Bioorthogonal labeling and profiling of N6-isopentenyladenosine (i6A) modified RNA

Chemical modifications in RNAs play crucial roles in diversifying their structures and regulating numerous biochemical processes. Since the 1990s, several hydrophobic prenyl-modifications have been discovered in various RNAs. Prenyl groups serve as precursors for terpenes and many other biological molecules. The processes of prenylation in different macromolecules have been extensively studied. We introduce here a novel chemical biology toolkit that not only labels i6A, a prenyl-modified RNA residue, by leveraging the unique reactivity of the prenyl group, but also provides a general strategy to incorporate fluorescence functionalities into RNAs for molecular tracking purposes. Our findings revealed that iodine-mediated cyclization reactions of the prenyl group occur rapidly, transforming i6A from a hydrogen-bond acceptor to a donor. Based on this reactivity, we developed an Iodine-Mediated Cyclization and Reverse Transcription (IMCRT) tRNA-seq method, which can profile all nine endogenous tRNAs containing i6A residues in Saccharomyces cerevisiae with single-base resolution. Furthermore, under stress conditions, we observed a decline in i6A levels in budding yeast, accompanied by significant decrease of mutation rate at A37 position. Thus, the IMCRT tRNA-seq method not only permits semi-quantification of i6A levels in tRNAs but also holds potential for transcriptome-wide detection and analysis of various RNA species containing i6A modifications.

Indole alkaloids isolated from the Nicotiana tabacum-derived Aspergillus fumigatus 0338 as potential inhibitors for tobacco powdery mildew and their mode of actions

To explore active natural products against tobacco powdery mildew caused by Golovinomyces cichoracearum, an extract from the fermentation of endophytic Aspergillus fumigatus 0338 was investigated. The mechanisms of action for active compounds were also studied in detail. As a result, 14 indole alkaloid derivatives were isolated, with seven being newly discovered (1-7) and the remaining seven previously described (8-14). Notably, compounds 1-3 are rare linearly fused 6/6/5 tricyclic prenylated indole alkaloids, with asperversiamide J being the only known natural product of this kind. The isopentenyl substitutions at the 5-position in compounds 4 and 5 are also rare, with only compounds 1-(5-prenyl-1H-indol-3-yl)-propan-2-one (8) and 1-(6-methoxy-5-prenyl-1H-indol3-yl)-propan-2-one currently available. In addition, compounds 6 and 7 are new framework indole alkaloid derivatives bearing a 6-methyl-1,7-dihydro-2H-azepin-2-one ring. The purified compounds were evaluated for their activity against G. cichoracearum, and the results revealed that compounds 7 and 9 demonstrated obvious anti-G. cichoracearum activities with an inhibition rate of 82.6% and 85.2%, respectively, at a concentration of 250 μg/mL, these rates were better than that of the positive control agent, carbendazim (78.6%). The protective and curative effects of compounds 7 and 9 were also better than that of positive control, at the same concentration. Moreover, the mechanistic study showed that treatment with compound 9 significantly increased the structural tightness of tobacco leaves and directly affect the conidiospores of G. cichoracearum, thereby enhancing resistance. Compounds 7 and 9 could also induce systemic acquired resistance (SAR), directly regulating the expression of defense enzymes, defense genes, and plant semaphorins, which may further contribute to increased plant resistance. Based on the activity experiments and molecular dockings, the indole core structure may be the foundation of these compounds' anti-G. cichoracearum activity. Among them, the indole derivative parent structures of compounds 6, 7, and 9 exhibit strong effects. Moreover, the methoxy substitution in compound 7 can enhance their activity. By isolating and structurally identifying the above indole alkaloids, new candidates for anti-powdery mildew chemical screening were discovered, which could enhance the utilization of N. tabacum-derived fungi in pesticide development.

What do windsurfers and kitesurfers in Germany know about surfer's ear and how is it influenced by protective measures?

OBJECTIVE

This study investigated the frequency of ear canal protection use and looked at its influence on external auditory exostosis severity and knowledge about external auditory exostosis among windsurfers and kitesurfers on the German coast.

METHOD

This retrospective cross-sectional study interviewed 130 windsurfers and kitesurfers along the German coast on knowledge of external auditory exostosis, exposure time, use of neoprene hoods and earplugs, and otological complaints. Participants underwent bilateral video-otoscopic examination.

RESULTS

Knowledge of external auditory exostosis was 'good' or 'excellent' in 78 of 130 (60 per cent) individuals and 'poor' or non-existent in 52 of 130 (40 per cent) individuals. Knowledge was positively correlated with hours of exposure, otological complaints and frequency of ear canal protection use. A significant negative influence of neoprene hood use on external auditory exostosis severity was shown.

CONCLUSION

The positive effect of external auditory exostosis knowledge on the frequency of ear canal protection and the reduction of external auditory exostosis risk implies a need for health education on this topic.

The Application of Neoprene Diving Boots in Reduction of Feet Injuries in the Sowing Process Among the Rice Farmers in Thailand

Foot injuries have been a problem among Thai farmers for a long time. The sowing process is one of the high-risk processes because farmers have to walk in the field to spray rice seed without footwear. Literature review showed that cuts from stepping on sharp material or snail shells were major sources of injury. Traditional footwear such as Ninja shoes or cloth socks have raised the questions regarding their ability in protection from such injuries. This study investigates using Neoprene diving boots to protect from foot injuries during the rice sowing process. The sample from this study were farmers from Sena District, Phra Nakhon Si Ayutthaya Province, Thailand. 29 farmer wearing Neoprene diving boots, 7 farmers wearing traditional Ninja shoes, and 19 farmers wearing cloth socks were asked to work in the sowing process and interviewed about any foot injuries that may have occurred. The statistical test showed there were no significant differences in characteristics among each group of farmers, except for work experience. The results show that there were no foot injuries in farmers wearing Neoprene diving boots, whereas 73% of farmers wearing Ninja shoes, and 14% of farmers wearing cloth socks still had foot injuries. Most injuries were alaceration that were caused by the golden apple snail. The satisfaction survey showed that farmers were satisfied and strongly satisfied with all of the aesthetics, utilization, and functionality factors. This study suggested that the Neoprene diving boots can be recommended for farmers to use as safeguarding against foot injuries in the rice sowing process.

A case series on the effect of dynamic neoprene orthosis on lower limb kinematic variables in children with cerebral palsy

PURPOSE

This study examined the effects of a dynamic neoprene orthosis on kinematic variables of gait in children with spastic bilateral cerebral palsy (CP).

METHODS

Five children (whose median age was 9.6 years and who ranged in age from six to 12) with spastic bilateral CP and flexed knee at levels I-III of the Gross Motor Function Classification System were examined using kinematic gait analysis in three different conditions: 1) with dynamic neoprene orthosis; 2) without dynamic neoprene orthosis (immediate effect); and 3) without orthosis after six weeks of intervention.

RESULTS

The comparison between condition one (with dynamic neoprene orthosis) and condition two (without dynamic neoprene orthosis) demonstrated the existence of improvements in minimum hip and knee flexion variables. Moreover, the results indicated that the improvements remained constant in several key gait variables after six weeks.

CONCLUSION

The results varied from subject to subject, and there were signs of improvement in some of the subjects. Therefore, it was not possible to draw conclusions at a group level. Nonetheless, a number of individuals may benefit from this type of orthosis.

