High statistics measurement of the K+-->pi0e+nu (K+e3) branching ratio

E865 at the Brookhaven National Laboratory AGS collected about 70 000 K(+)(e3) events to measure the K(+)(e3) branching ratio relative to the observed K+-->pi(+)pi(0), K+-->pi(0)micro(+)nu, and K+-->pi(+)pi(0)pi(0) decays. The pi(0) in all the decays was detected using the e(+)e(-) pair from pi(0)-->e(+)e(-)gamma decay and no photons were required. Using the 2002 Particle Data Group branching ratios for the normalization decays, we obtain BR(K(+)(e3(gamma)))=(5.13+/-0.02(stat)+/-0.09(syst)+/-0.04(norm))%, where K(+)(e3(gamma)) includes the effect of virtual and real photons. This result is approximately 2.3sigma higher than the current Particle Data Group value. Implications for the V(us) element of the CKM matrix, and the matrix's unitarity are discussed.

Experimental study of the radiative decays K+-->mu(+)nue(+)e(-) and K+-->e(+)nue(+)e(-)

Experiment 865 at the Brookhaven Alternating Gradient Synchrotron obtained 410 K+-->e(+)nue(+)e(-) and 2679 K+-->mu(+)nue(+)e(-) events including 10% and 19% background. The branching ratios were measured to be [2.48+/-0.14(stat)+/-0.14(syst)]x10(-8) (m(ee)>150 MeV) and (7.06+/-0.16+/-0.26)x10(-8) (m(ee)>145 MeV), respectively. Results for the decay form factors are presented.

New measurement of K(+)(e4) decay and the s-pave pi pi-scattering length a(0)(0)

A sample of 4 x 10(5) events from the decay K(+)-->pi(+)pi(-)e(+)nu(e) (K(e4)) has been collected in experiment E865 at the Brookhaven Alternating Gradient Synchrotron. The analysis of these data yields new measurements of the K(e4) branching ratio [(4.11+/-0.01+/-0.11) x 10(-5)], the s-wave pi pi scattering length [a(0)(0) = 0.216+/-0.013(stat)+/-0.004(syst)+/-0.005(theor)], and the form factors F, G, and H of the hadronic current and their dependence on the invariant pi pi mass.

Search for lepton flavor violation in K+ decays into a charged pion and two leptons

A search for lepton flavor violating decays, K+ --> mu+ mu+ pi-, K+ --> e+ e+ pi-, K+ --> pi+ e+ mu-, K+ --> mu+ e+ pi-, and pi0 --> e+ mu-, was performed using the data collected in Experiment E865 at the Brookhaven Alternating Gradient Synchrotron. No signal was found in any of the decay modes. At the 90% confidence level, the branching ratios are less than 3.0x10(-9), 6.4x10(-10), 5. 2x10(-10), 5.0x10(-10), and 3.4x10(-9), respectively.

Improved limit on the rate of the decay K+ --> pi(+)&mgr;(+)e(-)

We report results of a search for the lepton-family number violating decay K+-->pi(+)&mgr;(+)e(-) from data collected by experiment E865 in 1996 at the Alternating Gradient Synchroton of Brookhaven National Laboratory. We place an upper limit on the branching ratio at 3.9x10(-11) ( 90% C.L.). Together with results based on data collected in 1995 and an earlier experiment, E777, this result establishes a combined 90% confidence level upper limit on the branching ratio at 2.8x10(-11). We also report a new upper limit on the branching ratio for pi(0)-->&mgr;(+)e(-) of 3.8x10(-10) ( 90% C. L.).

New measurement of the rare decay K+ --> pi(+)&mgr;(+)&mgr;(-)

More than 400 K+-->pi(+)&mgr;(+)&mgr;(-) events were observed in a rare K+ decay experiment at the Brookhaven Alternating Gradient Synchrotron. Normalized to the K+-->pi(+)pi(+)pi(-) decay, the branching ratio is determined to be [9.22+/-0.60(stat)+/-0. 49(syst)]x10(-8). This branching ratio and the &mgr;&mgr; mass spectrum is in very good agreement with the measurement of the K+-->pi(+)e(+)e(-) decay, but deviates significantly from the previous measurement.

