Issues and options in addressing the environmental consequences of livestock sector’s growth

The growth of the livestock sector is being achieved at substantial environmental costs. Today, livestock are a major stressor of the global environmental, occupying a quarter of emerged land (including a third of arable land), contributing close to a fifth of the anthropogenic greenhouse gas emissions, using eight percent of all water resources and threatening a wide range of endangered species. At the same time, livestock are also a crucial engine of rural growth and a tool for improving food security. Policies are required to guide the sector in achieving sometimes conflicting development objectives. Potential pathways include encouraging resource use efficiency, correcting for environmental externalities and accelerating technological change.     

Unsteady Flow Predictions of Initial Surface Formation in Aluminum Strip Casting

A comprehensive multidomain computational fluid dynamics model is described for examining the unsteady thermal-fluid dynamic conditions at the early onset of surface formation in aluminum strip casting. By employing zones for the solidifying melt, substrate, high-speed water jets, and active film for thermal buffering between the melt and the substrate, a fully implicit in time solution is obtained. Furthermore, the melt domain transport equations are cast in an Eulerian–Lagrangian form to include the motion of a backward-facing compliant step and its associated contact line, both affecting the initial melt–substrate contact cooling conditions. The influence of the compliant step motion on the thermal-fluid history at the earliest stages of surface formation is examined. Results show a well-defined characteristic response between the contact line motion and the solid fraction/temperature history. Associated recirculation cells are affected profoundly by contact line motion and exhibit cyclical removal and reappearance. Coupled with large relative velocity between phases at the contact line, overall flow patterns suggest conditions for alloy segregation.     

Reporting risks and benefits of therapy by use of the concepts of unqualified success and unmitigated failure: applications to highly cited trials in cardiovascular medicine

BACKGROUND: The NNT (number needed to treat) and NNH (number needed to harm) are useful in conveying the results of clinical trials because they emphasize the effort that must be expended to accomplish a single, tangible outcome. But NNT conveys the effort required to achieve a positive outcome without distinguishing between the presence or absence of treatment-related adverse events. Similarly, NNH conveys harm without accounting for the achievement or lack of achievement of the benefit of therapy. Consequently, a mathematical model was developed to extend the NNT and NNH to represent the effort required to achieve "unqualified success" (NNTUS, treatment success without treatment-induced side effects) and "unmitigated failure" (NNHUF, lack of treatment success with treatment-induced side effects). METHODS AND RESULTS: NNTUS was calculated by adjusting the absolute risk reduction to allow for the probability of not incurring a treatment-related adverse event. NNHUF was similarly calculated by adjusting the absolute risk of incurring a treatment-related adverse event by the probability of not incurring any treatment-related benefit. The impact of conveying clinical trial data by the use of NNT, NNTUS, NNH, and NNHUF is illustrated by means of 11 highly cited trials identified systematically from the cardiovascular literature. The treatment effort measured by the NNTUS and the NNHUF was consistently higher than that given by the traditional NNT and NNH. These increments ranged from 1% to several hundred percent. CONCLUSIONS: The NNTUS and the NNHUF represent the treatment effort required on average to achieve 1 unqualified success and 1 unmitigated failure. NNTUS and NNHUF balance benefit and harm in an objective way and are relevant for making service delivery decisions.     

A comparison of forearm and thumb muscle electromyographic responses to the use of laparoscopic instruments with either a finger grasp or a palm grasp

Laparoscopic techniques allow for less-invasive treatment of common surgical problems. Laparoscopic instruments are different from standard surgical instruments and generally incorporate a pistol-grip handle configuration with rings for the fingers. This handle configuration has been reported as being uncomfortable, leading to finger compression neuropathies in some cases. As an alternative, the surgeon can choose to grasp laparoscopic instruments using a more powerful palm grip during grasping motions. This study evaluates the hypothesis that the use of the palm grip requires less muscle tension than the finger-grip when grasping with laparoscopic instruments. Nine general surgeons used an Autosuture laparoscopic grasper with a ringed pistol-grip handle held in both a finger-in-ring (F) or palm (P) hand grip position to grasp and close two spring-loaded metal plates. The same task was performed with a surgical haemostat clamp (H) for comparison. Each subject performed the grasping task in a random sequence for the three instrument configurations at two grasping forces levels (0.7 and 4.2 N), and with the instrument at three angles to the subjects' sagittal plane (0 degree, 45 degrees and 90 degrees). Surface electromyographic (EMG) signals were acquired from the flexor carpi ulnaris (FCU), flexor digitorum profundus (FDP), flexor digitorum superficialis (FDS), extensor carpi ulnaris (ECU), extensor digitorum comunis (EDC) and the thenar compartment (TH). The peak root mean squared (RMS) EMG voltage was averaged for five repetitions at each instrument, force and angle condition. Statistical analysis was carried out by repeated measures ANOVA. The muscle EMG RMS amplitude while using the palm grip was decreased in the FDS, TH and EDC, was unchanged in the ECU and FCU, and was slightly higher in the FDP when compared with the finger grip. These differences were most prominent at 90 degrees to the sagittal plane where the subjects' wrists neared maximal flexion. It is concluded that the palm grip is more powerful than the finger grip when grasping with laparoscopic instruments, particularly at angles perpendicular to the surgeon's sagittal plane.     