Mechanical characterization of human skin-A non-invasive digital twin approach using vibration-response integrated with numerical methods

This paper proposes an innovative approach to identify elastic material properties and mass density of soft tissues based on interpreting their mechanical vibration response, externally excited by a mechanical indenter or acoustic waves. A vibration test is performed on soft sheets to measure their response to a continuous range of excitation frequencies. The frequency responses are collected with a pair of high-speed cameras in conjunction with 3-D digital image correlation (DIC). Two cases are considered, including suspended/fully-free rectangular neoprene sheets as artificial tissue cutout samples and continuous layered human skin vibrations. An efficient theoretical model is developed to analytically simulate the free vibrations of the neoprene artificial sheet samples as well as the continuous layered human skins. The high accuracy and validity of the presented analytical simulations are demonstrated through comparison with the DIC measurements and the conducted frequency tests, as well as a number of finite element (FE) modeling. The developed analytical approach is implemented into a numerical algorithm to perform an inverse calculation of the soft sheets' elastic properties using the imported experimental vibration results and the predicted system's mass via the system equivalent reduction/expansion process (SEREP) method. It is shown that the proposed frequency-dependent inverse approach is capable of rapidly predicting the material properties of the tested samples with high accuracy.

Abdominal aortic branches of red-rumped agouti (Dasyprocta leporina Linnaeus, 1758)

Understanding the cardiovascular system is fundamental in diagnosing pathologies and interpreting exams, such as contrast radiographs. In this context, the present study describes the collateral abdominal aorta artery branches of red-rumped agouti. Ten red-rumped agoutis, six males and four females, were assessed. The vascular system was perfused with Neoprene 450 latex coloured with a yellow pigment, dissected and analysed. Three euthanized animals were perfused with a barium sulfate solution (1 g mL-1 ) associated with latex Neoprene 450 at a 1:3 ratio to obtain contrast-enhanced radiographs. The abdominal aorta emitted the celiac artery, which in turn originated the left gastric, hepatic and splenic arteries. The second collateral branch comprised the cranial mesenteric artery, followed by the renal arteries, which emitted the adrenal arteries, with the caudal emergence of the gonadal arteries. The caudal mesenteric artery appeared in a caudal direction. The abdominal aorta divided after reaching the pelvic cavity entrance, originating the right and left common iliac arteries. Before its bifurcation, the abdominal aorta dorsocaudally emitted its last collateral branch, the median sacral artery. The collateral branches of the aorta, therefore, resemble previously described rodent patterns, with few variations.

Influence of neoprene ankle orthoses on dynamic balance during a vertical jump in healthy individuals and with sprain history: A cross-sectional study

INTRODUCTION

A sprain describes an excessive amount of force or strain on a ligament, which may or may not lead to its rupture. Orthoses are among the most common modalities prescribed as a conservative treatment for ankle instability and sprain.

OBJECTIVE

We aimed to analyse the effect of neoprene orthosis on the balance and functionality of healthy individuals and volunteers with lateral ankle sprains METHODS: We evaluated 12 healthy volunteers (control group) and 12 volunteers diagnosed with a sprain and/or instability (patient group). A total of 14 men and 10 women participated in the study, with an average age of 26.15 (± 4.40) years. The volunteers' tasks consisted of performing vertical bipodal and unipodal jumps on a force platform, which were recorded in a video from the lateral view of the lower limb for posterior evaluation of the knee and ankle angles. Mann-Whitney and Wilcoxon tests were used for comparisons, considering p < 0.05 level of significance.

RESULTS

The control group presented a decrease in ground reaction force when using Orthosis during the bipodal jump (p < 0.05). A decrease in anteroposterior force displacement was also observed in the left unipodal jump (p < 0.01). The patient group presented an increase in force and moment of medial-lateral displacement for both bipodal (p < 0.02) and left unipodal jumps with Orthosis (p < 0.02). A kinematic analysis showed that the control group presented the smallest knee flexion angle (p < 0.01), while the patient group presented the smallest dorsiflexion ankle angle in the bipodal jump when using orthosis (p < 0.01).

CONCLUSION

We concluded that orthosis had influence on individuals' balance and joint angles. In healthy individuals presented better balance with and without orthosis and greater flexion with orthosis in the bipodal jump, regarding to the patient group presented smaller oscillations in the unipodal jump with orthosis and showed smaller knee flexion and ankle dorsiflexion.

A new monitoring approach for sustainability assessment of subsurface utilities gasket materials against gasoline and chlorinated solvents: Field evaluation and model development

Once installed, underground concrete pipes with rubber gaskets might be exposed to contaminated soil and groundwater. A pipe material monitoring capsule (PMMC) has been developed to evaluate volatile organic compounds (VOCs) breaking through three types of pipe gaskets; Neoprene, Buna-N, and Viton. The PMMCs were deployed in three contaminated sites: two with gasoline and one with chlorinated solvent (CS). A 3-D field-domain numerical model has been developed for each site to calibrate equivalent hydraulic parameters of each gasket material (k_e, D) against benzene and PCE diffusion. The calibrated parameters were then used to compute the concentrations as well as rate of breakthrough of the two study contaminants. A protocol was developed for installing/retrieval of PMMCs to monitor PCE and benzene mass breaking through the gasket material with time. Employing PMMC, benzene concentrations breaking through the Neoprene and Buna-N after 4 months were approximately 70% and 60% respectively of the monitoring wells concentration. The corresponding value for PCE breakthrough after 4 months was 60% for both the Neoprene and Buna-N. Both gasket materials of Neoprene and Buna-N yielded similar performances, including higher rate of contaminant breakthrough compared to Viton. A nonlinear relationship of mass breaking through the gaskets of benzene and PCE with time was discerned from the modeling and field data.

Three Australian Lepidosperma Labill. Species as sources of prenylated and oxyprenylated derivatives of piceatannol, resveratrol and pinosylvin: Melatoninergic binding and inhibition of quinone reductase 2

Prenylated and hydroxyprenylated piceatannol, resveratrol and pinosylvin derivatives were isolated from resin produced by three Australian Lepidosperma Labill. Species (Cyperaceae). From L. congestum R.Br. one known compound, 3',5'-bis-prenyl-E-resveratrol, and five undescribed compounds were isolated, 3'-O-prenyl-5'-prenyl-E-piceatannol, 5',6'-bis-prenyl-E-piceatannol, 5'-prenyl-E-piceatannol, 3',5'-bis(3-hydroxy-3-methylbutyl)-E-resveratrol and 3',5'-bis-E-hydroxyprenyl-E-resveratrol. From L. gunnii Boeckeler one undescribed compound was isolated, 3'-E-hydroxyprenyl-5'-Z-hydroxyprenyl-E-resveratrol. From L. laterale R.Br. six undescribed compounds were isolated, 3-O-prenyl-E-pinosylvin, 3-O-Z-hydroxyprenyl-E-pinosylvin, 3'-Z-hydroxyprenyl-E-resveratrol, 3-O-Z-hydroxyprenyl-E-resveratrol, 3-O-Z-hydroxyprenyl-4'-O-methyl-E-resveratrol, and 3-O-prenyl-3'-δ,δ'-dihydroxyprenyl-E-resveratrol. Compounds, including a reference compound 3-O-prenyl-3'-O-methyl-E-piceatannol, were screened in an assay for melatoninergic binding to MT1 and MT2 receptors and binding to QR2/MT3 enzyme, and for inhibition of QR2/MT3 in a functional assay. Strong binding was observed for 3-O-Z-hydroxyprenyl-E-resveratrol with a K_i of 0.022 nM and the strongest inhibition of QR2/MT3 observed was for the reference compound, 3-O-prenyl-3'-O-methyl-E-piceatannol, with an inhibition of 61% at 1 μM and 95% at 10 μM. The three most active binders and inhibitors of QR2/MT3 were found to have a common substructure corresponding to 3-O-prenylresveratrol.

