Potential role of SNP rs2071475 in rheumatoid arthritis and inflammatory bowel disease in the East Asian population: a Mendelian randomization study.

BACKGROUND: Previous observational studies have identified an association between rheumatoid arthritis (RA) and inflammatory bowel disease (IBD). However, the causal relationship between RA and IBD in the East Asian population remains uncertain. METHODS: The two-sample Mendelian randomization (MR) analysis was conducted to elucidate the potential causal relationship between RA and IBD. Summary-level data from genome-wide association studies (GWAS) in the East Asian population were utilized, including RA (n = 19,190) and IBD (n = 6543), including Crohn's disease (CD, n = 5409) and ulcerative colitis (UC, n = 4853). The inverse variance weighted (IVW) method was employed as the primary analysis, supplemented by weighted median, weighted mode, simple median, MR-Egger, and MR-PRESSO analyses. Sensitivity analyses were conducted to assess the robustness of the results. Genetic data for RA (n = 22,515) were utilized to validate the findings in the East Asian population. RESULTS: The IVW method showed no significant association between genetically predicted RA and overall IBD in the East Asian population (OR = 1.028; 95% CI: 0.935-1.129; P = 0.567). The subgroup analysis revealed a positive association between RA and CD (OR = 1.268; 95% CI: 1.108-1.451; P < 0.001), while a negative association was observed with UC (OR = 0.839; 95% CI: 0.710-0.993; P = 0.041). These findings were supported by another set of RA data. Additionally, an SNP rs2071475 was identified to play an important role in CD and UC. CONCLUSION: This study revealed a potential increased susceptibility to CD and a decreased susceptibility to UC in the East Asian population with RA. Furthermore, a key SNP rs2071475 was discovered along with its opposite effects in CD and UC. These findings provide new evidence for research on the corresponding molecular mechanisms and offer insights for clinical management of RA-associated IBD.

Circ_0000284 upregulates RHPN2 to facilitate pancreatic cancer proliferation, metastasis, and angiogenesis through sponging miR-1179.

BACKGROUND: Circular RNA (circRNA) has been confirmed to be a key regulator for pancreatic cancer (PC) progression, but the role of circ_0000284 in PC development remains unclear. METHODS: Quantitative real-time PCR was used to measure the expression of circ_0000284, microRNA (miR)-1179, and rhophilin 2 (RHPN2). PC cell proliferation, metastasis, angiogenesis, and apoptosis were assessed by EdU assay, transwell assay, tube formation assay, and flow cytometry. Relative protein expression was determined by western blot analysis. The interaction between miR-1179 and circ_0000284 or RHPN2 was confirmed by dual-luciferase reporter assay and RNA pull-down assay. RESULTS: Circ_0000284 was significantly upregulated in PC tissues and cells, and its knockdown inhibited PC cell proliferation, migration, invasion, and angiogenesis while promoting apoptosis. MiR-1179 was downregulated in PC tissues and cells, and it could be sponged by circ_0000284. Moreover, the miR-1179 inhibitor reversed the regulation of circ_0000284 knockdown on PC cell progression. The highly expressed RHPN2 was found in PC tissues and cells, and it could be targeted by miR-1179. Also, circ_0000284 sponged miR-1179 to regulate RHPN2 expression. Overexpressed RHPN2 could reverse the regulation of circ_0000284 knockdown on PC cell progression. In addition, interference of circ_0000284 was discovered to repress PC tumor growth by regulating miR-1179/RHPN2.RHPN2. CONCLUSION: To sum up, our data confirmed that circ_0000284 facilitated PC malignant progression depending on the regulation of miR-1179/RHPN2 axis, suggesting that circ_0000284 might be a potential target for PC treatment.

Adsorption of Cd2+ and Ni2+ from Aqueous Single-Metal Solutions on Graphene Oxide-Chitosan-Poly(vinyl alcohol) Hydrogels.

