Search for the Lepton Flavor Violating Decays B

We present a search for the lepton flavor violating decays B^{+}→K^{+}τ^{±}ℓ^{∓}, with ℓ=(e,µ), using the full data sample of 772×10^{6} BB[over ¯] pairs recorded by the Belle detector at the KEKB asymmetric-energy e^{+}e^{-} collider. We use events in which one B meson is fully reconstructed in a hadronic decay mode. We find no evidence for B^{±}→K^{±}τℓ decays and set upper limits on their branching fractions at the 90% confidence level in the (1-3)×10^{-5} range. The obtained limits are the world's best results.

Optimizing the photochemical conversion of UV-vis light of silver-nanoparticles decorated TiO2 nanotubes based photoanodes.

Homogeneous decoration of TiO2 nanotubes (NTs) by Ag metallic nanoparticles (NPs) was carried out by a relatively simple photoreduction process. This Ag-NPs decoration was found to improve the photoconversion efficiency of the TiO2-NTs based photoanodes. The x-ray photoelectron spectroscopy and x-ray diffraction analyses confirmed that all the Ag-NPs are metallic and the underlying TiO2-NTs crystallize in the anatase phase after their annealing at 400 °C, respectively. Transmission electron microscopy observations have confirmed the effective decoration of the TiO2-NTs' surface by Ag-NPs, and allowed to measure the average Ag-NPs size, which was found to increase linearly from (4 ± 2) nm to (16 ± 4) nm when the photoreduction time is increased from 5 to 20 min. The diffuse reflectivity of the Ag-NPs decorated TiO2-NTs was found to decrease significantly as compared to the undecorated TiO2-NTs. Interestingly, the Ag-NPs decorated TiO2-NTs exhibited a significantly enhanced photochemical response, under visible radiation, with regards to the undecorated NTs. This enhancement was found to reach its maximum for the TiO2-NTs decorated with Ag-NPs having the optimal average diameter of ∼8.5 nm. The maximum photoconversion efficiency of Ag-NPs decorated TiO2-NTs was about two times greater than for the undecorated ones. This improved photo-electro-chemical response is believed to be associated with the additional absorption of visible light of Ag-NPs through the localized surface plasmon resonance phenomenon. This interpretation is supported by the fact that the photoluminescence intensity of the Ag-NPs decorated TiO2-NTs was found to decrease significantly as compared to undecorated NTs, due to charge carriers trapping in the Ag NPs. This demonstrates that Ag-NPs decoration promotes photogenerated charges separation in the TiO2-NTs, increasing thereby their capacity for current photogeneration. The surface decoration of TiO2 NTs by noble metals NPs is expected to impact positively the use of TiO2-NTs based photoanodes in some energetic applications such as hydrogen generation and photo-electrochemical solar cells.

Search for CP Violation and Measurement of the Branching Fraction in the Decay D

We report a study of the decay D^{0}→K_{S}^{0}K_{S}^{0} using 921 fb^{-1} of data collected at or near the ϒ(4S) and ϒ(5S) resonances with the Belle detector at the KEKB asymmetric energy e^{+}e^{-} collider. The measured time-integrated CP asymmetry is A_{CP}(D^{0}→K_{S}^{0}K_{S}^{0})=(-0.02±1.53±0.02±0.17)%, and the branching fraction is B(D^{0}→K_{S}^{0}K_{S}^{0})=(1.321±0.023±0.036±0.044)×10^{-4}, where the first uncertainty is statistical, the second is systematic, and the third is due to the normalization mode (D^{0}→K_{S}^{0}π^{0}). These results are significantly more precise than previous measurements available for this mode. The A_{CP} measurement is consistent with the standard model expectation.

Search for bottomonium states in exclusive radiative Υ(2S) decays.

We search for bottomonium states in Υ(2S) → (bb)γ decays with an integrated luminosity of 24.7 fb(-1) recorded at the Υ(2S) resonance with the Belle detector at KEK, containing (157.8±3.6)×10(6) Υ(2S) events. The (bb) system is reconstructed in 26 exclusive hadronic final states composed of charged pions, kaons, protons, and K(S)(0) mesons. We find no evidence for the state recently observed around 9975 MeV (X(bb)) in an analysis based on a data sample of 9.3×10(6) Υ(2S) events collected with the CLEO III detector. We set a 90% confidence level upper limit on the branching fraction B[Υ(2S) → X(bb)γ] × ∑(i)B[X(bb) → h(i)] < 4.9×10(-6), summed over the exclusive hadronic final states employed in our analysis. This result is an order of magnitude smaller than the measurement reported with CLEO data. We also set an upper limit for the ηb(1S) state of B[Υ(2S) → ηb(1S)γ] × ∑(i)B[ηb(1S) → h(i)] < 3.7×10(-6).

