Social ties: Subgroup differences in costs and benefits.

Studied social support in response to stressful life events (i.e., whether social ties are stressful as well as supportive and whether there are subgroup differences in the efficacy of social support) among 314 women (mean age 34.7 yrs) with a mean educational level of 10.7 yrs and a mean family income of $7,500–20,000/yr. Ss completed measures of negative affect, perceived stressfulness of life events of significant others, and social support. Selected findings show that (1) the mobilization of social support was associated with better psychological well-being for Ss with greater personal resources; (2) Ss with lower levels of personal resources were more distressed by life events in the lives of their significant others, especially as the number of these events increased; and (3) subgroup effects of interpersonal support and stress on psychological well-being were independent and separate. It is concluded that Ss with greater material and psychological resources derived more beneficial support and suffered less stress from their social ties. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The biochemical relationships in anaerobic digestion after thermal hydrolysis at Davyhulme

The commissioning of the largest thermal hydrolysis plant in the world at Davyhulme, Manchester involved detailed analysis of the digestion process. The plant consists of eight digesters, 20 thermal hydrolysis reactors and a maximum throughput of 121 000 tDS/year. The plant was converted from conventional digestion with a loading rate of 1.25 kgVS/m³/day to digestion fed with thermally hydrolysed sludge with a loading rate of 4.16 kgVS/m³/day. At the start of the commissioning and ramp‐up of the loading rate, control actions were based on acid/alkalinity, pH and foaming; however, it was found that the methane concentration was the parameter that changed quickest during digester instability. The monitoring was changed during commissioning to use methane concentration as the primary control parameter. It was found that the rate of increased organic loading is dependent on the availability of seed biomass already acclimatised to thermally hydrolysed feed sludge and the presence of a high alkalinity buffer.     

Design of a Microchannel‐Nanochannel‐Microchannel Array Based Nanoelectroporation System for Precise Gene Transfection

A micro/nano‐fabrication process of a nanochannel electroporation (NEP) array and its application for precise delivery of plasmid for non‐viral gene transfection is described. A dip‐combing device is optimized to produce DNA nanowires across a microridge array patterned on the polydimethylsiloxane (PDMS) surface with a yield up to 95%. Molecular imprinting based on a low viscosity resin, 1,4‐butanediol diacrylate (1,4‐BDDA), adopted to convert the microridge‐nanowire‐microridge array into a microchannel‐nanochannel‐microchannel (MNM) array. Secondary machining by femtosecond laser ablation is applied to shorten one side of microchannels from 3000 to 50 μm to facilitate cell loading and unloading. The biochip is then sealed in a packaging case with reservoirs and microfluidic channels to enable cell and plasmid loading, and to protect the biochip from leakage and contamination. The package case can be opened for cell unloading after NEP to allow for the follow‐up cell culture and analysis. These NEP cases can be placed in a spinning disc and up to ten discs can be piled together for spinning. The resulting centrifugal force can simultaneously manipulate hundreds or thousands of cells into microchannels of NEP arrays within 3 minutes. To demonstrate its application, a 13 kbp OSKM plasmid of induced pluripotent stem cell (iPSC) is injected into mouse embryonic fibroblasts cells (MEFCs). Fluorescence detection of transfected cells within the NEP biochips shows that the delivered dosage is high and much more uniform compared with similar gene transfection carried out by the conventional bulk electroporation (BEP) method.     

Soot concentration and temperature measurements in co-annular, nonpremixed CH4/air laminar flames at pressures up to 4 MPa