Time-dependent changes in norepinephrine-induced left ventricular dysfunction and histopathologic condition

BACKGROUND

Intense activation of the sympathetic nervous system or administration of high concentrations of catecholamines diminishes myocardial contractility and produces infarct-like lesions throughout the heart. This study was conducted to determine whether norepinephrine-induced left ventricular (LV) dysfunction reverses with time and whether the histopathologic condition and the cardiac dysfunction produced by high doses of norepinephrine are causally related.

METHODS

Norepinephrine, 10 microg bolus followed by 2.5 microg/kg/min for 90 minutes, was administered to conscious New Zealand white rabbits. Control rabbits (n=8) received saline solution. LV function was evaluated either immediately (n=7), on day 4 (n=8), or on day 10 (n=7) after norepinephrine treatment. Transverse sections from the left ventricle were then prepared for light microscopic study.

RESULTS

Animals studied immediately after norepinephrine treatment demonstrated severe LV dysfunction and a decrease in global LV compliance. In contrast, LV function and compliance were normal in rabbits studied on day 4, but tissue sections from the left ventricle showed diffuse areas of inflammation. By day 10 the inflammatory process had progressed, and substantial collagen deposition had occurred. LV systolic function was normal, but a decrease in LV compliance was evident at this time.

CONCLUSIONS

The normal LV systolic function on days 4 and 10 in spite of multiple foci of inflammation suggests (1) that norepinephrine-induced LV systolic dysfunction is reversible and (2) that the histologic derangements and the LV dysfunction are not causally related.

Trisomy 8 is a characteristic finding in pleuropulmonary blastoma

The cytogenetic findings in pleuropulmonary blastoma (PPB) have not been widely studied and reported and are of interest in view of the implications that PPB has for additional tumors in the patient and the patient's relatives. Using standard tumor cytogenetic methodology, we investigated three cases of PPB encountered in our institution over a 5-year period. Trisomy 8 was the only karyotypic abnormality in a localized type 2 PPB and was present with other abnormalities in another type 2 PPB and a massive type 3 PPB. Review of the literature yielded three additional karyotyped PPBs; all had trisomy 8 as part of the abnormalities detected. Trisomy 8 appears to be a characteristic of PPB and may be related to the development of PPB and related tumors.

Selected sperm differ from nonselected cells in their electrophoretic mobility (EPM) after demembranation

Human semen samples were first treated by swim-up migration or by Percoll density gradient centrifugation for selection of spermatozoa. The net surface charges of spermatozoa in the resulting compartments were indirectly evaluated by the electrophoretic mobility (EPM) during spermatozoal microelectrophoresis. Significantly different electrophoretic mobilities were measured between the compartments after demembranation with 0.1% (v/v) Triton X-100. However, without intermediate treatment by the detergent no significant differences were detected between the spermatozoal EPM. In addition, spermatozoa were divided into migrated and nonmigrated spermatozoal populations by the swim-up technique, and then treated with urea to remove spermatozoal coats. No significant differences in EPM were detected between these two groups. This investigation demonstrates that selected spermatozoa from semen exhibit an additional dimension of superiority, in EPM, to nonselected spermatozoa, which may better equip them for the process of fertilization. Measurements of EPM, therefore, may provide yet another, perhaps valid, means of developing a clinical tool for evaluating the potential fertilizing capacity of a semen sample in infertility studies.

Influence of cryopreservation on the microelectrophoretic motility (EPM) of human spermatozoa

The net surface charge of spermatozoa represents a characteristic of the plasmamembrane. It can be evaluated indirectly, by the measurement of the sperm electrophoretic motility (EPM). The EPM of washed human spermatozoa was determined in the microelectrophoresis to investigate three problems: (a) intra- and interindividual variation coefficients of EPM of cryopreserved spermatozoa, (b) effects of cryopreservation medium, temperature shock and cryoprotection on the EPM, (c) relationship between the EPM and the cryotolerance of the spermatozoa. The inter- and intrain-dividual variation coefficients of the sperm EPM of 24 cryopreserved semen samples of 6 fertile semen donors amounted to 7% and to 6%, respectively. The cryopreservation did not cause a significant change of sperm EPM in contrast to the temperature shock in liquid nitrogen. Temporary incubation of spermatozoa with egg yolk decreased their EPM. A significant correlation between EPM and the cryotolerance ascertained by the alteration of sperm motile efficiency could be found. After contact with egg yolk spermatozoa achieved a behaviour that corresponded to a better cryotolerance.

