Two-Dimensional Terahertz Spectroscopy of Nonlinear Phononics in the Topological Insulator MnBi_{2}Te_{4}.

The interaction of a single-cycle terahertz electric field with the topological insulator MnBi_{2}Te_{4} triggers strongly anharmonic lattice dynamics, promoting fully coherent energy transfer between the otherwise noninteracting Raman-active E_{g} and infrared (IR)-active E_{u} phononic modes. Two-dimensional terahertz spectroscopy combined with modeling based on the classical equations of motion and symmetry analysis reveals the multistage process underlying the excitation of the Raman-active E_{g} phonon. In this nonlinear combined photophononic process, the terahertz electric field first prepares a coherent IR-active E_{u} phononic state and subsequently interacts with this state to efficiently excite the E_{g} phonon.

[The status and influencing factors of presenteeism among clinical nurses: a systematic review].

Objective: To systematically review the status and factors influencing presenteeism among clinical nurses. Methods: In December 2021, CNKI, CBM, Wanfang, VIP, Web of Science, PubMed, Embase, The Cochrane Library, CINAHL, PsyclNFO and other databases were electronically searched to cross sectional studies on the current situation and factors influencing the occurrence of presenteeism among clinical nurses. The search terms mainly included presenteeism, sick at work, Stanford Presenteeism Scale, nurse, level, risk factor, influence, et al. And the search time was from the establishment of the database to November 30, 2021. Literature screening, data extraction and evaluation of the risk of bias in the included literature were done independently by two researchers, and meta-analysis was performed using Stata 15.1 software. Results: A total of 29 studies involving 13 535 clinical nurses were included.The results of the meta-analysis showed that the score of presenteeism was 17.99 [95% CI (17.02-18.95), P =0.000]. Subgroup analysis showed that presenteeism scores were higher in articles published before 2020 (ES=19.28, 95%CI: 18.41-20.15, P=0.000) and in the group of nurses aged 36 to 40 years (ES=19.27, 95%CI: 17.35~21.19, P=0.000), female (ES= 17.04, 95%CI: 14.70-19.39, P=0.000), secondary school education (ES=21.01, 95%CI: 17.76-24.26, P= 0.007), married (ES=17.49, 95%CI: 15.13-19.85, P=0.000), working for 5 to 10 years (ES=17.78, 95%CI: 16.54-19.02, P=0.000), contract (ES=17.05, 95%CI: 15.23-18.87, P=0.000), working in pediatrics (ES= 16.65, 95% CI: 15.31-17.99, P=0.000) and European region (ES =21.21, 95% CI: 20.50-21.93, P=0.000) . Conclusion: Current evidence suggests that clinical nurses are at high risk of presenteeism, which is affected by variety of factors. The managers should pay attention to the physical and mental health of nurses, identify high-risk factors as early as possible and take measures to reduce the occurrence of presenteeism and improve the quality of nursing.

[Glucose excursion in senior patients with type 2 diabetes mellitus and coronary artery disease].

Objectives: To explore glucose excursion and incidence of hypoglycemia in senior patients with type 2 diabetes mellitus (T2DM) and coronary artery disease (CAD) with different hemoglobin A1c (HbA1c) values. Methods: Eighty-nine outpatients [58 male, 31 female, aged 69.0 (66.0, 73.0) years] diagnosed with T2DM and CAD in Beijing Anzhen Hospital between June 2013 and March 2016 were divided into group A (HbA1c<6.5%, n=25) and group B (HbA1c≥6.5%, n=64). Every patient wore continuous glucose monitoring system (CGMS) for 72 h. Glucose excursion parameters and incidence of hypoglycemia from CGMS readings were calculated. Results: Compared with group B, patients in group A experienced shorter diabetes duration [8.0 (3.5, 15.0) vs 15.0 (8.0, 20.0) years, Z=-2.222, P=0.026], lower standard deviation (SD) of blood glucose from CGMS, mean amplitude of glycemic excursions(MAGE) and mean of the daily differences(MODD) (P=0.001, 0.003, 0.001). However, incidence of hypoglycemia was significantly increased [56.0% (14/25) vs 32.8% (21/64), χ(2)=4.051, P=0.044] in group A. Compared to those who had not experienced hypoglycemia, patients with hypoglycemia had higher SD [1.8(1.4, 2.4) mmol/L vs 1.4(1.1, 1.8) mmol/L, Z=-3.198, P=0.001] and MAGE [6.0(3.2, 7.4) mmol/L vs 3.9(2.7, 4.8 )mmol/L, Z=-2.768, P=0.006] which were appropriate tools for assessing intraday glycemic variability. No statistical difference were found in MODD which was the index for estimating interday glycemic variability. Conclusions: Intensive glycemic control in senior patients with T2DM and CAD had higher incidence of hypoglycemia. Those with hypoglycemia experienced greater intraday glucose excursion.

