A black hole with quantum core

A model black hole, holding a ‘quantum core’ characterized by the Planck order matter density, is revisited here. Based on the quantum improved Newton’s potential drawn out of the loop quantum cosmology we propose a Schwarzschild class, quantum improved black hole line-element that upholds the existence of Planck-dense quantum matter core. Causality is kept preserved in this proposal. Quite in a natural way the quantum core emerges closely homogeneous in its interior matter distribution. The radius of the quantum core turns out to be necessarily proportional to one-third power of the black hole mass. Hawking process of black hole evaporation leads to a shrinking quantum core, and as the mass of black hole approaches near about the Planck mass, the rate of evaporation diminishes rapidly and eventually leaves a cold remnant having a Planck order mass. Proposed model supports the standard quantum geometrical logarithmic correction to black hole entropy-area law.     

Selective Binding of Open Frameworks Assembled from Nickel(II) Macrocyclic Complexes with Organic and Inorganic Guests

Inclusion studies for metal-organic open-frameworks, [Ni(C_10}H₂₄N₄)(H₂O)₂]₃[BTC]₂·24H₂O (1) and [Ni(C₁₀H₂₆N₆)]₃ [BTC]₂·18H₂O(2) (BTC^3- = 1,3,5-benzenetricarboxylate) with various organic andinorganic guest molecules have been carried out. 1 is the previously reportedmolecular floral lace with 1-D channels, where positively charged macrocyclic layersand negatively charged BTC^3- layers are alternately packed by hydrogen bondinginteractions. 2 is assembled in this study from nickel(II) hexaazamacrocyclic complexcontaining methyl pendant arms and BTC^3-. The X-ray structure of 2 shows thatthe nickel(II) complex and BTC^3- form a 2-D coordination polymer. The XRPD patternsof 2 indicate that framework of 2 is slightly deformed upon removal of waterguest molecules but restored upon rebinding of water. The host solid 1 binds MeOHin toluene, and 1,3,5-trihydroxybenzene (THB) and 4-hydroxyacetophenone (HAP) in EtOH/toluene (v/v = 1/4) solutions. The binding constants (K_f) of 1 forMeOH, THB, and HAP are 66.4 M^-1, 259 M^-1, and 13.9 M^-1,respectively. In the range of high concentration of the guest, however, the host showsvarious binding curves depending upon the types of guest. It binds PhOH in toluene,showing a sigmoid curve. It also binds transition metal complexes such as[Cu(NH₃)₄](ClO₄)₂, [Cu(ethylenediamine)₂](ClO₄)₂,[Cu(histamine)₂](ClO₄)₂, and[Cu(N,N'-bis(3-aminopropyl)ethylenediamine)](ClO₄)₂ in MeCN, with K_f values of 645 M^-1, 9.52 M^-1, 37.2 M^-1, and 6.00 M^-1,respectively. The host solid 2 binds selectively PhOH over PhCl and PhBr, showing that hydrogen bonding interaction between the host and guest plays an important role in the selectivity.     

Analysis of plasma free fatty acid cyanomethyl derivatives by GC-NPD for the diagnosis of mitochondrial fatty acid oxidation disorders

Summary Early diagnosis of fatty acid oxidation (FAO) disorders is important to reduce severe morbidity and mortality. Although analysis of plasma free fatty acids (FFAs) is frequently performed using stable isotope-dilution gas chromatography-mass-spectrometry (GC-MS), there are institutions where the required instrumentation is not available to support a rapid work-up of acutely ill patients. For this reason, we have developed a novel cyanomethyl derivatization method for FFAs which is followed by GC analysis of the resulting esters using nitrogen-phosphorus detector (NPD) for the rapid diagnosis of mitochondrial fatty acid oxidation disorders. FFAs were extracted from plasma and derivatized to the cyanomethyl ester by heating with bromoacetonitrile at 60°C for 30 min GC-NPD analysis was then performed. The mean recoveries of C6:0-C18:0FFAs were between 87% abd 96%. The method detection limits (S/N=3) were 0.1–0.5 ng for C6:0-C14:0 FFAs, and 0.001–0.01 ng for C16:0-C18:0 FFAs. We succesfully performed differential diagnosis of representative FAO disorders from the confimed patient's plasmas. This simple method offers cost-effective and time-saving alternative to GC-MS for the biochemical diagnosis of selected FAO disorders.     

Mixed-ligand metal-organic frameworks with large pores: gas sorption properties and single-crystal-to-single-crystal transformation on guest exchange

