Improving Representation Learning for Histopathologic Images with Cluster Constraints.

Recent advances in whole-slide image (WSI) scanners and computational capabilities have significantly propelled the application of artificial intelligence in histopathology slide analysis. While these strides are promising, current supervised learning approaches for WSI analysis come with the challenge of exhaustively labeling high-resolution slides-a process that is both labor-intensive and timeconsuming. In contrast, self-supervised learning (SSL) pretraining strategies are emerging as a viable alternative, given that they don't rely on explicit data annotations. These SSL strategies are quickly bridging the performance disparity with their supervised counterparts. In this context, we introduce an SSL framework. This framework aims for transferable representation learning and semantically meaningful clustering by synergizing invariance loss and clustering loss in WSI analysis. Notably, our approach outperforms common SSL methods in downstream classification and clustering tasks, as evidenced by tests on the Camelyon16 and a pancreatic cancer dataset. The code and additional details are accessible at https://github.com/wwyi1828/CluSiam.

Improving the Weak Gel Structure of an Oil-Based Drilling Fluid by Using a Polyamide Wax.

Oil-based drilling fluids (OBDFs) are widely used, but there are common problems associated with them, such as low yield point and poor cutting-carrying and hole cleaning ability. In this paper, a polyamide wax (TQ-1) was synthesized from dimeric acid and 1,6-hexanediamine to improve the weak gel structure of OBDFs. The TQ-1 was characterized by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Then the effect of the TQ-1 on the stability of the water-in-oil emulsion was studied by sedimentation observation, stability analysis, an electrical stability test, and particle size measurement. The effect of the TQ-1 on the rheological properties of the water-in-oil emulsion was analyzed by viscosity vs. shear rate test and the three-interval thixotropic test. Finally, the performance of the TQ-1 in OBDFs was comprehensively evaluated. The experimental results showed that the initial thermal decomposition temperature of the TQ-1 was 195 °C, indicating that the TQ-1 had good thermal stability. After adding the TQ-1, the emulsion became more stable since the emulsion stability index (TSI) value decreased when the emulsions were placed for a period of time and the demulsification voltage was increased. The TQ-1 could form a weak gel structure in the water-in-oil emulsions, which made the emulsions show excellent shear thinning and thixotropy. TQ-1 can improve the demulsification voltage of OBDFs, greatly improve the yield point and gel strength, and largely reduce the sedimentation factor (SF). In addition, TQ-1 has good compatibility with OBDFs, and in our study the high-temperature and high-pressure (HTHP) filtration decreased slightly after adding the TQ-1. According to theoretical analysis, the mechanism of TQ-1 of improving the weak gel structure of OBDFs is that the polar amide group can form a spatial network structure in nonpolar solvents through hydrogen bonding.

Nano-laponite/polymer composite as filtration reducer on water-based drilling fluid and mechanism study.

In drilling deep complex formations, most drilling fluid additives have insufficient temperature and salt tolerance, resulting in the decline of drilling fluid performance. This study used 2-acrylamide-2-methylpropane sulfonic acid, acrylamide, dimethyl diallyl ammonium chloride and modified nano-laponite to synthesize a nanocomposite filtrate reducer (ANDP) with excellent temperature and salt resistance, which can maintain the performance of drilling fluid. The structure of ANDP was analysed by a transmission electron microscope and an infrared spectrometer. The thermal stability of ANDP was studied by thermogravimetric analysis. The performance of ANDP was evaluated in a water-based drilling fluid. The mechanism was analysed per clay particle size distribution, Zeta potential, filter cake permeability and scanning electron microscopy imaging. The results show that ANDP has good thermal stability and the expected molecular structure. The filtration of freshwater drilling fluid after ageing at 200°C is 10.4 ml and that of saturated brine drilling fluid is 6.4 ml after ageing at 150°C. Mechanism analysis suggests that the ANDP increases the thickness of clay particle hydration layer and maintains the colloidal stability of the drilling fluid. ANDP inhibits the agglomeration of clay particles and significantly reduces the filtration by forming dense mud cake.

Improvement of Emulsion Stability and Plugging Performance of Nanopores Using Modified Polystyrene Nanoparticles in Invert Emulsion Drilling Fluids.

