Molecular Dynamics Investigation of Metastable Structure and Hybridization Bond Evolution in High-Entropy CoCrFeNi Heterostructured Amorphous Carbon Films.

Heterogeneous element doping in amorphous carbon films can reduce residual stresses and improve plastic deformation. Nevertheless, the effects of dopant content and size on the metastable transition mechanism between sp2-C and sp3-C atoms during the deformation process are unclear and difficult to be in situ observed and researched, experimentally. In this work, the mechanical properties and the structural evolution during the nanoindentation of amorphous CoCrFeNi sphere-doped carbon heterostructured films with different radii were simulated. The results indicate that the hardness H and elastic modulus E of the films decreased with the increase of the dopant addition. H decreases from 50.69 to 28.94 GPa, and E decreases from 664.39 to 448.62 GPa. The decrease in the elastic recovery and the enlargement of the shear transition zones indicate that the presence of the amorphous CoCrFeNi dopant can significantly improve the plastic deformation capacity of the films. During the nanoindentation process, the spherical dopants reduce the stress and shear strain of the regions under the indenter in a-C films. The reduction of compressive and shear stresses in the film can inhibit the C atom metastable transition from sp2-C to sp3-C. This can provide a theoretical basis for the development and design of heavy-load and high-deformation-rate a-C films.

Dams alter the control pattern of watershed land use to riverine nutrient distribution: Comparison of three major rivers under different hydropower development levels in Southwestern China.

Land use plays a critical role in managing water quality in a watershed, as it governs the import and distribution of nutrients. In addition to the land use, some rivers in Southwest China are encountering a new environmental stressor of damming, which is being driven by the national strategy of hydropower development. However, the coupling effect of land use and dams on nutrients remains poorly understood, challenging the effective management of riverine water quality. Therefore, this study examined the nutrients in the Nu, Yarlung Tsangpo (YT), and Lancang (LC) Rivers, which have no dam, 1 dam, and 11 dams, respectively, during different regulatory periods (spring and fall) to identify variations in nutrient control patterns influenced by land use and dams. The findings suggested that an increase in hydropower development contributed to a notable shift in nutrient patterns from land use regulation towards dam regulation and coupling effects. Land use dominated the nutrient variations of the Nu (27.4 %-32.8 %) and low hydropower development YT (25.2 %-30.9 %) Rivers during both seasons, but the primary contributors to the nutrient variations of the high hydropower development LC River were dams (17.9 %-41.6 %) and coupling effects (16.5 %-29.0 %). Dams transform nutrient levels and compositions through internal reservoir cycling, decoupling land use and nutrients. Partial least-squares structural equation model analysis further suggested that the coupling effects of the LC River were seasonal-specific, which was primarily attributed to hydrological variations that affected their interactions. During spring, the reservoir underwent a drainage mode characterized by high-level nutrients in the bottom water. Combined with the import of riverine nutrients, it exacerbated the increase of nutrients (synergistic effect). In contrast, the reservoir transitioned into a storage mode where it intercepted nutrients from the upstream and watershed during the fall, leading to a reduction in the previously observed increasing trend and an increase in nutrient variability (antagonism effect).

Cascade damming impacts on microbial mediated nitrogen cycling in rivers.

Rivers display essential role in nitrogen (N) cycling in terrestrial and aquatic ecosystems, but now they are suffering from damming worldwide, especially from cascade damming. Despite of the importance of microorganisms in biogeochemical nutrient cycling, little attention has been paid to microbial functional biogeography under damming disturbances. Here, the Geochip microarray was applied to investigate the microbial mediated N cycling across the single-dammed Yarlung Tsangpo-Brahmaputra River and the cascade-dammed Lancang-Mekong River in southwest China. Our results showed that the N cycling processes (nitrogen fixation, ammonification, denitrification, nitrification and anammox) were stimulated in reservoirs in both rivers and the enhancement was inversely coupled with hydraulic retention time, but the recovery of N-cycling gene abundance in downstream of dam was intervened by cascade damming. Moreover, N-cycling gene composition was significantly altered in the single-dammed river, while no remarkable change was found in the cascade-dammed reaches. However, different from the unvaried gene composition, cascade damming intervened the recovery of N-cycling gene flow connectivity and resulted in the continuous decrease of connectivity in cascade damming reaches. In addition, in the single-dammed river, nutrients were the important drivers for variation in gene abundance, while they did not influence gene composition. Meanwhile, the abundance and composition of N-cycling genes in the cascade-dammed river were both significantly correlated to geographical parameters and water physical characteristics. Therefore, our study has vital implications for anticipating microbial functional response and biogeochemical feedback to ongoing cascade damming, contributing to the protection of river ecosystems under river regulation.

