BackgroundMost organisms have evolved a circadian clock in order to anticipate daily environmental changes and many of these organisms are also capable of sophisticated measurement of daylength (photoperiodism) that is used to regulate seasonal events such as diapause, migration and polymorphism. It has been generally accepted that the same elements are involved in both circadian (daily) and seasonal (annual) rhythms because both rely upon daily light-dark cycles. However, as reasonable as this sounds, there remains no conclusive evidence of such a molecular machinery in insects. We have approached this issue by using RNA interference (RNAi) in Riptortus pedestris.ResultsThe cuticle deposition rhythm exhibited the major properties of circadian rhythms, indicating that the rhythm is regulated by a circadian clock. RNAi directed against the circadian clock genes of period and cycle, which are negative and positive regulators in the circadian clock, respectively, disrupted the cuticle deposition rhythm and distinct cuticle layers were produced by these RNAi. Simultaneously, period RNAi caused the insect to avert diapause under a diapause-inducing photoperiod whereas cycle RNAi induced diapause under a diapause-averting photoperiod. The expression patterns of juvenile hormone-regulated genes and the application of juvenile hormone analogue suggested that neither ovarian development itself nor a downstream cascade of juvenile hormone secretion, were disturbed by period and cycle RNAi.ConclusionsThis study revealed that the circadian clock genes are crucial not only for daily rhythms but also for photoperiodic diapause. RNAi directed against period and cycle had opposite effects not only in the circadian cuticle deposition rhythm but also in the photoperiodic diapause. These RNAi also had opposite effects on juvenile hormone-regulated gene expression. It is still possible that the circadian clock genes pleiotropically affect ovarian development but, based on these results, we suggest that the circadian clock operated by the circadian clock genes, period and cycle, governs seasonal timing as well as the daily rhythms.See Commentary: http://www.biomedcentral.com/1741-7007/8/115

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Leuchtkugel: Der atomar monodisperse Pt5‐Nanocluster hat eine niedrige Zytotoxizität und zeigt eine Fluoreszenzquantenausbeute von 18 %. Er kann als Fluoreszenzsonde für die zelluläre Bildgebung eingesetzt werden (siehe Schema; graue Kugel: Pt5‐Nanocluster; PAMAM (G4‐OH): Polyamidoamin‐Dendrimer der vierten Generation; Skalierung 20 μm).

The formation of a porous TiO 2 layer by immersing Ti in 5 M NaOH at 303 K was investigated using electrochemical measurements, a scanning electron microscope, and grazing incident X-ray diffraction. The porous layer was readily obtained in the case of the presence of titanium hydride (TiH 2 ) on the surface before immersion. The crystalline structure of the porous layer is composed of a mixture of the rutile and anatase type TiO 2 . The porous layer is hard to produce without the presence of TiH 2 . The TiH 2 is directly changed to TiO 2 by a dissolution reaction in alkaline solution. The presence of TiH 2 on the surface is an important factor for the preparation of the porous TiO 2 layer.

Electrochemical quartz-crystal nanobalance (EQCN) analysis of the behavior of Pt in aqueous H(2)SO(4) reveals that the interfacial mass reaches a minimum, the potential of minimum mass (E(pmm)), at 0.045 V. A similar behavior is observed for Pt in aqueous HClO(4) and NaOH. E(pmm) is a new parameter describing the electrochemical interface. The value of E(pmm) coincides with the completion of the saturation layer of electroadsorbed H (H(UPD)) and the commencement of H(2)(g) generation or H(2)(g) electro-oxidation. The value of E(pmm) and the structure of the Pt/electrolyte interface are discussed in terms of the interactions of the anions H(3)O(+), H(UPD), H(OPD), and H(2)O with Pt. The layer of H(UPD) embedded in the Pt surface lattice minimizes the surface dipole-water dipole and surface charge-water dipole interactions, thus reduces the wetting ability of Pt. Consequently, the discharge of H(3)O(+) in the electrolytic formation of H(2)(g) or the dissociative adsorption of H(2)(g) that precedes its electro-oxidation to H(3)O(+) proceed easily on Pt, because the species do not have to displace H(2)O molecules. Effective and inexpensive non-platinum electrocatalysts for the electrolytic H(2)(g) generation in water electrolyzers or H(2)(g) electro-oxidation in polymer electrolyte membrane fuel cells should mimic the interfacial behavior of Pt by minimizing the interaction of H(2)O molecules with the electrode.

