页
The aim of this study is to carry out hydrothermal alteration mapping and structural mapping using ASTER images in order to identify indices that could guide mining exploration work in the Poli area and its surroundin... The aim of this study is to carry out hydrothermal alteration mapping and structural mapping using ASTER images in order to identify indices that could guide mining exploration work in the Poli area and its surroundings. To achieve this, the ASTER images were first preprocessed to correct atmospheric effects and remove vegetation influence. Secondly, a lineament mapping was conducted by applying Discrete Wavelet Transform (DWT) algorithms to the First Principal Component Analysis (PCA1) of Visible Near-Infrared (VNIR) and Shortwave Infrared (SWIR) bands. Lastly, band ratio methods were applied to the VNIR, SWIR, and Thermal Infrared (TIR) bands to determine indices of iron oxides/hydroxides (hematite and limonite), hydroxyl-bearing minerals (chlorite, epidote, and muscovite), and the quartz index. The results obtained showed that the lineaments were mainly oriented NE-SW, ENE-WSW, and E-W, with NE-SW being the most predominant direction. Concerning hydrothermal alteration, the identified indices covered almost the entire study area and showed a strong correlation with lithological data. Overlaying the obtained lineaments with the hydrothermal alteration indices revealed a significant correlation between existing mining indices and those observed in the field. Mineralized zones generally coincided with areas of high lineament density exhibiting significant hydrothermal alteration. Based on the correlation between existing mining indices and the results of hydrothermal and structural mapping, the results obtained can then be used as a reference document for any mining exploration in the study area. 展开更多
关键词 Discrete Wavelets Transform Band Ratio LINEAMENTS Hydrothermal alteration
下载PDF
Investigation of the effect of diethylene triamine pentaacetic acid chelating agent as an enhanced oil recovery fluid on wettability alteration of sandstone rocks
17
作者 PARHIZGAR KERADEH Mahsa TABATABAEI-NEZHAD Seyyed Alireza 《Petroleum Exploration and Development》 SCIE 2023年第3期675-687,共13页
This study used the diethylene triamine pentaacetic acid(DTPA)-seawater(SW)system to modify the sandstone rock wettability and enhance oil recovery.The investigation involved conducting wettability measurement,Zeta po... This study used the diethylene triamine pentaacetic acid(DTPA)-seawater(SW)system to modify the sandstone rock wettability and enhance oil recovery.The investigation involved conducting wettability measurement,Zeta potential measurement,and spontaneous imbibition experiment.The introduction of 5%DTPA-sW solution resulted in a significant decrease in the rock-oil contact angle from 143°to 23,along with a reduction in the Zeta potential from-2.29 mV to-13.06 mV,thereby altering the rock surface charge and shifting its wettability from an oil-wet state to a strongly water-wet state.The presence or absence of potential determining ions(Ca^(2+),Mg^(2+),SO_(4)^(2-))in the solution did not impact the effectiveness of DTPA in changing the rock wettability.However,by tripling the concentration of these ions in the solution,the performance of 5%DTPA-SW solution in changing wettability was impaired.Additionally,spontaneous imbibition tests demonstrated that the 5%DTPA-SW solution led to an increase in oil recovery up to 39.6%.Thus,the optimum mass fraction of DTPA for changing sandstone wettability was determined to be5%. 展开更多
关键词 wettability alteration DTPA chelating agent Zeta potential spontaneous imbibition enhanced oil recovery
下载PDF
A Blade Altering Toolbox for Automating Rotor Design Optimization
18
作者 Akiva Wernick Jen-Ping Chen 《Communications on Applied Mathematics and Computation》 EI 2024年第1期688-704,共17页
The Blade Altering Toolbox(BAT)described in this paper is a tool designed for fast reconstruction of an altered blade geometry for design optimization purposes.The BAT algorithm is capable of twisting a given rotor’s... The Blade Altering Toolbox(BAT)described in this paper is a tool designed for fast reconstruction of an altered blade geometry for design optimization purposes.The BAT algorithm is capable of twisting a given rotor’s angle of attack and stretching the chord length along the span of the rotor.Several test cases were run using the BAT’s algorithm.The BAT code’s twisting,stretching,and mesh reconstruction capabilities proved to be able to handle reasonably large geometric alterations to a provided input rotor geometry.The test examples showed that the toolbox’s algorithm could handle any stretching of the blade’s chord as long as the blade remained within the original bounds of the unaltered mesh.The algorithm appears to fail when the net twist angle applied the geometry exceeds approximately 30 degrees,however this limitation is dependent on the initial geometry and other input parameters.Overall,the algorithm is a very powerful tool for automating a design optimization procedure. 展开更多