[Effect of curcumin on intestinal mucosal mechanical barrier in rats with non-alcoholic fatty liver disease].

Objective: To investigate the effect of curcumin on intestinal mucosal mechanical barrier in rats with non-alcoholic fatty liver disease. Methods: A total of 30 male Sprague-Dawley rats were equally divided into normal control group, model group, and curcumin intervention group. The rats in the model group and the curcumin intervention group were given high-fat feed for 16 weeks, and those in the curcumin intervention group were given curcumin 200 mg/kg/day by gavage once a day after 8 weeks of high-fat feeding. The rats were sacrificed at the end of week 16. A light microscope was used to observe pathological changes in the liver, an electron microscope was used to observe the tight junction of the intestinal mucosa, an automatic biochemical analyzer was used to measure the serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), chromogenic substrate Limulus amebocyte lysate assay was used to measure plasma lipopolysaccharide (LPS) level, spectrophotometric method was used to measure the activity of serum diamine oxidase, ELISA was used to measure the serum level of tumor necrosis factor-α (TNFα), and immunohistochemistry was used to measure the expression of the tight junction protein occludin. One-way ANOVA test and SNK-q test were used for statistical analysis. Results: Under the light microscope, the control group had no hepatocyte steatosis, the model group had significant hepatocyte steatosis and inflammatory cell infiltration, and the curcumin intervention group had reduced hepatocyte steatosis and inflammatory cell infiltration. Under the electron microscope, the control group had a clear and complete structure of the tight junction of the intestinal mucosa and normal structures of mitochondria and endoplasmic reticulum; in the model group, the structure of the tight junction of the intestinal mucosa was destroyed, the intercellular space was widened, the desmosomes had a loose structure, there was edema in some mitochondria, and the endoplasmic reticulum was dilated; the curcumin intervention group had improvements in the structure of tight junction of the intestinal mucosa, intercellular space, edema in the mitochondria, and dilation of the endoplasmic reticulum. Compared with the control group, the model group had significant increases in the serum levels of AST, ALT, DAO, TNFα, and LPS (q = -15.918, -14.402, -33.700, -8.944, and -10.832, P < 0.05); compared with the model group, the curcumin intervention group had significant reductions in the serum levels of AST, ALT, DAO, TNFα, and LPS (q = 10.457, 7.752, 18.802, 5.202, and 4.279, P < 0.05). In the control group, occludin showed a linear distribution along the top of small intestinal mucosal epithelial cells. The model group had a significant reduction in positive staining compared with the control group, and the curcumin intervention group had a significant increase in positive staining compared with the model group. The relative expression of occludin was 0.29±0.03 in the control group, 0.12±0.02 in the model group, and 0.21±0.02 in the curcumin intervention group (P < 0.05). Conclusion: Intestinal mucosal mechanical barrier is impaired in rats with NAFLD. Curcumin can reduce such damage, and its mechanism of action may be related to up-regulating the expression of occludin in the intestinal mucosa and reducing the levels of TNFα and LPS.

Activation of salt-inducible kinase 2 promotes the viability of peritoneal mesothelial cells exposed to stress of peritoneal dialysis.