[Effects of Reservoir Water Depth on Different Plankton Communities and Keystone Species of Network Interaction].

In order to understand the impacts of the reservoir construction on the diversity and ecological network of different microbial communities, seven sampling sites were set up in the Hengshan Reservoir in 2021. Water samples were collected from the surface and bottom of the reservoir. After filtering and extracting total DNA samples, high-throughput sequencing was carried out based on 16S and 18S rDNA to investigate the response of community structure, molecular ecological network, and keystone species of different microbial groups to water environment changes. The results showed that the Richness, Simpson, Shannon, and Pielou's Evenness indices of bacterial community in the surface and bottom layers were higher than those in the eukaryote community. The dominant community of bacteria included Proteobacteria, Actinobacteria, and Bacteroidetes, and the eukaryote community included Arthropoda, Ciliophora, Ochrophyta, etc. Moreover, the density and average clustering coefficient of the microbial networks in the surface waters of different phytoplankton communities were higher than those in the bottom waters. It was also observed that the microbial ecological networks in the surface waters were more closely related, and the number of nodes and edges, as well as the number of keystone species, of bacterial communities in the surface and bottom layers were significantly higher than those in the eukaryote microbial communities, indicating that the bacterial community network was larger, and the cooperative relationship and network connectivity between species were stronger. The interaction between bacterial community and eukaryote community in different water depths was dominated by positive correlation, and the negative correlation of the two groups in the bottom layer was slightly greater than that in the surface, indicating that the competition between bottom-layer species was greater than that between surface-layer species. In addition, the environmental impact factors of all species and keystone species of the community in surface water were basically the same, but they differed greatly in deep water, indicating that the influence mechanism of water depth change on keystone species was not the same as that of all species. The results further revealed the effects of reservoir construction on the stability and interspecific interactions of different microbial communities and provided a theoretical basis for predicting variations in microbial community and material cycling in reservoirs.

Ammonia-Induced Anomalous Ion Transport in Covalent Organic Framework Nanochannels.

More anomalous transport behaviors have been observed with the rapid progress in nanofabrication technology and characterization tools. The ions/molecules inside nanochannels can act dramatically different from those in the bulk systems and exhibit novel mechanisms. Here, we have reported the fabrication of a nanodevice, covalent organic frameworks covered theta pipette (CTP), that combine the advantages of theta pipette (TP), nanochannels framework, and field-effect transistors (FETs) for controlling and modulating the anomalous transport. Our results show that ammonia, a weak base, causes a continuous supply of ions inside covalent organic framework (COF) nanochannels, leading to an abnormally high current depending on the ionic/molecular size and the pore size of the nanochannel. Furthermore, CTP can distinguish different concentrations of ammonia and have all of the qualities of a nanosensor.

Nano-chlorapatite modification enhancing cadmium(II) adsorption capacity of crop residue biochars.

