Nine organic-rich shale samples of Lower Cambrian black shales were collected from a recently drilled well in the Qiannan Depression, Guizhou Province where they are widely distributed with shallower ...burial depth than in Sichuan Basin, and their geochemistry and pore characterization were investigated. The results show that the Lower Cambrian shales in Qiannan Depression are organic rich with TOC content ranging from 2.81% to 12.9%, thermally overmature with equivalent vitrinite reflectance values in the range of 2.92–3.25%, and clay contents are high and range from 32.4% to 53.2%. The samples have a total helium porosity ranging from 2.46% to 4.13% and total surface area in the range of 9.08–37.19 m2/g. The estimated porosity in organic matters (defined as the ratio of organic pores to the volume of total organic matters) based on the plot of TOC vs helium porosity is about 10% for the Lower Cambrian shales in Qiannan Depression and is far lower than that of the Lower Silurian shales (36%) in and around Sichan Basin. This indicates that either the organic pores in the Lower Cambrian shale samples have been more severely compacted than or they did not develop organic pores as abundantly as the Lower Silurian shales. Our studies also reveal that the micropore volumes determined by Dubinin–Radushkevich (DR) equation is usually overestimated and this overestimation is closely related to the non-micropore surface area of shales (i.e. the surface area of meso- and macro-pores). However, the modified BET equation can remove this overestimation and be conveniently used to evaluate the micropore volumes/surface area and the non-micropore surface areas of micropore-rich shales.
•Both mineral matrix and organic matter pores are developed in overmature black shales.•Lower Cambrian shales bear less organic pores than lower Silurian shales in South China.•Organic matter contains finer mesopores than matrix minerals.•TOC is positively related with total helium porosity and surface area of shales.•Modified BET equation can be conveniently used to evaluate micropore volume and non-micropore surface area.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
At present, phenolic acid derivatives and triazole derivatives have a good antifungal effect, which has attracted widespread attention. A series of novel phenolic acid triazole derivatives were ...synthesized, and their structures were characterized by IR, MS, NMR, and X-ray crystal diffraction. Compound methyl 4-(2-bromoethoxy)benzoate, methyl 4-(2-(1H-1,2,4-triazol-1-yl) ethoxy)benzoate, 4-(2-(1H-1,2,4-triazol-1-yl)ethoxy)benzoic acid and 4-(2-(1H-1,2,4-triazol-1-yl) ethoxy)-3-methoxybenzoic acid crystallize in the monoclinic system with space group P21/n, the monoclinic system with space group P21, the monoclinic system with space group P21 and the orthorhombic system with space group Pca21, respectively. At a concentration of 100 μg/mL and 200 μg/mL, the antifungal activity against seven plant pathogen fungi was determined. Compound methyl 4-(2-bromoethoxy)benzoate has the best inhibitory effect on Rhizoctonia solani AG1, and the inhibitory rate reached 88.6% at 200 μg/mL. The inhibitory rates of compound methyl 4-(2-(1H-1,2,4-triazol-1-yl) ethoxy)benzoate against Fusarium moniliforme and Sphaeropsis sapinea at a concentration of 200 μg/mL were 76.1% and 75.4%, respectively, which were better than that of carbendazim.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Solid bitumen occurs widely in the Early Paleozoic and Precambrian strata and its reflectance is a generally-accepted indicator for thermal maturity. Even though some recent papers have been ...published concerning the Raman characteristics and spectral parameters of solid bitumen, a systematic investigation on the relationship between the Raman spectral parameters and thermal maturity of solid bitumen is still lacking. In this study, a low maturity solid bitumen sample was pyrolysed under laboratory-controlled conditions to obtain a suite of artificial bitumen samples with different maturities (BRo=1.1–4.81%), which are used to investigate the relationships between Raman spectral parameters and reflectance of solid bitumen. The Raman spectral parameters of the artificial bitumens, including band position (WD and WG), band separation (RBS), full width at half maximum (FWHM-D and FWHM-G), and band intensity ratio (ID/IG) are all related to the bitumen reflectance, but with considerably different correlations, constrained apparently by thermal maturity. Linear regressions were performed between these parameters and bitumen reflectance, and two parameters with higher correlation were selected. They are RBS (within 1.5–3.5% of BRo) and ID/IG (within 3.0–5.0% of BRo), with a correlation coefficient as high as 0.97. It is believed that the two Raman spectral parameters of solid bitumen will be of significant practical use for the maturity assessment of the Early Paleozoic and Precambrian strata when standard measurement and curve fitting procedures are utilized.