Structural Basis of Substrate Promiscuity and Catalysis by the Reverse Prenyltransferase N-Dimethylallyl-l-tryptophan Synthase from Fusarium fujikuroi

The regiospecific prenylation of an aromatic amino acid catalyzed by a dimethylallyl-l-tryptophan synthase (DMATS) is a key step in the biosynthesis of many fungal and bacterial natural products. DMATS enzymes share a common "ABBA" fold with divergent active site contours that direct alternative C-C, C-N, and C-O bond-forming trajectories. DMATS1 from Fusarium fujikuroi catalyzes the reverse N-prenylation of l-Trp by generating an allylic carbocation from dimethylallyl diphosphate (DMAPP) that then alkylates the indole nitrogen of l-Trp. DMATS1 stands out among the greater DMATS family because it exhibits unusually broad substrate specificity: it can utilize geranyl diphosphate (GPP) or l-Tyr as an alternative prenyl donor or acceptor, respectively; it can catalyze both forward and reverse prenylation, i.e., at C1 or C3 of DMAPP; and it can catalyze C-N and C-O bond-forming reactions. Here, we report the crystal structures of DMATS1 and its complexes with l-Trp or l-Tyr and unreactive thiolodiphosphate analogues of the prenyl donors DMAPP and GPP. Structures of ternary complexes mimic Michaelis complexes with actual substrates and illuminate active site features that govern prenylation regiochemistry. Comparison with CymD, a bacterial enzyme that catalyzes the reverse N-prenylation of l-Trp with DMAPP, indicates that bacterial and fungal DMATS enzymes share a conserved reaction mechanism. However, the narrower active site contour of CymD enforces narrower substrate specificity. Structure-function relationships established for DMATS enzymes will ultimately inform protein engineering experiments that will broaden the utility of these enzymes as useful tools for synthetic biology.

Characterization of prenylated phenolics in Glycyrrhiza uralensis by offline two-dimensional liquid chromatography/mass spectrometry coupled with mass defect filter

Prenylated phenolics are an important class of natural products. In this study, an efficient strategy was established to systematically characterize the prenylated phenolics in Glycyrrhiza uralensis, a popular herbal medicine. Firstly, offline two-dimensional liquid chromatography/mass spectrometry (2DLC/MS) coupled with mass defect filter (MDF) technology was used to preliminarily detect 1631 potential prenylated phenolics. Secondly, the tandem mass spectrometry fragmentation features of different types of prenylated phenolics were investigated using 29 reference standards. Diagnostic fragmentations included neutral loss (NL) of 42 Da for the annular type and NL of 56 Da for the catenulate type in the positive ion mode, and NL of 56 Da for A-ring prenyl groups and NL of 69 Da for B-ring prenyl groups in the negative ion mode. As a result, the prenylation types, substitution sites, and adjacent OH and OCH₃ substitutions of 320 prenylated phenolics in G. uralensis were rapidly characterized. Moreover, three prenylated dihydrostilbenes were purified from the aerial part of G. uralensis to verify the structural characterizations.

Effect of a Neoprene Knee Sleeve on Performance and Muscle Activity in Men and Women During High-Intensity, High-Volume Resistance Training

ABSTRACT

Hatfield, DL, Stranieri, AM, Vincent, LM, and Earp, JE. Effect of a neoprene knee sleeve on performance and muscle activity in men and women during high-intensity, high-volume resistance training. J Strength Cond Res 35(12): 3300-3307, 2021-The purpose of this study was to assess the effects of a commercially available neoprene knee sleeve (KS) on exercise performance and muscle activity during an exhaustive leg press exercise. Twenty resistance-trained individuals, 11 men {21.0 ± 2.2 years; 77.7 ± 8.7 kg; 1 repetition maximum (1RM/body mass [BM]): 0.30 ± 0.04} and 9 women (22.0 ± 3.5 years; 66.1 ± 9.1 kg; 1RM/BM: 0.30 ± 0.04), all subjects (21.5 ± 2.8 years; 72.5 ± 10.5 kg; 1RM/BM: 0.30 ± 0.04), participated in 3 testing sessions. The second and third sessions were performed using a counterbalanced and randomized design in which subjects exercised with (WS) or without (NS) KSs and performed 6 sets of leg press exercise at 80% of 1RM until failure with a 3-minute rest between sets. Number of repetitions, blood lactate (BL), heart rate (HR), rating of perceived exertion (RPE), and peak and average power were recorded after each set. Surface electromyography (EMG) of the right and left vastus lateralis muscles was also recorded to compare muscle activity between conditions. Significance was set at p ≤ 0.05, and values are presented as mean ± SD. No significant differences were observed in the total number of repetitions for all sets (p = 0.3; WS 75.3 ± 33.7, NS 79.8 ± 34.3) and the number of repetitions per set between conditions (p ≤ 0.05) or between men and women. Similarly, no significance differences (p ≤ 0.05) were observed for BL, HR, RPE, or EMG per set between conditions or between men and women. These results suggest that wearing compressive neoprene KSs has no effect on improving performance and associated variables during high-load, high-volume lower-body resistance training.

Silica Gel-mediated Oxidation of Prenyl Motifs Generates Natural Product-Like Artifacts

Prenyl moieties are commonly encountered in the natural products of terpenoid and mixed biosynthetic origin. The reactivity of unsaturated prenyl motifs is less recognized and shown here to affect the acyclic Rhodiola rosea monoterpene glycoside, kenposide A (8: ), which oxidizes readily on silica gel when exposed to air. The major degradation product mediated under these conditions was a new aldehyde, 9: . Exhibiting a shortened carbon skeleton formed through the breakdown of the terminal isopropenyl group, 9: is prone to acetalization in protic solvents. Further investigation of minor degradation products of both 8: and 8-prenylapigenin (8-PA, 12: ), a flavonoid with an ortho-prenyl substituent, revealed that the aldehyde formation was likely realized through epoxidation and subsequent cleavage at the prenyl olefinic bond. Employment of ¹H NMR full spin analysis (HiFSA) achieved the assignment of all chemical shifts and coupling constants of the investigated terpenoids and facilitated the structural validation of the degradation product, 9: . This study indicates that prenylated compounds are generally susceptible to oxidative degradation, particularly in the presence of catalytic mediators, but also under physiological conditions. Such oxidative artifact/metabolite formation leads to a series of compounds with prenyl-derived (cyclic) partial structures that are analogous to species formed during Phase I metabolism in vivo. Phytochemical and pharmacological studies should take precautions or at least consider the impact of (unavoidable) exposure of prenyl-containing compounds to catalytic and/or oxidative conditions.