Cadmium (Cd) contamination in rivers or lakes has attracted worldwide concerns. Biochar pyrolyzed form crop residues (CR) could adsorb Cd(II) from aquatic environments, while the removal capacity of single CR biochar is relatively low. Nano-chlorapatite (nClAP) modification can enhance metal scavenging ability, but little is known about the behaviors and mechanisms of Cd(II) adsorption by nClAP-modified CR biochars. In this study, the influences of feedstock type, pyrolysis temperature, nClAP modification and aquatic environments on Cd(II) adsorption of biochars derived from rice (RB) and wheat (WB) husks were investigated comprehensively. Results showed that the pristine RB and WB showed low and similar Cd(II) adsorption capacities, while the rise of pyrolysis temperatures from 300 to 600 °C significantly improved the adsorption capacities. The Cd(II) adsorption of both RB and WB was regarded as monolayer chemical processes controlled by chemical precipitation, surface complexation and cation exchange mechanisms. Moreover, the nClAP modification notably enhanced Cd(II) adsorption capacities from 13.2 to 39.9 mg·g-1 of pristine biochars to 25.2-60.7 mg·g-1 of modified biochars attributed to the improved contribution of Cd(II)-phosphate precipitation. Among all biochars, the nClAP-modified RB and WB pyrolyzed at 500 °C had the highest Cd(II) adsorption capacities with 60.7 and 48.3 mg·g-1, respectively. These biochars could maintain good adsorption performances under the neutral-alkaline (pH 6-8), low ionic strength, high dissolved organic matter and all oxidation-reduction potential conditions. In conclusion, this study reveals the importance of nClAP modification to optimize Cd(II) adsorption of CR biochars, which provides a promising future for its practical application in aquatic Cd(II) scavenging.

Electronic, Tensile, and Sliding Characteristics of the C/Ti Interface: A First-Principles Study.

In this paper, according to the C(111) surface and Ti(112̅0) surface relative positions, three stacking interface models were constructed by the first-principles method, and they were defined as 1st-C(111)/Ti(112̅0), 2nd-C(111)/Ti(112̅0), and 4th-C(111)/Ti(112̅0), respectively. After calculation, the work of interfacial adhesion of the 1st-C(111)/Ti(112̅0), 2nd-C(111)/Ti(112̅0), and 4th-C(111)/Ti(112̅0) interface models is found to be 9.689, 10.246, and 9.714 J/m2, respectively, and their interface energies are observed to be 1.064, 0.507, and 1.039 J/m2, respectively. Moreover, the electronic characteristics of C(111)/Ti(112̅0) interfaces are dominated by polar covalent bonds, supplemented by certain metallicity. When the strain reaches 13, 15, and 12%, respectively, the maximum tensile stress values of 1st-C(111)/Ti(112̅0), 2nd-C(111)/Ti(112̅0), and 4th-C(111)/Ti(112̅0) interface models are observed to be 16.207, 19.183, and 17.393 GPa, respectively. After all C(111)/Ti(112̅0) interfaces fracture under tension, the Ti atoms of the Ti(112̅0) surface are transferred to the C(111) surface, indicating that the strength of Ti-C bonds at the interface is higher than the strength of Ti-Ti bonds inside the Ti(112̅0) surface. The maximum value of the sliding potential energy surface is 1.709 J/m2; the maximum value of the potential energy curve is 0.445 J/m2; and the ideal shear strength of the C(111)/Ti(112̅0) interface is 0.386 GPa. In summary, the interfacial adhesion property of the 2nd-C(111)/Ti(112̅0) interface is better than those of 1st-C(111)/Ti(112̅0) and 4th-C(111)/Ti(112̅0) interfaces.

The effect of transpyloric enteral nutrition on inflammatory response and prognosis for patients with Corona Virus Disease-19 in intensive care unit: A STROBE compliant study.

To investigate the effect of transpyloric enteral nutrition (TEN) on NLRP1, inflammatory response and prognosis for patients with Corona Virus Disease-19 (COVID-19) in intensive care unit (ICU). The present prospective observational study included 29 cases of COVID-19 patients in ICU who admitted to our hospital during February 2020 to March 2020. All the patients were divided into gastrogavage groups (n = 16) and TEN group (n = 13) according to route of enteral nutrition. Serum levels of C-reactive protein (CRP), interleukin-1 ß (IL-1ß), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and NLRP1 (NLR family pyrin domain containing 1) was detected by enzyme linked immunosorbent assay (ELISA). Serum levels of lymphocyte, albumin and hemoglobin was detected using an automatic biochemical analyzer. Patients' demographic and clinical characteristics were collected and analyzed. Kaplan-Meier (K-M) curve was conducted for survival analysis and receiver operating characteristic curve was used for the analysis of diagnostic value of biomarkers. All the patients were followed-up for 3 months. This study found that the survival group had higher rate of TEN therapies than the deceased. COVID-19 patients in ICU on TEN had lower APACHE II scores, frequency of feeding suspension and mortality, however, with higher content of albumin was found at 5th day. The incidence of nutritional intolerance including abdominal distension and gastric retention in patients on TEN was notably lower than those on gastrogavage. The serum levels of NLRP1, CRP, IL-1ß, IL-6 and TNF-α decreased in a time-dependent manner, but patients on TEN had lower levels of NLRP1, CRP and IL-1ß than patients on gastrogavage. A positive correlation was found among NLRP1 and inflammatory factors, and COVID-19 patients with lower NLRP1 had longer survival time. Serum NLRP1 also exhibited diagnostic value for the death of COVID-19 patients. TEN decreased inflammatory response and improved the prognosis for COVID-19 patients in ICU.

