Wearing long pants while working outdoors in the tropics does not yield higher body temperatures

Objective: To compare the thermoregulatory demands of outdoor workers wearing long or knee‐length pants while working in situ in a tropical environment. Methods: Fifteen male (35.8 ± 10.5 yr) outdoor Council workers completed their daily occupational duties (construction or gardening) in trials conducted six days apart: once wearing knee‐length shorts (SHORTS) and once wearing full‐length pants (PANTS). Body mass and hydration were assessed prior to and following each trial with core body (T_C) and mean skin temperature (MST; weighted from sites: chest, arm, thigh and calf) assessed at 30‐minute intervals throughout each trial. Results: No significant differences between SHORTS and PANTS for T_C, maximum T_C, heart rate, MST or body mass changes. Skin temperature at the calf was greater for PANTS (33.8 ± 0.4°C) compared to SHORTS (32.9 ± 0.4°C; p<0.05). Hydration assessments identified 36.7% of participants commenced work hypohydrated while the average body mass lost throughout the workday was 2.5 ± 1.5%. Main effects of time were observed for heart rate and MST but no other assessed variable. Conclusion: The additional exposed surface area available for heat exchange when wearing shorts is insufficient to elicit differences in thermoregulatory demands of outdoor employees under the assessed conditions. Implications: These results suggest the use of SHORTS or PANTS can be determined by occupational duty requirements rather than risk of heat‐related illness during very‐light to moderate workloads completed under warm and humid environmental conditions.     

Biodegradation of Phenanthrene by Pseudomonas sp. JPN2 and Structure-Based Degrading Mechanism Study

The strain Pseudomonas sp. JPN2 had a high potential to degrade phenanthrene degrading 98.52?% of the initial amount of 100 mg L^?1 after 10 days incubation. The analysis of metabolites demonstrated that the cleavage of phenanthrene started at the C₉ and C₁₀ positions on the aromatic ring by the dioxygenation reaction, and then further degraded via a phthalate pathway. To understand the interaction between phenanthrene and the amino acid residues in the active site of the target enzyme, a molecular docking simulation was performed. The results showed that the distances of C₉–O₁ and C₁₀–O₂ atoms were 3.47 and 3.67 Å, respectively. The C₉ and C₁₀ positions of the phenanthrene ring are much closer to the dioxygen molecule in the active site relative to the other atoms. Therefore, the C₉ and C₁₀ positions are vulnerable to attack in the initial oxygenation process.     

Chemical and biological characterization of volatile components of environmental samples after fractionation by vacuum line cryogenic distillation

Volatile components from diesel exhaust particles and coal gasifier process gas condensate were vacuum fractionated by cryogenic distillation and identified by infrared spectroscopy and gas chromatography/mass spectrometry. The vacuum distillation line consisted of a sample flask and nine traps cooled from 0°C to ?196°C in approximately 20°C steps. The pressure in the vacuum line of about 10^?2 Torr was maintained with a vacuum pump. Separated compounds were identified by comparison to reference infrared spectra and confirmed by comparison with standards when practical. Volatile compounds identified from the diesel exhaust particle sample included NO_x, carbon dioxide, sulfur dioxide, alkanes, aldehydes, and one and two ring aromatic hydrocarbons. Volatile compounds identified in process gas condensate from a coal gasifier were ammonia, carbonyl sulfide, carbon dioxide, C₃-C₇ hydrocarbons, one and two ring aromatic hydrocarbons, and phenols. Volatile components collected at either 0° or ?24°C were evaluated to determine their genotoxicity using the Chinese hamster ovary/hypoxanthine-guanine phosphoribosyltransferase (CHO/HGPRT) assay. Neither the gasifier condensate nor diesel particle samples produced mutations at the HGPRT locus. The diesel samples were not cytotoxic at the concentrations tested (100 μg/ml) but the gasifier samples resulted in 50% cell killing at concentrations between 25 and 100 μg/ml depending on the temperature of collection and the test conditions. Vacuum desorption with cryogenic distillation has provided a means to separate the volatile components in complex environmental samples to allow chemical and biological characterization of these components.     