Drilling fluid invasion and pressure transmission caused by the development of micropores and fractures in shale oil and gas formations are the major factors contributing to wellbore instability during drilling using oil-based drilling fluids (OBFs). In this study, a modified polystyrene latex (MPL) material was synthesized through emulsion polymerization and was characterized using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), particle size analysis, scanning electron microscopy (SEM) observations, and contact angle testing. The influence of the MPL on the stability of a water-in-oil emulsion was analyzed via sedimentation observations and electrical stability tests. The effects of the MPL on the plugging mechanism of white oil and water-in-oil emulsions were evaluated using 0.1-1.0 µm micro-porous filtration films. The experimental results revealed that the MPL has a favorable thermal stability, with an initial thermal decomposition temperature of 363°C, a median particle size (D50) of 233 nm, and a three-phase contact angle of 103.5°. The MPL can enhance the sedimentation stability of an emulsion to a considerable extent and can improve the electrical stability (ES) of the emulsion, which is conducive to the stability of OBFs. Due to the deformability of the MPL, it has a wide range of adaptations for micro-scale pores and fractures. In both the white oil and water-in-oil emulsions, the MPL can reduce the filtration loss through microporous membranes with pore sizes of 0.1-1.0 µm to within 10 ml. This paper details the methodology of the synthesis of nanomaterials that can effectively plug a formation's nanopores and fractures; thereby, stabilizing OBFs.

[Glucosides of chaenomeles speciosa attenuate ischemia/reperfusion-induced brain injury by regulating NF-κB P65/TNF-α in mouse model].

OBJECTIVE: To investigate the effect and mechanism of glucosides of chaenomeles speciosa (GCS) on ischemia/reperfusion-induced brain injury in mouse model. METHODS: Fifty 8-week C57BL/C mice were randomly divided into five groups with 10 in each group:sham group, model group, GCS 30 mg/kg group, GCS 60 mg/kg group and GCS 90 mg/kg group, and the GCS was administrated by gavage (once a day) for 14 d. HE staining was performed to investigate the cell morphology; the Zea-Longa scores were measured for neurological activity; TUNEL staining was performed to investigate the cell apoptosis; ELISA was used to detected the oxidative stress and inflammation; Western Blot was performed to investigate the key pathway and neurological functional molecules. RESULTS: Compared with the sham group, the brain tissues in model group were seriously damaged, presenting severe cell apoptosis, oxidative stress and inflammation, associated with increased NF-κB P65 and TNF-α levels as well as decreased myelin associate glycoprotein (MAG) and oligodendrocyte-myelin glycoprotein (OMgp)levels (all P<0.01). Compared with the model group, the brain tissues in GCS groups were ameliorated, and cell apoptosis, oxidative stress and inflammation were inhibited, associated with decreased NF-κB P65 and TNF-α levels as well as increased MAG and OMgp levels (all P<0.01), which were more markedly in GCS 60 mg/kg group. CONCLUSIONS: GCS can inhibit the NF-κB P65 and TNF-α, reduce the oxidative stress and inflammation, decrease the cell apoptosis in mouse ischemia/reperfusion-induced brain injury model, and 60 mg/kg GCS may be the optimal dose.

MRI and clinical manifestations of delayed encephalopathy after carbon monoxide poisoning.

To explore the relationship between the clinical manifestations and functional magnetic resonance images of delayed encephalopathy after carbon monoxide intoxication. Six patients received the MRI were diagnosed with delayed encephalopathy after carbon monoxide (CO) poisoning. Clinical manifestations were observed in each patient. MRI revealed multiple lesions. The majority of the lesions were located in the globus pallidus, sub cortical white matter, and basal ganglia. The cognitive injury, akinetic mutism, fecal and uroclepsia, forced crying, forced laughing and extra pyramidal syndromes such as chorea and parkinsonism were manifested in clinic. Cognitive impairment improved greatly while involuntary movements only improved slightly after several months. Meanwhile brain MRI suggested remarkable improvement. Neuroimaging directly correlated with the clinical manifestations.

[Response of microbial fuel cell anodic microbial communities to substrate switch of lactate-propionate-lactate].

OBJECTIVE: To study the effect of substrates variation on the electricity production of microbial fuel cell (MFC) and anodic microbial communities. METHODS: An MFC was started up and operated by feeding in turn with lactate, then with propionate and finally with lactate. The anodic microbial communities were monitored by using culture-independent microbial molecular ecological techniques. RESULTS: The switch of substrates markedly affected the power efficiency of MFC. It required relatively long time to recover the electricity generation capability as the substrate was switched. The substrates switch also changed the microbial community structure. Anaeromusa spp. , Pseudomonas spp. and Thiobacillus thioparus were dominated with lactate fed because they were enriched in the presence of lactate. When propionate was supplied as sole substrate, Dechloromonas spp. and Comamonas testosterone were selected. The electricity-producing bacteria, Geobacter spp. , were enriched by acetate from either lactate or propionate degradation. Hence, Geobacter spp. was an overlapping microbial population in the presence of the two different substrates. CONCLUSION: A well correspondence between substrate and anodic microbial community was observed in MFC with switching substrates. To reduce the effect of substrate fluctuation on the MFC electricity production, more complex organic substrate should be provided as broader nutrients which could improve the functional overlap of populations and MFC stability.

