Dynamic mechanical relaxation and loss in the incommensurate phase of quartz.

The dynamic mechanical properties of quartz have been studied as a function of temperature across the α-ß phase transition and in the vicinity of the incommensurate (IC) phase on cooling from the ß phase. The mechanical response of the IC phase shows strong anelasticity for measurement of Young's modulus (closely related to C(11) in our geometry) with modulated stress driven at 1 Hz. The dynamic shear modulus does not show similar strong effects in its imaginary component, although a very weak anomaly is barely detectable in the real part of the modulus. Our results indicate that the incommensurate microstructures within the quartz transition interval are susceptible to dilatational stress with relaxation times around 1 s.

Capsaicin may induce breast cancer cell death through apoptosis-inducing factor involving mitochondrial dysfunction.

The majority of breast cancer patients are resistant to chemotherapy or radiotherapy due to the down-regulation or lack of caspase-3 expression. Capsaicin was found to inhibit cancer cell growth in caspase-3-deficient human breast cancer cells. This study aimed to investigate the growth-inhibitive effect of capsaicin and its mechanisms in human breast cancer cell lines, MCF-7 and BT-20. The results showed that cell viability decreased in a dose-dependent manner in both the caspase-3-deficient and non-deficient cells through inducing cell apoptosis and arresting the cell cycle in the S phase. Capsaicin significantly decreased mitochondria membrane potential, induced the cleavage of PARP-1, and decreased procaspase-7 expression in both cells. Apoptosis-inducing factor (AIF) was distinctly released from mitochondria and translocated into the cytoplasm and nucleus in MCF-7 cells (52.9%), but not in BT-20 cells (2%) after treatment with 200 µM of capsaicin for 24 hours. Capsaicin inhibited breast cancer cell growth through inducing cell apoptosis and cell cycle arrest in the S phase. This apoptotic effect could be induced through the mitochondrial pathway, and PARP-1 subsequently cleaved by activation of caspase-7. The application of capsaicin in clinical therapy could be useful for breast cancer patients.

Crystallization and preliminary X-ray diffraction analysis of spermidine synthase from Helicobacter pylori.

Polyamines, such as putrescine, spermidine and spermine, are essential for the regulation of cell proliferation and differentiation in most organisms. Spermidine synthase catalyzes the transfer of the aminopropyl group from decarboxylated S-adenosylmethionine to putrescine in the biosynthesis of spermidine. In this study, spermidine synthase of Helicobacter pylori has been overexpressed in Escherichia coli and purified. Two kinds of spermidine synthase crystals were obtained. One belongs to the monoclinic P2(1) space group, with unit-cell parameters a = 62.78, b = 58.24, c = 74.28 A, beta = 90.9 degrees , and the other belongs to the orthorhombic C222(1) space group, with unit-cell parameters a = 100.43, b = 128.55, c = 143.60 A.

Endophthalmitis as a complication of meningococcal meningitis: report of one case.

Metastatic meningococcal endophthalmitis, although rare, is a rapidly progressive and sight-threatening infection. We present a 10-month-old infant with meningococcal meningitis who developed unilateral metastatic endophthalmitis. If patients develop a sepsis-like picture with cloudy cornea and purulent conjunctivitis, we have to consider the possibility of endophthalmitis and full ophthalmological evaluations are indicated. Treatment should be started as early as possible. The outcome of endophthalmitis is frequently permanent visual impairment. Endophthalmitis is a true medical emergency requiring early antibiotic therapy with full dose of antimicrobials to avoid morbidity and blindness.

Cooperative interaction between Cra and Fnr in the regulation of the cydAB operon of Escherichia coli.

In vivo and in vitro experiments are reported demonstrating that the catabolite repressor-activator (Cra) protein (formerly designated FruR) regulates expression of the cydAB operon of Escherichia coli encoding cytochrome d oxidase. The Fnr protein is required for Cra-mediated transcriptional control, but the ArcA protein antagonizes the response to Cra. The results establish that Fnr, ArcA, and Cra exert their effects in an interdependent fashion.