Neoprene Knee Sleeves of Varying Tightness Augment Barbell Squat One Repetition Maximum Performance Without Improving Other Indices of Muscular Strength, Power, or Endurance

ABSTRACT

Machek, SB, Cardaci, TD, Wilburn, DT, Cholewinski, MC, Latt, SL, Harris, DR, and Willoughby, DS. Neoprene knee sleeves of varying tightness augment barbell squat one repetition maximum performance without improving other indices of muscular strength, power, or endurance. J Strength Cond Res 35(2S): S6-S15, 2021-Neoprene knee sleeves are commonly used by powerlifters and recreational users but are heavily under-researched. Furthermore, no data exist on whether knee sleeves of varying compressive tightness impact muscular performance similar to commonly used knee wraps, which are both generally effective and more so when increasingly constrictive. Fifteen resistance trained, knee sleeve naive, recreational weight lifting men (22.1 ± 4.1 years; 177.5 ± 5.9 cm; 87.8 ± 7.8 kg) visited the laboratory on 3 separate occasions one week apart, assigned in a randomized, crossover, and counterbalanced fashion to either a minimally supportive control sleeve (CS) condition, a manufacturer-recommended sizing neoprene knee sleeve ("normal" sleeve; NS), or a one size smaller (than NS) neoprene knee sleeve (tighter sleeve [TS]). On each visit, subjects sequentially completed vertical jump (countermovement and squat jumps for both peak and mean power), one repetition maximum (1RM) barbell squat, and GymAware assessments (peak power, peak velocity, and dip) at 90% (reported) and 100% (tested) 1RM as well as one-leg extension (1RM, repetitions to failure, and total volume load at 75% 1RM) tests. All data were analyzed using one-way repeated measures analysis of variance at p < 0.05. Analysis revealed a significant condition effect on barbell squat 1RM (p = 0.003; η2 = 0.339), whereby both NS (p = 0.044; 166 ± 24 kg) and TS (p = 0.019; 166 ± 21 kg) outperformed CS (161 ± 22 kg), with no difference between neoprene sleeves. Conversely, no other tested parameters differed between knee sleeve conditions (p ≥ 0.05). The present results demonstrate that neoprene knee sleeves may function independent of tightness, relative to recommended sizing and ultimately unlike knee wraps. Furthermore, the singular benefits observed on barbell squat maximal strength potentially suggests an exercise-specific benefit yet to be fully elucidated.

Acoustic and ultrasonographic characterization of polychloroprene, beeswax, and carbomer-gel to mimic soft-tissue for diagnostic ultrasound

Materials with acoustic properties similar to soft-tissue are essential as tissue-mimicking materials (TMMs) for diagnostic ultrasound (US). The velocity (c_us), acoustic impedance (AI) and attenuation coefficient of US (µ) in a material collectively define its acoustic property. In this work, the acoustic properties of polychloroprene rubber, beeswax, and Carbomer-gel are determined. The pulse-echo technique is used to estimate c_us and µ. The product of a sample density (ρ) and c_us gives its AI. Using a reference based on the International Commission on Radiation Units and Measurements Report-61, Tissue Substitutes, Phantoms and Computational Modelling in Medical Ultrasound, the results are evaluated. The acceptance criteria are 1.043 ± 0.021 g/cm³ (ρ), 1561 ± 31.22 m/s (c_us), 1.63 ± 0.065 MRayls (AI) and µ within 0.5-0.7 dB/cm/MHz. Sample computerized tomography (CT) and US scanning are performed to evaluate their similarities (contrast and speckle pattern) with respective images of the human liver (a clinical soft-tissue). The average errors in measuring c_us and µ were 0.14% and 1.2% respectively. From the present findings, acoustic properties of polychloroprene and beeswax are unacceptable. However, the results of Carbomer-gel ρ = 1.03 g/cm³, c_us = 1567 m/s, AI = 1.61 MRayls are satisfactory and µ = 0.73 dB/cm/MHz, is higher than the reference (4.3%). Carbomer-gel could produce CT and US images, efficiently mimicking the respective liver images. Carbomer-gel containing 95% water is a low-cost material with a simple formulation. Present results suggest, Carbomer- gel mimics soft-tissue and can be used as a TMM for diagnostic US.

Automatic Resonance Frequency Retuning of Stretchable Liquid Metal Receive Coil for Magnetic Resonance Imaging

Stretchable magnetic resonance (MR) receive coils show shifts in their resonance frequency when stretched. An in-field receiver measures the frequency response of a stretchable coil. The receiver and coil are designed to operate at 128 MHz for a 3T MR scanner. Based on the measured frequency response, we are able to detect the changes of the resonance frequency of the coil. We show a proportional-integral-derivative controller that tracks the changes in resonance frequency and retunes the stretchable coil. The settling time of the control loop is less than 3.8ms. The retuning system reduces the loss in signal-to-noise ratio of phantom images from 1.6 dB to 0.3 dB, when the coil is stretched by 40% and the coil is retuned to 128 MHz.

Cardiovascular and respiratory effects of the neoprene wetsuit in non-immersed divers

A neoprene wetsuit is widely used to reduce thermal dispersion during diving. Recent observations have pointed out that elastic recoil of the wetsuit might have significant compressive effects, able to affect water and electrolyte homeostasis during both dry and immersed conditions. The aim of this study was to evaluate the possible cardiovascular and respiratory effects of the neoprene wetsuit in dry conditions in a sample of experienced divers. Twenty-four (24) healthy divers were evaluated by Doppler-echocardiography and by spirometry in basal conditions and while wearing a full neoprene wetsuit. During wetsuit conditions, we observed a significant decrease in heart rate (-5%; p ⟨ 0.05) and cardiac output (-12%; p ⟨ 0.05), and a significant increase in total peripheral resistances (15%; p ⟨ 0.05). Moreover, a significant reduction of right ventricular early diastolic filling was observed (-15%; p ⟨ 0.05). As concerns pulmonary function, a significant reduction of vital capacity (-2%; p ⟨ 0.001) and expiratory reserve volume (-25%; p ⟨ 0.001), and a significant increase of inspiratory capacity (9%; p ⟨ 0.001) and tidal volume (25%; p ⟨ 0.05) were observed. These data support the hypothesis that neoprene elastic recoil, possibly due to a compression exerted on chest, might affect systemic circulation (decreasing cardiac output and impairing right ventricular filling) and respiratory function.

Avertoxins A-D, Prenyl Asteltoxin Derivatives from Aspergillus versicolor Y10, an Endophytic Fungus of Huperzia serrata

Aspergillus versicolor Y10 is an endophytic fungus isolated from Huperzia serrata, which showed inhibitory activity against acetylcholinesterase. An investigation of the chemical constituents of Y10 led to the isolation of four new prenylated asteltoxin derivatives, named avertoxins A-D (2-5), together with the known mycotoxin asteltoxin (1). In the present study, we report structure elucidation for 2-5 and the revised NMR assignments for asteltoxin and demonstrated that avertoxin B (3) is an active inhibitor against human acetylcholinesterase with the IC50 value of 14.9 μM (huperzine A as the positive control had an IC50 of 0.6 μM). In addition, the cytotoxicity of asteltoxin (1) and avertoxins A-D (2-5) against MDA-MB-231, HCT116, and HeLa cell lines was evaluated.

Experiments on the mechanism of underwater hearing

CONCLUSION

The findings suggest that underwater sound perception is realized by the middle ear rather than by bone conduction, at least in shallow water conditions.

OBJECTIVE

To prove whether underwater sound perception is effected by bone conduction or by conduction via the middle ear.