•Bitumens with different maturities were obtained by pyrolysis of a low mature bitumen.•The D and G bands of their Raman spectra show regular changes with maturation.•Raman parameters RBS and ID/IG show the best correlation with BRo.•Raman data of natural bitumens follow the models of the artificial bitumens.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Although Lower Silurian black shales within and around the Sichuan Basin have received renewed attention during the past few years because of their potential prospectivity for shale gas, studies ...associated with shale gas reservoir evaluation are still rare. In this study, eight black shale core samples were collected from a well drilled recently in the Chuandong Thrust Fold Belt, southwestern China, and their geochemistry and pore structures were investigated using low pressure N2 adsorption analysis and field emission scanning electron microscopy (FE-SEM) observations. The results show that the black shales have total organic carbon (TOC) values ranging from 1.01% to 3.98% and their equivalent vitrinite reflectance values are in the range of 2.84%–3.05%. Both mineral matrix and organic matter pores are well developed with pore sizes ranging from several to several hundred nanometers. The total porosity for the eight samples ranges from 2.60% to 4.74% and the percentages of organic matter pores are estimated to be in the range of 31%–62%. The total surface area ranges from 5.06 m2/g to 19.32 m2/g and the micropore (<2 nm) surface area estimated by the t-plot method ranges from 3.13 m2/g to 9.27 m2/g. The TOC values have positive relationships with the total porosity, total surface area and the micropore (<2 nm) volume and surface area, indicating TOC may be an effective parameter for shale gas reservoir evaluation in the studied area.
•Both mineral matrix and organic matter pores are developed in overmature black shales.•Organic pores contribute significantly to the total porosity of black shales.•Organic matters contain more fine mesopores than matrix minerals.•TOC is positively related with total pore volume and surface area of shales.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Gas-in-place (GIP) is one of the primary controlling factors in shale gas production, but studies examining GIP have been lacking for the Lower Silurian Longmaxi shale in South China. In the present ...study, a suite of Longmaxi shale samples was collected from an exploratory well in Southeast Chongqing, South China, and the adsorption parameters were fitted using a supercritical Dubinin-Radushkevich (SDR) model based on the high-pressure methane adsorption experiment data for the samples. The results show that the adsorbed phase density and the adsorbed gas capacity of the samples have a positive correlation with the content of total organic carbon (TOC) but a negative correlation with temperature. Combined with the geological characteristics of the Longmaxi shale in Southeast Chongqing, GIP models were constructed under three different fluid pressure conditions. The absolute adsorbed amount of the samples increases and later decreases with increasing depth with a maximum corresponding to depths between 800 and 1200 m. The fluid pressure coefficient has no obvious effect on the absolute adsorbed amount when burial depth is over 2000 m but controls the free gas content. Overpressure primarily increases the free gas content and thus increases the total gas content. The free gas content of the Longmaxi shale in the Pengshui Block is reduced to 47%–58% of that in the Fuling Block, which is the main reason for its low gas production. Further exploration of the Longmaxi Formation should be expanded to deeper burial shales in the eastern area of Southeast Chongqing.
•High-pressure methane adsorption of Longmaxi shale samples was performed.•Adsorption data were extrapolated to geological conditions by the SDR model.•GIP models of Longmaxi shale systems with different pressure gradients were proposed.•GIP data was used to explain gas yield difference between Fuling and Pengshui blocks.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
A large number of new causative and risk genes for amyotrophic lateral sclerosis (ALS) have been identified mostly in patients of European ancestry. In contrast, we know relatively little regarding ...the genetics of ALS in other ethnic populations. This study aims to provide a comprehensive analysis of the genetics of ALS in an unprecedented large cohort of Chinese mainland population and correlate with the clinical features of rare variants carriers.
A total of 1587 patients, including 64 familial ALS (FALS) and 1523 sporadic ALS (SALS), and 1866 in-house controls were analysed by whole-exome sequencing and/or testing for G4C2 repeats in
. Forty-one ALS-associated genes were analysed.
155 patients, including 26 (40.6%) FALS and 129 (8.5%) SALS, carrying rare pathogenic/likely pathogenic (P/LP) variants of ALS causative genes were identified.
was the most common mutated gene, followed by
,
,
,
and
. By burden analysis, rare variants in
,
and
contributed to the collective risk for ALS (p<2.5e-6) at the gene level, but at the allelic level
p.Gly294Val and
p.Arg521Cys and p.Arg521His were the most important single variants causing ALS. Clinically, P/LP variants in
and
were associated with poor prognosis, in
linked with younger age of onset, and
repeats tended to affect cognition.
Our data provide essential information for understanding the genetic and clinical features of ALS in China and for optimal design of genetic testing and evaluation of disease prognosis.
Two sets of Lower Paleozoic organic-rich shales develop well in the Weiyuan area of the Sichuan Basin: the Lower Cambrian Jiulaodong shale and the Lower Silurian Longmaxi shale. The Weiyuan area ...underwent a strong subsidence during the Triassic to Early Cretaceous and followed by an extensive uplifting and erosion after the Late Cretaceous. This has brought about great changes to the temperature and pressure conditions of the shales, which is vitally important for the accumulation and preservation of shale gas. Based on the burial and thermal history, averaged TOC and porosity data, geological and geochemical models for the two sets of shales were established. Within each of the shale units, gas generation was modeled and the evolution of the free gas content was calculated using the PVTSim software. Results show that the free gas content in the Lower Cambrian and Lower Silurian shales in the studied area reached the maxima of 1.98–2.93 m3/t and 3.29–4.91 m3/t, respectively (under a pressure coefficient of 1.0–2.0) at their maximum burial. Subsequently, the free gas content continuously decreased as the shale was uplifted. At present, the free gas content in the two sets of shales is 1.52–2.43 m3/t and 1.94–3.42 m3/t, respectively (under a current pressure coefficient of 1.0–2.0). The results are roughly coincident with the gas content data obtained from in situ measurements in the Weiyuan area. We proposed that the Lower Cambrian and Lower Silurian shales have a shale gas potential, even though they have experienced a strong uplifting.
