Prolonged inhibitory effects against planktonic growth,adherence, and biofilm formation of pathogens causing ventilator-associated pneumonia using a novel polyamide/silver nanoparticle composite-coated endotracheal tube

Abstract

Microbial cells can rapidly form biofilm on endotracheal tubes (ETT) causing ventilator-associated pneumonia, a serious complication in patients receiving mechanical ventilation. A novel polyamide with a good balance of hydrophilic/hydrophobic moieties was used for the embedment of green-reduction silver nanoparticles (AgNPs) for the composite-coated ETT. The films were conformal with a thickness of ～ 17?±?3?µm accommodating high loading of 60?±?35?nm spherical-shaped AgNPs. The coated ETT resulted in a significant difference in reducing both planktonic growth and microbial adhesion of single and mixed-species cultures, compared with uncoated ETT (p?<?0.05). A time-kill assay demonstrated rapid bactericidal effects of the coating on bacterial growth and cell adhesion to ETT surface. Biofilm formation by Pseudomonas aeruginosa and Staphylococcus aureus, commonly encountered pathogens, was inhibited by > 96% after incubation for 72?h. Polyamide/AgNP composite-coated ETT provided a broad-spectrum activity against both Gram-positive and Gram-negative bacteria as well as Candida albicans and prolonged antimicrobial activity.     

Design,synthesis and antistaphylococcal activity of marine pyrrole alkaloid derivatives

Abstract

A novel set of 16 hybrids of bromopyrrole alkaloids with aroyl hydrazone were designed, synthesized and evaluated for antibacterial and antibiofilm activities against methicillin-resistant Staphylococcus aureus (MRSA; ATCC 43866), methicillin-susceptible Staphylococcus aureus (MSSA; ATCC 35556) and Staphylococcus epidermidis (SE, S. epidermidis ATCC 35984). Of the 16 tested hybrids, 14 exhibited equal or superior antibiofilm activity against MSSA and MRSA relative to standard vancomycin. Compound 4m showed highest potency with antibiofilm activity of 0.39?µg/mL and 0.78?µg/mL against MSSA and MRSA, respectively. Thus, this compound could act as a potential lead for further development of new antistaphylococcal drugs.     

Changes in fucosylation of human seminal IgG and secretory component of IgA in leukocytospermic patients

Our study compares the status of human seminal plasma immunoglobulin G (IgG) and IgA secretory component (SC) fucosylation between infertile leukocytospermic and normal, fertile normozoospermic patients. The seminal IgG and SC are decorated with AAL-reactive core fucose, and antennary UEA- and LTA-reactive fucose of Lewis^y and Lewis^x structures, respectively. However, a correlation between IgG core fucosylation and IgG concentration (r?=??0.52; p?<?0.0003) was observed. The IgG present in leukocytospermic samples is characterized by lower expression of core fucose than in the normal group (0.82?±?0.3 AU and 1.2?±?0.3 AU, respectively; p?<?0.002). In seminal plasma the SC is present in two forms: 78-kDa and 63-kDa. The present study has also shown a higher AAL and LTA specific reactivity of glycans expressed in 63-kDa SC, in comparison to 78-kDa SC, in the normal group. In leukocytospermia, the values of specific lectin reactivity for core fucose, fucose α(1-2)- and α(1-3)- linked, were similar for both SC bands. Moreover, the present study has shown that in leukocytospermic samples the mean concentrations of IgG and S-IgA are twice as high (131.68?±?102.6 mg/l and 36?±?27 mg/l, respectively) as in the normal group (67.68?±?29.2 mg/l; p?<?0.02, and 19?±?18 mg/l, p?<?0.019, respectively). The analysis of IgG and SC fucosylation status and the determination of IgG and S-IgA concentrations in seminal plasma might constitute a valuable diagnosis tools for the evaluation of male infertility associated with leukocytospermia with accompanying inflammation.     