The applications of graphene-based adsorbents were limited because of their complicated manufacturing technology and hi cost, thus it is very important to prepare new inexpensive and easily manufactured graphene-based adsorbents. Herein, novel GCP hydrogels with different graphene oxide (GO), chitosan (CS), and poly(vinyl alcohol) (PVA) ratios were facilely prepared through a method of freeze-thaw physical cross-linking, which was green and low-cost, and the structural characterization and adsorptive property of the optimum GCP1:2:4 hydrogel toward Cd2+ and Ni2+ in wastewater was evaluated. It was found that the GCP1:2:4 hydrogel had good mechanical strength and a special 3D interconnection porous structure. The isotherms of adsorption used the Langmuir model, and the kinetics of adsorption following the pseudo-second-order model were confirmed. Moreover, the adsorption property with respect to Cd2+ and Ni2+ in wastewater has been largely effected by the pH and was less influenced by the ionic strength and humic acid, and the GCP1:2:4 hydrogel possessed excellent adsorptive and recyclable properties. These results demonstrated that the GCP1:2:4 hydrogel could serve as a desirable adsorbent to get rid of heavy metal ions in sewage.

Importance of Sporopollenin Structure and Accessibility in the Sorption of Phenanthrene by Biota Spores and Pollens.

Although spores/pollens are so abundant and ubiquitous in the environment, the role of these natural organic matter concerning fate and transport of organic pollutants in the environment is neglected. Lipid-free fractions and sporopollenins were isolated from seven spores/pollens collected from lower and higher biota species and were characterized by elemental analysis, CO2 adsorption techniques, and advanced solid-state 13C nuclear magnetic resonance spectroscopy. Then, the sorption isotherms of phenanthrene (Phen) on all the samples were investigated by a batch technique. The sporopollenins were a highly cross-linked polymer including alkyl carbon, poly(methylene) carbon, and aromatic carbon as well as oxygen functionalities; additionally, their sorption capacities (Koc) for Phen reached up to 1 170 000 mL/g, suggesting that some of the sporopollenins were good biopolymeric sorbents for the removal of hydrophobic organic contaminants in aquatic media. A highly significant and positive correlation between the sorption capacity of Phen and the aliphaticity of the sporopollenins suggested that their structure was critical to Phen sorption. Meanwhile, the (O + N)/C atomic ratios and polar groups were significantly and negatively correlated with the sorption capacity of Phen, indicating that accessibility also played a significant role in the sorption process. Moreover, variable correlations between the sorption capacities (Koc) and the micropore volumes of the spore/pollen fractions were observed. This study sheds light on the importance of the polarity, microporosity, and structure of sporopollenins in the sorption process of Phen.

Age-related nomogram revealed optimal therapeutic option for older patients with primary liver cancer: less is more.

BACKGROUND: Age bias in therapeutic decisions for older patients with cancer exists. There is a clear need to individualize such decisions. METHODS: Based on the Surveillance, Epidemiology and End Results (SEER) database, 5081 primary liver cancer (PLC) patients between 2010 and 2014 were identified and divided into <64, 64-74 and >74 years group. Each group was randomly divided into training and internal validation cohorts, and patients who were diagnosed between 2015 and 2016 were included as an external validation. The nomogram model predicting overall survival (OS) was generated and evaluated based on the Cox regression for the influencing factors in prognosis. The K-M analysis was used to compare the difference among different treatments. RESULTS: KM analysis showed a significant difference for OS in three age groups (P < 0.001). At the same time, we also found different prognostic factors and their importance in different age groups. Therefore, we created three nomograms based on the results of Cox regression results for each age group. The c-index was 0.802, 0.766, 0.781 respectively. The calibration curve and ROC curve show that our model has a good predictive efficacy and the reliability was also confirmed in the internal and external validation set. An available online page was established to simplify and visualize our model (http://124.222.247.135/). The results of treatment analysis revealed that the optimal therapeutic option for PLCs was surgery alone. CONCLUSIONS: The optimal therapeutic option for older PLCs was surgery alone. The generated dynamic nomogram in this study may be a useful tool for personalized clinical decisions.

Depression increases the risk of gallstone: A cross-sectional study and Mendelian randomization analysis.