Purification and characterization of fructan and fructansucrase from Lactobacillus fermentum AKJ15 isolated from Kodo ko jaanr,a fermented beverage from north-eastern Himalayas

Fructansucrase and fructan produced from Lactobacillus fermentum AKJ15 were isolated from seeds of Kodo ko jaanr, a fermented mild-alcoholic beverage prepared in North East India. The strain was identified by 16S rRNA gene sequence analysis and biochemical characterization. The strain displayed maximum fructansucrase activity of 4.3 U/ml (1.02 U/mg) at 28°C at 180 rpm. The enzyme purified by polyethylene glycol-400 gave specific activity of 5 U/mg and showed 90 kDa band on non-denaturing Sodium Dodecyl Sulphate-Poly Acrylamide Gel Electrophoresis (SDS-PAGE). The purified enzyme confirmed the presence of fructan by periodic acid Schiff's staining which showed magenta colour bands with both sucrose and raffinose. The strain produced 10.2 mg/ml fructan in broth under optimized culture conditions. The purified fructansucrase displayed V_max of 5.42 U/mg and K_m of 16.65 mM. The enzyme showed maximum activity at 30°C and at pH 5. The structure of fructan was analysed by ¹H and ¹³C NMR spectra confirming β-(2-1) and β-(2-6) linkages.     

Long-term kinetics of daidzein and its main metabolites in human equol-producers after soymilk intake: identification of equol-conjugates by UPLC-orbitrap-MS and influence of the number of transforming bacteria on plasma kinetics

The main aim of the study was to establish in vivo a correlation between equol (EQU) production and a number of intestinal bacteria able to perform the transformation. Thus, healthy female volunteers were selected for their ability to convert slowly (n?=?6, 10⁵–10⁹ cells/g wet feces) or quickly (n?=?6, 10¹⁰–10¹² cells/g wet feces) daidzein (DAI) in EQU. After oral administration of 100?mg DAI in soymilk, plasma (0–99?h) and urine (0–96?h) samples were collected. DAI and its metabolites were determined by LC-MS/MS and EQU -conjugates by UPLC-High Resolution-MS. Only for EQU a direct correlation was found between the number of transforming microorganisms and parameters such as t_max and t_1/2 (p?=?0.027). Peak serum concentration time, C_max, AUC_0–72?h and t_1/2 for total EQU (n?=?12) were 36?±?10?h, 89?±?78?nM, 2.4?±?1.7 (μmol?×?h/L) and 15.6?±?3.3?h, respectively. In plasma and urine EQU was found mainly as 7-O-glucuronide.     

Alteration of Leopard Frog (Rana pipiens) Metamorphosis by the Herbicide Acetochlor

Based on the geographic correlation between the use of the pre-emergent herbicide acetochlor [2-chloro-N-(ethoxymethyl)-N-(2-ethyl-6-methylphenyl) acetamide] and the natural range of Northern leopard frogs (Rana pipiens), we investigated the effects of acetochlor (ACETO) on frog metamorphosis. We specifically examined the interaction of ACETO with thyroid hormone (T₃) and corticosterone (CORT), hormones that regulate natural metamorphosis. ACETO, T₃, and CORT were administered via immersion. Growth, developmental stage, and onset of metamorphic climax (forelimb emergence, FLE) were measured. We examined three hypotheses: (1) ACETO may alter metamorphosis. Premetamorphic tadpoles with low endogenous T₃ were exposed to ACETO ± 10⁻⁹ M T₃ for 7 days. 67% of tadpoles exposed to ACETO + T₃ attained FLE, while 0% of T₃ treated animals did. (2) ACETO mimics T₃ action at the thyroid receptor (TR). Tadpoles were pretreated with T₃ for 3 days to induce TR expression, then treated for 7 days with vehicle (DMSO), T₃, or ACETO ± T₃. ACETO treatment after T₃ priming did not accelerate FLE, suggesting that ACETO does not interact directly with the TR. Cotreatment with ACETO + T₃ after T₃ priming accelerated FLE relative to tadpoles primed with T₃, then treated with T₃. Because the ACETO + T₃ acceleration of FLE appeared similar to the effect of CORT, we examined a third hypothesis: (3) ACETO may interact with CORT to accelerate FLE. Premetamorphic tadpoles were exposed to various doses of ACETO ± T₃ in the presence or absence of 10⁻⁷ M CORT. CORT inhibited growth and hindlimb development and delayed FLE. ACETO never inhibited growth or hindlimb development, but ACETO did counteract the effects of CORT when T₃ was present. ACETO consistently accelerated T₃-induced metamorphosis, apparently interacting with T₃ via a non-TR–mediated mechanism. Received: 28 August 1998/Accepted: 11 January 1999     

