The coal-measure rock masses of China's Ordos Basin are mainly composed of typical soft rock with low strength, which bear loads together with the coal seams during coal mining activities. Accurately ...determining the mechanical behaviors of combination soft rock and coal masses can provide a basis for underground coal engineering designs. First, uniaxial compression tests were conducted on medium sandstone samples, coal samples, and coal-rock combination samples. It was observed that the peak axial strain, uniaxial compressive strength, stress-strain curve shape, and elastic modulus of the combination samples were closer to those of the coal samples, indicating that the mechanical characteristics of soft rock-coal combination samples were mainly affected by the coal. Then, using the static equilibrium and deformation continuous conditions, along with the Griffith strength criterion, the ultimate compressive strength of materials at different positions in a combination model was analyzed. The results revealed that the interface constraint effects had reduced the strength of the sandstone near the interface and improved that of the coal near the interface. The interface constraint effects were verified by comparing the generalized Poisson's ratio of materials at different positions with those of the standard coal and sandstone samples. Finally, based on the final failure modes, and the temporal characteristics of the acoustic emission (AE) count rate and peak frequency, the progressive failure mechanism of the soft rock-coal combination samples was studied. This failure process was found to be characterized by the synergistic failure of the material and structure. Furthermore, the effect of coal-rock height ratio on the strength of materials at different positions was discussed, which interpreted the experimental results observed in the previous related studies, namely, with the increase in the rock-coal height ratio, the strength of the combination samples had increased, and the impact tendency had been significantly enhanced.
•Natural high-F– groundwater mainly occurs in confined aquifers in the Guide basin.•Along the flow path, F– is gradually enriched in groundwater in confined aquifer.•High-F– groundwater is ...characterized by low Ca2+ and high Na+, pH, HCO3–•Precipitation of Ca2+ enhances dissolution of F–-bearing minerals and release of F–•Geothermal waters favor F– enrichment in confined groundwater.
High fluoride (F–) concentrations in groundwater affected by geothermal activity have been reported worldwide, but the genesis mechanism is not adequately understood. In this study, 92 groundwater samples and 63 sediment samples were collected from the China’s Guide basin for chemical analyses and laboratory tests. Results indicate that groundwater F– concentrations continuously increase along a flow path, being consistent with trends of Na+ and HCO3– concentrations, Na/Ca molar ratio, and pH values, while Ca2+ concentrations show a decreasing trend. Water-soluble F– contents in sediments increase as the depth increases. Higher-F– groundwater samples generally have lower δD and δ18O values than those of lower F– samples. The major hydrogeochemical processes controlling the formation of high-F– groundwater include precipitation of Ca2+ or cation exchange between Ca2+ and Na+ or both, which enhance dissolutions of F–-containing minerals and facilitate the release of F– into groundwater. Slightly alkaline environments and increased HCO3– and CO32– concentrations favor desorption of F– from solid surfaces into groundwater. Closed hydrogeological conditions and long-term water–rock interactions in confined aquifers accumulate F– in groundwater. Exposed geothermal springs around the Guide basin also contribute to the formation of high-F– groundwaters directly by the input of geothermal water and indirectly by heat transfer into aquifers at a regional scale, which is a problem deserving further investigation.
Immunohistochemistry has become an indispensable ancillary study in the identification and classification of undifferentiated neoplasms/tumors of uncertain origin. The diagnostic accuracy has ...significantly improved because of the continuous discoveries of tissue-specific biomarkers and the development of effective immunohistochemical panels.
To identify and classify undifferentiated neoplasms/tumors of uncertain origin by immunohistochemistry.
Literature review and authors' research data and personal practice experience were used.
To better guide therapeutic decisions and predict prognostic outcomes, it is crucial to differentiate the specific lineage of an undifferentiated neoplasm. Application of appropriate immunohistochemical panels enables the accurate classification of most undifferentiated neoplasms. Knowing the utilities and pitfalls of each tissue-specific biomarker is essential for avoiding potential diagnostic errors because an absolutely tissue-specific biomarker is exceptionally rare. We review frequently used tissue-specific biomarkers, provide effective panels, and recommend diagnostic algorithms as a standard approach to undifferentiated neoplasms.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK, VSZLJ
Accurate classification of follicular-patterned thyroid lesions is not always an easy task on routine surgical hematoxylin-eosin-stained or cytologic fine-needle aspiration specimens. The diagnostic ...challenges are partially due to differential diagnostic criteria that are often subtle and subjective. In the past decades, tremendous advances have been made in molecular gene profiling of tumors and diagnostic immunohistochemistry, aiding in diagnostic accuracy and proper patient management.
