Buzz off! An evaluation of ultrasonic acoustic vibration for the disruption of marine micro-organisms on sensor-housing materials.

Biofouling is a process of ecological succession which begins with the attachment and colonization of micro-organisms to a submerged surface. For marine sensors and their housings, biofouling can be one of the principle limitations to long-term deployment and reliability. Conventional antibiofouling strategies using biocides can be hazardous to the environment, and therefore alternative chemical-free methods are preferred. In this study, custom-made testing assemblies were used to evaluate ultrasonic vibration as an antibiofouling process for marine sensor-housing materials over a 28-day time course. Microbial biofouling was measured based on (i) surface coverage, using fluorescence microscopy and (ii) bacterial 16S rDNA gene copies, using Quantitative polymerase chain reaction (PCR). Ultrasonic vibrations (20 KHz, 200 ms pulses at 2-s intervals; total power 16·08 W) significantly reduced the surface coverage on two plastics, poly(methyl methacrylate) and polyvinyl chloride (PVC) for up to 28 days. Bacterial gene copy number was similarly reduced, but the results were only statistically significant for PVC, which displayed the greatest overall resistance to biofouling, regardless of whether ultrasonic vibration was applied. Copper sheet, which has intrinsic biocidal properties was resistant to biofouling during the early stages of the experiment, but inhibited measurements made by PCR and generated inconsistent results later on. SIGNIFICANCE AND IMPACT OF THE STUDY: In this study, ultrasonic acoustic vibration is presented as a chemical-free, ecologically friendly alternative to conventional methods for the perturbation of microbial attachment to submerged surfaces. The results indicate the potential of an ultrasonic antibiofouling method for the disruption of microbial biofilms on marine sensor housings, which is typically a principle limiting factor in their long-term operation in the oceans. With increasing deployment of scientific apparatus in aquatic environments, including further offshore and for longer duration, the identification and evaluation of novel antifouling strategies that do not employ hazardous chemicals are widely sought.

Incline Treadmill Interval Training: Short vs. Long Bouts and the Effects on Distance Running Performance.

This study compared 6 weeks of incline treadmill interval training (INC) performed on a 10% treadmill grade using either sprint-like efforts or slower, longer bouts. 24 individuals were randomly assigned between 2 groups that each completed 2 INC and one 30-min level-grade sessions∙wk-1. Training intensities, bout durations and the number of intervals per INC session were the velocity associated with VO2max (Vmax), 30 s and 10-14 (INCShort n=12), and 68%Vmax, ~3 min and 4-6 (INCLong n=12), respectively. All 30-min sessions were at 65%Vmax. Pre- and post-testing assessed VO2max; lactate threshold (VLT); running economy; and time-to-exhaustion at various conditions including 80%Vmax and 20% grade (CFMod). Both groups improved significantly in all tests; additionally, INCShort improved significantly more so in VLT and CFMod despite INCLong performing more than 2 times the running each INC session (P<0.05). Mean effect size (ES) of the relative improvement in a majority of tests revealed a trivial to very large ES of INCShort vs. INCLong training (ES range: 0.05-4.05). We conclude sprint-like INC better than slower, longer INC at improving a key determinant of distance running performance (VLT), and better at preparing individuals for running on courses with a variety of grades.

Effect of Mulligan's and Kinesio knee taping on adolescent ballet dancers knee and hip biomechanics during landing.

Taping is often used to manage the high rate of knee injuries in ballet dancers; however, little is known about the effect of taping on lower-limb biomechanics during ballet landings in the turnout position. This study investigated the effects of Kinesiotape (KT), Mulligan's tape (MT) and no tape (NT) on knee and hip kinetics during landing in three turnout positions. The effect of taping on the esthetic execution of ballet jumps was also assessed. Eighteen pain-free 12-15-year-old female ballet dancers performed ballet jumps in three turnout positions, under the three knee taping conditions. A Vicon Motion Analysis system (Vicon Oxford, Oxford, UK) and Advanced Mechanical Technology, Inc. (Watertown, Massa chusetts, USA) force plate collected lower-limb mechanics. The results demonstrated that MT significantly reduced peak posterior knee shear forces (P = 0.025) and peak posterior (P = 0.005), medial (P = 0.022) and lateral (P = 0.014) hip shear forces compared with NT when landing in first position. KT had no effect on knee or hip forces. No significant differences existed between taping conditions in all landing positions for the esthetic measures. MT was able to reduce knee and the hip forces without affecting the esthetic performance of ballet jumps, which may have implications for preventing and managing knee injuries in ballet dancers.

