Effects of high intensity / low volume and low intensity / high volume isokinetic resistance exercise on postexercise glucose tolerance

The purpose of this study was to determine the effects of high intensity/ low volume (HILV) and low intensity/high volume (LIHV) isokinetic resistance exercise on postexercise glucose tolerance. Subjects (n = 10) participated in a counterbalanced, randomized design of 2 separate isokinetic resistance exercise trials (HILV and LIHV) of reciprocal concentric knee flexion and knee extension in a fasted state. Each bout was followed by a 45-minute oral glucose tolerance test (OGTT; 1.8 g.kg fat free mass(-1)). Blood samples were obtained every 15 minutes to determine glucose and insulin concentrations. There was no difference in total work between the 2 trials (p = 0.229). Blood glucose was significantly higher at all time points compared with time 0 following the LIHV trial (p < 0.05). Following the HILV trial, blood glucose was significantly elevated at 15 and 30 minutes (p < 0.05), but returned to resting values by 45 minutes. Insulin concentration was significantly elevated following both trials at all time points (p < 0.05). Blood glucose and insulin were significantly higher following the LIHV at 30 and 45 minutes compared with the HILV trial (p < 0.05). These results demonstrate that although the total work output was similar across trials, high intensity muscle contraction is associated with an enhanced normalization of glucose homeostasis following a large postexercise oral glucose feed.     

Bicinchoninic acid (BCA) assay in low volume

The BCA assay is a colorimetric method for estimating protein concentration. In 96-well plates, the relationship between protein content and absorbance is nearly linear over a wide range; however, performance is reduced in lower volume. To overcome this limitation, we performed the BCA assays in opaque, white 384-well plates. These plates emit fluorescence between 450–600 nm when excited at 430 nm; thus, their fluorescence is quenched by the BCA chromophore (λ_max 562 nm). This arrangement allowed accurate determination of protein content using only 2 μL of sample. Moreover, soluble flourescein could replace the white plates, creating a homogenous format.     

Potato gangrene control by ultra low volume sprays of thiabendazole

A method is described by which a mist of thiabendazole (TBZ) is applied to potato tubers using an ultra low volume sprayer set over rotating rollers. The fungicidal solution (2 % a.i. TBZ) is applied at 2 1/t of potatoes moving through the mist at 50 kg/min. Effective control of gangrene in storage was achieved in laboratory and farm trials.     

A low volume 3D-printed temperature-controllable cuvette for UV visible spectroscopy

We report the fabrication of a 3D-printed water-heated cuvette that fits into a standard UV visible spectrophotometer. Full 3D-printable designs are provided and 3D-printing conditions have been optimised to provide options to print the cuvette in either acrylonitrile butadiene styrene or polylactic acid polymers, extending the range of solvents that are compatible with the design. We demonstrate the efficacy of the cuvette by determining the critical micelle concentration of sodium dodecyl sulphate at 40 °C, the molar extinction coefficients of cobalt nitrate and dsDNA and by reproducing the thermochromic UV visible spectrum of a mixture of cobalt chloride, water and propan-2-ol.     

白僵菌超低容量油剂林间应用对生物多样性的影响

2001～2003年在福建省云霄县进行了白僵菌超低容量油剂林间防治马尾松毛虫后对生物多样性的影响研究(包括使用前后的物种丰富度S、个体数N、多样性指数H'、均匀度指数R和优势度指数D等),结果表明,未防治区和白僵菌油剂防治区的物种数分别为473种和392种,而化学防治区的物种数只有266种;白僵菌油剂防治区天敌和害虫个体数与未防治区的比例相近,分别为0．1049：1和0．1051：1．明显高于化学防治区(0．0558：1);化学防治和白僵菌油剂防治均降低了物种的丰富度和多样性。同时也增强了物种的优势度,但化学防治区与未防区的差异显著,白僵菌油剂防治区与未防区的差异不显著,尤其对天敌和非目标昆虫无显著影响。     

A method for low volume and low Se concentration samples and application to paired cerebrospinal fluid and serum samples