To evaluate the diagnostic utility of the most commonly studied immunomarkers in the field of thyroid pathology by review of the literature, using the database of indexed articles in PubMed (US National Library of Medicine) from 1976-2013.
Literature review, authors' research data, and personal practice experience.
The appropriate use of immunohistochemistry by applying a panel of immunomarkers and using a standardized technical and interpretational method may complement the morphologic assessment and aid in the accurate classification of difficult thyroid lesions.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK, VSZLJ
Iron oxyhydroxides are among the most important colloids that control rare earth elements (REE) concentrations and transport in natural hydrosystems. In this study, REE surface complexation to iron ...oxyhydroxides (Fe(OH)3(a)) was described by using the Donnan diffuse layer model and a two-site (i.e. ≡FesOH and ≡FewOH) model. The specific surface area and pH of zero charge were fixed as 100000 m2/mol and 8.0, respectively. The surface site density for weak and strong binding sites were fixed at 0.1 moL/mol Fe (≡FewOH) and 0.001 moL/mol Fe (≡FesOH) respectively. The two site types were used with pKa1int = 7.29 and pKa2int = 8.93. Using linear free energy relationship, the estimated equilibrium surface complexation constants (log K) increased from light REE (LREE) to heavy REE (HREE). Results of REE modeling calculation using the determined log K revealed a good fit of experimental data, showing an order of sorption on iron oxyhydroxides: HREE > MREE > LREE and preferential sorption of HREE at a lower pH. However, sorption edges only showed a slight change with ionic strength (0.1–0.7 moL/L) for the whole REE series. The generalized model was subsequently used to evaluate the impact of iron oxyhydroxides on REE speciation in groundwater. Application of the model to “model groundwater” showed that iron oxyhydroxide complexes of REE were significant in near neutral and weakly alkaline pH. This study contributes to putting forward a comprehensive database which would be useful for the application of surface complexation model to describe REE sorption by amorphous ferric hydroxides in nature.
Display omitted
•Modeling study of the REE sorption onto iron oxyhydroxide is proposed.•Binding was described using two sites Donnan diffuse layer.•Heavy REE show a greater affinity for iron oxyhydroxide than light REE and middle REE.•Modeling suggests a preferential accumulation of Ce on solid phase than its neighboring La and Pr.•The proposed model is able to predict the impact of iron oxyhydroxide on REE in nature.
Circular RNAs (circRNAs) have confirmed to participate in diverse biological functions in cancer. However, the expression patterns of circRNAs on hepatocellular carcinoma (HCC) remains unclear. In ...the present study, we clarified that hsa_circRNA_104348 was dramatically upregulated in HCC tissues and cells. Patients with HCC displaying high hsa_circRNA_104348 level possessed poor prognosis. Has_circ_104348 facilitated proliferation, migration, and invasion, meanwhile suppressed apoptosis of HCC cell. Furthermore, hsa_circRNA_104348 directly targeted miR-187-3p, could regulate miR-187-3p to affect proliferation, migration, invasion, and apoptosis of HCC cells, and may have effect on Wnt/β-catenin signaling pathway. Moreover, RTKN2 could be a direct target of miR-187-3p. In addition, knockdown of hsa_circRNA_104348 attenuated HCC tumorigenesis and lung metastasis in vivo. Taken together, these findings indicated that circular RNA hsa_circRNA_104348 might function as a competing endogenous RNA (ceRNA) to promotes HCC progression by targeting miR-187-3p/RTKN2 axis and activating Wnt/β-catenin pathway.