Effects of two different knee tape procedures on lower-limb kinematics and kinetics in recreational runners.

The purpose of this study was to compare the effects of Mulligan's tape (MT) and kinesio tape (KT) with no tape (NT) on hip and knee kinematics and kinetics during running. Twenty-nine female recreational runners performed a series of 'run-throughs' along a 10-m runway under the three taping conditions. Two force plates and a 14-camera Vicon motion analysis system (Oxford Metrics, Inc., Oxford, UK) captured kinematic and kinetic data for each dependent variable from ground contact to toe off. Comparisons of each dependent variable under three taping conditions were assessed through Statistical Package for the Social Sciences (SPSS; SPSS, Inc., Chicago, Illinois, USA; P-value < 0.01) using repeated measure analyses of variance. For each dependent variable with a P-value < 0.01, repeated measures with pairwise comparisons and Bonferroni adjustment were conducted to compare the three taping conditions. MT induced a significant reduction in anterior and posterior hip forces, knee flexion angular velocity, knee extensor moments, and hip flexion and extension moments compared with NT and KT (P = 0.001). There was no difference in hip or knee, kinematics or kinetics, between KT and NT (P = 1.000). MT appears to influence hip and knee biomechanics during running in an asymptomatic sample, whereas KT appeared to be biomechanically not different from NT.

Structure of the 2,4'-dihydroxyacetophenone dioxygenase from Alcaligenes sp. 4HAP.

The enzyme 2,4'-dihydroxyacetophenone dioxygenase (DAD) catalyses the conversion of 2,4'-dihydroxyacetophenone to 4-hydroxybenzoic acid and formic acid with the incorporation of molecular oxygen. Whilst the vast majority of dioxygenases cleave within the aromatic ring of the substrate, DAD is very unusual in that it is involved in C-C bond cleavage in a substituent of the aromatic ring. There is evidence that the enzyme is a homotetramer of 20.3 kDa subunits, each containing nonhaem iron, and its sequence suggests that it belongs to the cupin family of dioxygenases. In this paper, the first X-ray structure of a DAD enzyme from the Gram-negative bacterium Alcaligenes sp. 4HAP is reported, at a resolution of 2.2 Å. The structure establishes that the enzyme adopts a cupin fold, forming dimers with a pronounced hydrophobic interface between the monomers. The catalytic iron is coordinated by three histidine residues (76, 78 and 114) within a buried active-site cavity. The iron also appears to be tightly coordinated by an additional ligand which was putatively assigned as a carbonate dianion since this fits the electron density optimally, although it might also be the product formate. The modelled carbonate is located in a position which is highly likely to be occupied by the α-hydroxyketone group of the bound substrate during catalysis. Modelling of a substrate molecule in this position indicates that it will interact with many conserved amino acids in the predominantly hydrophobic active-site pocket where it undergoes peroxide radical-mediated heterolysis.

Crystallization and preliminary X-ray characterization of the 2,4'-dihydroxyacetophenone dioxygenase from Alcaligenes sp. 4HAP.

The enzyme 2,4'-dihydroxyacetophenone dioxygenase (or DAD) catalyses the conversion of 2,4'-dihydroxyacetophenone to 4-hydroxybenzoic acid and formic acid with the incorporation of molecular oxygen. Whilst the vast majority of dioxygenases cleave within the aromatic ring of the substrate, DAD is very unusual in that it is involved in C-C bond cleavage in a substituent of the aromatic ring. There is evidence that the enzyme is a homotetramer of 20.3 kDa subunits each containing nonhaem iron and its sequence suggests that it belongs to the cupin family of dioxygenases. By the use of limited chymotrypsinolysis, the DAD enzyme from Alcaligenes sp. 4HAP has been crystallized in a form that diffracts synchrotron radiation to a resolution of 2.2 Å.

Dance training intensity at 11-14 years is associated with femoral torsion in classical ballet dancers.