Maintaining mesothelial cell viability is critical to long-term successful peritoneal dialysis (PD) treatment. To clarify the viability mechanism of peritoneal mesothelial cells under PD solutions exposure, we examined the mechanisms of cellular response to this stress conditions. Here we report that the proteasome activity is inhibited when treated with PD solutions. Proteasome inhibition-mediated activation of salt-inducible kinase 2 (SIK2), an endoplasmic reticulum-resident protein, is important for mesothelial cell viability. SIK2 is mobilized to promote autophagy and protect the cells from apoptosis under PD solution or MG132 treatment. Immunofluorescence staining showed that SIK2 is colocalized with LC3B in the autophagosomes of mesothelial cells treated with PD solution or derived from patients undergoing PD treatment. SIK2 activation is likely via a two-step mechanism, upstream kinases relieving the autoinhibitory conformation of SIK2 molecule followed by autophosphorylation of Thr175 and activation of kinase activity. These results suggest that activation of SIK2 is required for the cell viability when proteasome activity is inhibited by PD solutions. Maintaining or boosting the activity of SIK2 may promote peritoneal mesothelial cell viability and evolve as a potential therapeutic target for maintaining or restoring peritoneal membrane integrity in PD therapy.

Effect of male body mass index on clinical outcomes following assisted reproductive technology: a meta-analysis.

Overweight and obese males might exhibit a great risk of infertility. However, according to the current studies, the association between elevated male body mass index (BMI) and the clinical adverse results after assisted reproductive technology (ART) remains controversial. Hence, we conducted a meta-analysis to evaluate the effects of raised male BMI on clinical outcomes following ART. PubMed, EMBASE and three Chinese databases were used to identify relevant studies. The primary outcome was clinical pregnancy rate. Secondary outcomes included live birth rate and sperm parameters. A total of 5262 male participants from 10 cohort studies were subjected to meta-analysis. Results indicated that overweight or obese had no significant impact on clinical pregnancy rate [in vitro fertilisation (IVF): odds ratio (OR), 0.73; 95% confidence interval (CI), 0.39-1.39; intracytoplasmic sperm injection (ICSI): OR, 1.03; 95% CI, 0.92-1.15], live birth rate (IVF: OR, 0.91; 95% CI, 0.78-1.06; ICSI: OR, 1.00; 95% CI, 0.50-1.99) and sperm concentration (SMD, -0.28; 95% CI, -0.65 to 0.08) compared with normal weight following IVF/ICSI treatments. Exclusion of any single study and almost all the sensitivity analyses showed that our results were reliable. At present, the role of male BMI in the process of ART is only partly understood and should be further investigated.

Tailoring low-dimensional structures of bismuth on monolayer epitaxial graphene.

To improve graphene-based multifunctional devices at nanoscale, a stepwise and controllable fabrication procedure must be elucidated. Here, a series of structural transition of bismuth (Bi) adatoms, adsorbed on monolayer epitaxial graphene (MEG), is explored at room temperature. Bi adatoms undergo a structural transition from one-dimensional (1D) linear structures to two-dimensional (2D) triangular islands and such 2D growth mode is affected by the corrugated substrate. Upon Bi deposition, a little charge transfer occurs and a characteristic peak can be observed in the tunneling spectrum, reflecting the distinctive electronic structure of the Bi adatoms. When annealed to ~500 K, 2D triangular Bi islands aggregate into Bi nanoclusters (NCs) of uniform size. A well-controlled fabrication method is thus demonstrated. The approaches adopted herein provide perspectives for fabricating and characterizing periodic networks on MEG and related systems, which are useful in realizing graphene-based electronic, energy, sensor and spintronic devices.

Cannabinoid receptor agonist WIN55,212-2 and fatty acid amide hydrolase inhibitor URB597 suppress chronic cerebral hypoperfusion-induced neuronal apoptosis by inhibiting c-Jun N-terminal kinase signaling.