The well-known beneficial health effects of Se have demanded the development of rapid and accurate methods for its analysis. A flow injection (FI) method with inductively coupled plasma mass spectrometry (ICP-MS) as a selenium-selective detector was optimized. Flow injection was carried out using a Knauer 1100 smartline inert series liquid chromatograph coupled with a Perkin Elmer DRC II ICP-mass spectrometer. For sample injection a Perkin Elmer electronic valve equipped with a 25 μL sample loop was employed. Before measurement, standards or samples were administered with 1 μg/L rhodium as internal standard for correction of changes in detector response according to changes in sample electrolyte concentration. The method characterization parameters are: LOD (3σ criterion): 26 ng/L, LOQ (10σ criterion): 86 ng/L, linearity: 0.05–>10 μg/L, r²=0.9999, serial or day-to-day precision at 2 μg/L: 4.48% or 5.6%. Accuracy was determined by (a) recovery experiments (CSF spiked with 2 μg/L Se); (b) comparison of FI-ICP-MS measurement with graphite furnace atomic absorption (GFAAS) measurements of 1:10 diluted serum samples; (c) Se determination in urine and serum control materials. Recovery (a) was 101.4%, measurement comparison with GFAAS (b) showed 98.8% (5 serum samples, 1:10 diluted in the range of 0.5–1.3 μg/L, compared to GFAAS determination, which was set to 100%), and accuracy was 96.8% or 105.6% for the serum or urine control material. Analysis time per sample was short and typically below 2 min for the complete measurement, including sample introduction, sample-line purge and quadruplicate Se determination.This method was used to determine Se in cerebrospinal fluid (CSF) and plasma (here parallel to GFAAS) in 35 paired serum and CSF samples. Se determination gave values in the range of 42–130 μg/L for serum and 1.63–6.66 μg/L for CSF. The median for Se in 35 individual CSF samples was 3.28 μg/L, the mean (±SD) was 3.67 (1.35) μg/L, whilst for individual serum samples the median was 81 μg/L and the mean (±SD) was 85 (26) μg/L. When relating the paired Se concentrations of CSF samples to respective serum samples it turned out that Se-CSF (behind blood brain barrier (BBB)) is independent on Se-serum concentration (before BBB).     

Separation of red blood cells at high volume concentration under low centrifugal accelerations

The separation process of blood and RBC suspensions in a hematocrit range between 0.3-0.7 was investigated with a centrifuge allowed to run at low accelerations (100 xg-1000 xg). The position of the interface between the supernatant of plasma and the RBC column was continuously recorded by a new optoelectronic measuring system. The separation process could be mathematically described by an exponential decrease of the cell column approaching a final packing. At a given centrifugal acceleration the time constant is influenced by hematocrit, aggregation, deformation and plasma viscosity. The final packing depends linearly on the starting hematocrit (0.3-0.7) and can be used as a measure of deformability.     

High in comparison with low tidal volume ventilation aggravates oxidative stress-induced lung injury

Ventilator settings influence the development and outcome of acute lung injury. This study investigates the influence of low versus high tidal volume (V(t)) on oxidative stress-induced lung injury.Isolated rabbit lungs were subjected to one of three ventilation patterns (V(t)-positive end-expiratory pressure, PEEP): LVZP (6 ml/kg-0 cm H(2)O), HVZP (12 ml/kg-0 cm H(2)O), LV5P (6 ml/kg-5 cm H(2)O). These ventilation patterns allowed a comparison between low and high V(t) without dependence on peak inspiratory pressure (PIP). Infusion of hypochlorite (1000 nmol/min) or buffer (control) was started at t=0 min. Pulmonary artery pressure (PAP), PIP and weight were continuously recorded. Capillary filtration coefficient [K(f,c) (10(-4) ml s(-1) cm H(2)O(-1) g(-1))] was gravimetrically determined (-15/30/60/90/120 min).PIP averaged 5.8+/-0.6/13.9+/-0.6/13.9+/-0.4 cm H(2)O in the LVZP, HVZP and LV5P groups. PIP, K(f,c) or PAP did not change in control groups, indicating that none of the ventilation patterns caused lung injury by themselves. Hypochlorite-induced increase in K(f,c) but not hypochlorite-induced increase in PAP, was significantly attenuated in the LVZP-/LV5P- versus the HVZP-group (K(f,c,max.) 1.0+/-0.23/1.4+/-0.40 versus 3.2+/-1.0*). Experiments with hypochlorite were terminated due to excessive edema (>50 g) at 97+/-2.2/94.5+/-4.5 min in the LVZP-/LV5P-group versus 82+/-3.8* min in the HVZP-group (*: P<0.05).Low V(t) attenuated oxidative stress-induced increase in vascular permeability independently from PIP and PEEP.     

Evaluation of phase correction and low gas density to improve thoracic gas volume measurement

We investigated two methods of decreasing the error on plethysmographic determinations of thoracic gas volume (TGV) related to cheeks movements during panting maneuvers: lowering gas density in the airways with an 80% He-20% O2 mixture and computing TGV from the in-phase component of the plethysmographic signal (TGVr). The methods were tested by measuring how TGV estimates varied when panting frequency was raised from 0.8 to 2.5 Hz during the same occlusion. The measurements were performed in 6 normal subjects and 12 patients with chronic bronchitis with and without cheeks support and when the airway was connected to an external device simulating an increased cheeks compliance. A small negative frequency dependence of TGV (delta TGV/delta f = -1.2 +/- 0.8%/Hz with cheeks support), most probably unrelated to upper airway walls, was found in normal subjects. Delta TGV/delta f was positive and algebraically larger in patients than in normals, reaching 2.2 +/- 3.4%/Hz without cheeks support and 11.8 +/- 8.0%/Hz with the additional cheeks. The latter value was only 20% smaller when computed on the basis of TGVr, demonstrating the limited usefulness of the phase-based correction. In contrast, breathing He-O2 decreased delta TGV/delta f to approximately 50% of its air value (P less than 0.01) and appears as an effective way to diminish the error in obstructive patients.     