BACKGROUND: Gallstone, a common digestive disorder, poses a significant public health burden. Concurrently, depression is acknowledged as a health risk. However, limited information exists on depression's impact on gallstone formation. This study investigates depression's causal effect on gallstone risk. METHODS: Using National Health and Nutrition Examination Survey (NHANES) data, we conducted an observational study. The severity of depression was assessed using the Patient Health Questionnaire-9 (PHQ-9). Multivariable logistic regression and subgroup analyses explored the correlation between depression and gallstone risk. Mendelian Randomization (MR) analysis, leveraging Genome-Wide Association Studies (GWAS) data, reduced observational bias and elucidated causality. Inverse Variance Weighting (IVW) was the primary method, with sensitivity analyses validating results. RESULTS: In the observational study (7707 participants), gallstone risk was elevated in mild (OR: 1.58, 95 % CI 1.31-1.90, P < 0.001), moderate (OR: 2.07, 95 % CI 1.59-2.67, P < 0.001), and severe (OR: 2.41, 95 % CI 1.70-3.34, P < 0.001) depression groups (P for trend <0.001). Subgroup analyses revealed a stronger association in those under 65, females, non-Hispanic Black, individuals with obesity, smokers, and those with college education or higher. Mendelian Randomization indicated a causal link between genetically predicted depression and higher cholelithiasis risk (OR: 2.06, 95 % CI 1.34-3.17, P = 0.001), validated through sensitivity analyses and multi-cohort verification. CONCLUSION: Depression independently increases gallstone risk, particularly in those under 65, females, non-Hispanic Black, individuals with obesity, smokers, and those with college education or higher. Further validation is needed through multi-center, prospective cohort studies.

Shorter telomere length increases the risk of lymphocyte immunodeficiency: A Mendelian randomization study.

BACKGROUND: For a long time, the prevailing viewpoint suggests that shorter telomere contribute to chromosomal instability, which is a shared characteristic of both aging and cancer. The newest research presented that T cell immune deficiency rather than chromosome instability predisposes patients with short telomere syndromes to some cancers. However, the relationship between genetically determined telomere length (TL) and immune cells remains unclear. METHODS: The two-sample Mendelian randomization analysis was conducted to elucidate the potential causal relationship. The genetic data of TL and immune cells were obtained from the Genome-Wide Association Study. The inverse variance weighted (IVW) method was used to estimate the effects primarily and another four methods were as a supplement. Sensitivity analysis was used to test the results. RESULTS: The IVW method showed a significant correlation between TL and the percentage of T cells in lymphocytes (odds ratio [OR]: 1.222, 95% confidence interval [CI]: 1.014-1.472, p = .035), indicating that shorter TL significantly increases the risk of low T cell percentage. Further analysis of T cell subsets indicated that shorter TL may primarily lead to a lower percentage of Natural Killer T cells (OR: 1.574, 95% CI: 1.281-1.935, p < .001). Analysis of B cell subsets revealed that shorter TL may be associated with a higher percentage of Naive-mature B cells, and a lower percentage of Memory B cells. And the sensitivity analysis indicated the validity and robustness of our findings. CONCLUSION: In summary, our findings suggest that shorter TL may be associated with a decline in the percentage of T cell, as well as impediments in the differentiation of B cell, consequently leading to the onset of immunosenescence and immunodeficiency. The relevant mechanisms and potential therapeutic avenues still need further investigation.

OTUD1 Deficiency Alleviates LPS-Induced Acute Lung Injury in Mice by Reducing Inflammatory Response.