•Two sets of Lower Paleozoic shales are characterized by a strong uplifting and a very high maturity.•Geological, geochemical and porosity models of the two sets of shales were established.•Evolution history of free gas contents of the shales were modeled using the PVTSim software.•Current free gas content of the shales is 1.52–3.42 m3/t, similar with their measured result.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Permian organic-rich shales occur throughout the Lower Yangtze region in Eastern China and are potentially a future target for shale gas exploration. Due to the lack of data, the gas potential of ...these Permian shales is difficult to evaluate. In this study, a total of 22 Permian shale samples were collected from two wells and their geochemical and rock property (porosity) characteristics were investigated. The results show that the samples have a total organic carbon (TOC) content of 0.6–17.4wt.% derived from mainly gas-prone kerogen with a vitrinite reflectance (Ro) value ranging from 2.3 to 2.7%. Total porosity of the samples ranges between 1 and 5.5%. The micropore and mesopore surface areas range between 5.41–35.69m2/g and 3.59–11.23m2/g, respectively. Micropore and mesopore volumes range between 0.22–1.44cm3/100g and 0.67–1.76cm3/100g, respectively. Total porosity and pore structure data of these samples show a correlation with TOC. For samples with TOC<12wt.%, their total porosity has a positive correlation with TOC, while for samples with TOC>12wt.%, negative correlation relationships were observed. TOC content strongly impacts gas storage capacity of the Permian shales in the Lower Yangtze region, and the preliminary results of the present study have important implications for the shale gas play evaluation in this area.
•Permian shales in the Lower Yangtze region contain mainly gas-prone kerogen.•Porosity increases with TOC when TOC<12wt.%, but decreases for higher TOC samples.•Positive correlation exists between TOC and micropore volume for all samples.•Permian shales with TOC>4wt.% are suggested to have shale gas potential.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•Five complexes were designed and synthesized with H2BCBA ligand by solvothermal condition.•All of the complexes 1–5 have been structurally characterized by infrared spectra (IR), elemental analyses, ...single-crystal X-ray diffraction analyses and thermogravimetric analyses (TGA).•The reciprocal H…O/H/Br/C contacts dominate over 86 % of total Hirshfeld surface.•Photo-luminescence properties and Solid-state UV–Vis diffuse reflectance spectroscopy of complexes 1–5 were investigated.•Antifungal activity for complexes 1–5 were investigated.
Five complexes Co(BCBA)(H2O)3n (1), Co(BCBA)(4,4′-Bipy)2·(H2O)n (2), Cu(BCBA)(H2O)n (3), Zn(BCBA)(H2O)n (4) and Cd(BCBA)(2,2′-Bipy)(H2O)·(H2O)n (5) (H2BCBA= 5‑bromo-2-(carboxymethoxy)benzoic acid, 4,4′-Bipy = 4,4′-bipyridine and 2,2′-Bipy = 2,2′-bipyridine) have been synthesized with H2BCBA ligand by solvothermal condition. All the complexes have been structurally characterized by infrared spectra (IR), elemental analyses and single-crystal X-ray diffraction analyses. Complex 1 is a zero-dimensional structure, and complexes 2–5 are one-dimensional chain structure. Furthermore, thermogravimetric analyses (TGA), Hirshfeld surface analysis, photo-luminescence properties, Solid-state UV–Vis diffuse reflectance spectroscopy and antifungal activity for complexes 1–5 were investigated. The reciprocal H···O/H/Br/C contacts dominate over 86 % of total Hirshfeld surface. Complexes 1–5 have certain inhibitory effects on 8 pathogenic fungi. Among them, complex 5 has the strongest antibacterial activity against Rhizoctonia solani AG1, Sphaeropsis sapinea and Colletotrichum fructicola, and the inhibitory rate reached 100 %.
Five complexes were synthesized and structurally characterized. The reciprocal H…O/H/Br/C contacts dominate over 86 % of total Hirshfeld surface. Photo-luminescence properties and Solid-state UV–Vis diffuse reflectance spectroscopy were investigated. Complex 5 has the strongest antibacterial activity and the inhibitory rate reached 100 %. Display omitted
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Disseminated nocardiosis is liable to be misdiagnosed owing to the non-specific clinical manifestations and laboratory/imaging findings. Metagenomic next-generation sequencing (mNGS) is a ...culture-independent and rapid method for direct identification of all microorganisms in clinical specimens.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
PDF