OBJECTIVE: To examine in a cross sectional study the influence of femoral torsion (FT) and passive hip external rotation (PER) on turnout (TO). Starting age, years of classical ballet training, and current and past dance training intensity were assessed to determine their influence on FT, PER, and TO in pre-professional female dancers. METHODS: Sixty four dancers (mean (SD) age 18.16 (1.80) years) were recruited from four different dance training programmes. They completed a dance history questionnaire. FT was measured using a clinical method. PER was measured with the subjects prone, and TO was measured with the subjects standing. RESULTS: Mean TO was 136 degrees, mean unilateral PER was 49.4 degrees, and mean FT was 18.4 degrees. A positive correlation was observed between PER combined (PERC) and TO (r = 0.443, p < 0.001). A negative association was found between FT combined (FTC) and PERC (r = -0.402, p = 0.001). No association was found between starting age or years of classical ballet training and FTC, PERC, or TO. Dancers who trained for six hours a week or more during the 11-14 year age range had less FT than those who trained less (mean difference 6 degrees, 95% confidence interval 1.4 to 10.3). Students currently training for longer had higher levels of TO (p < 0.001) but comparable PERC and FTC. CONCLUSION: FT is significantly associated with PERC. Dancers who trained for six hours a week or more at 11-14 years of age had significantly less FT. FTC had a significant influence on PERC, but no influence on the execution of TO.

Dynamic soft tissue mobilisation increases hamstring flexibility in healthy male subjects.

OBJECTIVES: The purpose of this study was to investigate the effect of dynamic soft tissue mobilisation (STM) on hamstring flexibility in healthy male subjects. METHODS: Forty five males volunteered to participate in a randomised, controlled single blind design study. Volunteers were randomised to either control, classic STM, or dynamic STM intervention. The control group was positioned prone for 5 min. The classic STM group received standard STM techniques performed in a neutral prone position for 5 min. The dynamic STM group received all elements of classic STM followed by distal to proximal longitudinal strokes performed during passive, active, and eccentric loading of the hamstring. Only specific areas of tissue tightness were treated during the dynamic phase. Hamstring flexibility was quantified as hip flexion angle (HFA) which was the difference between the total range of straight leg raise and the range of pelvic rotation. Pre- and post-testing was conducted for the subjects in each group. A one-way ANCOVA followed by pairwise post-hoc comparisons was used to determine whether change in HFA differed between groups. The alpha level was set at 0.05. RESULTS: Increase in hamstring flexibility was significantly greater in the dynamic STM group than either the control or classic STM groups with mean (standard deviation) increase in degrees in the HFA measures of 4.7 (4.8), -0.04 (4.8), and 1.3 (3.8), respectively. CONCLUSIONS: Dynamic soft tissue mobilisation (STM) significantly increased hamstring flexibility in healthy male subjects.

An evaluation of differences in hip external rotation strength and range of motion between female dancers and non-dancers.

OBJECTIVES: To evaluate the differences in hip external rotation (ER) strength and inner, outer, and total hip ER range of motion (ROM) between dancers and non-dancers and between left and right sides in each group. METHODS: Seventy one subjects (34 dancers and 37 non-dancers) volunteered for this study. The strength (truncated range average torque (TRAT), work, and angle specific torque (AST)) of the hip external rotator muscle group, through the full available active hip ER ROM, was evaluated using concentric isokinetic (30 degrees /s) testing on a KinCom dynamometer. Adjustment for lean body mass (LBM) was made for comparison of strength between groups. A two way repeated analysis of covariance was used to compare strength between groups. A two way repeated analysis of variance was used to compare strength between sides and ROM between groups and sides. Bonferroni correction was made for multiple analyses, and significance was accepted at p

Assessment of pacemaker chronotropic response: implementation of the Wilkoff mathematical model.