The effect of triiodothyronine on the primary antibody response to sheep red blood cells in moderately undernourished weanling mice

Weanling male CBA/J mice were fed a complete, semipurified diet either ad libitum or in restricted daily quantities. The undernourished mice were fed such that they gained 18% of their initial weight over the 6-week experimental period. A 2×2 design was used in which animals from each dietary group received food either with or without a triiodothyronine (T₃) supplement of 0.2 mg/kg diet. In mice immunized with sheep red blood cells, undernutrition decreased the number of nucleated spleen cells and the number of IgG plaque-forming cells (PFC's) per spleen, increased the number of IgM PFC's per 10⁶ nucleated spleen cells, and had no effect on the number of IgM PFC's per spleen, the number of IgG PFC's per 10⁶ nucleated spleen cells or the serum hemagglutinin titre. T₃ supplements increased nucleated spleen cell numbers and IgM PFC's per spleen in both well-nourished and undernourished mice, and also increased hemagglutinin titres in undernourished mice. According to carcass composition (dry matter, protein and lipid) and serum protein measurements the effect of T₃ was not attributable to improved nutritional status in spite of increased feed intake by the T₃-treated animals.     

Absorption and metabolism of cyanidin-3-glucoside and cyanidin-3-rutinoside extracted from wild mulberry (Morus nigra L.) in rats

The mechanism of uptake of anthocyanins (as well as the type) from food in the intestine is not clear. Anthocyanin-rich extract from wild mulberry, composed of cyanidin-3-glucoside (79%) and cyanidin-3-rutinoside (cy-3-rut) (19%), was orally administered to Wistar rats, and their concentrations were determined in plasma, kidney, and the gastrointestinal (GI) tract. The 2 glycosylated forms showed maximum concentration at 15 minutes after oral administration, both in plasma and kidney. The cyanidin-3-glucoside and cy-3-rut were found in plasma as glucuronides, as sulfates of cyanidin, and as unchanged forms. The area under the curve of concentration vs time (AUC_0-8h) was 2.76 ± 0.88 μg hour/mL and 9.74 ± 0.75 μg hour/g for plasma and kidney, respectively. In spite of the low absorption, the increase in plasma anthocyanin level resulted in a significant increase in antioxidant capacity (P < .05). In the GI tract (stomach and small and large intestines), cyanidin glycosides were found unchanged, but a low amount of the aglycone form was present. Anthocyanin glycosides were no longer detected in the GI tract after 8 hours of administration. In vitro fermentation showed that the 2 cyanidin glycosides were totally metabolized by the rat colonic microflora, explaining their disappearance. In addition, the 2 products of their degradation, cyanidin and protocatechuic acid, were not detected in plasma and probably do not influence plasma antioxidant capacity. As found by the everted sac model, anthocyanins were transported across the enterocyte by the sodium-dependent glucose transporter.     