METHODS

Five divers, breathing through snorkels, were tested in a swimming pool, to determine whether a sound was louder when the acoustic source placed was in front of the head in comparison with a lateral application facing the ear region. The second experiment investigated whether sound perception is influenced by ear protection plugs in underwater conditions. Also, the effect of a 5 mm thick neoprene hood was determined, with and without an additional perforation in the ear region.

RESULTS

Sounds were louder when applied from a position laterally facing the ear, louder without than with a protection plug, louder without than with a neoprene hood on, and louder when the neoprene hood had a perforation in the region of the ear than with an intact hood.

Permeation of gasoline, diesel, bioethanol (E85), and biodiesel (B20) fuels through six glove materials

Biofuels and conventional fuels differ in terms of their evaporation rates, permeation rates, and exhaust emissions, which can alter exposures of workers, especially those in the fuel refining and distribution industries. This study investigated the permeation of biofuels (bioethanol 85%, biodiesel 20%) and conventional petroleum fuels (gasoline and diesel) through gloves used in occupational settings (neoprene, nitrile, and Viton) and laboratories (latex, nitrile, and vinyl), as well as a standard reference material (neoprene sheet). Permeation rates and breakthrough times were measured using the American Society for Testing and Materials F739-99 protocol, and fuel and permeant compositions were measured by gas chromatography/mass spectrometry. In addition, we estimated exposures for three occupational scenarios and recommend chemical protective clothing suitable for use with motor fuels. Permeation rates and breakthrough times depended on the fuel-glove combination. Gasoline had the highest permeation rate among the four fuels. Bioethanol (85%) had breakthrough times that were two to three times longer than gasoline through neoprene, nitrile Sol-Vex, and the standard reference materials. Breakthrough times for biodiesel (20%) were slightly shorter than for diesel for the latex, vinyl, nitrile examination, and the standard neoprene materials. The composition of permeants differed from neat fuels, e.g., permeants were significantly enriched in the lighter aromatics including benzene. Viton was the best choice among the tested materials for the four fuels tested. Among the scenarios, fuel truck drivers had the highest uptake via inhalation based on the personal measurements available in the literature, and gasoline station attendants had highest uptake via dermal exposure if gloves were not worn. Appropriate selection and use of gloves can protect workers from dermal exposures; however, current recommendations from the National Institute for Occupational Safety and Health should be revised to account for contemporary fuel formulations that routinely contain ethanol.

Methyl methacrylate permeability of dental and industrial gloves

Our study was undertaken to measure the amount and time it took for methyl methacrylate monomer (MMA) to permeate latex, vinyl and industrial neoprene gloves and to compare the results to obtain a rating of the permeability of each of the gloves studied to MMA. The monomer, permeated under static conditions, was measured using a spectrophotometer. Latex and vinyl clinical gloves became permeable to MMA in a very short amount of time. Neoprene industrial gloves remained impervious for 25 minutes. Dentists and dental technicians should be aware of the toxic effects of MMA and understand that clinical gloves do not afford protection from MMA.

The effect of ambient temperature on cold saline during simulated infusion to induce therapeutic hypothermia

BACKGROUND

This study was done to determine the effect of ambient temperature on cold saline during simulated infusion to induce therapeutic hypothermia. The study hypothesis was that cold saline would warm rapidly during simulated infusion and that an insulating SIGG neoprene pouch would slow the process.

METHODS

Paired 1-l bags of normal saline [with or without an insulating SIGG neoprene pouch (NEO+ and NEO- respectively)] were refrigerated together for at least 24h. With an ambient room temperature (RT) between 32 and 34 degrees C, the fluid was allowed to flow unrestricted through standard tubing connected to a 20-guage angiocath while the line reservoir temperature was monitored every 30s. The order of the bags was pre-determined and alternated for each session. During 5 sessions, ten 1-l bags were included (5 NEO+ and 5 NEO-). The data were analyzed descriptively using Stata SE v8.1 for Macintosh.

RESULTS

The average ambient RT during the experimental sessions was 32.6 degrees C (StDev: 0.8 degrees C). The relative humidity was a constant 16%. The average low saline temperature at the beginning of infusion was 6.2 degrees C (StDev: 2.7 degrees C). The average rate of infusion was 48.2cm(3)/min (StDev: 3.7cm(3)/min). The average rise in saline temperature during the first 15min of the infusion was 2.9 degrees C (StDev: 1.2 degrees C). The average high saline temperature reached near the end of the infusion was 13.4 degrees C (StDev: 4.1 degrees C). The average temperature change during infusion was 7.2 degrees C (StDev: 3.5 degrees C). The baseline data for the NEO+ and NEO- samples were not statistically different. The average temperature change over the first 15min for the NEO+ group was 2.0 degrees C (95% CI: 1.4 degrees C and 2.5 degrees C) and for the NEO- group it was 3.9 degrees C (95% CI: 2.6 degrees C and 5.1 degrees C). The average change over the entire infusion for the NEO+ group was 4.3 degrees C (95% CI: 3.1 degrees C and 5.5 degrees C) and for the NEO- group it was 10.2 degrees C (95% CI: 7.4 degrees C and 12.9 degrees C).

CONCLUSIONS

During simulated infusion to induce therapeutic hypothermia, cold saline begins to warm toward ambient temperature but the rate is not rapid. An insulating SIGG neoprene pouch slows the rate of warming.

The ideal rotation flap: an experimental study

BACKGROUND/PURPOSE

Numerous modifications exist and opinions vary between surgeons with regard to the design of the ideal rotation flap. A literature review revealed inconsistencies as well as three different designs of rotation flap (standard rotation flap, Ahuja's modified rotation flap, divine rotation flap) based on entirely different concepts. It is not clear which of these designs serves its purpose best in wound reconstruction since they have not been previously examined experimentally and directly compared. The aim of this study is to determine the optimal rotation flap design in wound reconstruction. Several modifications of the standard rotation flap are examined and the three different rotation flap designs are directly compared.

METHODS

This study tests the ability of various rotation flaps to close triangulated defects on sheets of neoprene, a synthetic rubber compound. Section A examines four important features in the design of the standard rotation flap: triangulation of a lesion, rotation flap circumference, pivot point and the back cut. Section B compares the standard rotation flap, Ahuja's modified rotation flap and the divine rotation flap. Tension resulting from wound closure is measured and the length of scar calculated.

RESULTS/CONCLUSION

The standard rotation flap remains superior in comparison to the modified rotation flap and the divine rotation flap. Triangulation of a lesion should be performed with care and, in particular, the apex of the triangle should coincide with the geometrical pivot point. A flap circumference more than five times the width of the defect is of minimal benefit. The back cut is an effective modification and should be used if necessary.

The effect of neoprene shorts on leg proprioception in Australian football players

Our purpose was to assess the effect of wearing close-fitting neoprene shorts on swinging leg movement discrimination (MD) scores in elite level Australian Football players. Twenty players had their swinging leg MD assessed using the active movement extent discrimination apparatus (AMEDA), once wearing close-fitting neoprene and once wearing loose-fitting running shorts. Subjects were randomly allocated to one of the shorts conditions prior to repeating the test in the other condition. The AMEDA was used to assess the accuracy at which subjects judge the extent of a standing backward swinging leg movement corresponding to the late swing early stance phase of running. Each subject performed 40 movements made to one of five randomly set physical limits, and without the aid of vision made a judgment as to the perceived limit position. From the accuracy of these judgments, a movement discrimination (MD) score was calculated for each subject under each condition. Subjects were grouped as having low or high neuromuscular control, or ability to use proprioception when controlling active movements without vision, based on their loose-shorts MD score. Analysis was performed on the MD scores obtained for each limb from subjects in the two groups, under the two shorts-wearing conditions. There was no main effect of wearing close-fitting shorts when the cohort was treated as a whole. A significant interaction effect was obtained (F=17.027, p=0.0006) whereby the mean MD score of the low neuromuscular control ability group was improved when wearing neoprene shorts but was reduced for the high ability group. Wearing close-fitting neoprene shorts has a beneficial effect on leg swing judgment accuracy in subjects with low neuromuscular control ability. Conversely, leg swing judgment accuracy for subjects with high ability was reduced by wearing neoprene shorts.