There are few practical guidelines for proper adjustment of rate responsive pacemaker sensor parameters. This study describes the application of the chronotropic assessment exercise protocol (CAEP) and the Wilkoff model of chronotropic response to assess the adjustment of pacemaker sensor parameters. In 31 patients implanted 1 month previously with a dual sensor pacemaker, pacemaker sensor parameters were adjusted to yield a peak sensor rate of 100 beats/min on a simple 6-minute walk (low intensity treadmill exercise [LITE] protocol); the maximum sensor rate was set to the age predicted maximum heart rate (220-age). The rate response behavior of the pacemaker was then assessed using the slope of metabolic-chronotropic relation (MCR) during CAEP exercise. After adjustments based on the LITE protocol, CAEP exercise yielded MCR slopes of 0.92 +/- 0.25 for the entire study group, which compares well with the predicted normal slope of 1. However, 7 of the 31 patients had sensor MCR slopes during CAEP exercise that were 2 SD or more below expected. To test the sensitivity of this approach to suboptimal pacemaker programming or suboptimal exercise, simulations were performed with the maximum sensor rate programmed below age-predicted maximum heart rate or with exercise truncated before maximum exertion; with these conditions, MCR slopes were sharply lower for the entire group. The authors conclude that a simple treadmill walk (LITE) allowed for optimum programming of sensor parameters in most patients, but in a minority the chronotropic behavior was underresponsive. Failure to appropriately adjust pacemaker maximum sensor rate or failure to achieve peak exercise sharply limits the accuracy of this methodology.

Conversion of 4-hydroxyacetophenone into 4-phenyl acetate by a flavin adenine dinucleotide-containing Baeyer-Villiger-type monooxygenase.

An arylketone monooxygenase was purified from Pseudomonas putida JD1 by ion exchange and affinity chromatography. It had the characteristics of a Baeyer-Villiger-type monooxygenase and converted its substrate, 4-hydroxyacetophenone, into 4-hydroxyphenyl acetate with the consumption of one molecule of oxygen and oxidation of one molecule of NADPH per molecule of substrate. The enzyme was a monomer with an M(r) of about 70,000 and contained one molecule of flavin adenine dinucleotide (FAD). The enzyme was specific for NADPH as the electron donor, and spectral studies showed rapid reduction of the FAD by NADPH but not by NADH. Other arylketones were substrates, including acetophenone and 4-hydroxypropiophenone, which were converted into phenyl acetate and 4-hydroxyphenyl propionate, respectively. The enzyme displayed Michaelis-Menten kinetics with apparent K(m) values of 47 microM for 4-hydroxyacetophenone, 384 microM for acetophenone, and 23 microM for 4-hydroxypropiophenone. The apparent K(m) value for NADPH with 4-hydroxyacetophenone as substrate was 17.5 microM. The N-terminal sequence did not show any similarity to other proteins, but an internal sequence was very similar to part of the proposed NADPH binding site in the Baeyer-Villiger monooxygenase cyclohexanone monooxygenase from an Acinetobacter sp.

Quantitative telomerase expression in glioblastomas shows regional variation and down-regulation with therapy but no correlation with patient outcome.

Despite the nearly ubiquitous expression of telomerase in almost all types of malignant human tumors, studies have shown widely varying positivity in the highest-grade glioma, the glioblastomas (GBMs), ranging from 26% to 100% of tumors analyzed. We have previously shown significant variability in positive versus negative telomerase expression from region to region within the same GBM. In this study, we hypothesized that application of new quantitative methodology would extend our previous observations and identify whether there is heterogeneity in levels of protein expression even within areas positive for telomerase in high-grade gliomas. Finally, we sought to correlate quantitative telomerase expression with patient outcome and therapeutic response. Quantitative analysis was achieved by polymerase chain-based TRAP assay with phosphorimager analysis and compared with clinical information obtained from 19 patients, most with primary, untreated GBMs. Results showed up to 3-fold variability in telomerase levels across multiple regional samples from the same patient, as well as between patients. In 5 of 6 patients with recurrent tumors who had received intervening radiation therapy or chemotherapy, telomerase was downregulated in the second, post-therapy sample. These data provide in vivo corroboration of recent in vitro experiments showing telomerase downregulation after radiation therapy or chemotherapy treatment of cell lines. Our finding of variability in levels of telomerase expression in GBMs parallels the known heterogeneity of these tumors for histologic features and cell growth-related factors. Statistical analysis showed no relationship between TRAP score and either time to clinical progression or time to death.

Peroneal latency in normal and injured ankles at varying angles of perturbation.