Identification by physical means of organic moieties of conjugates produced from carbaryl by tobacco cells in suspension culture

Carbaryl (1-naphthyl methylcarbamate), labeled with¹⁴C in the C₁-naphthyl, carbonyl, orN-methyl position, was introduced into the culture medium of tobacco cells in suspension culture. Following incubation, cells were homogenized in water, centrifuged, and supernatants hydrolyzed with-glucosidase or HCl. Organic moieties (moieties) were characterized by two-dimensional thin-layer chromatography (TLC), and many were subsequently identified by infrared and mass spectrometry. On the basis of the data obtained with¹⁴C₁-naphthyl-labeled carbaryl, it appeared that 18.4% of the total characterized metabolites represented unconjugatedN-CH₂OH- carbaryl [1-naphthylN-(hydroxymethyl)carbamate], excreted by the cells into the culture medium. The metabolites found in the cells primarily consisted of conjugates of 1-naphthol (73.6% of the total characterized metabolites) andN-CH₂OH-carbaryl (2.5%). Conjugates of 7-hydroxycarbaryl (7-hydroxy-1-naphthyl methylcarbamate), 4-hydroxycarbaryl (4-hydroxy-1-naphthyl methylcarbamate), and 5-hydroxycarbaryl (5-hydroxy-1-naphthyl methylcarbamate) were also detected in small amounts. Of five unknown¹⁴C₁-naphthyl-labeled carbaryl metabolites, three were tentatively characterized as:O-1-naphthylcholesterol (cholest-5-en-3-yl-1-naphthol; 3.0%); an unconjugated hydroxylated 1,4-dihydro-1,4-epiperoxynaphthalene (1.4%); and an acidlabile,-glucosidase-resistant conjugate of acis-dihydrodiol of 1-naphthol (0.3%; other than thetrans-5,6-dihydrodiol). The cholesterol derivative may represent a new detoxification mechanism in plants; the epiperoxide may help to elucidate plant oxidation mechanisms. A new TLC procedure was developed which successfully separated the acetate derivative ofN-hydroxycarbaryl (1-naphthylN-hydroxy-N-methylcarbamate) from 12 other common moieties of carbaryl metabolites and their acetate derivatives. A new two-dimensional TLC system was developed for the separation of underivatizedN-hydroxycarbaryl from 14 other moieties of carbaryl metabolites; two additional two-dimensional TLC systems were utilized for moiety separations. With these TLC procedures, no conjugated or unconjugatedN-hydroxycarbaryl could be detected in any tobacco cell culture fraction after incubation of cells in medium containing radiolabeled carbaryl. Authentic¹⁴C₁-naphthyllabeledN-CH₂OH-carbaryl was shown to be converted to desmethylcarbaryl (1-naphthylcarbamate) (97%) and 1-naphthol (3%) by 0.1N HCl hydrolysis.Deceased.     

Continuous dosing of a novel contraceptive vaginal ring releasing Nestorone® and estradiol: pharmacokinetics from a dose-finding study

Background

As part of a program to develop a novel estradiol-releasing contraceptive vaginal ring (CVR), we evaluated the pharmacokinetic (PK) profile of CVRs releasing segesterone acetate (Nestorone® (NES)) combined with one of three different estradiol (E₂) doses.

Effect of Moisture, Organic Matter, Microbial Population and Fortification Level on Dissipation of Pyraclostrobin in Soils

The dissipation of pyraclostrobin, a strobilurin fungicide, in soil was found to be influenced by soil moisture, organic matter content and microbial population. Among the different moisture regimes, dissipation was faster under submerged condition (T_1/2 10 days) followed by field capacity (T_1/2 28.7 days) and in dry soil (T_1/2 41.8 days). Use of sludge at 5 % level to Inceptisol favoured a faster dissipation of pyraclostrobin, whereas a slower rate of dissipation was observed in partial organic matter removed soil as compared to normal soil. Slower rate of dissipation was also observed in sterile soil (T_1/2 47 days) compared to normal soil. Pyraclostrobin dissipated faster in Vertisol (T_1/2 21.8 days) than in Inceptisol (T_1/2 28.7 days). No significant difference in the dissipation rate was observed at 1 and 10 μg g^?1 fortification levels.     