Study on Ammonia Content and Distribution in the Microenvironment Based on Covalent Organic Framework Nanochannels.

A crack-free micrometer-sized compact structure of 1,3,5-tris(4-aminophenyl)benzene-terephthaldehyde-covalent organic frameworks (TAPB-PDA-COFs) was constructed in situ at the tip of a theta micropipette (TMP). The COF-covered theta micropipette (CTP) then created a stable liquid-gas interface inside COF nanochannels, which was utilized to electrochemically analyze the content and distribution of ammonia gas in the microenvironments. The TMP-based electrochemical ammonia sensor (TEAS) shows a high sensing response, with current increasing linearly from 0 to 50,000 ppm ammonia, owing to the absorption of ammonia gas in the solvent meniscus that connects both barrels of the TEAS. The TEAS also exhibits a short response and recovery time of 5 ± 2 s and 6 ± 2 s, respectively. This response of the ammonia sensor is remarkably stable and repeatable, with a relative standard deviation of 6% for 500 ppm ammonia gas dispensing with humidity control. Due to its fast, reproducible, and stable response to ammonia gas, the TEAS was also utilized as a scanning electrochemical microscopy (SECM) probe for imaging the distribution of ammonia gas in a microspace. This study unlocks new possibilities for using a TMP in designing microscale probes for gas sensing and imaging.

High Spatial Resolution of Ultrathin Covalent Organic Framework Nanopores for Single-Molecule DNA Sensing.

Ultrathin nanosheets of two-dimensional covalent organic frameworks covered a quartz nanopipette and then acted as a nanopore device for single-molecule DNA sensing. Our results showed that a single DNA homopolymer as short as 6 bases could be detected. The dwell times of 30-mer DNA homopolymers were obviously longer than the times of 10- or 6-mer ones. For different bases, poly(dA)6 showed the slowest transport speed (∼595 µs/base) compared with cytosine (∼355 µs/base) in poly(dC)6 and thymine (∼220 µs/base) in poly(dT)6. Such translocation speeds are the slowest ever reported in two-dimensional material-based nanopores. Poly(dA)6 also showed the biggest current blockade (94.74 pA) compared with poly(dC)6 (79.54 pA) and poly(dT)6 (71.41 pA). However, the present difference in blockade current was not big enough to distinguish the four DNA bases. Our study exhibits the shortest single DNA molecules that can be detected by COF nanopores at the present stage and lights the way for DNA sequencing based on solid-state nanopores.

Pressure-induced structure, elasticity, intrinsic hardness and ideal strength of tetragonal C4N.

A tetragonal C4N (t-C4N) structure was predicted via CALYPSO code, and the effects of pressure on its structural and mechanical properties were studied. The results show that t-C4N is different from various 2D CxNy compounds with a new type 3D crystal structure, which is similar to diamond. Bulk t-C4N is equipped with excellent elastic properties. When the pressure is increased from 0 GPa to 350 GPa, its bulk modulus B, shear modulus G and Young's modulus E are increased from 426.9 GPa to 1123.1 GPa, 371.4 GPa to 582.9 GPa and 863.7 GPa to 1490.9 GPa, respectively. The anisotropic Bmax, Gmax and Emax are increased from 582.38 GPa to 1751.41 GPa, 478.29 GPa to 1033.97 GPa and 1281.26 GPa to 2490.14 GPa, respectively. When the pressure is 0 GPa, the hardness calculated by Chen's and Tian's models are 51.15 GPa and 51.81 GPa, respectively. Its ideal tensile strength in [111] orientation is the smallest (63.46 GPa), which indicates that the (111) planes allow easy cleavage. The smallest ideal shear strength (67.98 GPa) can be obtained in the (111)[11̄0] orientation, which suggests its theoretical hardness is about 67.98 GPa. Due to its excellent mechanical properties, t-C4N can be used as an industrial superhard material.