A new solid-phase synthesis of N-linked glycans featuring 1) highly stereoselective beta-mannosylation and microfluidic alpha-sialylation and 2) efficient glycosylation of the N-phenyltrifluoroacetimidate units on JandaJel resin is reported. Reagent concentration effects by a fluorous solvent are effectively applied, and the use of these methods results in the first synthesis of a sialic acid containing complex-type N-glycan on a solid support.

The influence of hydrogen on the formation of porous TiO2 in alkaline solution was investigated using an electrochemical measurement, a scanning electron microscope, and a grazing incident X-ray diffraction technique. The porous TiO2 was not obtained on the surface of titanium in 5 M NaOH solution at 303 K for 3 h. When the titanium was charged with hydrogen in 1 M H2SO4 at 303 K for 1 h before immersion, the porous TiO2 was readily produced on the surface under the same experimental conditions. The anodic polarization measurement indicated that the hydrogen-charged titanium was more readily dissolved in alkaline solution than the titanium. The cathodic reaction was the hydrogen evolution reaction on both the titanium and the hydrogen-charged titanium. For titanium, although the hydrogen penetrated into the inside of the material due to the side reaction of hydrogen evolution, the hydrogen content in the inside was so small that porous TiO2 was not produced under this condition. © 2002 The Electrochemical Society. All rights reserved.

The value of EV is generally clcse to EB at high illumination intensity.The finding of a constant E B fo,' n-CdTe, independent of Eredo x or s, leads to the conclusion that n-CdTe is Fermi level pinned. 2 ' 5 We take the term "Fermi level pinned" to refer to a semiconductor that is measured to have a constant EB, independent of the contacting medium for a wide range of Eredox or 0. The origin of a constant EB can be attributed to surface states situated between the top of the valence band, EVB, and the bottom of the conduction band, ECB. The density and distribution of surface states can control the value of EB as a function of E redox or 0.5,6 When the region between ECB and EVB is free of surface states, EB of an n-type semiconductor is expected to vary with Eredox according to equation (1)7for E redox situated between EVB and ECB whereEFB is the electrochemical potential of the semiconductor, Ef, when there is no band bending. When Ef = EFB there is no accumulation or depletion of the majority charge carrier at the surface and E B = 0. But even for surface-state-free semiconductors, equation (1) Pyrex tube and all surfaces but the exposed front surface of CdTe were sealed with ordinary epoxy. The exposed surface of the CdTe was the (111)face. Just prior to use all electrodes were etched and cleaned as described below.Etching Procedures. Two different types of etchants were used, oxidizing and reducing. An oxidizing etch was one of the following: (i) 4 g K 2 Cr 2 0 7 , 10 ml concentrated HNO 3 , and 20 ml H 2 0; 12 (ii) 1/1/l by volume saturated solution of K 2 Cr20 7 , concentrated HCl, and concentrated HNO 3;13 (11) 3/2/1 by volume solution of 48% HF, 30% H 2 0 2 , and H 2 0 and then briefly rinsed with concentrated HCl;14 (iv) 3/2/1/0.01 by volume of concentrated HNO 3 , concentrated H 2 SO 4 , glacial aceic acid, and concentrated HCl; (v) 2/1/l by volume solution of 48% HF, concentrated HNO 3 , and glacial' acetic acid. 15 For an oxidizing etch the CdTe electrode was immersed in the etchant for Abbreviations for redox couples are MV 2+ E N,N'-dimethyl-4,4'-bipyridinium; gun was used to produce a 2 keV Ar ion beam for sputtering. The pressure was maintained at 3 x -10 torr in the main vacuun, chamber and 1.5 x 10 -4 torr of Ar in the ionization chamber, while sputtering.X-ray photoelectron spectra (XPS) were obtained ona Physical Electronics model 548 spectrometer with a magnesium anode. The broad scans (0-1000 eV)were recorded with a pass energy of 100 eV and the narrow scans with a pass energy of 25 eV. The peak energies at the Cd and Te peaks were referenced to the Cls binding energy (284.6 eV) to correct for charging. Samples were mounted as above and sputtering was oune with a 5 keV Ar+ beam, after introducing Ar into the vacuum chamber to bring the pressure to -7 x 10 torr.Elements detected by Auger and XPS were identified by reference to data previously reported using these techniques. 17 ' 18. . Results a.Determination of EV vs. E redox for n-CdTe. Scheme I illustrdte', the interface enerqetLi...