Family Members' Obstructive Behaviors Appear to Be More Harmful Among Adults With Type 2 Diabetes and Limited Health Literacy

Family members' diabetes-specific obstructive behaviors (e.g., nagging/arguing or getting in the way of patients' self-care) are associated with adults having worse glycemic control (HbA_1C), with diabetes-specific supportive family behaviors protecting against this detrimental effect. Given the role of family members in helping patients with limited health literacy, patients' health literacy status may moderate these relations. The authors tested this hypothesis with 192 adults with type 2 diabetes. Twenty-six percent had limited health literacy, and limited health literacy was associated with more supportive family behaviors (p < .05), but not with obstructive family behaviors or with patients' HbA_1C. Adjusted stratified analyses indicated obstructive family behaviors were more strongly associated with worse HbA_1C among participants with limited health literacy and low supportive family behaviors than for participants with adequate health literacy and low supportive family behaviors (adjusted simple slopes β = 0.70, p = .05 vs. β = 0.36, p = .009). However, there was no association between obstructive family behaviors and HbA_1C in the context of high supportive family behaviors, regardless of health literacy status. Involving family members in adults' self-care without teaching them to avoid obstructive behaviors may be particularly harmful for patients with limited health literacy. Future research should identify intervention content to reduce obstructive family behaviors and identify which supportive family behaviors may be protective.     

Anthocyanins in purple and blue wheat grains and in resulting bread: quantity,composition, and thermal stability

Abstract

The anthocyanin composition of blue (Triticum aestivum L., cv. Skorpion) and purple wheat (Triticum aethiopicum JAKUBZ cv. Abyssinskaja arrasajta cv. Abyssinskaja arrasajta), cultivated in the Czech Republic, and of the prepared whole blue and purple wheat bread was determined. In blue and purple wheat, 19 and 26 anthocyanins, respectively, were tentatively identified by liquid chromatography and mass spectrometry. The total content of anthocyanins determined in blue and purple wheat was 9.26 and 13.23?mgkg^?1, respectively. The breads were baked at 240 and 180?°C. Some significant differences in anthocyanins content were observed between breads prepared at different baking temperatures. The content of cyanidin-3-glucoside, delphinidin-3-glucoside and pelargonidin-3-glucoside was determinated in starting material, whole meal flours and baked breads. These kinds of wheat are suitable for baking bread, since intake of anthocyanins may play an important role in the prevention of human diseases.     

Atmospheric CO<Subscript>2</Subscript> Level and Temperature Affect Degradation of Pretilachlor and Butachlor in Indian Soil

This study was conducted at ambient (398?±?10 µmol mol^?1), elevated (450?±?10 µmol mol^?1) and elevated (550?±?10 µmol mol^?1) atmospheric CO₂ under three moisture regime and also three level of temperature (4, 25, and 40°C) to assess the degradation of pretilachlor and butachlor. Under dry condition at 398?±?10 µmol mol^?1, T_1/2 was 28.5 and 59.4 days for pretilachlor and butachlor, respectively; slowly decreased to 18.2 and 44.5 days at 550?±?10 µmol mol^?1 indicated that elevated condition enhanced degradation than ambient condition. Under field capacity with increasing CO₂ levels from ambient to elevated, T_1/2 decreased from 18.9 to 11.6 days and 39.4 to 16.2 days for of pretilachlor and butachlor, respectively. Similarly, under submerged conditions with increasing CO₂ levels T_1/2 decreased 14.7–7.1 and 26.3–11.8 days for pretilachlor and butachlor, respectively. Study also revealed that both pretilachlor and butachlor dissipated faster at 40°C (T_1/2, 9.7 and 19.4 days) than 25°C (T_1/2, 16.2 and 36.7 days). Slower dissipation was recorded at 4°C (T_1/2, 87.6 and 182.4 days).     