关键词 Mesh reconstruction Mesh alteration Rotor alteration Design optimization
下载PDF
Multi-scale data joint inversion of minerals and porosity in altered igneous reservoirs—A case study in the South China Sea
19
作者 Xin-Ru Wang Bao-Zhi Pan +2 位作者 Yu-Hang Guo Qing-Hui Wang Yao Guan 《Petroleum Science》 SCIE EI CAS CSCD 2024年第1期206-220,共15页
There are abundant igneous gas reservoirs in the South China Sea with significant value of research,and lithology classification,mineral analysis and porosity inversion are important links in reservoir evaluation.Howe... There are abundant igneous gas reservoirs in the South China Sea with significant value of research,and lithology classification,mineral analysis and porosity inversion are important links in reservoir evaluation.However,affected by the diverse lithology,complicated mineral and widespread alteration,conventional logging lithology classification and mineral inversion become considerably difficult.At the same time,owing to the limitation of the wireline log response equation,the quantity and accuracy of minerals can hardly meet the exploration requirements of igneous formations.To overcome those issues,this study takes the South China Sea as an example,and combines multi-scale data such as micro rock slices,petrophysical experiments,wireline log and element cutting log to establish a set of joint inversion methods for minerals and porosity of altered igneous rocks.Specifically,we define the lithology and mineral characteristics through core slices and mineral data,and establish an igneous multi-mineral volumetric model.Then we determine element cutting log correction method based on core element data,and combine wireline log and corrected element cutting log to perform the lithology classification and joint inversion of minerals and porosity.However,it is always difficult to determine the elemental eigenvalues of different minerals in inversion.This paper uses multiple linear regression methods to solve this problem.Finally,an integrated inversion technique for altered igneous formations was developed.The results show that the corrected element cutting log are in good agreement with the core element data,and the mineral and porosity results obtained from the joint inversion based on the wireline log and corrected element cutting log are also in good agreement with the core data from X-ray diffraction.The results demonstrate that the inversion technique is applicable and this study provides a new direction for the mineral inversion research of altered igneous formations. 展开更多
关键词 Joint inversion altered igneous rock Element correction method Lithology identification Multi mineral volume model
下载PDF
Research on the Application of Electromagnetic Method in the Exploration of Altered Rock-type Gold Deposits in the East Kunlun Metallogenic Belt
20
作者 DONG Ji’en ZHANG Huiqing +4 位作者 WANG Peng LI Hua YE Gaofeng YU Xiaoliang LI Jie 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2024年第S01期18-21,共4页
Introduction The East Kunlun Orogenic Belt is located in the northeastern part of the Qinghai–Tibet Plateau(Li et al.,2007),stretching from the East Kunlun to the Elashan area in an east–west direction(Guo et al.,20... Introduction The East Kunlun Orogenic Belt is located in the northeastern part of the Qinghai–Tibet Plateau(Li et al.,2007),stretching from the East Kunlun to the Elashan area in an east–west direction(Guo et al.,2018).It is an important part of the Central Orogenic Belt(Xiong et al.,2023).It is considered one of the important gold mineralization regions in the Tethys tectonic domain(Norbu et al.,2023)and an essential potential base for mineral resources in China.Wulonggou and Gouli gold mines have been discovered successively,earning the reputation of the"Golden Belt of Qinghai Province"(Feng et al.,2004;He et al.,2023). 展开更多
关键词 electromagnetic method altered rock-type gold deposits Mailong mining area East Kunlun metallogenic belt
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部