Here we have used Raman spectroscopy to investigate molecular level changes in the zeolitic imidazolate framework ZIF-8 (a prototypical zeolite-like porous metal organic framework) as a function of temperature. Temperature dependent Raman spectra suggest that at low temperature the softening of the C-H stretching frequencies is due to the decrease in steric hindrance between the methyl groups of methyl imidazole. The larger separation between the methyl groups opens the window for increased nitrogen and methane uptake at temperatures below 153 K. The appearance of Raman bands at 2323 cm(-1) and 2904 cm(-1) at or below 153 K in ZIF-8 are characteristic signatures of the adsorbed nitrogen and methane gases respectively. Nanoscale ZIF-8 uptakes more molecules than bulk ZIF-8, and as a result we could provide evidence for encaged CO2 at 203 K yielding its Raman mode at 1379 cm(-1).

Reversible acetylation of histone and nonhistone proteins plays pivotal role in cellular homeostasis. Dysfunction of histone acetyltransferases (HATs) leads to several diseases including cancer, neurodegenaration, asthma, diabetes, AIDS, and cardiac hypertrophy. We describe the synthesis and characterization of a set of p300-HAT-specific small-molecule inhibitors from a natural nonspecific HAT inhibitor, garcinol, which is highly toxic to cells. We show that the specific inhibitor selectively represses the p300-mediated acetylation of p53 in vivo. Furthermore, inhibition of p300-HAT down regulates several genes but significantly a few important genes are also upregulated. Remarkably, these inhibitors were found to be nontoxic to T cells, inhibit histone acetylation of HIV infected cells, and consequently inhibit the multiplication of HIV.

Thus the inferred isotropic energy loss in g-rays is E G ϳ3 ϫ 10 53 erg: This is remarkably coincident with the gravitational binding energy released during the merger of two neutron stars 24 .Even though E G is much greater than E A , the afterglow measurements pose a clear problem to GRB models. At the time the ␥-rays are emitted, the shocked gas is moving with very large Lorentz factor (Γ). The initial Γ is assumed to be 10 2 -10 3 and expected to evolve as t −3/8 . Due to relativistic beaming, only a small portion, solid angle ϳΓ −2 , of the fireball is visible to us. Hence we remain ignorant of the true shape of the fireball. The estimate of E G can be reduced by assuming that the emitting surface is a narrow jet directed towards the observer. However, Γ is smaller during the optical afterglow emission than during the ␥-ray emission. Relativistic beaming is less of a limitation, and the full extent of the fireball is gradually revealed to the observer. The monotonic power-law decay at optical wavelengths seen in the OTs of previous transients 13-15 is not consistent with the narrow jet-like emitting surfaces. We recognize that more complicated models (in which energy is injected non-spherically) could account for such monotonic decays whilst having nonspherical geometry. However, the main issue that we discuss here is the inferred energetics. It is by no means clear that the energy requirements inferred from afterglow observations (when the Lorentz factor is small) is any lower than the simplest case considered here.According to the models discussed here, the afterglow emission is supposed to arise from non-radiative shocks; that is, the efficiency of the shock in converting E 0 (the total energy in the GRB event) to afterglow radiation is low. Thus, E 0 is significantly larger than the E A reported above. This finding is in direct contrast to the assumptions made by most practitioners in this field, namely E 0 ¼ 10 51 erg. As an aside we note that equation (1) predicts that the break frequency should evolve with time as t −3/2 . Measurement of the break frequency at successive epochs for future bursts offers the possibility of directly confirming or refuting the non-radiative shock assumption.The evidence presented here favours GRB models which produce energy vastly in excess of 10 51 erg; see for example, refs 24, 25, 29. The afterglow emission is similar in nature to the emission from supernovae but is more energetic by two orders of magnitude. Following the naming sequence, nova and supernova, it is only appropriate to refer to GRB afterglow as hypernova 29 .Ⅺ

In this work, the covalent attachment of an amine functionalized metal‐organic framework (UiO‐66‐NH2 = Zr6O4(OH)4(bdc‐NH2)6; bdc‐NH2 = 2‐amino‐1,4‐benzenedicarboxylate) (UiO‐Universitetet i Oslo) to the basal‐plane of carboxylate functionalized graphene (graphene acid = GA) via amide bonds is reported. The resultant GA@UiO‐66‐NH2 hybrid displayed a large specific surface area, hierarchical pores and an interconnected conductive network. The electrochemical characterizations demonstrated that the hybrid GA@UiO‐66‐NH2 acts as an effective charge storing material with a capacitance of up to 651 F g−1, significantly higher than traditional graphene‐based materials. The results suggest that the amide linkage plays a key role in the formation of a π‐conjugated structure, which facilitates charge transfer and consequently offers good capacitance and cycling stability. Furthermore, to realize the practical feasibility, an asymmetric supercapacitor using a GA@UiO‐66‐NH2 positive electrode with Ti3C2TX MXene as the opposing electrode has been constructed. The cell is able to deliver a power density of up to 16 kW kg−1 and an energy density of up to 73 Wh kg−1, which are comparable to several commercial devices such as Pb‐acid and Ni/MH batteries. Under an intermediate level of loading, the device retained 88% of its initial capacitance after 10 000 cycles.

-Raman study on a select few orthochromites, RCrO 3 (R = Y, Lu, Gd, Eu and Sm) shows that the phonon behavior at T N in compounds with magnetic R-ion (Gd and Sm) is remarkably different from that of non-magnetic R-ion (Y, Lu and Eu). While anomalies in most of the observed phonon frequencies in all these compounds may result from the distortion of CrO 6 octahedra due to size effect and magnetostriction arising from Cr-ordering, the anomalous behavior of their linewidths observed at T N for the compounds with only magnetic R-ion suggests spin-phonon coupling. The presence of spin-phonon coupling and the anomalies in the low frequency modes related to R-ion motion in orthochromites (R = Gd and Sm) support the suggestion that the coupling between 4f-3d moments play important role in inducing switchable electric polarization.Introduction.-Magnetoelectric multiferroic materials with their coupled ferroelectric and ferromagnetic order parameters are promising for developing a new generation of both electrically and magnetically controlled multifunctional devices [1][2][3][4][5]. Multiferroic materials are broadly classified into two types; in type I multiferroics, the ferroelectricity and magnetism occur at high temperatures but with different temperature scale. However, the coupling between the two order parameters are rather weak. Type II multiferroics are generally centrosymmetric and magnetic where the ferroelectricity is caused by certain type of magnetic ordering. In the well-known example of TbMnO 3 , the manganese moments order antiferromagnetically at T N = 41 K and at 25 K it undergoes another magnetic transition below which a cycloidal spin structure breaks the inversion symmetry and thus induces ferroelectricity [6]. In case of HoMnO 3 [7], a collinear magnetic ordering with E-type magnetic structure gives rise to ferroelectricity. It has been shown recently that canted antiferromagnetic ordering with two non-equivalent spin pairs in the orthoferrite, SmFeO 3 [8] induces ferroelectric polarization at the magnetic ordering temperature of iron. Rajeswaranet al. [9] have reported electric polar order at the magnetic ordering temperature of chromium in the isostructural orthochromites, RCrO 3 with magnetic R ion, where the interactions between R 3+ and Cr 3+ ions have been