Enhancement of lomefloxacin Hcl ocular efficacy via niosomal encapsulation: in vitro characterization and in vivo evaluation

The aim of this study is to develop and evaluate niosomal dispersions loaded with the hydrophilic drug; lomefloxacin Hcl (LXN) for the management of ocular bacterial conjunctivitis. LXN-loaded niosomes were prepared by the thin film hydration method following a full factorial formulation design. Two independent variables were evaluated: the type of surfactant (X1) and the surfactant:cholesterol ratio (X2). The dependent variables comprised entrapment efficiency (EE%: Y1), particle size (PS: Y2) and zeta potential (ZP: Y3). The optimum formulation, N-LXN14 (Tw60: CH, 1:1), was spherical in shape and exhibited EE% of 68.41?±?0.07, PS of 176.0?±?0.98 and ZP of -40.70?±?2.20 with a sustained release profile over 8?hours following the Higuchi model. N-LXN14 proved good physicochemical stability under refrigeration up to 3 months. Ocular irritancy test showed no signs of ocular toxicity, confirming the safety and suitability for ocular application. Microbiological evaluation of the antibacterial effect of N-LXN14 was conducted using the susceptibility test and through the induction of topical conjunctivitis by Staphylococcus aureus (S. aureus) followed by topical therapy. Susceptibility test manifested significantly higher percent inhibition of S. aureus and higher AUC_0–12?h of N-LXN14 (604.59?±?0.05) compared to the commercial product (126.25?±?0.049). Both clinical observation and colony count of the infected eyes after eight days of treatment demonstrated significant improvement in therapeutic response. The infected eyes were completely healed with eradication of S. aureus. In conclusion, the results showed that LXN niosomal dispersions may serve as a promising superior ocular delivery system in the treatment of bacterial conjunctivitis.     

Partial purification and characterization of bacteriocin produced by Enterococcus faecalis DU10 and its probiotic attributes

A novel bacteriocin produced by avian duck isolated lactic acid bacterium Enterococcus faecalis DU10 was isolated. This bacteriocin showed a broad spectrum of antibacterial activity against important food-borne pathogens and was purified by size exclusion chromatography followed by reverse-phase high-performance liquid chromatography in a C-18 column. Tricine–SDS PAGE revealed the presence of a band with an estimated molecular mass of 6.3?kDa. The zymogram clearly linked the antimicrobial activity with this band. This result was further confirmed by mass-assisted laser desorption ionization time-of-flight mass spectrometry, since a sharp peak corresponding to 6.313?kDa was detected and the functional groups were revealed by Fourier transform infrared spectroscopy. Bacteriocin DU10 activity was found sensitive to proteinase-K and pepsin and partially affected by trypsin and α-chymotrypsin. The activity of bacteriocin DU10 was partially resistant to heat treatments ranging from 30 to 90°C for 30?min. It also withstood a treatment at 121°C for 10?min. Cytotoxicity of bacteriocin DU10 by methyl-thiazolyl-diphenyl-tetrazolium bromide assay showed that the viability of HT-29 and HeLa cells decreased 60?±?0.7% and 43?±?4.8%, respectively, in the presence of 3,200?AU/mL of bacteriocin. The strain withstood 0.3% w/v of bile oxgall and pH 2 affected the bacterial growth between 2 and 4?hr of incubation. Adhesion properties examined with HT-29 cell line showed 69.85% initial population of strain E. faecalis DU10, which was found to be strongly adhered to this cell line. These results conclude bacteriocin DU10 may be used as a potential biopreservative and E. faecalis DU10 may be used as a potential probiont to control Salmonella infections.     