The disease-information coupling propagation dynamics model is a widely used model for studying the spread of infectious diseases in society, but the parameter settings and sensitivity are often ...overlooked, which leads to enlarged errors in the results. Exploring the influencing factors of the disease-information coupling propagation dynamics model and identifying the key parameters of the model will help us better understand its coupling mechanism and make accurate recommendations for controlling the spread of disease. In this paper, Sobol global sensitivity analysis algorithm is adopted to conduct global sensitivity analysis on 6 input parameters (different cross regional jump probabilities, information dissemination rate, information recovery rate, epidemic transmission rate, epidemic recovery rate, and the probability of taking preventive actions) of the disease-information coupling model with the same interaction radius and heterogeneous interaction radius. The results show that: (1) In the coupling model with the same interaction radius, the parameters that have the most obvious influence on the peak density of nodes in state AI and the information dissemination scale of the information are the information dissemination rate βI and the information recovery rate μI. In the coupling model of heterogeneous interaction radius, the parameters that have the most obvious impact on the peak density of nodes in the AI state of the information layer are: information spread rate βI, disease recovery rate μE, and the parameter that has a significant impact on the scale of information spread is the information spread rate βI and information recovery rate μI. (2) Under the same interaction radius and heterogeneous interaction radius, the parameters that have the most obvious influence on peak density of nodes in state SE and the disease transmission scale of the disease layer are the disease transmission rate βE, the disease recovery rate μE, and the probability of an individual moving across regions pjump.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Carbon dots (CDs) are known as the rising star of carbon-based nanomaterials and, by virtue of their unique structure and fascinating properties, they have attracted considerable interest in ...different fields such as biological sensing, drug delivery, photodynamic therapy, photocatalysis, and solar cells in recent years. Particularly, the outstanding electronic and optical properties of the CDs have attracted increasing attention in biomedical and photocatalytic applications owing to their low toxicity, biocompatibility, excellent photostability, tunable fluorescence, outstanding efficient up-converted photoluminescence behavior, and photo-induced electron transfer ability. This article reviews recent progress on the synthesis routes and optical properties of CDs as well as biomedical and photocatalytic applications. Furthermore, we discuss an outlook on future and potential development of the CDs based biosensor, biological dye, biological vehicle, and photocatalysts in this booming research field.
A kind of nitrogen- and oxygen-containing activated carbon nanotubes (ACNTs) has been prepared by carbonization and activation of polyaniline nanotubes obtained by rapidly mixed reaction. The ACNTs ...show oxygen content of 15.7% and nitrogen content of 2.97% (atomic ratio). The ACNTs perform high capacitance and good rate capability (327 F g−1 at the current density of 10 A g−1) when used as the electrode materials for supercapacitors. Hydrogen reduction has been further used to investigate the effects of surface functional groups on the electrochemical performance. The changes for both structural component and electrochemical performance reveal that the quinone oxygen, pyridinic nitrogen, and pyrrolic nitrogen of carbon have the most obvious influence on the capacitive property because of their pseudocapacitive contributions.
•Activated carbon nanotubes were prepared using polyaniline as precursor.•The activated carbon nanotubes show high N, O contents and high surface areas.•Both high specific capacitance and rate capability were achieved.•Effects of surface functional groups were investigated by hydrogen reduction.
Nature has provided a fantastic array of enzymes that are responsible for essential biochemical functions but not usually suitable for technological applications. Not content with the natural ...repertoire, protein engineering holds promise to extend the applications of improved enzymes with tailored properties. However, engineering of robust proteins remains a difficult task since the positive mutation library may not cooperate to reach the target function in most cases owing to the ubiquity of epistatic effects. The main demand lies in identifying an efficient path of accumulated mutations. Herein, we devised a computational strategy (greedy accumulated strategy for protein engineering, GRAPE) to improve the robustness of a PETase from Ideonella sakaiensis. A systematic clustering analysis combined with greedy accumulation of beneficial mutations in a computationally derived library enabled the redesign of a variant, DuraPETase, which exhibits an apparent melting temperature that is drastically elevated by 31 °C and a strikingly enhanced degradation toward semicrystalline poly(ethylene terephthalate) (PET) films (30%) at mild temperatures (over 300-fold). Complete biodegradation of 2 g/L microplastics to water-soluble products under mild conditions is also achieved, opening up opportunities to steer the biological degradation of uncollectable PET waste and further conversion of the resulting monomers to high-value molecules. The crystal structure revealed the individual mutation match with the design model. Concurrently, synergistic effects are captured, while epistatic interactions are alleviated during the accumulation process. We anticipate that our design strategy will provide a broadly applicable strategy for global optimization of enzyme performance.
PDF