Effect of Knee Sleeve on Static and Dynamic Balance in Patients with Knee Osteoarthritis

Patients with knee osteoarthritis (OA) find that use of elastic knee sleeves gives them partial pain relief and a greater sense of joint stability. However, the scientific effects of knee OA patients wearing braces are unclear. The purpose of this study was to investigate the effects of knee sleeves on static and dynamic balance in knee OA patients. Fifty patients with knee OA were enrolled in the study and all subjects were randomly divided into two groups. Initially, subjects in group A did not wear a neoprene sleeve while receiving balance tests but then wore them to be re-tested. Subjects in group B did just the reverse procedure. In this investigation, an instrument (KAT 2000; Breg Inc., Vista, CA, USA), which quantified motor control performance of the lower extremities was used and balance scores from the KAT 2000 software were obtained. The results revealed that the scores of patients wearing braces were significantly lower than those of patients without braces (p < 0.05).The finding of this study demonstrated that knee OA patients wearing knee sleeves could experience increased balance ability in both static and dynamic conditions. The improvement might prevent knee OA patients from falling down and increase their sense of security during physical activities.

The Effect of a Neoprene Sleeve on Knee Joint Position Sense

The aims of the study were, first, to assess the effect of a neoprene knee brace on prop rioceptive acuity of normal subjects and, second, to assess the relationships between a variety of tests of proprioceptive acuity. Twenty healthy, physically active subjects had absolute error scores measured while carrying out three different established tests of proprioceptive ability (active tracking, active reproduction, and perceived angle tests) under two conditions, either with or without the presence of a neoprene sleeve. The neoprene sleeve significanltly improved the degree of error scores in all tests. For the active tracking, test accuracy was improved by 28% (p = 0.004), the angle reproduction test showed a 23% increase in accuracy (p = 0.029), and the accurancy of the perceived angle test improved by 27% (p = 0.035). The relationship between magnitude of error scores between the test all showed nonsignificant low correlation. The findings of this study support the previous literature, which indicates that the application of a knee sleeve improves proprioceptive acuity. The study also indicates that when testing proprioceptive acuity, a test battery should be used because of the limited correlatiotn between any of the tests used.

Efficacy of double gloving with an intrinsic indicator system

BACKGROUND

Blood-borne infection is an ever-present fear for medical professionals, especially surgeons and operating room personnel. Safety is paramount, and the reliability and efficacy of surgical gloves are crucial, as gloves are the most important barriers protecting hospital personnel and patients. Unfortunately, glove perforation rates are as high as 78% in high-risk procedures. As well as being efficacious, surgical gloves must be comfortable and easy to don, and when holes are present, it is imperative they be detected expeditiously. The purpose of this double-blind randomized study was to evaluate the ability of participants to locate 30-micron laser holes in surgical gloves while performing simulated surgery and to evaluate the Biogel Indicator Glove System, which reveals punctures.

METHODS

Twenty glove configurations (eight single, twelve double) were tested, half of which had laser-created holes. Each of the 25 participants tested and evaluated 20 configurations randomly. Simulated surgery terminated when a hole was identified by the participant or at the end of two minutes, whichever occurred first. Participants also rated their perceptions of each glove's features on questionnaires, all of which were returned, with 95.8% being complete.

RESULTS

Participants found 84% and 56% of the holes in the two indicator systems, latex and synthetic, in an average of 22 seconds and 42 seconds, respectively. In the worst-performing latex and synthetic glove configurations, participants found only 8% and 12% of the holes at an average of 47 seconds and 67 seconds, respectively. Indicator gloves were highly rated for comfort and ease of use.

CONCLUSIONS

Double gloving with an indicator system provides the best protection and allows the timeliest identification of perforations. Participants failed to identify most of the holes in the non-indicator gloves.

Consequences of prolonged total body immersion in cold water on muscle performance and EMG activity

The consequences of a prolonged total body immersion in cold water on the muscle function have not been documented yet, and they are the object of this French Navy research program. Ten elite divers were totally immerged and stayed immobile during 6 h in cold (18 and 10 degrees C) water. We measured the maximal voluntary leg extension (maximal voluntary contraction, MVC) and evoked compound muscle potential (M wave) in vastus lateralis and soleus muscles at rest, after a submaximal (60% MVC) isometric extension allowing the measurement of the endurance time (Tlim). The power spectrum of surface electromyograms (EMG) was computed during 60% MVCs. MVCs and 60% MVC maneuvers were repeated four times during the immersion. Data were compared with those obtained in a control group studied in dry air condition during a 6-h session. Total body cooling did not affect MVC nor Tlim. The M wave duration increased in the coolest muscle (soleus), but only at 10 degrees C at rest. There were no further fatigue-induced M wave alterations in both muscles. During 60% the MVCs, a time-dependant increase in the leftward shift of the EMG spectrum occurred at the two temperatures. These EMG changes were absent in the control group of subjects studied in dry air. The plasma lactate concentration was elevated throughout the 18 and mostly the 10 degrees C immersion conditions. Throughout the 18 degrees C immersion study, the resting potassium level did not significantly vary, whereas at 10 degrees C, a significant potassium increase occurred soon and persisted throughout the study. Thus, total body immersion in cold water did not affect the global contractile properties of leg muscles during static efforts but elicited significant alterations in electromyographic events which may be related to the variations of interstitial fluid composition.

Splinting the degenerative basal joint: custom-made or prefabricated neoprene?

The purpose of this study was to compare the objective, subjective, and radiographic responses of patients with carpometacarpal joint osteoarthritis (CMCJ-OA) wearing a prefabricated neoprene splint (PFN), which crosses the CMCJ and metacarpophalangeal joint, with those of patients wearing a custom-made thermoplastic short opponens splint (CMT), which crosses only the CMCJ. Patients ( N = 25) with first CMCJ stage I and II osteoarthritis were assigned randomly to wear either the PFN splint or the CMT splint for one week. After one week, the subjects rated their function in the splint and their satisfaction and pain levels on visual analogue scales. Pinch measurements were performed and x-rays were taken to assess carpometacarpal subluxation. The second splint was then applied for one week and all measures were repeated. The subjects rated the PFN splint significantly higher, and most reported that they would choose the PFN splint over the CMT splint for daily and long-term use. Both pain and function were improved with splinting, but the effect was amplified with the PFN splint compared with the CMT splint. Both splints reduced subluxation at the first carpometacarpal joint, but the CMT effect was greater. This study further supports current evidence that subjects with stage I and II first CMCJ-OA will have pain relief with thumb splinting. In addition, the PFN splint will provide greater relief when compared with the CMT splint. Furthermore, this study reveals that patients prefer the PFN splint to the CMT splint.