The endocannabinoid system (ECS) has therapeutic potential for treating chronic cerebral hypoperfusion (CCH)-induced cerebral diseases. This study investigated the protective effects of two ECS compounds, cannabinoid receptor agonist WIN55,212-2 (WIN) and fatty acid amide hydrolase inhibitor URB597 (URB) on CCH-induced neuronal apoptosis in vivo. CCH was induced in male Sprague-Dawley rats by bilateral common carotid artery occlusion (BCCAo); the rats were then treated with WIN or URB for 12weeks and their spatial learning and memory abilities were assessed using the Morris water maze. Changes in neuronal number were examined by labeling neurons with an antibody against the neuronal nuclei antigen, and apoptosis of cortical and hippocampal CA1 neurons was detected by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling. The expression of B cell lymphoma (Bcl)-2, Bcl-2-associated X protein (Bax), and activated caspase-3 as well as mitogen-activated protein kinases including extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), p38, phosphorylated (p-)ERK, p-JNK, and p-P38 was examined by Western blotting. Rats treated with WIN or URB showed better learning and memory performance than controls. The neuroprotective effects of URB were greater than those of WIN, and co-administration of WIN and URB had a synergistic effect. In addition, WIN and URB blocked JNK phosphorylation as well as the decrease in Bcl-2/Bax ratio and caspase-3 activation induced by CCH, implying that these agents modulate neuronal survival. Moreover, the selective JNK inhibitor SP600125 improved mitochondrial membrane dysfunction and blocked neuronal apoptosis induced by JNK-dependent Bcl-2 signaling. WIN and URB enhanced the effects of SP600125, implying that they may exert anti-apoptotic effects in part by inhibiting a non-nuclear JNK pathway. These findings indicate that WIN and URB promote neuronal survival and may potentially be used to protect neurons against chronic ischemic insults.

Rate of tree carbon accumulation increases continuously with tree size.

Forests are major components of the global carbon cycle, providing substantial feedback to atmospheric greenhouse gas concentrations. Our ability to understand and predict changes in the forest carbon cycle--particularly net primary productivity and carbon storage--increasingly relies on models that represent biological processes across several scales of biological organization, from tree leaves to forest stands. Yet, despite advances in our understanding of productivity at the scales of leaves and stands, no consensus exists about the nature of productivity at the scale of the individual tree, in part because we lack a broad empirical assessment of whether rates of absolute tree mass growth (and thus carbon accumulation) decrease, remain constant, or increase as trees increase in size and age. Here we present a global analysis of 403 tropical and temperate tree species, showing that for most species mass growth rate increases continuously with tree size. Thus, large, old trees do not act simply as senescent carbon reservoirs but actively fix large amounts of carbon compared to smaller trees; at the extreme, a single big tree can add the same amount of carbon to the forest within a year as is contained in an entire mid-sized tree. The apparent paradoxes of individual tree growth increasing with tree size despite declining leaf-level and stand-level productivity can be explained, respectively, by increases in a tree's total leaf area that outpace declines in productivity per unit of leaf area and, among other factors, age-related reductions in population density. Our results resolve conflicting assumptions about the nature of tree growth, inform efforts to undertand and model forest carbon dynamics, and have additional implications for theories of resource allocation and plant senescence.

Evaluation of wall correction factor of INER's air-kerma primary standard chamber and dose variation by source displacement for HDR ¹9²Ir brachytherapy.

The aim of the present study was to estimate the wall effect of the self-made spherical graphite-walled cavity chamber with the Monte Carlo method for establishing the air-kerma primary standard of high-dose-rate (HDR) ¹9²Ir brachytherapy sources at the Institute of Nuclear Energy Research (INER, Taiwan). The Monte Carlo method established in this paper was also employed to respectively simulate wall correction factors of the ¹9²Ir air-kerma standard chambers used at the National Institute of Standards and Technology (NIST, USA) and the National Physical Laboratory (NPL, UK) for comparisons and verification. The chamber wall correction calculation results will be incorporated into INER's HDR ¹9²Ir primary standard in the future. For the brachytherapy treatment in the esophagus or in the bronchi, the position of the isotope may have displacement in the cavity. Thus the delivered dose would differ from the prescribed dose in the treatment plan. We also tried assessing dose distribution due to the position displacement of HDR ¹9²Ir brachytherapy source in a phantom with a central cavity by the Monte Carlo method. The calculated results could offer a clinical reference for the brachytherapy within the human organs with cavity.

Multispecies coexistence of trees in tropical forests: spatial signals of topographic niche differentiation increase with environmental heterogeneity.

Neutral and niche theories give contrasting explanations for the maintenance of tropical tree species diversity. Both have some empirical support, but methods to disentangle their effects have not yet been developed. We applied a statistical measure of spatial structure to data from 14 large tropical forest plots to test a prediction of niche theory that is incompatible with neutral theory: that species in heterogeneous environments should separate out in space according to their niche preferences. We chose plots across a range of topographic heterogeneity, and tested whether pairwise spatial associations among species were more variable in more heterogeneous sites. We found strong support for this prediction, based on a strong positive relationship between variance in the spatial structure of species pairs and topographic heterogeneity across sites. We interpret this pattern as evidence of pervasive niche differentiation, which increases in importance with increasing environmental heterogeneity.