Exclusion of poly(ethylene glycol) from liposome surfaces

The electrophoretic mobility of vesicles is measured for concentrations of poly(ethylene glycol) from 0 wt.% to 10 wt.%. Mixtures of phosphatidylcholines and phosphatidic acid are used. The zeta potential calculated from the electrophoretic mobility and the viscosity of the suspension becomes more negative for all vesicles studied. Binding of poly(ethylene glycol) to the phospholipid surface by addition of the poly(oxyethylene)-containing surfactant C12E8 has the opposite effect and a decrease of the zeta potential is observed. Independent measurements of the surface potential of the vesicles in the presence of PEG by use of a positively charged spin probe and ESR spectroscopy and a fluorescent pH indicator and fluorescence spectroscopy show that actually the surface potential is not changed. A theory of the electrophoretic behaviour of vesicles in the presence of PEG is given which explains the contradiction between the two methods. It is assumed that the polymer is excluded from the vesicle surface (depletion layer) and that the viscosity near the surface is lower than the viscosity in the bulk phase. The thickness of the depletion layer is calculated from the experiments. The decrease of the zeta potential in the presence of poly(oxyethylene) chains linked to the vesicle surface results from the friction increase.

[Rate of evaporation of tear fluid in the human compared with a physical model]

Evaporation of tears occurs by diffusion, free (thermal), and forced convection. Under resting conditions only diffusion and free convection play a role. Therefore, a device should be applied with only these two parameters working. Creating a stationary known pressure gradient of water vapor over the eye, the evaporation rate was found to be 24.8 +/- 6.8 mg cm-2 h-1 in 21 test persons (no spectacle or contact lens wearers, no known general or eye disease, average age 25.6 years). The same test arrangement over a water surface of 1.7 cm2 gave a value of 43 mg cm-2 h-1 and simplified calculation, applying Fick's law of diffusion, 54 mg cm-2 h-1. These results suggest that there is a water vapor pressure of less than half the saturation water vapor pressure of less than half the saturation water vapor pressure corresponding to 32 degree C over the surface of the eye. Calculation yields a value of 230 mg per eye per 16 hours, corresponding to 32 degrees C (50% air humidity) over the surface of the eye and 22 degrees C (50% air humidity) room temperature. Assuming a tear secretion of 0.6 g per eye per 16 hours (Schirmer), about 40% of this amount evaporates under normal conditions.

Skin and core temperatures as determinants of heat production and heat loss in the goat

In 82 experiments on 10 goats body core temperature (Tcore) was altered between 35 degrees and 42 degrees C by external heat exchangers acting on blood temperature while skin temperature (Tskin) was maintained constant, by a circulating shower bath, at different levels between 32 degrees and 44 degrees C. At all skin temperatures at least fourfold increases of heat production (M) and respiratory evaporative heat loss (REHL) occurred when Tcore was lowered or raised, respectively. The lower Tskin was, the higher were the thresholds of Tcore, at which M or REHL exceeded resting levels. The lower Tskin was, the higher were the slopes, at which M or REHL changed per unit of Tcore. At a given Tskin, the slopes decreased with increasing M or REHL, and were dependent on the range of Tcore. The higher the range of Tcore, the steeper changed M and REHL with changing Tcore, if all other variables were held constant. The results support the concept that an exponential relationship between Tcore and the rate of core temperature signals is the primary cause of the effects exerted by Tskin on the slopes, at which M or REHL change per unit of Tcore.

[Muscle as a system with parametric excitation]

A mechanical model for oculorotatory muscle consisting of a neurally controlled Voigt element in parallel with a mass and in series with a passive elastic element, is proposed. The magnitude of each element without the mass and the series elasticity is shown as a function of length and the viscosity as a function of velocity. The non-linear Voigt element is shown as a time-varying element to describe the activation of muscle. The characteristics resulting from the mathematical development agree well with the experimental data published for the operating range.