Choosing the right glove for the right purpose

With the increase in the number of health-care workers developing allergies to natural rubber latex, knowing what alternative gloves can be used is becoming increasingly important. This article provides a guide to the various types of gloves available and their specific uses in health care.

A double-blinded randomized trial testing the tolerability and efficacy of a novel topical agent with and without occlusion for the treatment of cellulite: a study and review of the literature

Cellulite is the unsightly dimpling and nodularity frequently found on the thighs and buttocks of post-adolescent women. The anatomy and pathophysiology of this unwanted condition is poorly understood. The paucity of research studies to date has led to a dormancy of scientifically based therapeutic options that are effective and tolerable. The purpose of this study is to evaluate the tolerability and efficacy of a novel topical agent based on a plausible pathophysiologic mechanism in the treatment of cellulite, and to compare the efficacy of this agent used in combination with an occlusive bioceramic-coated neoprene garment, to the agent used alone without occlusion. We will also review the current understanding of the etiology and nature of cellulite and summarize available treatment options. Twenty women with a moderate degree of cellulite were entered into a four-week, double-blinded, randomized trial where an anti-cellulite cream was applied to the affected sites on a nightly basis. Each subject was randomized to receive occlusion by a bioceramic-coated neoprene garment on either the right or left leg, with the contralateral side serving as a control with no occlusion. High-quality digital photography was taken before treatment and after four weeks at various angles, with tangential full-spectrum lighting. Four blinded, independent dermatologist reviewers assessed the photographs for improvement. Subjects completed questionnaire forms to assess tolerability and efficacy. Of the 17 subjects who completed the study, 76% noticed an overall improvement in their cellulite, with 54% reporting greater improvement in the thigh that received garment occlusion. The average measured decrease in thigh circumference was 1.2 cm, noting a 1.3 cm reduction with occlusion and a 1.1 cm reduction without occlusion. Upon review of the pre- and post-study photographs, the dermatologist evaluators found an improvement in 65% of treated legs with occlusion, and 59% of treated legs without occlusion. Further, the evaluators found the occluded thighs to show greater improvement than the non-occluded thighs in 65% of subjects. The topical agent used in this study was found to be effective in reducing the appearance of cellulite. Bioceramic-coated neoprene garment occlusion potentiates the effect of this topical agent in cellulite reduction. The success of this study validates the pathophysiologic mechanism used to formulate the topical agent used.

Testing for viral penetration of non-latex surgical and examination gloves: a comparison of three methods

Currently, there are no international standards based on microbiological methodology for testing the ability of medical examination or surgical gloves to prevent the passage of viruses. Three protocols for the direct examination of the viral barrier properties of non-latex gloves were compared with 1080 gloves (270 gloves from each of two surgical brands and two medical examination brands). In two of the methods, gloves were filled with and suspended in a nutrient broth solution, and bacteriophage phiX174 was placed either inside or outside the glove, while the entire test vessel was agitated. Gloves tested using the third method were filled with a suspension of bacteriophage and allowed to rest in a vessel containing nutrient broth. Gloves were tested directly from the manufacturer's packaging, or after being punctured intentionally or subjected to a stress protocol. The passage of bacteriophage was detected with plaque assays. Significant differences in failure rates between glove brands were apparent only among gloves that had been subjected to the stress protocol. Overall, the two methods in which bacteriophage were placed inside the gloves provided more sensitivity than the method in which bacteriophage was spiked into broth outside the gloves. Thus the placement of bacteriophage inside test gloves (or the use of pressure across the glove barrier during testing), and the use of a standardised stress protocol, will improve significantly the ability of a glove test protocol to determine the relative quality of the barrier offered by medical examination and surgical gloves. Further research is needed to provide test methods that can incorporate reproducibly both the use of bacteriophage and simulated glove use in an industrial quality control setting.

Neoprene wet-suit hood affects low-frequency underwater hearing thresholds

INTRODUCTION

Psychophysical measures of wet-suit hood sound attenuation are needed to provide the diving community with guidance on protection from underwater sound.

METHODS

Underwater hearing thresholds were obtained from 15 male and 5 female recreational divers with and without a 3-mm thick wet-suit hood. Dives were conducted at a depth of 1 m in a large quiet anechoic pool. Thresholds were determined using a two-interval forced-choice procedure with a 0.71 probability of positive response at convergence. A 1-s pure tone was presented with a 20-ms rise and fall time at 100, 200, 250, 300, 400, and 500 Hz.

RESULTS

Without a wet-suit hood, mean thresholds decreased from 99 dB re 1 microPa at 100 Hz to 85 dB at 500 Hz. Thresholds were statistically similar at 100 to 300 Hz with and without the wet-suit hood, but were significantly increased at 400 and 500 Hz with the hood (p < 0.001).

CONCLUSIONS

In conclusion, at shallow depths, a 3-mm neoprene wet-suit hood attenuates underwater sound by approximately 10 dB for frequencies between 400 Hz and 500 Hz. At frequencies below 400 Hz, a 3-mm neoprene wet-suit hood offers no sound protection.

Quantification of prosthetic outcomes: Elastomeric gel liner with locking pin suspension versus polyethylene foam liner with neoprene sleeve suspension

For this randomized crossover trial, we compared two common transtibial socket suspension systems: the Alpha liner with distal locking pin and the Pe-Lite liner with neoprene suspension sleeve. Our original hypotheses asserted that increased ambulatory activity, wear time, comfort, and satisfaction would be found with the elastomeric suspension system. Thirteen subjects completed the study. Following 2.5-month accommodation to each condition, ambulatory activity was recorded (steps/minute for 2 weeks), and subjects completed three questionnaires specific to prosthesis use and pain: the Prosthesis Evaluation Questionnaire (PEQ), a Brief Pain Inventory (BPI) excerpt, and the Socket Comfort Score (SCS). Upon completion, subjects selected their favored system for continued use. Ten subjects preferred the Pe-Lite and three the Alpha. Subjects spent 82% more time wearing the Pe-Lite and took 83% more steps per day. Ambulatory intensity distribution did not differ between systems. No statistically significant differences were found in questionnaire results. Subject feedback for each system was both positive and negative.

Development of composite materials for non-leaded gloves for use in radiological hand protection

Lead is a hazardous material, and the U.S. Congress has mandated the rapid reduction of all hazardous waste generation as a matter of national policy. With the large amount of plutonium handling in numerous projects including the development of mixed oxide (MOX) fuel, 238Pu power sources, etc., hand glove protection for the emitted alpha, beta, and low energy photons is an important issue. Leaded gloves are the prime shields used for radiological hand protection. U.S. Department of Energy laboratories require a substitute material for the lead oxide in the gloves as a way to reduce mixed waste. To solve this problem, a new blend of non-hazardous materials that have the same radiological properties and approximately the same cost of production have been investigated. The investigations have produced alternative materials using calculations and experiments. The selection of the constituent compounds for the new composite materials was based on the k-absorption edge energy of the main constituent element(s) in the compounds. The formulations of these composites were fashioned on the principle of blending Neoprene rubber formulation with several constituent compounds. Calculations based on the Lambert-Beer attenuation law together with the mass attenuation coefficient values from the XCOM cross section database program were used to determine the transmission fractions of these proposed composite materials. Selected composite materials that compared favorably with the leaded-Neoprene were fabricated. These fabricated composite materials were tested with attenuation experiments and the results were in excellent agreement with the calculations using the Lambert-Beer attenuation law.