白僵菌超低容量油剂林间应用对生物多样性的影响

2001～2003年在福建省云霄县进行了白僵菌超低容量油剂林间防治马尾松毛虫后对生物多样性的影响研究(包括使用前后的物种丰富度S、个体数N、多样性指数H'、均匀度指数R和优势度指数D等).结果表明,未防治区和白僵菌油剂防治区的物种数分别为473种和392种,而化学防治区的物种数只有266种;白僵菌油剂防治区天敌和害虫个体数与未防治区的比例相近,分别为0.1049:1和0.1051:1,明显高于化学防治区(0.0558:1);化学防治和白僵菌油剂防治均降低了物种的丰富度和多样性,同时也增强了物种的优势度,但化学防治区与未防区的差异显著,白僵菌油剂防治区与未防区的差异不显著,尤其对天敌和非目标昆虫无显著影响.     

Cation transport in different volume populations of genetically low K+ lamb red cells

During the first three months after birth lambs produce sequentially three erthryocyte populations of different mean volume as demonstrated by electric sizing methods (Valet, Franz, and Lauf, J. Cell. Physiol. 94 (1978) 215). We separated by centrifugal elutriation the small volume population (type II) red cells of a genotypically low K⁺ (LK) lamb from the population containing the larger volume type I and III cells, an admixture of fetal (I) and adult (III) erythrocytes. The cells were separated at various time intervals after birth and analyzed with respect to their volumes, cation contents, and cation flux properties by means of ⁸⁶Rb uptake. The effect of anti-L on K⁺ pump and leak fluxes was ascertained in unseparated and separated red cells. It was found that the small red cells of population II, transiently present for several weeks, were fully developed LK cells with K⁺ pumps responding characteristically to the stimulatory action of anti-L. In constrast, the larger cells of population I and III were of high K⁺ (HK) nature at early time points, the K⁺ pump activities approximately ten times higher than adult LK cells. These cells constitute an admixture of type I fetal HK cells, and type III reticulocytes which are precursors for the final type III adult LK cells, since anti-L had a small stimulatory effect. At later times, however, only adult type III LK cells predominated. The data directly support our earlier finding that the HK-LK transition in genotypically LK lambs is primarily governed by cellular replacement.     

Temperature affects lung fluid and recoil during high tidal ventilation at low resting volume

Effects of tidal volume (VT), end-expiratory pressure (EEP), and environmental temperature (Tenv) on elastic recoil force (Pel) and edema formation were examined in open-chest anesthetized rabbits. Sixty-two rabbits in four groups were ventilated for 3 h with VT of either 10 or 25 ml/kg body wt, EEP of 0 or 2 cmH2O, and Tenv of 18 or 35 degrees C. After ventilation, Pel at 80% of total lung capacity (P80) was significantly increased when ventilation was performed with the combination of large VT, 0 EEP, and low Tenv. This change was prevented by altering any one of the three conditions, e.g., small VT, positive EEP, or high Tenv. Similarly, elevation of minimum surface tension and reduction of surface activity index of lavages from excised lungs after ventilation were observed only when increased P80 was noted. Additionally, the increase of P80 was well correlated with increment of wet weight-to-dry weight ratio and degree of perivascular cuffing and alveolar edema formation of excised lungs. These results indicate that elevation of Pel after high tidal ventilation in open-chest animals in vivo was influenced by level of EEP and Tenv and that the degree of edema formation was closely related to the increase of Pel. The increased Pel is presumably primary and causes fluid accumulation.     

A low volume, high-throughput forward mutation assay in Salmonella typhimurium based on fluorouracil resistance