Responses of some matrix metalloproteinases activities to an acute session of endurance exercise and electrical stimulation in induced myocardial infarction in Wistar rats.

OBJECTIVE: Myocardial infarction is the irreversible cell death of cardiac muscle that takes place after the blood flow is cut off to a specific region of the heart muscle. The molecular angiogenesis process that may follow after the incidence, due to any activity or its intensity, is unknown. The purpose of this research was to examine some of the matrix metalloproteinase (MMP) responses to an acute course of endurance exercise and electrical stimulation in induced myocardial infarcted Wistar rats. MATERIALS AND METHODS: In this experimental case-control study, 40 induced myocardial infarcted Wistar rats (8-week-old, mean weight 130±30 g) were randomly assigned into 4 conditions: endurance exercise, exercise + electrical stimulation, only electrical stimulation, and control group. The infarction was induced 24 hours after the subcutaneous injection of 150 mg/kg of Isoproterenol. The exercise and exercise plus electrical stimulation groups performed a session of endurance exercise on an animal treadmill, at 20 m/min for one hour. The electrical stimulation was delivered by foot shock, set with the intensities of 0.5 mA for 20 minutes. Immediately after the cessation of the treatment protocol, MMP1, MMP2, and MMP9 were measured by the ELISA method. Data analysis was performed by using Two-way ANOVA and significance was set at α = 0.05. RESULTS: One session of endurance exercise or electric stimulation, or their combination, had no significant effect on the level of MMPs. CONCLUSIONS: One session of acute endurance exercise, stimulation, or their combination, elicited no significant effect on the level of MMPs of artificially induced myocardial infarcted Wistar rats.

Observation of X(3872)→J/ψγ and search for X(3872)→ψ'γ in B decays.

We report a study of B→(J/ψγ)K and B→(ψ'γ)K decay modes using 772×106 B ̅B events collected at the Υ(4S) resonance with the Belle detector at the KEKB energy-asymmetric e(+)e(-) collider. We observe X(3872)→J/ψγ and report the first evidence for χ(c2)→J/ψγ in B→(X_{c ̅cγ)K decays, while in a search for X(3872)→ψ'γ no significant signal is found. We measure the branching fractions, B(B(±)→X(3872)K(±))B(X(3872)→J/ψγ)=(1.78(-0.44)(+0.48)±0.12)×10(-6), B(B(±)→χ(c2)K(±))=(1.11(-0.34)(+0.36)±0.09)×10(-5), B(B(±)→X(3872)K(±))B(X(3872)→ψ'γ)<3.45×106 (upper limit at 90% C.L.), and also provide upper limits for other searches.

Evidence for the suppressed decay B(-)→DK(-), D→K(+)π(-).

The suppressed decay chain B(-)→DK(-), D→K(+)π(-), where D indicates a D(¯)(0) or D(0) state, provides important information on the CP-violating angle ϕ(3). We measure the ratio R(DK) of the decay rates to the favored mode B(-)→DK(-), D→K(-)π(+) to be R(DK)=[1.63(-0.41)(+0.44)(stat)(-0.13)(+0.07)(syst)]×10(-2), which indicates the first evidence of the signal with a significance of 4.1σ. We also measure the asymmetry A(DK) between the charge-conjugate decays to be A(DK)=-0.39(-0.28)(+0.26)(stat)(-0.03)(+0.04)(syst). The results are based on the full 772×10(6) BB(¯) pair data sample collected at the Υ(4S) resonance with the Belle detector.

[Toxoplasmosis in Sfax, Tunisia]. / Etat actuel de la toxoplasmose dans la région de Sfax, Tunisie.