Laminar nonpremixed methane-air flames were studied over the pressure range of 0.5 to 4 MPa using a new high-pressure combustion chamber. Flame characterization showed very good flame stability over the range of pressures, with a flame tip rms flicker of less than 1% in flame height. At all pressures, soot was completely oxidized within the visible flame. Spectral soot emission (SSE) and line-of-sight attenuation (LOSA) measurements provided radially resolved measurements of soot volume fraction and soot temperature at pressures from 0.5 to 4.0 MPa. Such measurements provide an improved understanding of the influence of pressure on soot formation and have not been reported previously in laminar nonpremixed flames for pressures above 0.4 MPa. SSE and LOSA soot concentration values typically agree to within 30% and both methods exhibit similar trends in the spatial distribution of soot concentration. Maximum soot concentration depended on pressure according to a power law, where the exponent on pressure is about 2 for the range of pressures between 0.5 and 2.0 MPa, and about 1.2 for 2.0 to 4.0 MPa. Peak carbon conversion to soot also followed a power-law dependence on pressure, where the pressure exponent is unity for pressures between 0.5 and 2.0 MPa and 0.1 for 2.0 to 4.0 MPa. The pressure dependence of sooting propensity diminished at pressures above 2.0 MPa. Soot concentrations measured in this work, when transformed to line-integrated values, are consistent with the measurements of Flower and Bowman for pressures up to 1.0 MPa [Proc. Combust Inst. 21 (1986) 1115-1124] and Lee and Na for pressures up to 0.4 MPa [JSME Int. J. Ser. B 43 (2000) 550-555]. Soot temperature measurements indicate that the overall temperatures decrease with increasing pressure; however, the differences diminish with increasing height in the flame. Low down in the flame, temperatures are about 150 K lower at pressures of 4.0 MPa than those at 0.5 MPa. In the upper half of the flame the differences reduce to 50 K.     

The economics of chipping logging residues at roadside: A study of three systems

Three biomass chipping operations of roadside logging residues were studied in New Brunswick and Maine. Two of the operations used a skidder-loader to form the roadside debris into larger piles closer to the road edge prior to chipping. Average chipping productivity ranged from 8.l oven dry Mg per Productive Machine Hour (OdMg PMH⁻¹) to 28.2 OdMg PMH⁻¹ depending on the site and chipping system used. The average cost of chips on board the chip vans ranged from $15.29 CAN OdMg⁻¹ to $25.86 CAN OdMg⁻¹. The chips were transported to three energy plants in Maine. One-way hauling distances varied from 29 km to 105 km.     

Novel aspects of wet milling for the production of microsuspensions and nanosuspensions of poorly water-soluble drugs

Micronization and nanoparticle production of poorly water-soluble drugs was investigated using single wet milling equipment operating in the attritor and stirred media modes. The drug particles in the median size range of 0.2?2??m were prepared by changing the milling mode and operating conditions of a Micros mill with a purpose of elucidating the dynamics of the wet milling process. It was determined that particle breakage due to mechanical stresses and aggregation due to insufficient stabilization are two competing mechanisms which together control the wet milling dynamics of the poorly water-soluble drugs. The study in the attritor mode using four different classes of stabilizers with six drugs indicated that steric stabilization worked better than electrostatic stabilization for the drugs studied. In addition, the existence of different minimum polymer concentrations for the stabilization of microsuspensions and nanosuspensions was indicated. The major role of a non-ionic polymer during the production of fine particles is its stabilization action through steric effects, and no experimental evidence was found to support the so-called Rehbinder effect. Periodic addition of the polymer as opposed to the addition of the polymer at the start of milling process was introduced as a novel processing method. This novel method of polymer addition provided effective stabilization and breakage of drug particles leading to a narrower and finer particle size distribution. Alternatively, it may allow shorter processing time and lower overall power consumption of the milling process for a desired particle size.     

Noninvasive estimation of dynamic pressures in vitro and in vivo using the subharmonic response from microbubbles

The purpose of this study was to develop and validate a noninvasive pressure estimation technique based on subharmonic emissions from a commercially available ultrasound contrast agent and scanner, unlike other studies that have either adopted a single-element transducer approach and/ or use of in-house contrast agents. Ambient pressures were varied in a closed-loop flow system between 0 and 120 mmHg and were recorded by a solid-state pressure catheter as the reference standard. Simultaneously, the ultrasound scanner was operated in pulse inversion mode transmitting at 2.5 MHz, and the unprocessed RF data were captured at different incident acoustic pressures (from 76 to 897 kPa). The subharmonic data for each pulse were extracted using band-pass filtering with averaging, and subsequently processed to eliminate noise. The incident acoustic pressure most sensitive to ambient pressure fluctuations was determined, and then the ambient pressure was tracked over 20 s. In vivo validation of this technique was performed in the left ventricle (LV) of 2 canines. In vitro, the subharmonic signal could track ambient pressure values with r(2) = 0.922 (p < 0.001), whereas in vivo, the subharmonic signal tracked the LV pressures with r(2) > 0.790 (p < 0.001) showing a maximum error of 2.84 mmHg compared with the reference standard. In conclusion, a subharmonic ultrasound-based pressure estimation technique, which can accurately track left ventricular pressures, has been established.     