Hyperhalophilic archaeal biofilms: growth kinetics,structure, and antagonistic interaction in continuous culture

Biofilms by the hyperhalophilic archaea Halorubrum sp. and Halobacterium sp. were analyzed, and for the first time the progression of structural features and the developmental parameters of these sessile populations are described. Optical slicing and digital analysis of sequential micrographs showed that their three dimensional structure was microorganism dependent. Biofilms of Halobacterium sp. developed in clusters that covered about 30% of the supporting surface at the interface level and expanded over about 86?±?4 μm in thickness, while Halorubrum sp. biofilms covered less than 20% of the surface and reached a thickness of 41?±?1 μm. The kinetics of growth was lower in biofilms, with generation times of 27?±?1 and 36?±?2 h for Halobacterium sp. and Halorubrum sp., respectively, as compared to 8.4?±?0.3 and 14?±?1 h in planktonic cultures. Differences between microorganisms were also observed at the cell morphology level. The interaction between the two microorganisms was also evaluated, showing that Halobacterium sp. can outcompete already established Halorubrum sp. biofilms by a mechanism that might include the combined action of tunnelling swimmers and antimicrobial compounds.     

The Influences of Chromium Supplementation on Glycemic Control,Markers of Cardio-Metabolic Risk,and Oxidative Stress in Infertile Polycystic ovary Syndrome Women Candidate for In vitro Fertilization: a Randomized,Double-Blind,Placebo-Controlled Trial

This study was carried out to investigate the effects of chromium intake on glycemic control, markers of cardio-metabolic risk, and oxidative stress in infertile polycystic ovary syndrome (PCOS) women candidate for in vitro fertilization (IVF). This randomized double-blind, placebo-controlled trial was done among 40 subjects with infertile PCOS candidate for IVF, aged 18–40 years old. Individuals were randomly allocated into two groups to take either 200 μg/day of chromium (n?=?20) or placebo (n?=?20) for 8 weeks. Biochemical parameters were assessed at baseline and at end-of-trial. Compared with the placebo, taking chromium supplements led to significant reductions in fasting plasma glucose (??2.3?±?5.7 vs. +?0.9?±?3.1 mg/dL, P?=?0.03), insulin levels (??1.4?±?2.1 vs. +?0.4?±?1.7 μIU/mL, P?=?0.004), homeostatic model of assessment for insulin resistance (??0.3?±?0.5 vs. +?0.1?±?0.4, P?=?0.005), and a significant increase in quantitative insulin sensitivity check index (+?0.004?±?0.008 vs. ??0.001?±?0.008, P?=?0.03). In addition, chromium supplementation significantly decreased serum triglycerides (??19.2?±?33.8 vs. +?8.3?±?21.7 mg/dL, P?=?0.004), VLDL- (??3.8?±?6.8 vs. +?1.7?±?4.3 mg/dL, P?=?0.004) and total cholesterol concentrations (??15.3?±?26.2 vs. ??0.6?±?15.9 mg/dL, P?=?0.03) compared with the placebo. Additionally, taking chromium supplements was associated with a significant increase in plasma total antioxidant capacity (+?153.9?±?46.1 vs. ??7.8?±?43.9 mmol/L, P?<?0.001) and a significant reduction in malondialdehyde values (?0.3?±?0.3 vs. +?0.1?±?0.2 μmol/L, P?=?0.001) compared with the placebo. Overall, our study supported that chromium administration for 8 weeks to infertile PCOS women candidate for IVF had beneficial impacts on glycemic control, few variables of cardio-metabolic risk, and oxidative stress.     

Sleep,Sleepiness, and Neurobehavioral Performance While on Watch in a Simulated 4 Hours on/8 Hours off Maritime Watch System