The ovarian tumor (OTU) family consists of deubiquitinating enzymes thought to play a crucial role in immunity. Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) pose substantial clinical challenges due to severe respiratory complications and high mortality resulting from uncontrolled inflammation. Despite this, no study has explored the potential link between the OTU family and ALI/ARDS. Using publicly available high-throughput data, 14 OTUs were screened in a simulating bacteria- or LPS-induced ALI model. Subsequently, gene knockout mice and transcriptome sequencing were employed to explore the roles and mechanisms of the selected OTUs in ALI. Our screen identified OTUD1 in the OTU family as a deubiquitinase highly related to ALI. In the LPS-induced ALI model, deficiency of OTUD1 significantly ameliorated pulmonary edema, reduced permeability damage, and decreased lung immunocyte infiltration. Furthermore, RNA-seq analysis revealed that OTUD1 deficiency inhibited key pathways, including the IFN-γ/STAT1 and TNF-α/NF-κB axes, ultimately mitigating the severity of immune responses in ALI. In summary, our study highlights OTUD1 as a critical immunomodulatory factor in acute inflammation. These findings suggest that targeting OTUD1 could hold promise for the development of novel treatments against ALI/ARDS.

Compound SJ-12 attenuates streptozocin-induced diabetic cardiomyopathy by stabilizing SERCA2a.

Heart failure (HF) is one of the major causes of death among diabetic patients. Although studies have shown that curcumin analog C66 can remarkably relieve diabetes-associated cardiovascular and kidney complications, the role of SJ-12, SJ-12, a novel curcumin analog, in diabetic cardiomyopathy and its molecular targets are unknown. 7-week-old male C57BL/6 mice were intraperitoneally injected with single streptozotocin (STZ) (160 mg/kg) to develop diabetic cardiomyopathy (DCM). The diabetic mice were then treated with SJ-12 via gavage for two months. Body weight, fast blood glucose, cardiac utrasonography, myocardial injury markers, pathological morphology of the heart, hypertrophic and fibrotic markers were assessed. The potential target of SJ-12 was evaluated via RNA-sequencing analysis. The O-GlcNAcylation levels of SP1 were detected via immunoprecipitation. SJ-12 effectively suppressed myocardial hypertrophy and fibrosis, thereby preventing heart dysfunction in mice with STZ-induced heart failure. RNA-sequencing analysis revealed that SJ-12 exerted its therapeutic effects through the modulation of the calcium signaling pathway. Furthermore, SJ-12 reduced the O-GlcNAcylation levels of SP1 by inhibiting O-linked N-acetylglucosamine transferase (OGT). Also, SJ-12 stabilized Sarcoplasmic/Endoplasmic Reticulum Calcium ATPase 2a (SERCA2a), a crucial regulator of calcium homeostasis, thus reducing hypertrophy and fibrosis in mouse hearts and cultured cardiomyocytes. However, the anti-fibrotic effects of SJ-12 were not detected in SERCA2a or OGT-silenced cardiomyocytes, indicating that SJ-12 can prevent DCM by targeting OGT-dependent O-GlcNAcylation of SP1.These findings indicate that SJ-12 can exert cardioprotective effects in STZ-induced mice by reducing the O-GlcNAcylation levels of SP1, thus stabilizing SERCA2a and reducing myocardial fibrosis and hypertrophy. Therefore, SJ-12 can be used for the treatment of diabetic cardiomyopathy.

Determination of intermolecular and intramolecular isotopic compositions of low-abundance gaseous hydrocarbons using an online hydrocarbon gas concentration method.

The stable isotopic composition of natural gas can be used to identify its origin and source. However, low concentrations of gaseous hydrocarbons in high-mature natural and shale gases hinder accurate determination of their compound- and position-specific isotopic compositions. In this study, an online C2+ hydrocarbon gas concentration system combined with gas chromatography-isotope ratio mass spectrometry (GC-IRMS) or gas chromatography-pyrolysis-gas chromatography-isotope ratio mass spectrometry (GC-Py-GC-IRMS) was developed to determine compound- and position-specific isotopic compositions of low-abundance gaseous hydrocarbons. The lower limit of the gas concentration required for isotope ratio determination using the online concentration system is 0.001% (0.003%) for compound-specific carbon (hydrogen) isotopes and 0.005% for position-specific carbon isotopes and is thus applicable to most natural gas samples. The online concentration technique does not cause significant isotopic fractionation effects, and the combination with GC-IRMS and GC-Py-GC-IRMS can accurately and precisely determine the compound-specific δ13C and δD values of low-content C2+ gaseous hydrocarbons and the position-specific δ13C values (δ13Ca, δ13Cb, and SP values) of propane in low-content propane samples, respectively. The application of our method to two natural gas samples from the Ordos and Sichuan basins further confirms that the online concentration method allows simple and rapid determination of the compound- and position-specific isotopic compositions of low-abundance gaseous hydrocarbons.