Phosphatidylinositol 3-kinase is required for CD28 but not CD3 regulation of the TEC family tyrosine kinase EMT/ITK/TSK: functional and physical interaction of EMT with phosphatidylinositol 3-kinase

Ligation of the TCR or CD28 induces activation of phosphatidylinositol 3-kinase (PI3K), the TEC family protein tyrosine kinase, EMT/ITK/TSK (EMT), and the SRC family tyrosine kinase, LCK. LCK is required for the activation and phosphorylation of EMT induced by ligation of the TCR or CD28 placing LCK upstream of EMT in T cell signaling cascades. We report herein that inhibition of PI3K activity with the specific inhibitors LY294002 and wortmannin markedly decreased EMT activation induced by CD28 cross-linking but not by CD3 cross-linking. Further, inhibition of PI3K markedly decreased EMT in vitro autokinase activity induced by activated LCK. In contrast, PI3K inhibitors did not alter CD28 or CD3 cross-linking or LCK-induced EMT phosphorylation. Consistent with the requirement of PI3K activity for CD28 but not CD3-induced stimulation of the EMT in vitro autokinase activity, a small but significant portion of cellular EMT associates with PI3K following CD28 cross-linking but not following CD3 cross-linking. CD28-induced association of EMT with PI3K also requires functional expression of LCK. Fusion proteins containing the SRC homology 2 domain of EMT interact with PI3K or a PI3K-associated molecule in a tyrosine phosphorylation-dependent manner. Taken together, the data suggest that EMT is differentially regulated and recruited to different signaling complexes following ligation of CD28 or the TCR complex, perhaps contributing to the disparate roles that EMT appears to play downstream of CD28 and the TCR.     

The envelope glycoprotein ectodomains determine the efficiency of CD4+ T lymphocyte depletion in simian-human immunodeficiency virus-infected macaques

CD4+ T lymphocyte depletion in human immunodeficiency virus type 1 (HIV-1)-infected humans underlies the development of acquired immune deficiency syndrome. Using a model in which rhesus macaques were infected with chimeric simian-human immunodeficiency viruses (SHIVs), we show that both the level of viremia and the structure of the HIV-1 envelope glycoprotein ectodomains individually contributed to the efficiency with which CD4(+) T lymphocytes were depleted. The envelope glycoproteins of recombinant SHIVs that efficiently caused loss of CD4(+) T lymphocytes exhibited increased chemokine receptor binding and membrane-fusing capacity compared with those of less pathogenic viruses. These studies identify the HIV-1 envelope glycoprotein ectodomains as determinants of CD4(+) T lymphocyte loss in vivo and provide a foundation for studying pathogenic mechanisms.     

IL-5 is required for eosinophil recruitment, crystal deposition, and mononuclear cell recruitment during a pulmonary Cryptococcus neoformans infection in genetically susceptible mice (C57BL/6)

CBA/J (highly resistant), BALB/c (moderately resistant), and C57BL/6 (susceptible) mice displayed three resistance patterns following intratracheal inoculation of Cryptococcus neoformans 52. The inability to clear the infection correlated with the duration of the eosinophil infiltrate in the lungs. The role of IL-5 in promoting the pulmonary eosinophilia and subsequent inflammatory damage in susceptible C57BL/6 mice was investigated. C57BL/6 mice developed a chronic alveolar, peribronchiolar, and perivascular eosinophilia following C. neoformans infection. This resulted in the accumulation of intracellular Charcot-Leyden-like crystals in alveolar macrophages by wk 4 and the extracellular deposition of these crystals in the bronchioles with associated destruction of airway epithelium by wk 6. IL-5 mRNA was expressed in the lungs, and injections of anti-IL-5 mAb prevented eosinophil recruitment and crystal deposition but did not alter cryptococcal clearance. Depletion of CD4+ T cells (but not CD8+) ablated IL-5 production by lung leukocytes in vitro and eosinophil recruitment in vivo. Neutralization of IL-5 also inhibited the recruitment of macrophages, CD8+ T lymphocytes, and B lymphocytes by 47 to 57%. Anti-IL-5 mAb inhibited CD4+ T lymphocyte recruitment by 30% but did not affect neutrophil recruitment. Thus, the development of a chronic eosinophil infiltrate in the lungs of C. neoformans-infected C57BL/6 mice is a nonprotective immune response that causes significant lung pathology. Furthermore, IL-5 promotes the recruitment and activation of eosinophils, resulting in the recruitment of additional macrophages and lymphocytes into the lungs.     

Radiofrequency and cryoablation of atrial fibrillation in patients undergoing valvular operations

BACKGROUND: Previous studies have shown that the maze operation can restore sinus rhythm and atrial transport function in patients with chronic atrial fibrillation. The purpose of this study was to test the feasibility of the application of radiofrequency and cryoablation as an alternative to the classic maze operation. METHODS: Twelve patients undergoing mitral valve procedures were included in this study. Radiofrequency and cryoablation were applied to create lesions in both atria to simulate the classic maze operation. RESULTS: There were two surgical deaths. At the mean follow-up of 10.25 months for the remaining 10 patients; 6 were in sinus rhythm, 2 in atrial rhythm, 1 in paroxysmal atrial tachycardia, and 1 in atrial fibrillation. Doppler echocardiography at 6-month follow-up showed emergence of biatrial transport function in 3 patients and right atrial contractility in 8. At 12-month follow-up of 5 patients, Doppler echocardiography showed biatrial transport function in 3 and right atrial contractility in 4. CONCLUSIONS: Our modified maze procedure during valvular operation is effective for achieving an acceptable success rate to restore sinus rhythm and atrial transport function in patients with chronic atrial fibrillation.