A laboratory-based study to assess the performance of surgical gloves

The inherent tear resistance and elasticity of latex and the touch sensitivity it provides has made it the traditional material of choice for surgical gloves, protecting both health care workers and patients from the transmission of bloodborne infections. Although increased incidence of latex allergy has led to increased use of nonlatex surgical gloves, the effectiveness of these gloves as a barrier to infection has not been examined thoroughly. This laboratory-based study compared the performance of latex and nonlatex surgical gloves in a simulated stress protocol. The propensity of surgical gloves to fail was dependent on glove material, manufacturer, and stress. Nonlatex neoprene and nitrile gloves were comparable to latex and can provide a good alternative to latex for allergic patients and health care workers. In this study, isoprene was found to be inferior to latex and other nonlatex materials. The presence or absence of glove powder had no significant influence on the probability of glove failure.

Determination of the effectiveness of materials in attenuating high frequency shock during gait using filterbank analysis

OBJECTIVE

To develop an accurate method for quantifying the frequency content of the ground reaction force transient.

DESIGN

Repeated measures design comparing the impact severity during walking with different insole materials.

BACKGROUND

The body experiences a brief but sizeable impact upon heel strike during walking. This impact transient is believed to result in musculoskeletal injuries. It is important to accurately quantify this impact as a step towards decreasing the risk of injury.

METHODS

Seven subjects walked barefoot at their normal cadence across a force platform, while insole materials (Spenco, Microcel-puff, and Plastazote) were placed on the surface of the force platform. A filterbank program was developed to determine the percent root mean square in 10 Hz frequency bands from zero to 400 Hz. Analysis focused on the impact transient contained in a 20 ms window after heel contact.

RESULTS

The high frequency (>60 Hz) power was significantly larger in the barefoot condition compared to the insole conditions. The barefoot condition also resulted in significantly higher initial peak forces and force loading rates.

CONCLUSIONS

The frequency content of the ground reaction force can be effectively quantified using a filterbank approach. Shoe insole materials can reduce the initial peak force, force loading rate, and frequency content of the impact transient in walking. The frequency content of the initial ground reaction force extends up to 400 Hz in some footwear conditions.

RELEVANCE

The new filterbank procedure illustrates that the vertical ground reaction force in walking has a higher frequency content than previously thought. This signal requires high sampling rates to avoid aliasing, and appropriate signal processing algorithms, such as filter banks, for analysis.

The effect of bracing on proprioception of knees with anterior cruciate ligament injury

This paper is a comprehensive review on the effect of bandaging, bracing, and neoprene sleeves on knee proprioception following anterior cruciate ligament (ACL) injury and reconstruction with a focus on studies that have measured joint position sense and threshold to detection of passive knee motion. Disruption of the ACL does not appear to alter joint position sense soon after injury, although there is evidence that in some subjects deterioration may occur over time. An ACL tear creates a deficit in the threshold to detection of passive knee motion soon after injury and in those with chronic tears. The magnitude of worsening is less then 1.0 degree of movement in flexion-extension and of questionable concern from a clinical and functional perspective. Application of a functional brace or neoprene sleeve to the ACL-deficient limb does not improve the threshold to detection of passive knee motion; however, application of an elastic bandage to a knee with an ACL tear improves joint position sense. Reconstruction of a torn ACL is associated with a deficit in the threshold to detection of passive knee motion, and during the first year of healing the use of a neoprene sleeve provides improvement. Two years following ACL reconstruction there is no deficit in the threshold to detection of passive knee motion and the use of a brace has no effect on this outcome.

Effects of exposure time, material type, and granular pesticide on glove contamination

Chemical-resistant gloves are recommended for pesticide applicators to reduce their exposure to agricultural chemicals. In this research, three chemical-resistant glove materials-nitrile, neoprene, and barrier laminate-were studied in relation to contamination with granular terbufos and tefluthrin. Surfaces of specimens backed with alpha cellulose were contaminated with 300 mg of either granular terbufos or tefluthrin for 1-, 2-, 4-, 8-, 16-, and 24-h time periods in petri dishes in the laboratory. Residues were extracted using ethyl acetate for terbufos and iso-octane for tefluthrin in test tubes for 24 h. Analysis of extracts by gas chromatograph and statistical analysis of the data showed that contamination levels varied with the time of exposure, material type, and pesticide used. Pesticide was not detected in the alpha cellulose even after 24 h contamination time. A linear relationship was found between contamination level and exposure time for terbufos in the three materials, with longer exposure times causing higher contamination levels. Contamination of nitrile was significantly less than neoprene or barrier laminate. Exposed glove materials contained higher levels of contamination of terbufos than tefluthrin.

MCPA permeation through protective gloves

Permeation of 4-chloro-2-methylphenoxyacetic acid (MCPA) in commercial herbicide formulations through common protective glove types was evaluated to aid in the selection of appropriate skin protection. The ASTM test method F739-91 was used to measure the permeation of two undiluted formulations, one containing a salt, and the other an ester form of MCPA. The four glove types tested were natural rubber, neoprene 73, nitrile 37-145, and Viton-coated chloroprene. Triplicate tests of each combination of formulation and glove material were conducted. Permeation cells with a 0.01 M sodium hydroxide collection medium were used for the experiments. Aliquots of the collection medium were withdrawn at regular intervals and acidified, and quantification of the free acid was achieved using HPLC-UV (230 nm). There was no appreciable permeation of the salt formulation over a 24-hour test period. For the ester formulation, the following mean steady-state permeation rate (microg x cm(-2) min(-1)) and mean lag time (hours), respectively, were measured: Viton (0.06, 17.8), natural rubber (0.08, 15.4), neoprene 73 (0.21, 15.1), and nitrile (0.04, 24.2). Permeation was associated with significant swelling, averaging a nearly 30 percent increase from the pre-immersion thickness. All four glove types provide adequate protection against permeation by the salt formulation and at least eight-hour protection against the ester formulation. Given the greater permeation of the ester formulation, the salt formulation of MCPA herbicide should be used whenever possible.

[Tension force in dynamic splints made of neoprene]

Dynamic splints are the most difficult ortheses to make. Unrestricted finger joint mobility is usually prevented by the size of their components. Ortheses made out of neoprene material have the advantage of being pliable and at the same time can be constructed as dynamic splints. Neoprene material elasticity allows conforming it into a tube that can be fitted over a finger, spreading uniform pressure. A traction slip can be cemented to the neoprene finger tube. With neoprene splints, lever arms are more efficient. Their tubular design applies and spreads traction and countertraction forces in all directions. Neoprene material's elasticity contributes in reducing edema formation as well as distributes forces applied to the finger over a large area. The risk of excessive pressure is the only drawback of an elastic tubular design, it may cause pain and tissue ischemia. A meticulous tailoring prevents this potential risk.

Failure of glove hole detection device for synthetic gloves

Holes in latex gloves can be reliably detected by commercially available electronic devices. The purpose of this study was to compare the performance of an electronic glove hole detection device using latex gloves to that of neoprene, vinyl, and nitrile latex-free gloves. The electronic hole detection device accurately detected holes in the latex gloves during the 2-h study. In contrast, the latex-free gloves were immediately conductive of electricity in the absence of holes. Consequently, electronic glove hole detection devices cannot be reliably used with latex-free gloves.