Assessment of cognitive function in adult patients with hemorrhagic moyamoya disease who received no surgical revascularization.

BACKGROUND AND PURPOSE: Due to controversial surgical treatment for hemorrhagic moyamoya disease (MMD), a large proportion of these patients chose conservative treatment. The aim of this study was to assess cognitive function in adult patients with hemorrhagic MMD who received no surgical revascularization. METHODS: Twenty-six adult hemorrhagic MMD patients with only intraventricular hemorrhage (IVH) confirmed by positive computed tomography and magnetic resonance imaging scan, 20 patients with spontaneous IVH whose digital subtraction angiography results were negative, and 30 healthy controls were identified and matched for age, gender, education background and living area. Cognitive function was evaluated by Montreal Cognitive Assessment (MoCA). The non-parametric test was used for comparisons among the three groups. RESULTS: No patient was confirmed cognitive dysfunction at the initial screening. Twenty-four (92%) cases presented mild cognitive impairment (MCI) after 1 year. All the cases demonstrated MCI after 2 years. The difference between cases and healthy controls was statistically significant at the second screening (P = 0.000) and the third screening (P = 0.000), as was that between cases and patients with spontaneous IVH at the second screening (P = 0.000) and the third screening (P = 0.000). In addition, there were significant decreases in all MoCA subscores (P = 0.000) with special regards to delayed recall, visual space and executive function in cases compared with the other two groups. Moreover, significant differences were found in the subgroups of smoking (P = 0.021) and Suzuki angiographic classification of MMD (P = 0.030). CONCLUSIONS: Cognitive impairment is a long-term complication for adult hemorrhagic MMD patients who underwent conservative treatment.

Validation of Spilornis cheela hoya TaqMan probes for potential gender identification of many Accipitridae species.

The objective of this study was to test the hypothesis that genders of Accipitridae species, with the same or similar sequences to our previously proposed Spilornis cheela hoya (S. c. hoya) chromo-helicase-DNA binding protein (CHD)-W-specific and CHD-ZW-common TaqMan probes, can be successfully determined. Eight species of Accipitridae with known genders were collected. After PCR, TA cloning, sequencing, and alignment analyses, sequence length differences of Griffiths P2/P8 PCR amplicons between CHD-Z and CHD-W genes ranged from 2 to 19 bp for these Accipitridae species, and they were unsolved in 3% agarose gel. Using our previous proposed S. c. hoya TaqMan probes, the genders of Circaetus gallicus, completely homologous to the sequences for these CHD probes, were successfully identified. With one nucleotide difference to S. c. hoya CHD-W-specific probe, gender identification of Accipiter gularis, Accipiter soloensis, Accipiter trivirgatus, Accipiter virgatus, and Butastur indicus were validated. With two nucleotide differences in the CHD-W-specific probe and one nucleotide difference in the CHD-ZW-common probe, Pernis ptilorhyncus also performed well for gender identification. In conclusion, the S. c. hoyaCHD probes, coupled with the Griffiths P2/P8 primers, were validated to provide accurate and high-throughput gender identification for many Accipitridae species.

High-throughput gender identification of Accipitridae eagles with real-time PCR using TaqMan probes.

The objective was to develop high-throughput gender identification of eagles. Based on BLAST and alignment analyses, the CHD-Z and CHD-W sequences of nine species of eagles were highly homologous with Spilornis cheela hoya (S. c. hoya); therefore, TaqMan probes were designed to target their CHD-ZW-common and CHD-W-specific regions. In S. c. hoya, genders were identified using TaqMan-based, real-time PCR (amplified by P2/P8 primers); this method was validated with anatomically confirmed controls (one of each gender). Both genders had high intensities of the HEX-labeled (CHD-ZW-common) probe, whereas only females had high intensity of the FAM-labeled (CHD-W-specific) probe. The sequence of the CHD-W-specific probe designed for S. c. hoya was completely homologous with the CHD-W-specific region in Circaetus gallicus, Gyps indicus, and Gyps bengalensis, and was only one nucleotide different from those of Accipiter nisus, Spizaetus nipalensis, Aquila chrysaetos, Circus spilonotus, and Milvus migrans. For the CHD-ZW-common probe, all species listed were completely conserved. Using real-time PCR software, we established auto-calling of the genders of 15 individuals of S. c. hoya. In conclusion, this method provided accurate, high-throughput gender identification for S. c. hoya, and has considerable potential for identifying the gender of several related species of eagles.