Single Molecule DNA Analysis Based on Atomic-Controllable Nanopores in Covalent Organic Frameworks.

We explored the application of two-dimensional covalent organic frameworks (2D COFs) in single molecule DNA analysis. Two ultrathin COF nanosheets were exfoliated with pore sizes of 1.1 nm (COF-1.1) and 1.3 nm (COF-1.3) and covered closely on a quartz nanopipette with an orifice of 20 ± 5 nm. COF nanopores exhibited high size selectivity for fluorescent dyes and DNA molecules. The transport of long (calf thymus DNA) and short (DNA-80) DNA molecules through the COF nanopores was studied. Because of the strong interaction between DNA bases and the organic backbones of COFs, the DNA-80 was transported through the COF-1.1 nanopore at a speed of 270 µs/base, which is the slowest speed ever observed compared with 2D inorganic nanomaterials. This study shows that the COF nanosheet can work individually as a nanopore monomer with controllable pore size like its biological counterparts.

Effects of Ti Doping on Structure and Internal Stress of Amorphous Carbon Films on the γ-Fe Substrate: Molecular Dynamics Simulation.

In this paper, C and Ti were used as the deposition atoms in the molecular dynamics model. The effects of Ti doping percentages (2, 8, 14, and 20 atom %) on the structure and internal stress of a-C films were investigated. The results showed that with the increase in the Ti percentage, the density of the intrinsic zone is gradually increased, while the growth rate is slowly decreased. The internal stress is gradually changed from compressive stress to tensile stress. Among them, when the Ti percentage is 14 atom %, the internal stress is closer to 0. The C percentage with sp3 hybridization is decreased, while those with sp2 and sp hybridizations are increased. The positions of the first and second peaks in the RDF were shifted to the left. Moreover, the distribution of bond lengths and bond angles in the intrinsic zone tend to change from diamond to graphite, which proves that Ti doping leads to the graphitization of a-C films. In addition, Ti doping affects the internal stress of a-C films by changing the C percentage with sp3 hybridization in them.

Effects of nFe3O4 capping on phosphorus release from sediments in a eutrophic lake.

This study applied the techniques of high-resolution dialysis (HR-Peeper) and diffusive gradients in thin films (DGT) to explore the effects and the behind mechanism for inhibition phosphorus (P) releasing from sediments by nFe3O4 capping. The highest decreasing rates of SRP and labile P (i.e., 49% and 47%, respectively) and the decreased flux of SRP showed that nFe3O4 capping can successfully control sediment internal P release. Adsorption by Fe(III) hydroxides with the oxidation of Fe(II) was one of the reasons for the decrease of P concentrations in nFe3O4 capping sediments. This was supported by the increase of Eh and significant negative correlation between Eh with Fe(II) (soluble and labile Fe(II)) and P (SRP and labile P) and significant positive correlation between Fe(II) and P in sediments by nFe3O4 capping. An outer-sphere complex between positively charged nFe3O4 surface groups and P formation was the other reason to decrease the concentrations of P in the nFe3O4 capping sediments. This was supported by the decrease of pH value in sediments by the capping of nFe3O4. This study shows that nFe3O4, when used as capping agent, can effectively control the sediment internal P release, which is expected to be used as a potential material for repairing lake eutrophication.

The decomposition of macrozoobenthos induces large releases of phosphorus from sediments.