Two isomorphous 3D metal-organic frameworks, {[Cu2(BPnDC)2(bpy)].8 DMF.6 H2O}n (1) and {[Zn2(BPnDC)2(dabco)].13 DMF.3 H2O}n (2), have been prepared by the solvothermal reactions of benzophenone 4,4'-dicarboxylic acid (H2BPnDC) with Cu(NO3)(2).2.5 H2O and 4,4'-bipyridine (bpy), and with Zn(NO3)(2).6 H2O and 4-diazabicyclo[2.2.2]octane (dabco), respectively. Compounds 1 and 2 are composed of paddle-wheel {M2(O2CR)4} cluster units, and they generate 2D channels with two different large pores (effective size of larger pore: 18.2 A for 1, 11.4 A for 2). The framework structure of desolvated solid, [Cu2(BPnDC)2(bpy)]n (SNU-6; SNU=Seoul National University), is the same as that of 1, as evidenced by powder X-ray diffraction patterns. SNU-6 exhibits high permanent porosity (1.05 cm3 g(-1)) with high Langmuir surface area (2910 m2 g(-1)). It shows high H2 gas storage capacity (1.68 wt % at 77 K and 1 atm; 4.87 wt % (excess) and 10.0 wt % (total) at 77 K and 70 bar) with high isosteric heat (7.74 kJ mol(-1)) of H2 adsorption as well as high CO2 adsorption capability (113.8 wt % at 195 K and 1 atm). Compound 2 undergoes a single-crystal-to-single-crystal transformation on guest exchange with n-hexane to provide {[Zn2(BPnDC)2(dabco)].6 (n-hexane).3 H2O}n (2hexane). The transformation involves dynamic motion of the molecular components in the crystal, mainly a bending motion of the square planes of the paddle-wheel units resulting from rotational rearrangement of phenyl rings and carboxylate planes of BPnDC2-.     

Measurement and Identification of (R)- and (S)-6-O-Desmethylnaproxen Enantiomers as Diastereomeric O-Ethoxycarbonyl/(R)-(+)-1-Phenylethylamides in Urine by GC and GC-MS

Enantioseparations of (R)- and (S)-6-O-desmethylnaproxens as O-ethoxycarbonyl/(R)-(+)-1-phenylethylamides and (R)- and (S)-naproxens as (R)-(+)-1-phenylethylamides were achieved by achiral gas chromatography in a single run within 11 min. The characteristic mass spectral patterns facilitated easier peak identification. The method for determinations of (R)-naproxen (1.0 to 50 ng) and (S)-naproxen (100 to 2000 ng) was linear with acceptable repeatability and accuracy. The enantiomeric composition ratios between (R)- and (S)-6-O-desmethylnaproxens and between (R)- and (S)-naproxens in urine sample collected six hours after oral administration of (S)-naproxen tablets were measured to be 2.2 (± 0.2):97.8 (± 0.2) and 2.1 (± 0.1):97.9 (± 0.1), respectively.     

Determination of the arc-root position in a DC plasma torch

The behavior of an arc operated in the nontransferred mode with a conical-shaped cathode and a nozzle-shaped anode is studied by applying general tyro-dimensional conservation equations and auxiliary relations for the simulation of arc channel flows. The position of the arc-root attachment at the anode surface is determined by using Steenbeck's minimum principle, which postulates a minimum arc voltage for a given current and certain given boundary conditions. The overall effects of the anode-arc root on the plasma flow are, studied by comparing the results with those of the transferred mode of operation. Specific arc-channel diameters are chosen in the simulation in order to verify flit, numerical model through comparisons with experimental results. The results show that Steenbeck's minimum principle is useful for determining the position of the arc-root attachment at the anode surface. Application of this method for control of the arc-anode attachment may be valuable in the design and operation of plasma spray torches to avoid jet instabilities.     

Synthesis and characterization of graft copolymers of poly(vinyl chloride) with styrene and (meth)acrylates by atom transfer radical polymerization

Graft copolymers of poly(vinyl chloride) with styrene and (meth)acrylates were prepared by atom transfer radical polymerization. Poly(vinyl chloride) containing small amount of pendent chloroacetate units was used as a macroinitiator. The formation of the graft copolymer was confirmed with size exclusion chromatography (SEC), ¹H NMR and IR spectroscopy. The graft copolymers with increasing incorporation of butyl acrylate result in an increase of molecular weight. One glass transition temperature (T_g) was observed for all copolymers. T_g of the copolymer with butyl acrylate decreases with increasing content of butyl acrylate.     

Transition-state effects in acid-catalyzed aryl epoxide hydrolyses

The hydronium ion-catalyzed hydrolyses of 5-methoxyindene 1,2-oxide and of 6-methoxy-1,2,3,4-tetrohydronaphthalene-1,2-epoxide were each found to yield 75-80% of cis diol and only 20-25% of trans diol as hydrolysis products. The relative stabilities of the cis and trans diols in each system were determined by treating either cis or trans diols with perchloric acid in water solutions and following the approach to an equilibrium cis/trans mixture as a function of time. These studies establish that the trans diol in each system is more stable than the corresponding cis diol. Thus, acid-catalyzed hydrolysis of each epoxide, which proceeds via a carbocation intermediate, yields the less stable cis diol as the major product. Transition-state effects, presumably of a hydrogen-bonding nature, selectively stabilize the transition state for attack of water on the intermediate 2-hydroxy-1-indanyl carbocation leading to the less stable cis diol in this system. Transition-state effects must also be responsible for formation of the less stable cis diol as the major product in the acid-catalyzed hydrolysis of 5-methoxy-1,2,3,4-tetrahydronaphthalene 1,2-epoxide. However, in this system steric effects at the transition state may be more important than hydrogen bonding in determining the cis/trans diol product ratio. The synthesis of 5-methoxyindene 1,2-oxide and a study of its rate of reaction as a function of pH in water and dioxane-water solutions are reported. Both an acid-catalyzed reaction leading to only diol products and a pH-independent reaction yielding 71% of 5-methoxy-2-indanone and 29% of diols are observed; the half-life of its pH-independent reaction in water is only 2.4 s.