Successful heart transplantation after 13 hours of donor heart ischemia with the use of HTK solution: a case report.

INTRODUCTION: For heart transplantation (HTx), the recommended ischemic time (IT) for donor heart is not to exceed 6 hours. Though Dr Christiaan Barnard used a donor heart with IT of 16 hours, 50 minutes with a portable hypothermic perfusion system in 1981, the recorded IT of donor hearts reported recently is 8 hours, with no adverse effects. CASE REPORT: The patient, a 14-year-old boy of blood type O, was diagnosed with cardiomyopathy at age 12. In early September 2003, the patient was recommended for HTx. His condition deteriorated 18 days later with low CO, elevated pulmonary vascular resistance, and frequent ventricular tachycardia, further complicated by pneumonia and multiorganism infections, which were contraindications for HTx. On September 22, 2003, a donor heart of blood type O was available 370 km away. Another patient of blood type B with severe heart failure was matched for the HTx. During the intervening time, another donor heart of blood type B became available locally. We matched the type B donor heart to the type B recipient. Since the type O donor heart seemed to be wasted, we performed HTx for the boy. Though preserved for 12 hours in cold cardioplegia, the donor heart was implanted with biatrial anastomosis that took 1 hour. The total IT of this donor heart was 13 hours. The recipient recovered and was discharged 3 months later. CONCLUSIONS: The IT of 13 hours for this donor heart is believed to be a world record. Our experience demonstrates that preservation time of donor heart may exceed 6 hours.

In vitro hemocompatibility studies of drug-loaded poly-(L-lactic acid) fibers.

Our objective was to evaluate the hemocompatibility of biodegradable stent fibers, employing a closed-loop circulation system filled with human blood. We also investigated the effects of the anti-inflammatory and anti-proliferative drugs curcumin and paclitaxel, incorporated into stent fibers. Fresh whole blood was circulated in four parallel closed-loop systems: the empty tube circuit (control) and tubes containing either a PLLA fiber coil (PLLA), a curcumin-loaded PLLA coil (C-PLLA) or a paclitaxel-loaded PLLA coil (P-PLLA). The influence of PLLA fiber, alone or loaded with drug incorporated during melt-extrusion, on leukocyte and platelet adhesion and activation was determined by flow cytometry. The effects of blood flow and fiber properties on cell deposition were assessed by scanning electron microscopy (SEM). The flow cytometry results clearly demonstrated that PLLA triggers blood cell activation at the site of deployment, as shown by increases in CD11b, CD62P and leukocyte-platelet aggregates, compared to controls. Curcumin and paclitaxel treatments both significantly reduced leukocyte and platelet activation and adhesion to PLLA fibers, as shown by flow cytometry and SEM. Activated leukocytes and platelets revealed significantly lower CD11b and CD62P receptor binding for C-PLLA compared with PLLA alone, and slightly lower for P-PLLA. Reductions in platelet-leukocyte aggregates were observed as well. In addition, there was less leukocyte and platelet adhesion to C-PLLA, compared with PLLA fiber controls, as shown by SEM. A continuous linear thrombus, composed of platelets, leukocytes, red blood cells and fibrin was occasionally detected along the line of tangency between the coil and the tube wall. Flow separation and eddying, proximal and distal to the line of tangency of coil and tube, is thought to contribute to this deposit. Curcumin was more effective than paclitaxel in reducing leukocyte and platelet activation and adhesion to PLLA stent fibers in this setting. However there was evidence of paclitaxel degeneration during melt extrusion that may have inhibited its effectiveness. Incorporation of the anti-inflammatory and anti-proliferative drug curcumin into bioresorbable stent fibers is proposed to prevent thrombosis and in-stent restenosis.

C57BL/6 and BALB/c bronchoalveolar macrophages respond differently to exercise.