A forward mutation assay based on 5-fluorouracil (FU) resistance has been developed using a strain of Salmonella typhimurium derived from the Ames strain TA100. The sensitivity of the assay benefits from the genetic characteristics present in the standard Ames strain that enhances the response to genotoxic agents. A mutation conferring resistance to 5-fluorouridine was also introduced into the test strain to avoid unwanted toxicity resulting from cross-feeding of 5-fluorouridine between wild-type and FU-resistant (FU(R)) cells during selection with FU. In the mutation assay 1 ml aliquots of exponentially growing bacteria are exposed to the test agent for 2 h in the presence and absence of a rat-liver S-9 metabolizing system. The aliquots are then diluted, allowed to grow for 3 h, and assessed for treatment-related toxicity/inhibition by optical density. The cultures are diluted a second time and grown overnight to permit full recovery from toxicity and to allow expression of the FU(R) phenotype. Samples of the cultures are then plated in 384-well microtiter dishes in the presence of 2 microg/ml FU and the pH-sensitive indicator bromcresol purple. Three days later positive wells containing FU(R) colonies are detected by their yellow color and enumerated. Results were obtained using a variety of 45 compounds to validate the assay. Of the 25 mutagens and 20 non-mutagens tested, the results correlated 100% with those collected using the battery of standard Ames reversion strains, further supporting the use of the FU Assay as an alternative screen to the Ames assay. The use of a single strain exposed in liquid suspension permits assessment of high concentrations of test compound but with a low overall compound requirement (30 mg total). The highly parallel nature of culture handling/dilution and use of standard microtiter plates also offers the possibility of assay automation.     

Acclimation of photosynthesis in Zea mays to low water potentials involves alterations in protoplast volume reduction

Effects of water-stress treatment of Zea mays L. plants on protoplast volume and photosynthesis in leaf slices exposed to solutions of different osmotic potential ( _s) were studied. Decreased photosynthetic capacity in the leaf slices at low tissue _w was associated with dehydration-induced protoplast-volume reduction. Leaf slices from plants exposed to in-situ water deficits exhibited greater photosynthetic capacity and relative protoplast volume at low water potential ( _w) invitro than tissue from control plants.In-situ water stress induced osmotic adjustment of the leaf tissue as determined by pressure/volume analysis. It is concluded that plant acclimation to low leaf _w may involve a reduced degree of cell shrinkage at a given _w. This acclimation would allow for the maintenance of relatively higher photosynthetic capacity at low water protentials.Symbols _s Osmotic potential - _w water potential New Jersey Agricultural Experiment Station Publication No. 12149-6-87     

Stimulation of single isolated adult ventricular myocytes within a low volume using a planar microelectrode array

Microchannels (40- microm wide, 10- microm high, 10-mm long, 70- microm pitch) were patterned in the silicone elastomer, polydimethylsiloxane on a microscope coverslip base. Integrated within each microchamber were individually addressable stimulation electrodes (40- microm wide, 20- microm long, 100-nm thick) and a common central pseudo-reference electrode (60- microm wide, 500- microm long, 100-nm thick). Isolated rabbit ventricular myocytes were introduced into the chamber by micropipetting and subsequently capped with a layer of mineral oil, thus creating limited volumes of saline around individual myocytes that could be varied from 5 nL to 100 pL. Excitation contraction coupling was studied by monitoring myocyte shortening and intracellular Ca(2+) transients (using Fluo-3 fluorescence). The amplitude of stimulated myocyte shortening and Ca(2+) transients remained constant for 90 min in the larger volume (5 nL) configuration, although the shortening (but not the Ca(2+) transient) amplitude gradually decreased to 20% of control within 60 min in the low volume (100 pL) arrangement. These studies indicate a lower limit for the extracellular volume required to stimulate isolated adult cardiac myocytes. Whereas this arrangement could be used to create a screening assay for drugs, individual microchannels (100 pL) can also be used to study the effects of limited extracellular volume on the contractility of single cardiac myocytes.     

Platelet count and mean platelet volume in an Algerian population indicating a low prevalence of Mediterranean macrothrombocytopenia

Platelet count was 225 X 10(9)/l in 225 healthy male Algerians and 263 X 10(9)/l in 208 females. The mean platelet volume was 9.15 fl in the males and 9.30 in the females. The figures agree with those obtained in a British and an American population, but differed from those of an Australian population of immigrants from Mediterranean countries, essentially Italy and Greece. The prevalence of Mediterranean thrombocytopenia must therefore be low in Algeria.     

Highly sensitive SERS detection of cancer proteins in low sample volume using hollow core photonic crystal fiber

Enzyme-linked immunosorbent assays (ELISA) are commonly used for detecting cancer proteins at concentration in the range of about ng-μg/mL. Hence it often fails to detect tumor markers at the early stages of cancer and other diseases where the amount of protein is extremely low. Herein, we report a novel photonic crystal fiber (PCF) based surface enhanced Raman scattering (SERS) sensing platform for the ultrasensitive detection of cancer proteins in an extremely low sample volume. As a proof of concept, epidermal growth factor receptors (EGFRs) in a lysate solution from human epithelial carcinoma cells were immobilized into the hollow core PCF. Highly sensitive detection of protein was achieved using anti-EGFR antibody conjugated SERS nanotag. This SERS nanotag probe was realized by anchoring highly active Raman molecules onto the gold nanoparticles followed by bioconjugation. The proposed sensing method can detect low amount of proteins at ～100 pg in a sample volume of ～10 nL. Our approach may lead to the highly sensitive protein sensing methodology for the early detection of diseases.