Enrichment of anodic biofilm inoculated with anaerobic or aerobic sludge in single chambered air-cathode microbial fuel cells.

Aerobic sludge after anaerobic pretreatment and anaerobic sludge were separately used as inoculum to start up air-cathode single-chamber MFCs. Aerobic sludge-inoculated MFCs arrived at 0.27 V with a maximum power density of 5.79 W m(-3), while anaerobic sludge-inoculated MFCs reached 0.21 V with 3.66 W m(-3). Microbial analysis with DGGE profiling and high-throughput sequencing indicated that aerobic sludge contained more diverse bacterial populations than anaerobic sludge. Nitrospira species dominated in aerobic sludge, while anaerobic sludge was dominated by Desulfurella and Acidithiobacillus species. Microbial community structure and composition in anodic biofilms enriched, respectively from aerobic and anaerobic sludges tended gradually to be similar. Potentially exoelectrogenic Geobacter and Anaeromusa species, biofilm-forming Zoogloea and Acinetobacter species were abundant in both anodic biofilms. This study indicated that aerobic sludge performed better for MFCs startup, and the enrichment of anodic microbial consortium with different inocula but same substrate resulted in uniformity of functional microbial communities.

[Electricity generation and dynamics characteristics of microbial community of microbial fuel cells started up with mixture of aerobic/anaerobic sludge].

OBJECTIVE: To explore electricity generation and dynamic characteristics of microbial community of microbial fuel cells (MFC) started-up with mixed sludge of aerobic/anaerobic sludge. METHODS: Single-chamber MFCs were constructed and characteristics of microbial community composition and structure were investigated by culture-independent microbial molecular techniques. RESULTS: MFC started up successfully after three cycles' operation, and the maximum output voltage was up to 230 mV. The maximum power density reached 11.15 W/m3 at the outer resistance of 1656 Ω. The structure of microbial community on the anodic biofilm was different from that of seed sludge and microbial diversity reduced. The dominant microbial groups on anodic biofilm were Betaproteobacteria (24.90%), Bacteroidetes (21.30%), Firmicutes (9.70%), Gammaproteobacteria (8.50%), Deltaproteobacteria ( 7.90%), Chloroflexi (4.20%) and Alphaproteobacteria (3.60%). The biofilm-forming microbial genera Zoogloea and Acinetobacter accounted for 5.00% and 3.90% of total community. The abundance of electricity-producing bacteria Geobacter spp. increased from 0.60% in mixed sludge to 2.60% on the biofilm. CONCLUSION: Dominant microbial populations in mixed sludge were selected by long-term acclimation and finally a beneficial microbial group was built on the anodic biofilm. The populations group was helpful to form a functional and active biofilm, which consequently benefited to produce electricity under anaerobic condition by fermenting organic matter.

Biological treatment of steroidal drug industrial effluent and electricity generation in the microbial fuel cells.

The single chamber microbial fuel cells (MFCs) were used to treat steroidal drug production wastewater (SPW) and generate electricity simultaneously. The results indicated that the maximum COD removal efficiency reached 82%, total nitrogen and sulfate removal rate approached 62.47% and 26.46%, respectively. The maximum power density and the Coulombic efficiency reached to 22.3Wm(-3) and 30%, respectively. The scanning electron microscope showed that the dominant microbial populations were remarkably different in morphology on the surface of SPW and acetate-fed anodes. PCR-denaturing gradient gel electrophoresis profiles revealed that the microbial community structure fed with different concentrations of SPW presented a gradual succession and unique bacterial sequences were detected on the SPW and acetate-fed anodes. This research demonstrates that MFCs fed with SPW achieved a high efficiency of power density and simultaneous nutrient removal, and the dominant microorganisms on the anode were related to the types and the concentrations of substrates.

[Effect of tillage and fertilization on bacterial community structure in different depth of black soil].

OBJECTIVE: To analyze the impact of tillage and fertilization on bacterial community structure under different depth in black soil. METHODS: We used denaturing gradient gel electrophoresis (DGGE) profile analysis of bacterial community based on the 16S rRNA gene combining soil physico-chemical characteristics. RESULTS: DGGE profiles showed that tillage and fertilization influenced more on bacterial community structrue in the surface soil than the subsurface and deep soil, and the divergence distance between the tillage soil and the control was about 4%. Subsurface and deep soil affected less compared with the control, and the divergence distance was 2%. The vertical similarity of bacterial community structure between subsurface and the deep soil was higher than that of suface soil. CONCLUSION: Tillage and fertilization affected the surface bacterial community (0-30 cm), whereas little on the deeper soil (> 100 cm) bacterial community.