Seafarer sleepiness jeopardizes safety at sea and has been documented as a direct or contributing factor in many maritime accidents. This study investigates sleep, sleepiness, and neurobehavioral performance in a simulated 4?h on/8?h off watch system as well as the effects of a single free watch disturbance, simulating a condition of overtime work, resulting in 16?h of work in a row and a missed sleep opportunity. Thirty bridge officers (age 30?±?6 yrs; 29 men) participated in bridge simulator trials on an identical 1-wk voyage in the North Sea and English Channel. The three watch teams started respectively with the 00–04, the 04–08, and the 08–12 watches. Participants rated their sleepiness every hour (Karolinska Sleepiness Scale [KSS]) and carried out a 5-min psychomotor vigilance test (PVT) test at the start and end of every watch. Polysomnography (PSG) was recorded during 6 watches in the first and the second half of the week. KSS was higher during the first (mean?±?SD: 4.0?±?0.2) compared with the second (3.3?±?0.2) watch of the day (p?<?0.001). In addition, it increased with hours on watch (p?<?0.001), peaking at the end of watch (4.1?±?0.2). The free watch disturbance increased KSS profoundly (p?<?0.001): from 4.2?±?0.2 to 6.5?±?0.3. PVT reaction times were slower during the first (290?±?6?ms) compared with the second (280?±?6?ms) watch of the day (p?<?0.001) as well as at the end of the watch (289?±?6?ms) compared with the start (281?±?6?ms; p?=?0.001). The free watch disturbance increased reaction times (p?<?0.001) from 283?±?5 to 306?±?7?ms. Similar effects were observed for PVT lapses. One third of all participants slept during at least one of the PSG watches. Sleep on watch was most abundant in the team working 00–04 and it increased following the free watch disturbance. This study reveals that—within a 4?h on/8?h off shift system—subjective and objective sleepiness peak during the night and early morning watches, coinciding with a time frame in which relatively many maritime accidents occur. In addition, we showed that overtime work strongly increases sleepiness. Finally, a striking amount of participants fell asleep while on duty.     

Analysis of myosmine,cotinine and nicotine in human toenail,plasma and saliva

Myosmine is a minor tobacco alkaloid with widespread occurrence in the human diet. Myosmine is genotoxic in human cells and is readily nitrosated and peroxidated yielding reactive intermediates with carcinogenic potential. For biomonitoring of short-term and long-term exposure, analytical methods were established for determination of myosmine together with nicotine and cotinine in plasma, saliva and toenail by gas chromatography–mass spectrometry (GC/MS). Validation of the method with samples of 14 smokers and 10 non-smokers showed smoking-dependent differences of myosmine in toenails (66?±?56 vs 21?±?15?ng?g^?1, p?<0.01) as well as saliva (2.54?±?2.68 vs 0.73?±?0.65?ng ml^?1, p <0.01). However, these differences were much smaller than those with nicotine (1971?±?818 vs 132?±?82?ng g^?1, p <0.0001) and cotinine (1237?±?818 vs <35?ng?g^?1) in toenail and those of cotinine (97.43?±?84.54 vs 1.85?±?4.50?ng ml^?1, p <0.0001) in saliva. These results were confirmed in plasma samples from 84 patients undergoing gastro-oesophageal endoscopy. Differences between 25 smokers and 59 non-smokers are again much lower for myosmine (0.30?±?0.35 vs 0.16?±?0.18?ng?ml^?1, p <0.05) than for cotinine (54.67?±?29.63 vs 0.61?±?1.82?ng ml^?1, p <0.0001). In conclusion, sources other than tobacco contribute considerably to the human body burden of myosmine.     

Sulphate transport in the cyanobacterium Synechococcus R-2 (Anacystis nidulans, S. leopoliensis) PCC 7942

Synechococcus R-2 (PCC 1942) actively accumulates sulphate in the light and dark. Intracellular sulphate was 1.35 ± 0.23 mol m^?3 (light) and 0.894 ± 0.152 mol m^?3 (dark) under control conditions (BG-11 media: pH_o, 7.5; [SO₄^2?]_o, 0.304 mol m^?3). The sulphate transporter is different from that found in higher plants: it appears to be an ATP-driven pump transporting one SO₄^2?/ATP [ΔμSO₄^2?_i,o=+ 27.7 ± 0.24 kJ mol^?1 (light) and + 24 ± 0.34 kj mol^?1 (dark)]. The rate of metabolism of SO₄^2?at pH_o, 7.5 was 150 ± 28 pmol m^?2 s^?1 (n = 185) in the light but only 12.8 ± 3.6 pmol m^?2 s^?1 (n = 61) in the dark. Light-driven sulphate uptake is partially inhibited by DCMU and chloramphenicol. Sulphate uptake is not linked to potassium, proton, sodium or chloride transport. The alga has a constitutive over-capacity for sulphate uptake [light (n= 105): K_m= 0.3 ± 0.1 mmol m^?3, V_max, = 1.8 ± 0.6 nmol m^?2 s^?1; dark (n= 56): K_m= 1.4 ± 0.4 mmol m^?3, V_max= 41 ± 22 pmol m^?2 s^?1]. Sulphite (SO₃^2?) was a competitive inhibitor of sulphate uptake. Selenate (SeO₄^2?) was an uncompetitive inhibitor.     