Lake eutrophication and algal blooms may result in the mortality of macrozoobenthos. However, it is still not clear how macrozoobenthos decomposition affect phosphorus (P) mobility in sediments. High-resolution dialysis (HR-Peeper) and the diffusive gradients in thin films (DGT) technique were used in this study to assess the dissolved organic matter (DOM), dissolved/DGT-labile iron (Fe), P, and sulfur (S(-II)) profiles at a millimeter resolution. The decomposition of Bellamya aeruginosa significantly increased the internal loading of sediments P. The Fe(III) and sulfate were reduced under anaerobic conditions and promoted P desorption from sediments. This was supported by the significant increase in DGT-labile S(-II) and dissolved/DGT-labile P, Fe(II) and the significant positive correlation between Fe and P on day 8. The simultaneous increase in DOM and soluble reactive phosphorus (SRP) and the significant positive relationship between these factors were observed during the decomposition of B. aeruginosa. This suggested that complexation of DOM with metals may promotes the release of P from sediments.

High-Temperature Sliding Friction Behavior of Amorphous Carbon Films: Molecular Dynamics Simulation.

With the development of the aerospace industry, the requirement for mechanical parts, which are serviced under extreme conditions such as high temperature, is more and more severe. Amorphous carbon (a-C) films are widely used in the aviation field as a protective coating because of their excellent antiwear and friction-reduction properties. However, a-C films are vulnerable to failure in a high-temperature environment, and a series of complex changes in the friction process make it a challenge to put forward the friction mechanism. Here, the sliding friction behaviors of amorphous carbon (a-C) films at different simulated temperatures (STs) (300-1300 K) were analyzed by molecular dynamics. The density, average coordination number, and local residual stress as well as the hybridization of sp, sp2, and sp3 of a-C films were analyzed to reveal the high-temperature sliding friction mechanism of a-C films. The results show that the friction coefficient (µ) of a-C films increased with increase in ST. Meanwhile, the friction mechanisms of a-C films are different at an ST lower than 800 K and higher than 1100 K. Compared with those before sliding, the local residual stress of all a-C films is relaxed, which causes transformation of sp3 into sp2. Moreover, when ST is lower than 800 K, the µ increased with increase in sp3%. When ST is higher than 1100 K, the stability of a-C films is broken, which results in the rapid increase in µ.

Growth characteristics of primary M7C3 carbide in hypereutectic Fe-Cr-C alloy.

The microstructure of the hypereutectic Fe-Cr-C alloy is observed by optical microscopy (OM). The initial growth morphology, the crystallographic structure, the semi-molten morphology and the stacking faults of the primary M7C3 carbide are observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The in-suit growth process of the primary M7C3 carbide was observed by confocal laser microscope (CLM). It is found that the primary M7C3 carbide in hypereutectic Fe-Cr-C alloy is irregular polygonal shape with several hollows in the center and gaps on the edge. Some primary M7C3 carbides are formed by layers of shell or/and consist of multiple parts. In the initial growth period, the primary M7C3 carbide forms protrusion parallel to {} crystal planes. The extending and revolving protrusion forms the carbide shell. The electron backscattered diffraction (EBSD) maps show that the primary M7C3 carbide consists of multiple parts. The semi-molten M7C3 carbide contains unmelted shell and several small-scale carbides inside, which further proves that the primary M7C3 carbide is not an overall block. It is believed that the coalescence of the primary M7C3 carbides is ascribed to the growing condition of the protrusion and the gap filling process.

Expression of costimulatory molecule CD86 in HL-60 cells induced by MG132 and its effect on allogeneic mixed lymphocyte reaction.