Oxidative stability and triacylglycerols structure of lipid fraction from cookies for infants

The aim of this research was to analyse the quality of the lipid fraction extracted from commercially available cookies intended for infants. The composition, fatty acid distribution and oxidative stability of fats, interpreted as the resistance of fats against autooxidation, were studied. In addition, the kinetic parameters of the oxidation process, such as activation energies (E_a), pre-exponential factors (Z) and reaction rate constants (k) for fat oxidation under the differential scanning calorimetry tests conditions were calculated using the Ozawa–Flynn–Wall method and the Arrhenius equation. The distribution of fatty acids in the tested cookies is similar to that present in most of infant formulas, but differs significantly from that in human milk. Based on the results obtained, high oxidative stability of tested fats can be observed. The E_a values ranged from 86.22 to 116.13 kJ/mol; Z from 1.95 × 10⁹ to 1.05 × 10¹³; and k values ranged from 5.70 × 10^{? 4} min^{? 1} at 100°C to 2.12 × 10^{? 1} min^{? 1} at 170°C.     

Effect of (C6H5)3PbCl and (C6H5)3SnCl on Delayed Luminescence Intensity, Evolving Oxygen and Electron Transport Rate in Photosystem II of Chlorella vulgaris

The effect of the organometallic compounds containing lead, (C₆H₅)₃PbCl, and tin, (C₆H₅)₃SnCl, on Chlorella green algae photosystem II was studied. Suspension of the algae treated with (C₆H₅)₃SnCl at concentrations of 1.0 and 4.0 μmol dm⁻³ for 22 h revealed a decrease in most physiological parameters studied, particularly in decasecond component of delayed chlorophyll luminescence, photosynthetic electron transport rate and diluted oxygen concentration, which implies an inhibition of photosynthetic electron transport as well as oxygen evolving system. On the other hand, (C₆H₅)₃PbCl caused stronger inhibition than (C₆H₅)₃SnCl, particularly in the higher concentration.     

Stability and absorption of anthocyanins from blueberries subjected to a simulated digestion process

Numerous studies have shown that anthocyanins usually have better in vitro bioactivity than in vivo bioactivity. This may be due to physiochemical degradation during gastrointestinal digestion and their poor bioavailability in in vivo studies. Therefore, this study aims to investigate the effects of anthocyanin structure on their stability under simulated gastrointestinal digestion and to assess their absorption in the intestines using Caco-2 human intestinal cell monolayers. The results show that gastric digestion does not significant affect blueberry anthocyanins in terms of composition and antioxidative activity. However, approximately 42% of the total anthocyanin and 29% of the antioxidative activity were lost during intestinal digestion. Structural analysis indicated that fewer free hydroxyl groups and more methoxy groups in the B-ring improve anthocyanin stability. The absorption trials demonstrated that more hydrophobic anthocyanins have better absorption efficiency than more hydrophilic anthocyanins. Furthermore, the glycoside structure also determines the absorption efficiency of anthocyanins.     

The Impact of the Disease Trend on the Macro and Micro-Nutrients Intake in Patients with Gastric Cancer

Abstract

Background: Disease-related malnutrition, as a major cause of morbidity and mortality in cancer patients, is very common in patients with gastric cancer (GC). Malnutrition in cancer patients was reported to have important adverse effects, including a decreased response and tolerance to treatment, a decrease of performance, shorter survival, and lower quality of life. The treatment approaches involving chemotherapy is known to develop various acute and chronic symptoms that restrict eating and, thereby, exert a profound impact on nutritional status.

Method: In this study, 82 patients with GC with an average age of 48.33?±?10.74 were enrolled. Patients were followed up for 6 months without any nutritional intervention and/or education. A 168 item semi-quantities food frequency questioner was completed by a trained nutritionist at the beginning of the study and six months after the start of chemotherapy.