Antimicrobial photodynamic activity of toluidine blue encapsulated in mesoporous silica nanoparticles against Pseudomonas aeruginosa and Staphylococcus aureus

In the present study, the antimicrobial and antibiofilm efficacy of toluidine blue (TB) encapsulated in mesoporous silica nanoparticles (MSN) was investigated against Pseudomonas aeruginosa and Staphylococcus aureus treated with antimicrobial photodynamic therapy (aPDT) using a red diode laser 670?nm wavelength, 97.65?J cm^?2 radiant exposure, 5?min). Physico-chemical techniques (UV-visible (UV-vis) absorption, photoluminescence emission, excitation, and FTIR) and high-resolution transmission electron microscopy (HR-TEM) were employed to characterize the conjugate of TB encapsulated in MSN (TB MSN). TB MSN showed maximum antimicrobial activities corresponding to 5.03 and 5.56 log CFU ml^?1 reductions against P. aeruginosa and S. aureus, respectively, whereas samples treated with TB alone showed 2.36 and 2.66 log CFU ml^?1 reductions. Anti-biofilm studies confirmed that TB MSN effectively inhibits biofilm formation and production of extracellular polymeric substances by P. aeruginosa and S. aureus.     

Alkaloid profiling and anticholinesterase activity of South American Lycopodiaceae species

The alkaloid extracts of four Huperzia and one Lycopodiella species, from Brazilian habitats, were tested for their in vitro anticholinesterase activities. IC₅₀ values showed a potent acetylcholinesterase inhibition for H. reflexa (0.11?±?0.05 μg/mL), followed by H. quadrifariata (2.0?±?0.3 μg/mL), H. acerosa (5.5?±?0.9 μg/mL), H. heterocarpon (25.6?±?2.7 μg/mL) and L. cernua (42.6?±?1.5 μg/mL). A lower inhibition of butyrylcholinesterase was observed for all species with the exception of H. heterocarpon (8.3?±?0.9 μg/mL), whose alkaloid extract presented a selectivity for pseudocholinesterase. Moreover, the chemical study of the bioactive extracts performed by GC-MS, revealed the presence of a number of Lycopodium alkaloids belonging to the lycopodane, flabellidane and cernuane groups. Surprisingly, the potent acetylcholinesterase inhibitors huperzines A and B were not detected in the extracts, suggesting that other alkaloids may be responsible for such an effect.     

Carboxymethyl cellulase production optimization from Glutamicibacter arilaitensis strain ALA4 and its application in lignocellulosic waste biomass saccharification

