Miracle-dz/UniFAR-FTUs huggingface dataset:
BBB pathophysiology–independent delivery of siRNA in traumatic brain injury

We describe a nanoparticle platform for brain delivery of nucleic acid–based therapeutics to treat TBI. Small interfering RNA (siRNA)–based therapeutics can mitigate the long-term sequelae of traumatic brain injury (TBI) but suffer from poor permeability across the blood-brain barrier (BBB). One approach to overcoming this challenge involves treatment administration while BBB is transiently breached after injury. However, it offers a limited window for therapeutic intervention and is applicable to only a subset of injuries with substantially breached BBB. We report a nanoparticle platform for BBB pathophysiology–independent delivery of siRNA in TBI. We achieved this by combined modulation of surface chemistry and coating density on nanoparticles, which maximized their active transport across BBB. Engineered nanoparticles injected within or outside the window of breached BBB in TBI mice showed threefold higher brain accumulation compared to nonengineered PEGylated nanoparticles and 50% gene silencing. Together, our data suggest that this nanoparticle platform is a promising next-generation drug delivery approach for the treatment of TBI.
Molecular Rotation in Crystals of N2 and CO

Molecular rotation in low‐temperature crystals of nitrogen and carbon monoxide is investigated. The following contributions to the crystal field hindering free rotation are taken into account: (a) the interaction of the molecular quadrupoles; (b) the effect of the anisotropic molecular polarizabilities; and (c) the short‐range repulsive forces. The results of a theoretical calculation of the minimum‐energy configuration at 0°K support the generally accepted structure; it is shown that the crystal field in this structure is axially symmetric at each lattice site. The Schrodinger equation for a rigid rotor in the crystal field is solved for the lowest rotational states of N2 and CO. It is found that a classical treatment of the rotation is not justified for these crystals due to the large separations of the lowest eigenvalues. The zero‐point energy of rotation is found to be about half as large as the zero‐point vibrational energy for these crystals.
Contact Heterogeneity as a Mediator of the Relationship between Social Class and Altruistic Giving

Research on the relationship between social class and altruistic giving has provided inconsistent evidence. Using the dictator game, in which one participant is endowed with a certain amount of money and has to allocate this amount between herself and another individual, several studies found that higher-class actors have a lower tendency toward altruistic giving than lower-class actors; other studies found the opposite pattern. We show that social class has a positive effect on altruistic giving in the dictator game with a sizeable sample of residents of the United States using both an objective measure of social class—that is, a composite of income, education, and occupational prestige—and a subjective measure. Shedding more light on the mechanisms underlying the positive effect of social class, it is demonstrated that class affects altruistic giving not so much by differences in empathic concern but by differences in the marginal utility of money and contact heterogeneity. It is argued that the latter effect can be derived from Collins’s theory of interaction rituals and class cultures.
LiMn2O4: a spinel-related low-temperature modification

Single-crystal synchrotron X-ray diffraction at 297 K revealed the spinel-related low-temperature orthorhombic form of black octahedrally shaped single crystals of lithium dimang­anate, LiMn2O4, grown by the flux method. Three of five MnO6 octahedra show typical Jahn–Teller distortions associated with MnIII states. The bond valence sums indicate that these three sites are enriched with MnIII and the other two with MnIV, though the charge distribution among these sites is still partially disordered.
Synthesis of chitin derivatives having peptide side groups by the water‐soluble active ester method

Full Paper: Novel chitin derivatives having pendant monopeptide and tripeptide units, i.e., N-(N'-acetylglycyl)chitin (3a) and N-(N'-acetylglycylglycylglycyl)chitin (3b), were synthesized from 50% deacetylated chitin by the water-soluble active ester method in a homogeneous system at 27-50°C. Without protection of hydroxyl groups, amino groups of the partially deacetylated chitin were selectively acylated by using esters of the corresponding N-acetylated amino acids with (4-hydroxyphenyl)dimethylsulfonium methyl sulfate in water. The degree of substitution of the D-glucosamine moiety of chitin is changed with the feed mole ratio of the active ester reagent to amino groups. As a new type of amphiphilic polysaccharides of lipid/peptide/polysaccharide conjugates, N-(N'-lauroylglycyl)chitin (3c) and N-(N'-lauroylsarcosyl)chitin (3d) were synthesized in the corresponding way.
High-Yield Synthesis of Boron Nitride Nanosheets with Strong Ultraviolet Cathodoluminescence Emission