Determination of carbon isotopic composition of crocetane in sediments by heart-cutting two-dimensional gas chromatography-isotope ratio mass spectrometry.

Compound-specific isotope analysis of crocetane in sediments can be used to determine its origin. However, the co-elution of crocetane with phytane and complex substrates hinders the accurate determination of its isotopic composition. A heart-cutting two-dimensional gas chromatography-isotope ratio mass spectrometry (2D-GC-IRMS) method was developed to determine δ13C values of crocetane. Full chromatographic separation of crocetane was achieved with a 30 m CycloSil-B chiral capillary first column and a 60 m Chiraldex B-pH capillary second column (two series-connected 30 m Chiraldex B-pH capillary columns). Analyses of standard mixtures confirmed that the new method has satisfactory accuracy (deviations from the authentic values <0.5‰) and precision (RSDs <5%) for carbon isotope analyses of crocetane and phytane. The application of the method to two sediment samples indicates that baseline resolution is achieved (R >1.5) for crocetane and phytane, with 13C-depleted crocetane (δ13C values of -119.5‰ and -111.5‰ in the two natural samples, respectively) being an indicator of anaerobic oxidation of methane in cold seep areas. The new 2D-GC-IRMS method allows simple and efficient determination of the compound-specific carbon isotopic compositions of crocetane.

Using Nanoindentation to Characterize the Mechanical and Creep Properties of Shale: Load and Loading Strain Rate Effects.

The mechanical and creep properties of shale strongly influence artificial hydraulic fracturing, wellbore stability, and the evaluation of reservoir performance in shale gas exploration. This study characterized these mechanical and creep properties at the microscale through nanoindentation tests and evaluated their dependence on the indentation test parameters, specifically, the indentation load and the loading strain rate. The mechanical parameters (the Young's modulus and hardness) of shale were strongly influenced by the magnitude of an indentation load (2-400 mN). Both parameters decreased sharply as the load increased from 2 to 200 mN; they then remained relatively stable at loads of 200-400 mN, suggesting that large indentation loads (200-400 mN) can be used to detect the mechanical responses of bulk shale. In contrast, both parameters increased slightly as the loading strain rate increased from 0.005 to 0.1 s-1. The indentation creep (C IT), related to creep behavior, and the creep strain rate sensitivity (m), related to the creep mechanism of shale, both increased with increasing the indentation load, whereas they decreased with increasing the loading strain rate. This demonstrates that increasing the load or decreasing the loading strain rate can increase creep deformation in shale during nanoindentation creep testing. The values of m varied from 0.040 to 0.124 under different loading conditions, suggesting that dislocation power-law creep may be the main mechanism controlling creep in shale. This study standardizes the testing parameters for the characterization of the mechanical properties of shale by nanoindentation testing and also advances our understanding of the deformation mechanisms of shale at the microscale.

Nonflammable, robust and flexible electrolytes enabled by phosphate coupled polymer-polymer for Li-metal batteries.

