407 research outputs found

    Ocular hypotensive effect of fixed-combination brinzolamide/brimonidine adjunctive to a prostaglandin analog: a randomized clinical trial

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    To determine whether intraocular pressure (IOP) lowering with fixed-combination brinzolamide/brimonidine (BBFC) adjunctive to a prostaglandin analog (PGA) was superior to that of vehicle+PGA in patients with open-angle glaucoma or ocular hypertension who were inadequately controlled with PGA monotherap

    Limitations of biosurfactant strength produced by bacteria

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    Biosurfactants which reduce the surface or interfacial tension of liquids and act as emulsifiers, foaming and dispersing agents with low toxicity, are finding increasing applications in biotechnology and driving the search for novel compounds for further exploitation. Potential biosurfactants sourced from bacteria are often selected first by qualitative assessment of surface tension using simple assays such as the drop collapse technique or by quantitative tensiometry measuring air-liquid interfacial tension of cell-free culture supernatants or purified samples, and subsequently tested for appropriate physicalchemical behaviours using a range of application-specific assays. Highly active or strong biosurfactants have been reported to reduce the surface tension of water to approximately 22 – 25 mN.m-1, and show a range of behaviours determined by the choice of conditions (temperature, pH, salt concentration, etc.) used to test particular aqueous-hydrophobic (oil) mixtures. However, recent analyses of biosurfactant strengths using a predictive statistical approach (Individual distribution identification) have shown that it is unlikely that new compounds will be identified able to significantly reduce aqueous surface tensions below 24 mN.m-1. The mechanistic basis of this limit requires an explanation of why stronger compounds are not produced by bacteria, with a limitation of self-harm to producing cells probably the most likely biophysical explanation. However, behavioural analyses using a combination of emulsion, foam stability and oil-dispersion assays indicates high chemical diversity exists amongst biosurfactants exhibiting the strongest levels of activity (24 – 28 mN.m-1), suggesting that bacteria are still likely to provide a rich source of potentially novel compounds for use in biotechnology

    Physiological and Biomechanical Differences Between Seated and Standing Uphill Cycling

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    International Journal of Exercise Science 13(2): 996-1011, 2020. Despite differences in economy, cyclists climb in seated and standing positions. Prompted by gaps in research, we compared VO2 and heart rate (HR) (Study 1), muscle activation (Study 2) and breathing and pedaling entrainment (Study 3). METHODS: Subjects rode their bicycles on a treadmill in seated and standing positions. In Study 1, VO2 and HR of four male cyclists (21.3 ± 1.7 yrs; 69.1 ± 6 ml/kg/min) were collected, alternating positions every 5 minutes for 20 minutes (8 mph, 8% grade). In Study 2, muscle activations of eight male cyclists (24 ± 5 yrs, 67.6 ± 5.5 ml/kg/min) were collected on Rectus Femoris (RF), Biceps Femoris, Vastus Medialis (VM) and Gastrocnemius alternating positions every minute (8 mph, 8% grade). In Study 3, flow rate and entrainment of nine male cyclists (28 ± 7 yrs, 62.7 ± 7.7 ml/kg/min) were collected in 2-minute stages at 6, 8 and 10 mph, (8% grade) alternating positions every minute. RESULTS: VO2 and HR increased standing (3.17± 0.43 L/min, 175 ± 4 bpm) compared to seated (3.06 ± 0.37 L/min, 166 ± 5 bpm) (p \u3c 0.05). Normalized EMG for RF and VM increased standing (47 ± 5%, 57 ± 15%) compared to seated (34 ± 3%, 36 ± 8%) (p \u3c 0.05). Peak Inspiratory and Expiratory Flow increased standing (3.44±0.07 and 2.45±0.05 L/sec) compared to seated (3.09 ±0.06 and 2.21±0.04 L/sec) (p \u3c 0.05). CONCLUSION: Uphill cycling while standing results in decreased cycling economy due to physiological and biomechanical variations compared to riding seated
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