Association of betel nut chewing with exercise performance in a military male cohort: the CHIEF study.

INTRODUCTION: Betel nut chewing may cause obesity, neurohormonal activation and inflammation, possibly impairing exercise performances. METHODS: We examined the cross-sectional association in 4388 military male adults aged 18-50 years from the cardiorespiratory fitness in armed forces study in Taiwan between 2013 and 2014. The status of betel nut chewing was classified as current and former/never based on each participant's response to a questionnaire. Physical fitness was evaluated by three basic exercise tests including 3000 m running, 2 min sit-ups and 2 min push-ups. Multiple logistic regression for the best 10% and the worst 10% performers in each exercise, and linear regression were used to determine the relationship. RESULTS: There were 564 current chewers and 3824 non-current chewers for the analysis. The linear regression shows that current betel nut chewing was positively correlated with 3000 m running duration (r=0.37, p=0.042) after adjusting for age, service specialty, body mass index, exercise frequency and alcohol intake. In addition, the logistic regression shows that as compared with non-current chewers, current chewers had lower odds of being the top 10% performers in 2 min push-ups and higher odds of being the bottom 10% performers in 2 min sit-ups (ORs and 95% CIs: 0.71 (0.50 to 0.99) and 1.32 (1.00 to 1.75), respectively). However, the associations between betel nut chewing and physical fitness were all insignificant after further adjusting for current smoking. CONCLUSIONS: Our findings suggest that the impairment of physical fitness associated with betel nut chewing of military young men might be mainly mediated or moderated by the coexisted cigarette smoking.

Dynamic intracellular delivery of antibiotics via pH-responsive polymersomes.

Reversible addition-fragmentation chain transfer (RAFT) polymerization was employed to prepare a series of copolymers consisting of 2-hdroxyethyl methacrylate (HEMA) and poly(ethylene glycol) methyl ether methacrylate (FWavg ~ 950 Da) (O950) with variable comonomer compositions and molecular weights for use as polymeric scaffolds. Reactivity ratios for the monomer pair were determined to be 1.37 and 0.290 respectively. To these scaffolds trithiocarbonate-based RAFT chain transfer agents (CTAs) were grafted using carbodiimide chemistry. The resultant graft chain transfer agents (gCTA) were subsequently employed to polymerize dimethylaminoethyl methacrylate (DMAEMA) and (HPMA) between degrees of polymerization (DP) of 25 and 200. Kinetic analysis for the polymerization of DMAEMA targeting a DP of 100 from a 34 arm graft gCTA show linear Mn conversion and pseudo first order rate plots with narrow molecular weight distributions that move toward lower elution volumes with monomer conversion. D values for these polymerizations remain low at around 1.20 at monomer conversions as high as 70 %. pH-responsive endosomalytic brushes capable of spontaneously self-assembling into polymersomes were synthesized and a combination of dynamic light scattering (DLS), cryoTEM, and red blood cell hemolysis were employed to evaluate the aqueous solution properties of the polymeric brush as a function of pH. Successful encapsulation of ceftazidime and pH-dependent drug release properties were confirmed by HPLC. Intracellular antibiotic activity of the drug-loaded polymersomes was confirmed in a macrophage coculture model of infection with B. thailandensis and RAW 264.7 cells.

Well-defined single polymer nanoparticles for the antibody-targeted delivery of chemotherapeutic agents.

Aqueous reversible addition-fragmentation chain transfer (RAFT) polymerization was employed to prepare a series of linear copolymers of N,N-dimethylacrylamide (DMA) and 2-hydroxyethylacrylamide (HEAm) with narrow D values over a molecular weight range spanning three orders of magnitude (103 to 106 Da). Trithiocarbonate-based RAFT chain transfer agents (CTAs) were grafted onto these scaffolds using carbodiimide chemistry catalyzed with DMAP. The resultant graft chain transfer agent (gCTA) was subsequently employed to synthesize polymeric brushes with a number of important vinyl monomer classes including acrylamido, methacrylamido, and methacrylate. Brush polymerization kinetics were evaluated for the aqueous RAFT polymerization of DMA from a 10 arm gCTA. Polymeric brushes containing hydroxyl functionality were further functionalized in order to prepare 2nd generation gCTAs which were subsequently employed to prepare polymers with a brushed-brush architecture with molecular weights in excess of 106 Da. These resultant single particle nanoparticles (SNPs) were employed as drug delivery vehicles for the anthracycline-based drug doxorubicin via copolymerization of DMA with a protected carbazate monomer (bocSMA). Cell-specific targeting functionality was also introduced via copolymerization with a biotin-functional monomer (bioHEMA). Drug release of the hydrazone linked doxorubicin was evaluated as function of pH and serum and chemotherapeutic activity was evaluated in SKOV3 ovarian cancer cells.

Effect of temperature on leg kinematics in sprinting tarantulas (Aphonopelma hentzi): high speed may limit hydraulic joint actuation.

Tarantulas extend the femur-patella (proximal) and tibia-metatarsal (distal) joints of their legs hydraulically. Because these two hydraulically actuated joints are positioned in series, hemolymph flow within each leg is expected to mechanically couple the movement of the joints. In the current study, we tested two hypotheses: (1) at lower temperatures, movement of the two in-series hydraulic joints within a leg will be less coupled because of increased hemolymph viscosity slowing hemolymph flow; and (2) at higher temperatures, movement of the two in-series hydraulic joints will be less coupled because the higher stride frequencies limit the time available for hemolymph flow. We elicited maximal running speeds at four ecologically relevant temperatures (15, 24, 31 and 40°C) in Texas Brown tarantulas (Aphonopelma hentzi). The spiders increased sprint speed 2.5-fold over the temperature range by changing their stride frequency but not stride length. The coefficient of determination for linear regression (R(2)) of the proximal and distal joint angles was used as the measure of the degree of coupling between the two joints. This coupling coefficient between the proximal and distal joint angles, for both forelegs and hind-legs, was significantly lowest at the highest temperature at which the animals ran the fastest with the highest stride frequencies. The coordination of multiple, in-series hydraulically actuated joints may be limited by operating speed.