Abstract

In this context, carboxymethyl cellulase (CMCase) production from Glutamicibacter arilaitensis strain ALA4 was initially optimized by one factor at a time (OFAT) method using goat dung as proficient feedstock. Two-level full factorial design (2⁵ factorial matrix) using first-order polynomial model revealed the significant (p?<?0.05) influence of pH, moisture, and peptone on CMCase activity. Central composite design at N?=?20 was further taken into account using a second-order polynomial equation, and thereby liberated maximum CMCase activity of 4925.56?±?31.61?U/g in the goat dung medium of pH 8.0 and 100% moisture containing 1% (w/w) peptone, which was approximately two fold increment with respect to OFAT method. Furthermore, the partially purified CMCase exhibited stability not only at high pH and temperature but also in the presence of varied metal ions, organic solvents, surfactants, and inhibitors with pronounced residual activities. The enzymatic hydrolysis using partially purified CMCase depicted the maximum liberation of fermentable sugars from alkali pretreated lignocellulosic wastes biomass in the order of paddy straw (13.8?±?0.15?mg/g)?>?pomegranate peel (9.1?±?0.18?mg/g)?>?sweet lime peel (8.37?±?0.16?mg/g), with saccharification efficiency of 62.1?±?0.8, 40.95?±?0.4, and 37.66?±?0.4%, respectively after 72?hr of treatment.     

Prostaglandin Endoperoxide H Synthase-2 (PGHS-2) Variants and Risk of Obesity and Microvascular Dysfunction Among Tunisians: Relevance of rs5277 (306G/C) and rs5275 (8473T/C) Genetic Markers

The purpose of this study was to determine the impact of six PGHS-2 genetic variants on obesity development and microvascular dysfunction. The study included 305 Tunisian subjects (186 normal weights, 35 overweights and 84 obeses). PCR analyses were used for allelic discrimination between polymorphisms. Prostaglandin (PGE2, PGI2), leptin, and matrix metalloproteinase (MMP1, 2, 3, 9) levels were evaluated by ELISA. Fatty acid composition was performed by gas chromatography–mass spectrometry. Our results revealed that subjects carrying the PGHS-2 306CC (rs5277) and 8473CC (rs5275) genotypes present higher anthropometric values compared to wild-type genotypes (306GG, BMI (Kg/m²): 27.11?±?0.58; WC (cm): 93.09?±?1.58; 306CC, BMI: 33.83?±?2.46; WC: 109.93?±?5.41; 8473TT, BMI: 27.75?±?0.68; WC: 93.96?±?1.75; 8473CC, BMI: 33.72?±?2.2; WC: 117.89?±?2.94). A reduced microvascular reactivity and a higher PGE2 level were also found in individuals with the 306CC and 8473CC genotypes in comparison to 306GG and 8473TT carriers (306GG, Peak Ach-CVC (PU/mmHg): 0.46?±?0.03; PGE2 (pg/ml): 7933.1?±?702; 306CC, Peak Ach-CVC: 0.24?±?0.01; PGE2: 13,380.3?±?966.2; 8473TT, Peak Ach-CVC: 0.48?±?0.05; PGE2: 7086.41?±?700.31; 8473CC, Peak Ach-CVC: 0.23?±?0.01; PGE2: 13,175.7?±?1165.8). Fatty acid analysis showed a significant increase of palmitic acid (PA) (34.2?±?2.09 vs. 16.82%?±?1.76, P?<?0.001), stearic acid (SA) (25.76?±?3.29 vs. 9.05%?±?2.53, P?<?0.001), and linoleic acid (LA) (5.25?±?1.18 vs. 0.5%?±?0.09, P?<?0.001) levels in individuals carrying the PGHS-2 306CC genotype when compared to GG genotype individuals. Subjects with the 8473CC genotype showed also a significant increase of PA, SA ,and LA levels when compared to TT genotype carriers (PA: 38.02?±?1.51 vs. 12.65%?±?1.54, P?<?0.001; SA: 32.96?±?1.87 vs. 1.38%?±?0.56, P?<?0.001; LA: 26.84?±?2.09 vs. 3.7%?±?1.54, P?<?0.001). Logistic regression analysis revealed that PGHS-2 306CC and 8473CC variants are significantly associated with obesity status (OR 6.25, CI (1.8–21.6), P?=?0.004; OR 3.01, CI (1.13–8.52), P?=?0.03, respectively). Haplotypes containing the C₃₀₆:T₈₄₇₃ (OR 2.91; P?=?0.01) and G_306:C₈₄₇₃ (OR 5.25; P?=?0.002) combinations were associated with an enhanced risk for obesity development in the studied population. In conclusion, our results highlight that PGHS-2 306G/C and 8473T/C variants could be useful indicators of obesity development, inflammation, and microvascular dysfunction among Tunisians.