Macrophages from prototypical Th1 strains (e.g., C57BL/6) and Th2 strains (e.g., BALB/c) are classified as M-1 and M-2 phenotypes. We investigated the different phagocytic responses between M-1 and M-2 bronchoalveolar macrophages (BAMs) under resting and two various exercise conditions. At rest, M-1 BAMs showed higher phagocytic capacity of unopsonized particles, higher expression of MARCO (macrophage receptor with collagenous structure), and higher generation of NO than M-2 BAMs. Severe exercise, but not moderate exercise, significantly enhanced both phagocytosis of unopsonized particles and expression of MARCO in M-2 BAMs. In contrast, M-1 BAMs were unaffected by either exercise protocol. The phagocytosis of unopsonized particles was largely mediated by MARCO, especially in M-1 BAMs. Secreted products from cultured M-2 BAMs isolated after severe exercise, but not those from M-1 BAMs, enhanced BAM phagocytosis. The cultured M-1 BAMs secreted phagocytosis inhibitors, and this effect could be blocked by NO antagonists. Moreover, the extent of phagocytosis suppression induced by M-1 BAM-secreted products correlated with their production of nitrite/nitrate. Exogenous NO donors as well as NO derivatives, nitrite and nitrate, suppressed the BAM phagocytosis. We propose that while the severe exercise-enhanced phagocytosis in M-2 BAMs was largely mediated by MARCO up-regulation and secretion of stimulators, the lack of exercise effect in M-1 BAMs could be partially due to the constitutive secretion of NO-related suppressors. In conclusion, genetically different mice use different strategies in regulating BAM activity under resting conditions and in response to various exercise paradigms.

Role of cupric ions in the H2O2/UV oxidation of humic acids.

The purpose of this study is to reveal the role of cupric ions as a natural water contaminant in the H2O2/UV oxidation of humic acids. Humic acids are naturally occurring organic matter and exhibit a strong tendency of complexation with some transition metal ions. Chlorination of humic acids causes potential health hazards due to formation of trihalomethane (THM). The removal of THM precursors has become an issue of public concern. The H2O2/UV process is capable of mineralizing humic acids due to formation of a strong oxidant, hydroxyl radicals, in reaction solution. Experiments were conducted in a re-circulated photoreactor. Different cupric concentrations (0-3.8 mg/l) and different pH values (4-9) were controlled to determine their effects on the degradation of humic acids, UV light absorbance at 254 nm, and H2O2. The presence of cupric ions inhibits humic mineralization and decreases the rate of destruction of humic acids which absorb UV light at 254 nm. On the other hand, the higher the cupric concentration, the lower the H2O2 decomposition rate. In the studied pH range, the minimum of total organic carbon (TOC) removal occurs at pH = 6 in the presence of 2.6 mg/l of cupric ions; both acidification (pH = 4) and alkaline condition (pH = 9) lead to a better removal of TOC. It is inferred from this study that the cupric-complexed form of humic acids is more refractory than the non-complexed one.

Severe exercise enhances phagocytosis by murine bronchoalveolar macrophages.

Because physical activity affects the immune competency of individuals by an unknown mechanism, we investigated the effect of acute exercise on phagocytosis of bronchoalveolar macrophages (BAMs). Male BALB/c mice, 7-9 weeks old, ran on a treadmill to exhaustion (severe exercise, SE) or at a final speed of 17 m/min for 30 min (moderate exercise, ME). Although both exercise protocols induced differential leukocytosis, 95% leukocytes from lung lavages of both groups were BAMs. The BAM phagocytic capacity of nonopsonized beads increased immediately after SE but not after ME, gradually returning to the basal level after 4 h. SE upregulates the macrophage scavenger receptors (SR-A type I/II and MARCO), CR3, and ICAM-1, but not Fc gammaR. Although the blocking effect of MARCO antibody was most pronounced, that of ICAM-1 antibody was totally reversed by cross-linking CR3. Our results showed that SE, but not ME, activated BAMs and that the enhanced nonopsonized phagocytosis was mainly mediated by scavenger receptors and ICAM-1/CR3.

Antimicrobial coatings: a remedy for medical device-related infections.

This article discusses the mechanisms involved in the different approaches to antimicrobial coatings and reports on a new application that seems to offer an antimicrobial surface that is effective for long-term medical implants and suitable for a variety of drugs.