Liquid organic electrolytes commonly employed in commercial Li-ion batteries suffer from safety issues such as flammability and explosions. Replacing liquid electrolytes with nonflammable electrolytes has become increasingly attractive in the development of safe, high-energy Li-metal batteries (LMBs). In this work, nonflammable, robust, and flexible composite polymer-polymer electrolytes (PPEs) were successfully fabricated by flame-retardant solution casting with polyimide (PI) and polyvinylidene fluoride (PVDF). The optimized nonflammable PPEs (e.g., PPE-50) demonstrate not only good mechanical properties (i.e., a high tensile strength of 29.6 MPa with an elongation at break of 87.2%), but also high Li salts dissolubility, the former of which ensures the suppression of Li dendrites, while the latter further improves the ionic conductivity (∼1.86 × 10-4 S cm-1 at 30 °C). The resulting symmetric cells (Li|PPE-50|Li) offer excellent Li stripping and plating stability for 1000 h at 0.5 mA cm-2/0.25 mAh cm-2 and 600 h at 2.0 mA cm-2/1.0 mAh cm-2. In addition, the LiFePO4|PPE-50|Li half cells show high cycling performance (e.g., a reversible discharge capacity of 135.9 mAh g-1 after 300 cycles at 1C) and rate capability (e.g., 117.2 mAh g-1 at 4C). The PPE-50 is also compatible with a high-voltage cathode (e.g., LiNi0.5Mn0.3Co0.2O2), and the resulting batteries demonstrate long-term cycling stability with a high cut-off voltage of 4.5 V vs. Li/Li+. Because of the incorporation of a mechanically robust and thermally stable PI, a polar PVDF, and flame-retardant trimethyl phosphate (TMP) within PPEs, as well as the coordination between Li salts and TMP, and the interaction between Li salts and polymers (especially between Li bis(oxalato)borate) and PI, as well as the bis(oxalato)borate anion and PI), PPEs show great potential for practical and high-energy LMBs without safety concerns.

Pore Size Distribution and Fractal Characteristics of the Nanopore Structure in Organic-Rich Shales Using the Neimark-Kiselev Fractal Approach.

Shale gas has been playing an increasingly important role in meeting global energy demands. The heterogeneity of the pore structure in organic-rich shales greatly affects the adsorption, desorption, diffusion and flow of gas. The pore size distribution (PSD) is a key parameter of the heterogeneity of the shale pore structure. In this study, the Neimark-Kiselev (N-K) fractal approach was applied to investigate the heterogeneity in the PSD of the lower Silurian organic-rich shales in South China using low-pressure N2 adsorption, total organic carbon (TOC) content, maturity analysis, X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) measurements. The results show that (1) the fractal dimension DN-K obtained by N-K theory better represents the heterogeneity of the PSD in shale at an approximately 1-100 nm scale. The DN-K values range from 2.3801 to 2.9915, with a mean of 2.753. The stronger the PSD heterogeneity is, the higher the DN-K value in shale is. (2) The clay-rich samples display multimodal patterns at pore sizes greater than 20 nm, which strongly effect the PSD heterogeneity. Quartz-rich samples display major peaks at less than or equal to a 10 nm pore size, with a smaller effect on the PSD heterogeneity in most cases. In other brittle mineral-rich samples, there are no obvious major peaks, and a weak heterogeneity of the PSDs is displayed. (3) A greater TOC content, maturity, clay content and pore size can cause stronger heterogeneity of the PSD and higher fractal dimensions in the shale samples. This study helps to understand and compare the PSD and fractal characteristics from different samples and provides important theoretical guidance and a scientific basis for the exploration and development of shale gas resources.

Preparation and Antimicrobial Activity of Antibacterial Silver-Loaded Polyphosphazene Microspheres.

Poly(cyclotriphosphazene-co-4,4'-diaminodiphenyl ether) (PPO) microspheres were prepared via a precipitation polymerization method, using hexachlorocyclotriphosphazene (HCCP) and 4,4'-diaminodiphenyl ether (ODA) as monomers. Silver-loaded PPO (PPOA) microspheres were generated by the in situ loading of silver nanoparticles onto the surface by Ag+ reduction. Our results showed that PPOA microspheres were successfully prepared with a relatively uniform distribution of silver nanoparticles on microsphere surfaces. PPOA microspheres had good thermal stability and excellent antibacterial activity towards Escherichia coli and Staphylococcus aureus. Furthermore, PPOA microspheres exhibited lower cytotoxicity when compared to citrate-modified silver nanoparticles (c-Ag), and good sustained release properties. Our data indicated that polyphosphazene-based PPOA microspheres are promising antibacterial agents in the biological materials field.

Importance of the structure and micropores of sedimentary organic matter in the sorption of phenanthrene and nonylphenol.