Characteristics of the microbial community in rhizosphere of Camptotheca acuminata cultured with exotic invasive plant Eupatorium adenophorum.

The traditional culture-dependent plate counting and culture-independent small-subunit-ribosomal RNA gene-targeted molecular techniques, Single-Strand Conformation Polymorphism (SSCP) and terminal Restriction Fragment Length Polymorphism (tRFLP) combined with 16S rDNA clone library were adopted to investigate the impacts of secretion from Camptotheca acuminata (abbreviated to Ca) roots on the quantities and structure of eukaryotic microbes and bacteria in the rhizosphere, and the possibility that Ca controls exotic invasive plant Eupatorium adenophorum (Ea). The counting results indicated that the number of bacteria increased in turn in rhizospheres of Ea, Ca-Ea mixed culture and Ca, while that of eukaryotic microbes decreased. PCR-SSCP profiles showed eukaryotic microbial bands (corresponding to biodiversity) in rhizosphere of Ea were more complex than those of Ca and CE. Meristolohmannia sp., Termitomyces sp. and Rhodophyllus sp. were the dominant populations in the rhizosphere of Ca. Bacterial terminal restriction fragments (TRFs) profiles showed no difference among three kinds of rhizospheres, and the sequences of the 16S rDNA clone library from Ca rhizospheres were distributed in 10 known phyla, in which phylum Proteobacteria were the absolute dominant group and accounted for 24.71% of the cloned sequences (delta-Proteobacteria accounted for up to 17.65%), and phyla Acidobacteria and Bacteroidetes accounted for 16.47% and 10.59% of the cloned sequences, respectively. In addition, high performance liquid chromatography detected a trace amount of camptothecin and hydroxycamptothecin in the rhizospheric soil of Ca and CE, but examined neither camptothecin nor hydroxycamptothecin in rhizospheric soil of Ea. Therefore, invasion and diffusion of Ea evidently depended on distinguishing the eukaryotic community structure, but not on that of the bacterial pattern. Ca was able to alter the eukaryotic community structure of invasive Ea by secreting camptothecin and hydroxycamptothecin into rhizospheres, and may benefit the control of overspread of Ea. This study provided theoretical evidence for rhizospheric microbial aspects on substituting Ca for Ea.

The effect of decreasing alkalinity on microbial community dynamics in a sulfate-reducing bioreactor as analyzed by PCR-SSCP.

PCR-single-strand conformation polymorphism (SSCP) and Southern blotting techniques were adopted to investigate microbial community dynamics in a sulfate-reducing bioreactor caused by decreasing influent alkalinity. Experimental results indicated that the sulfate-removal rate approached 87% in 25 d under the conditions of influent alkalinity of 4000 mg/L (as CaCO3) and sulfate-loading rate of 4.8 g/(L*d), which indicated that the bioreactor started up successfully. The analysis of microbial community structure in this stage showed that Lactococcus sp., Anaerofilum sp. and Kluyvera sp. were dominant populations. It was found that when influent alkalinity reduced to 1000 mg/L, sulfate-removal rate decreased rapidly to 35% in 3 d. Then influent alkalinity was increased to 3000 mg/L, the sulfate-removal rate rose to 55%. Under these conditions, the populations of Dysgonomonas sp., Sporobacte sp., Obesumbacterium sp. and Clostridium sp. got to rich, which predominated in the community together with Lactococcus sp., Anaerofilum sp. and Kluyvera sp. However, when the alkalinity was decreased to 1500 mg/L, the sulfate-removal rate rose to and kept stable at 70% and populations of Dysgonomonas sp., Sporobacter sp. and Obesumbacterium sp. died out, while some strains of Desulfovibrio sp. and Clostridium sp. increased in concentration. In order to determine the minimum alkalinity value that the system could tolerate, the influent alkalinity was decreased from 1500 to 400 mg/L secondly. This resulted in the sulfate-removal rate, pH value and effluent alkalinity dropping quickly. The amount of Petrotoga sp., Prevotella sp., Kluyvera sp. and Neisseria sp. reduced obviously. The result data from Southern blotting indicated that the amount of sulfate-reducing bacteria (SRBs) decreased with influent alkalinity dropping. Analysis of the microbial community structure and diversity showed that the SRBs populations were very abundant in the inoculated activated sludge and the alkalinity decrease caused the reduction of the populations noted. Most of resident populations in the bioreactor were fermentative acidogenic bacteria (FABs), among which the phylum Firmicute was in the majority, but SRBs were very few. This community structure demonstrates the cooperation between SRBs and FABs, which sustains the system's high sulfate-removal and operation stability.