     

Effects of logging on carbon dynamics of a jack pine forest in Saskatchewan,Canada

We calculated carbon budgets for a chronosequence of harvested jack pine (Pinus banksiana Lamb.) stands (0‐, 5‐, 10‐, and～29‐year‐old) and a～79‐year‐old stand that originated after wildfire. We measured total ecosystem C content (TEC), above‐, and belowground net primary productivity (NPP) for each stand. All values are reported in order for the 0‐, 5‐, 10‐, 29‐, and 79‐year‐old stands, respectively, for May 1999 through April 2000. Total annual NPP (NPP_T) for the stands (Mg C ha^?1 yr^?1±1 SD) was 0.9±0.3, 1.3±0.1, 2.7±0.6, 3.5±0.3, and 1.7±0.4. We correlated periodic soil surface CO₂ fluxes (R_S) with soil temperature to model annual R_S for the stands (Mg C ha^?1 yr^?1±1 SD) as 4.4±0.1, 2.4±0.0, 3.3±0.1, 5.7±0.3, and 3.2±0.2. We estimated net ecosystem productivity (NEP) as NPP_T minus R_H (where R_H was calculated using a Monte Carlo approach as coarse woody debris respiration plus 30–70% of total annual R_S). Excluding C losses during wood processing, NEP (Mg C ha^?1 yr^?1±1 SD) for the stands was estimated to be ?1.9±0.7, ?0.4±0.6, 0.4±0.9, 0.4±1.0, and ?0.2±0.7 (negative values indicate net sources to the atmosphere.) We also calculated NEP values from the changes in TEC among stands. Only the 0‐year‐old stand showed significantly different NEP between the two methods, suggesting a possible mismatch for the chronosequence. The spatial and methodological uncertainties allow us to say little for certain except that the stand becomes a source of C to the atmosphere following logging.     

Soil–atmosphere exchange of CH4, CO,N2O and NOx and the effects of land‐use change in the semiarid Mallee system in Southeastern Australia

The semiarid and arid zones cover a quarter of the global land area and support one‐fifth of the world's human population. A significant fraction of the global soil–atmosphere exchange for climatically active gases occurs in semiarid and arid zones yet little is known about these exchanges. A study was made of the soil–atmosphere exchange of CH₄, CO, N₂O and NO_x in the semiarid Mallee system, in north‐western Victoria, Australia, at two sites: one pristine mallee and the other cleared for approximately 65 years for farming (currently wheat). The mean (± standard error) rates of CH₄ exchange were uptakes of ?3.0 ± 0.5 ng(C) m^?2 s^?1 for the Mallee and ?6.0 ± 0.3 ng(C) m^?2 s^?1 for the Wheat. Converting mallee forest to wheat crop increases CH₄ uptake significantly. CH₄ emissions were observed in the Mallee in summer and were hypothesized to arise from termite activity. We find no evidence that in situ growing wheat plants emit CH₄, contrary to a recent report. The average CO emissions of 10.1 ± 1.8 ng(C) m^?2 s^?1 in the Mallee and 12.6 ± 2.0 ng(C) m^?2 s^?1 in the Wheat. The average N₂O emissions were 0.5 ± 0.1 ng(N) m^?2 s^?1 from the pristine Mallee and 1.4 ± 0.3 ng(N) m^?2 s^?1 from the Wheat. The experimental results show that the processes controlling these exchanges are different to those in temperate systems and are poorly understood.     