Factors associated with food workers working while experiencing vomiting or diarrhea

This study sought to determine the frequency with which food workers said they had worked while experiencing vomiting or diarrhea, and to identify restaurant and worker characteristics associated with this behavior. We conducted interviews with food workers (n=491) and their managers (n=387) in the nine states that participate in the Centers for Disease Control and Prevention's Environmental Health Specialists Network. Restaurant and worker characteristics associated with repeatedly working while experiencing vomiting or diarrhea were analyzed via multivariable regression. Fifty-eight (11.9%) workers said they had worked while suffering vomiting or diarrhea on two or more shifts in the previous year. Factors associated with workers having worked while experiencing vomiting or diarrhea were (i) high volume of meals served, (ii) lack of policies requiring workers to report illness to managers, (iii) lack of on-call workers, (iv) lack of manager experience, and (v) workers of the male gender. Our findings suggest that policies that encourage workers to tell managers when they are ill and that help mitigate pressures to work while ill could reduce the number of food workers who work while experiencing vomiting or diarrhea.     

Stimuli-responsive releasing of gold nanoparticles and liposomes from aptamer-functionalized hydrogels

Controlled release of therapeutic agents is important for improving drug efficacy and reducing toxicity. Recently, hydrogels have been used for controlled release applications. While the majority of the previous work focused on releasing the cargo in response to physical stimuli such as temperature, light, electric field, and pH, we aim to trigger cargo release in the presence of small metabolites. In our system a DNA aptamer that can bind to adenosine, AMP, and ATP was used as a linker to attach either DNA-functionalized gold nanoparticles or liposomes to DNA-functionalized hydrogels. In the presence of the metabolite, both the nanoparticle and liposome cargos were released. The effect of salt, temperature, target concentration, and drying has been systematically studied. Interestingly, we found that the gel can be completely dried while retaining the DNA linkages and adenosine induced release was still achieved after rehydration. Our work demonstrates that aptamers can be used to control the release of drugs and other materials attached to hydrogels.     

Characterisation of acid mine drainage in a high rainfall mountain environment, New Zealand

The Stockton coal mine lies at 700-1100 m above sea level in a mountainous orographic precipitation zone on the West Coast of the South Island of New Zealand. Rainfall exceeds 6000 mm/year and arrives with frequent flood events that can deliver > 200 mm/day. Streams vary in discharges by up to two orders of magnitude over a time scale of hours. Pyritic waste rock at the mine interacts chemically with even the most intense rainfall, and almost all runoff is acidic to some degree. In the most intense rain event recorded in this study (> 10 mm/hour), dilution of acid mine drainage (AMD) occurred and pH rose from 3 to > 5 over several hours, with stream discharge at a monitoring point rising from < 0.5 to > 100 cumecs. However, most rain events of similar magnitude are less intense, longer duration, and only raise AMD pH to ~ 4 with similar high discharges. Results presented here for Stockton confirm that it is the intensity of rain events on the hourly scale, rather than the total amount of rainwater delivered to the site, that governs the amount and composition of AMD generated during flood events. Stream discharge loads of dissolved iron and aluminium range from ~ 20 to 1000 kg/hour. Dissolved sulfate and acidity loads are typically ~ 500 kg/hour but can exceed 20 tonnes/hour in rain events.First flush effects observable elsewhere around the world involving peak metal loads following dry periods or seasonal changes are not obvious at Stockton due to the high and variable rainfall environment. Dissolved Fe concentrations may be limited in runoff waters by precipitation of jarosite and schwertmannite, especially when rainfall is sufficiently intense to raise pH to 4 or higher. These minerals are widespread in the exposed waste rock on site. Likewise, precipitation of alunite may occur as pH rises in rain events, but no field evidence for this has been observed.