The aim of this study was to determine whether there was a difference in latency of the peroneus longus muscle at varying amplitudes of ankle inversion perturbation and between individuals with and without a history of ankle injury. Thirty-four male athletes from different football codes (soccer, rugby) received four random tilts to their left ankles at 5 degrees, 10 degrees, and 15 degrees in the frontal plane on a dual platform trap door. Peroneal latency was defined as the time difference between onset of the trap door movement, as detected by an accelerometer, and the onset of muscle activation above a resting baseline, as recorded using surface electromyography. Latency was determined using an algorithm. A series of repeated measures analyses of variance indicated that the latency was reliable between trials. There was no statistical evidence that history of injury or subjective ankle instability influenced the latency; however, there was a systematic difference between dominant and nondominant legs (dominant, 6.3 ms faster), and there was a small systematic effect (3 ms) for the angle of inversion perturbation. Muscle latency responses in male football players are thought to be influenced more by dominance than by history of injury or amplitude of perturbation.

Landing in netball: effects of taping and bracing the ankle.

OBJECTIVES: To investigate the effect of bracing and taping on selected electromyographic, kinematic, and kinetic variables when landing from a jump. METHODS: Fifteen netball players performed a jump, so as to land on their dominant limb on a force plate. Electromyographic activity was recorded from the gastrocnemius, tibialis anterior, and peroneus longus muscles. Subjects were also filmed and measures of rearfoot motion were derived. RESULTS: Significantly less electromyographic activity (p<0.007) was observed from the gastrocnemius and peroneus longus muscle groups when subjects were braced. No other significant electromyographical findings were observed. Peak vertical ground reaction force and time to peak for vertical ground reaction force were not affected by bracing and taping, nor were the rearfoot and Achilles tendon angles at foot strike. CONCLUSIONS: The effect of bracing and taping on the selected biomechanics variables associated with landing was specifically limited to a reduction in muscle action, particularly for the braced condition. Netball players can be confident that the biomechanics of their landing patterns will not be altered whether they choose to wear a brace or tape their ankle joints.

Effects of the pesticide amitraz and its metabolite BTS 27271 on insulin and glucagon secretion from the perfused rat pancreas: involvement of alpha2D-adrenergic receptors.

The study purpose was to investigate the direct effect of amitraz, a formamidine insecticide/acaricide, and its active metabolite BTS 27271 on insulin and glucagon secretion from the perfused rat pancreas. Amitraz and BTS 27271 (0.01, 0.1, 1, and 10 micromol/L) inhibited insulin secretion in a concentration-dependent manner. Amitraz increased glucagon secretion at 10 micromol/L, whereas BTS 27271 increased glucagon secretion at 1 and 10 micromol/L. Amitraz- and BTS 27271-induced decreases in insulin secretion and increases in glucagon secretion were not abolished during the 10-minute washout period. During the arginine treatment, both amitraz and BTS 27271 groups (0.1, 1, and 10 micromol/L) had lower insulin secretion and higher glucagon secretion than the control group. Idazoxan, an alpha2A/2D-adrenergic receptor (AR) antagonist, prevented the inhibitory effect of amitraz on insulin secretion in a concentration-dependent manner, but prazosin, an alpha1- and alpha2B/2C-AR antagonist, failed to antagonize the effect of amitraz. These results demonstrate that (1) amitraz and BTS 27271 inhibit insulin and stimulate glucagon secretion from the perfused rat pancreas, (2) amitraz inhibits insulin secretion by activation of alpha2D-ARs, since rats have alpha2D- but not alpha2A-ARs, and (3) amitraz and BTS 27271 may have a high binding affinity to the alpha2D-ARs of pancreatic islets.

2,4'-Dihydroxyacetophenone dioxygenase (EC 1.13.11.41) from Alcaligenes sp. 4HAP: a novel enzyme with an atypical dioxygenase sequence.

2,4'-Dihydroxyacetophenone dioxygenase (EC 1.13.11.41) was purified to homogeneity from Alcaligenes sp. 4HAP grown on 4-hydroxyacetophenone. Measurements of the M(r) of the native enzyme ranged from 81600 to 87000, whereas values of 21000 and 20379 were given by SDS/PAGE and electrospray MS respectively. The enzyme is a homotetramer and contains one atom of iron per molecule of enzyme. From C- and N-terminal analyses, primers for PCR were designed and the dad gene cloned and sequenced. The predicted amino acid sequence of dad, deduced from the nucleotide sequence, confirms the N-terminal amino acid sequencing data and contains the sequence of an internal tryptic peptide. It gave a calculated M(r) of 20364. The gene was expressed in Escherichia coli and yielded active enzyme. The derived amino acid sequence does not show significant similarity to other dioxygenases or any strong similarity to protein sequences presently available in the databases.