The demineralized fraction (DM), lipid-free fraction (LF), nonhydrolyzable organic carbon fraction (NHC), and black carbon (BC) were isolated from five marine surface sediments, and they were characterized by elemental analysis as well as CO2 and N2 adsorption techniques, respectively. The NHC fractions were characterized using advanced solid-state 13C nuclear magnetic resonance (NMR) and x-ray photoelectron spectroscopy (XPS). Then, the sorption isotherms of phenanthrene (Phen) and nonylphenol (NP) on all of the samples were investigated by a batch technique. The CO2 micropore volumes were corrected for the outer specific surface areas (SSAs) by using the N2-SSA. Significant correlations between the micropore-filling volumes of Phen and NP and the micropore volumes suggested that the micropore-filling mechanism dominated the Phen and NP sorption. Meanwhile, the (O + N)/C atomic ratios were negatively and significantly correlated with the sorption capacities of Phen and NP, indicating that the sedimentary organic matter (SOM) polarity also played a significant role in the sorption process. In addition, a strong linear correlation was demonstrated between the aromatic C and the sorption capacity of Phen for the NHC fractions. This study demonstrates the importance of the micropores, polarity, and aromaticity on the sorption processes of Phen and NP in the sediments.

Can AFM be used to measure absolute values of Young's modulus of nanocomposite materials down to the nanoscale?

At present, a technique potentially capable of measuring values of Young's modulus at the nanoscale is atomic force microscopy (AFM) working in the indentation mode. However, the question if AFM indentation data can be translated into absolute values of the modulus is not well-studied as yet, in particular, for the most interesting case of stiff nanocomposite materials. Here we investigate this question. A special sample of nanocomposite material, shale rock, was used, which is relatively homogeneous at the multi-micron scale. Two AFM modes, force-volume and PeakForce QNM were used in this study. The nanoindentation technique was used as a control benchmark for the measurement of effective Young's modulus of the shale sample. The indentation rate was carefully controlled. To ensure the self-consistency of the mechanical model used to analyze AFM data, the model was modified to take into account the presence of the surface roughness. We found excellent agreement between the average values of effective Young's modulus calculated within AFM and the nanoindenter benchmark method. At the same time, the softest and hardest areas of the sample were seen only with AFM.

Compound-specific stable carbon isotopic composition of petroleum hydrocarbons as a tool for tracing the source of oil spills.

With the increasing demand for and consumption of crude oils, oil spill accidents happen frequently during the transportation of crude oils and oil products, and the environmental hazard they pose has become increasingly serious in China. The exact identification of the source of spilled oil can act as forensic evidence in the investigation and handling of oil spill accidents. In this study, a weathering simulation experiment demonstrates that the mass loss of crude oils caused by short-term weathering mainly occurs within the first 24h after a spill, and is dominated by the depletion of low-molecular weight hydrocarbons (

Nanopore-filling effect of phenanthrene sorption on modified black carbon.

Black carbon was produced by slow pyrolysis under an oxygen-limited condition at 500 °C, and was modified by some chemical methods (oxidation, hydrolysis, activation, and surface recombination). The modified samples were characterized by using elemental analysis, Fourier transformed infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) surface analysis, Boehm titration, cation exchange capacity(CEC)analysis, CO2 adsorption analysis, and then used to investigate the sorption behavior of phenanthrene. The results showed that the activation of ZnCl2 gave a maximum nanopore volume of 96.5 µL/g and a specific surface area of 241 m2/g, while the oxidation of NaClO gave a minimum nanopore volume of 63.3 µL/g and a specific surface area of 158 m2/g. The FTIR, XPS, and Boehm titration analysis showed that the new oxygen-containing functional groups were introduced during the oxidation treatments of H2O2 and NaClO. The sorption of phenanthrene on all samples was typically nonlinear, and the nonlinear factor (n) was negatively correlated with Vo, especially with Vo at 0-1.1 nm. The sorption parameter (log KOC) was positively correlated with nanopore volume (Vo) and specific surface area (SSA). Moreover, the model analysis showed that the nanopore filling was the main sorption mechanism, and molecular sieve effect was observed in the sorption of phenanthrene.