Left ventricular diastolic dysfunction in type 2 diabetes patients: a novel 2D strain analysis based on cardiac magnetic resonance imaging

Objective: This study was to develop a strain analysis method to evaluate the left ventricular (LV) functions in type 2 diabetic patients with an asymptomatic LV diastolic dysfunction. Methods: Two groups (10 asymptomatic type 2 diabetic subjects and 10 control ones) were considered. All of the subjects had normal ejection fraction values but impaired diastolic functions assessed by the transmitral blood flow velocity. For each subject, based on cardiac MRI, global indexes including LV volume, LV myocardial mass, cardiac index (CI), and transmitral peak velocity, were measured, and regional indexes (i.e., LV deformation, strain and strain rate) were calculated through an image-registration technology. Results: Most of the global indexes did not differentiate between the two groups, except for the CI, LV myocardial mass and transmitral peak velocity. While for the regional indexes, the global LV diastolic dysfunction of the diabetic indicated an increased strain (0.08?±?0.044 vs. ?0.031?±?0.077, p?=?0.001) and a reduced strain rate (1.834?±?0.909 vs. 3.791?±?2.394, p?=?0.033) compared to the controls, moreover, the local LV diastolic dysfunction reflected by the strain and strain rate varied, and the degree of dysfunction gradually decreased from the basal level to the apical level. Conclusions: The results showed that the strain and strain rates are effective to capture the subtle alterations of the LV functions, and the proposed method can be used to estimate the LV myocardial function based on cardiac MRI.     

Remediation of Explosive-Contaminated Soils: Alkaline Hydrolysis and Subcritical Water Degradation

Alkaline hydrolysis and subcritical water degradation were investigated as ex-situ remediation processes to treat explosive-contaminated soils from military training sites in South Korea. The addition of NaOH solution to the contaminated soils resulted in rapid degradation of the explosives. The degradation of explosives via alkaline hydrolysis was greatly enhanced at pH ≥12. Estimated pseudo-first-order rate constants for the alkaline hydrolysis of 2,4-dinitrotoluene (DNT), 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in contaminated soil at pH 13 were (9.6?±?0.1)×10^?2, (2.2?±?0.1)×10^?1, and (1.7?±?0.2)×10^?2 min^?1, respectively. In the case of subcritical water degradation, the three explosives were completely removed at 200–300°C due to oxidation at high temperatures and pressures. The degradation rate increased as temperature increased. The pseudo-first-order rate constants for DNT, TNT, and RDX at 300°C were (9.4?±?0.8)×10^?2, (22.8?±?0.3)×10^?2, and (16.4?±?1.0)×10^?2, respectively. When the soil-to-water ratio was more than 1:5, the extent of alkaline hydrolysis and subcritical water degradation was significantly inhibited.     

Association Between Zinc, Copper, and Iron Concentrations in Breast Milk and Growth of Healthy Infants in Tabriz, Iran

The aims of this study were to determine the effect of breast milk zinc, copper, and iron concentrations on infants’ growth and their possible correlations with maternal dietary intake. Milk samples and information on food intake were collected from 182 lactating women. Concentrations of zinc, copper, and iron in milk were analyzed using atomic absorption spectrophotometry. The infant’s weight for age Z-score (WAZ) and height for age Z-score (HAZ) were calculated. The mean milk zinc, copper, and iron concentrations were 1.85?±?0.5, 0.53?±?0.3, and 0.85?±?0.2 mg/l, respectively. Only zinc mean level was lower than the recommended range. Association between zinc, copper, and iron concentrations of milk and WAZ or HAZ of infants were not significant. However, the WAZ of infants whose mothers' milk zinc was more than 2 mg/l was significantly (P?<?0.039) higher than for others. The mean dietary zinc (5.31?±?2.3 mg/day) and copper (1.16?±?0.7 mg/day) intake of mothers was significantly less than the required daily intake (RDA) recommendations (P?<?0.05). The mean dietary iron intake (11.8?±?8.2 mg/day) was significantly higher than RDA recommendation (P?<?0.001). No significant association was found between maternal mean dietary zinc, copper, and iron intakes with their concentrations in milk. Dietary consultation or/and zinc supplementation is suggested for lactating women and infants.