This study was aimed to elucidate the expression of costimulatory molecule CD80 and CD86 in HL-60 cells induced by proteasome inhibitor MG132 and its effect on allogeneic mixed lymphocyte reaction. Acute myelocytic leukemia cell line HL-60 and chronic myelocytic leukemia cell line K562 were cultured. The viability of the cells was measured by flow cytometry. Proteasome inhibitor MG132 at the concentrations of 2 or 3 µmol/L was used to stimulate the HL-60 cell cultured for 24 h and 48 h respectively, and the Annexin V/7-AAD staining and flow cytomotry were used to detect the apoptosis of the HL-60 cells. HL-60 and K562 cells were treated with 1 µmol/L MG132 for 24 h and 48 h respectively, then CD80 and CD86 antibodies were added, finally the expression of CD80 and CD86 was analysed by flow cytomery. The mRNA expression of CD86 in the HL-60 cells treated with 1 µmol/L MG132 was detected by RT-PCR. HL-60 and K562 cells were treated by 1 µmol/L MG132 and then underwent irradiation of 75 Gy (60)Co to kill the cells with their antigenicity preserved. Peripheral blood mononuclear cells (PBMNCs) of healthy volunteers, as reactive cells, were isolated and inoculated into the (60)Co irradiated HL-60 cells of different concentrations, as stimulating cells, CCK-8 was added and then the A value of absorbance was measured at the wave length of 450 nm in an enzyme labeling instrument. The results showed that the cell viability of the HL-60 cells treated with 1 µmol/L MG132 for 24 h an d 48 h was 92.95% and 85.87% respectively. The apoptotic rates of the HL-60 cells treated with MG132 increased in dose-and time-dependent manner. High-concentration of MG132 directly killed HL-60 cells. Before MG132 treatment K562 cells did not express CD86, but the CD86 expression of the HL-60 cells was up-regulated time-dependently after MG132 treatment (P < 0.01). The mRNA expression of CD86 in the HL-60 treated with MG132 was up-regulated time-dependently (P < 0.01). CCK-8 test showed that the proliferation level of PBMNC gradually increased along with the concentration of HL-60 cells treated with MG132 and reached its peak when the concentration of the HL-60 cells was 1×10(5) (P < 0.01). No remarkable proliferation of PBMNC was observed in the K562 groups no matter if the HL-60 cells had been treated with MG132. It is concluded that the high concentration of MG132 can directly kill HL-60 cells, low-concentration of MG132 can induce the expression of costimulatory molecule CD86 in HL-60 cells, also can improve the proliferation of PBMNC.

[Mechanism of HL-60 cells apoptosis induced by proteasome inhibitor MG132].

The purpose of this study was to elucidate the apoptosis, apoptotic pathway of HL-60 cells induced by proteasome inhibitor MG132 and its effect on allogeneic mixed lymphocyte reaction. Apoptosis of HL-60 cells was detected by flow cytometry, the expression of P21, P27 and P53 proteins in HL-60 cells treated with MG132 was assayed by Western blot. The HL-60 cells were treated with 1 µmol/L MG132 for 48 h, and irradiated by 75 Gy of (60)Co γ-ray, but their antigenicity was preserved. The effect of irradiated HL-60 cells treated with MG132 on proliferation of peripheral blood mononuclear cells (PBMNC) was measured by CCK-8 method. The results showed that the apoptotic rate of MG132-treated HL-60 cells increased in dose-and time-dependent manner. No significant changes in MG132-induced apoptosis were observed after inhibiting caspase-8 and caspase-9 pathway. The expression of P21 and P27 protein increased after treatment of HL-60 cells with MG132. CCK-8 test showed that HL-60 cells induced with low-dose of MG132 displayed the enhancing effect on proliferation of PBMNC. It is concluded that high dose of MG132 can induce the apoptosis of HL-60 cells, and has direct killing effect on HL-60 cells, but this inducing apoptotic effect on HL-60 cells can not be realized through caspase-8 and caspase-9 pathway. The P21 and P27 protein may be involved in MG132 induced HL-60 cell apoptosis. Low dose of MG132 promotes the proliferation of PBMNC in healthy individuals and enhance the immunity of organism.

A synopsis of phosphate disorders in the nursing home.

Elderly patients are at an increased risk of developing both hypophosphatemia and hyperphosphatemia. Renal insufficiency predisposes elderly patients to elevated serum concentrations of phosphate. On the other hand, poor dietary intake and loss of phosphorus in the urine can lead to deficiency states. It is well documented that hyperphosphatemia is correlated with an increase in morbidity and mortality as a result of vascular calcification. This article reviews the etiology, pathophysiology, symptoms, and treatment of hypophosphatemia and hyperphosphatemia.