Abstract The frequency of toxoplasmosis depends on life-style and environment. Our objective was to study different epidemiological, clinical and biological aspects of toxoplasmosis in the Sfax area (Tunisia). This retrospective study has been performed on seria of 40,566 pregnant women in the Parasitology-Mycology Laboratory of Habib-Bourguiba Sfax hospital-Tunisia for 13 years from 1994 to 2006; 1,691 patients presenting with lymphadenopathy; 191 immunocompromised patients (78 HIV infected patients and 113 transplanted patients) and 21 patients presenting clinical signs of ocular toxoplasmosis. In pregnant women, the seroprevalence was 39.3% (15,952/40,567). Among 24,089 seronegative women, only 6,890 (28.6%) had been followed up during their pregnancy. An active toxoplasmosis possibly acquired during pregnancy was detected in 1.3% of cases. Sixteen congenital toxoplasmosis were detected. Toxoplasmosis was confirmed in 13.7% of the 169 patients with lymphadenitis. For HIV positive patients, 11.7% had cerebral toxoplasmosis. It revealed the HIV infection in four cases. Among transplant recipients, one case of active toxoplasmosis was diagnosed in a renal transplant recipient who received transplant from a seronegative donor. Twenty-one patients presenting toxoplasmic retinochoroiditis were treated by subconjonctival injections of clindamycin and systemic corticotherapy at a dose of 1 mg/kg per day. This clinical toxoplasmosis diversity explains the need for bioclinical confrontation to establish diagnosis.

Using an amplitude analysis to measure the photon polarisation in B → K π π γ decays.

A method is proposed to measure the photon polarisation parameter λ γ in b → s γ transitions using an amplitude analysis of B → K π π γ decays. Simplified models of the K π π system are used to simulate B + → K + π - π + γ and B 0 → K + π - π 0 γ decays, validate the amplitude analysis method, and demonstrate the feasibility of a measurement of the λ γ parameter irrespective of the model parameters. Similar sensitivities to λ γ are obtained with both the charged and neutral hadronic systems. In the absence of any background and distortion due to experimental effects, the statistical uncertainty expected from an analysis of B + → K + π - π + γ decays in an LHCb data set corresponding to an integrated luminosity of 9  fb - 1 is estimated to be 0.009. A similar measurement using B 0 → K + π - π 0 γ decays in a Belle II data sample corresponding to an integrated luminosity of 5  ab - 1 would lead to a statistical uncertainty of 0.018.

Bacterial adhesion and inactivation on Ag decorated TiO2-nanotubes under visible light: Effect of the nanotubes geometry on the photocatalytic activity.

This study investigates the effect of the diameter of TiO2 nanotubes and silver decorated nanotubes on optical properties and photocatalytic inactivation of Escherichia coli under visible light. The TiO2 nanotubes (TiO2-NTs) were prepared using the electrochemical method varying the anodization potential starting from 20 V until 70 V. The Ag nanoparticles were carried out using the photoreduction process under the same experimental conditions. The diameter size was determined using the scanning electronic microscopy (SEM). TiO2-NTs diameter reached ∼100 nm at 70 V. Transmission electronic microscopy (TEM) imaging confirmed the TiO2-NTs surface decoration by silver nanoparticles. The Ag-NPs average size was found to be equal to 8 nm. The X-Ray diffraction (XRD) analysis confirm that all TiO2-NTs crystallize in the anatase phases regardless the used anodization potential. The decrease of the photoluminescence (PL) intensity of Ag NPs decorated TiO2-NTs indicates the decrease of the specific area when the nanotubes diameter increases. The UV-vis absorbance show that the absorption edges was bleu shifted with the increasing of nanotubes diameter, which can be explained by the increase of the crystallites average size. The bacterial adhesion and inactivation tests were carried in the dark and under light. Bacteria were seen to adhere on TiO2-NTs in the dark; however, under light the bacteria were killed before they establish a strong contact with the TiO2-NTs and Ag/TiO2-NTs surfaces. Bacterial inactivation kinetics were faster when the anodizing potential of the NTs-preparation increases. A total bacterial inactivation was obtained on ∼100 nm nanotubes diameter within 90 min. This result was attributed to the enhancement of the TNTs crystallinity leading to reduced surface defects. Redox catalysis was seen to occur under light on the TiO2-NTs and Ag/TiO2-NTs. the photo-induced antibacterial activity on the AgO/Ag2O decorated TiO2-NTs was attributed to the interfacial charge transfer mechanism (IFCT).