Results: Intake of vitamin A (T₀:585.52?±?203.34 vs. T₆:529.48?±?138.91, t?=?2.96), Thiamin (T₀:2.09?±?0.76 vs. T₆:1.80?±?0.72, t?=?2.81), vitamin B6 (T₀:2.03?±?0.53 vs. T₆:2.29?±?0.73, t?=?2.56), and vitamin B12 (T₀:5.79?±?3.96 vs. T₆:4.48?±?2.20, t?=?2.43) significantly decreased after 6 months of receiving chemotherapy. On the other intake of beef (T0:17.79?±?25.48 vs. T6:12.58?±?16.66, t?=?2.06), low-fat milk (T0:52.57?±?69.80 vs. T6:29.18?±?45.89, t?=?2.95), cream (T0:2.42?±?4.16 vs. T6:1.06?±?1.68, t?=?2.88), and raw vegetable (T0:6.54?±?9.55 vs. T6:3.85?±?5.23, t?=?2.54) significantly decreased.

Conclusion: Nutritional deterioration is an important part of the pathogenesis of cancer and its treatment that can occur at any point in the timeline of cancer diagnosis, treatment or support. Therefore nutritional counseling and supportive services are needed for cancer patients, especially when their disease is diagnosed.     

Acute Toxicity of Heavy Metals to Tetrahymena in an In Vitro Experiment and Envelope Damage Study

The toxicity of Cr³⁺, Cu²⁺ and Cd²⁺ to Tetrahymena growth metabolism was studied by microcalorimetry at 28°C, and the growth constant (k), peak time (T) and generation times (T _G) were calculated. The metal ion concentrations that resulted in 50 % inhibition (IC ₅₀) of population growth were obtained through the dynamic parameters. The results indicated that the order of toxicity was Cd²⁺ > Cr³⁺ > Cu²⁺. Inductively coupled plasma-atomic emission spectrometry results suggested that the metal ions affected the permeability of the cell membrane. Observations of the Cd-exposed organisms by scanning electron microscopy revealed damage to the cell membrane in the form of an altered surface appearance. The cells suffered serious damage after sufficient acting time. Attenuated total reflection Fourier transform infrared spectra revealed that amide groups and PO₂ ^? of the phospholipid phospho-diester, both located in the hydrophobic end of the outer layer of the cell membrane, were most readily affected.     

Photochemical Production of Atmospheric Carbonyls in a Rural Area in Southern China

For the first time, ambient carbonyls were measured in a rural area in southern China from August 2012 to February 2013 to investigate their distribution characteristics and sources. Formaldehyde, acetaldehyde, and acetone were the three most abundant carbonyls, which accounted for 83–95 % of total seven carbonyls identified. The O₃ formation potential of carbonyls in summer (59.55 μg/m³) was approximately ten times greater than that (6.37 μg/m³) in winter, and calculated photolysis rates were significantly faster in summer than those in winter, suggesting intensive photochemical activities in summer. Seasonal and diurnal variations of carbonyls showed that (1) the concentration of total carbonyls in summer (12.62 ± 10.83 μg/m³) was approximately five times greater than that in winter (2.33 ± 0.90 μg/m³), and a similar trend applied to the three abundant carbonyls; (2) the average summer to winter (S/W) ratio of formaldehyde and acetaldehyde was 10–13, and the S/W ratio of acetone was ~2.59; and (3) the highest concentrations of the three carbonyls and total carbonyls occurred at 14:00–16:00 with high temperature and intensive sunlight, especially in summer. These variations provided direct evidence for significant photochemical production of ambient carbonyls. Average C₁/C₂ ratios (3.07 ± 1.62) in summer were much greater than those (1.28 ± 0.25) in winter, and average C₂/C₃ ratios (35.09 ± 58.67) in summer were significantly greater than those (4.75 ± 2.12) in winter, both cases indirectly implying positive photochemical productions in summer. Especially, strong correlations (R ² = 0.63–0.98) of temperature and sunlight intensity with the three abundant carbonyls and total carbonyls were observed, indicating a similar causal source such as significant photochemical production.