Bulk quantities of hexagonal boron nitride (h-BN) nanosheets have been synthesized via a simple template- and catalyst-free chemical vapor deposition process at 1100−1300 °C. Adjusting the synthesis and chemical reaction parameters, the thickness of the BN nanosheets can be tuned in a range of 25−50 nm. Fourier transform infrared spectra and electron energy loss spectra reveal the typical nature of sp2-hybridization for the BN nanosheets. It shows an onset oxidation temperature of 850 °C for BN nanosheets compared with only about 400 °C for that of carbon nanotubes under the same conditions. It reveals a strong and narrow cathodoluminescence emission in the ultraviolet range from the h-BN nanosheets, displaying strong ultraviolet lasing behavior. The fact that this luminescence response would be rather insensitive to size makes the BN nanosheets ideal candidates for lasing optical devices in the UV regime. The h-BN nanosheets are also better candidates for composite materials in high-temperature and hazar.
A pseudobond approach to combining quantum mechanical and molecular mechanical methods

A major challenge for combined quantum mechanical and molecular mechanical methods (QM/MM) to study large molecules is how to treat the QM/MM boundary that bisects some covalent bonds. Here a pseudobond approach has been developed to solve this problem for ab initio QM/MM calculations: a one-free-valence atom with an effective core potential is constructed to replace the boundary atom of the environment part and to form a pseudobond with the boundary atom of the active part. This pseudobond, which is described only by the QM method, is designed to mimic the original bond with similar bond length and strength, and similar effects on the rest of the active part. With this pseudobond approach, some well-known deficiencies of the link atom approach have been circumvented and a well-defined potential energy surface of the whole QM/MM system has been provided. The construction of the effective core potential for the pseudobond is independent of the molecular mechanical force field and the same effective core potential is applicable to both Hartree–Fock and density functional methods. Tests on a series of molecules yield very good structural, electronic, and energetic results in comparison with the corresponding full ab initio quantum mechanical calculations.
THIRD-ORDER NONLINEAR OPTICAL PROPERTIES OF HETEROAROMATIC POLYMERS

Third-order nonlinear optical properties, χ(3) of novel heteroaromatic polymers having large χ(3) with processabilities are discussed. Several types of heteroaromatic polymers have been developed with a structure where π-excessive heteroaromatic compounds and π-deficient heteroaromatic compounds are combined to induce a strong nonlinearity. The charge transfer between heteroaromatic rings on the π-conjugated sequences is thought to influence the properties of certain excited states that contribute to the χ(3) enhancement. The χ(3) value of the polymer at 1.50 μm wavelength is 5×10-10 esu. These polymers reported here have a potential to fabricate optical switching devices.
High‐pressure single‐crystal structure determinations for ruby up to 90 kbar using an automatic diffractometer

Complete high‐pressure single‐crystal structure determinations have been performed up to 90 kbar on ruby (Al2O3 with less than 0.05 wt% Cr2O3) using an automatic diffractometer. The rhombohedral lattice constant aR is found to decrease linearly within the given error limits from aR=5.136±0.004 to aR=5.075±0.005 A at 90 kbar. The rhombohedral angle αR=55.30°±0.06° as well as the atom‐position parameters u (Al, Cr) =0.3520±0.0004 for Al (or Cr) and u (0) =0.556±0.003 for oxygen remain constant up to at least 86 kbar. These results are in very good agreement with earlier measurements up to 25 kbar by Schiferl and Jamieson as well as with the Birch and Murnaghan equations of state with the literature values of the isothermal compresssibility K0 and its pressure derivative K′.
Inelastic Cold Neutron Scattering from Different Forms of Silica

Coherent inelastic cold neutron scattering experiments have been carried out at room temperature on polycrystalline quartz, on three polycrystalline cristobalite specimens of different degrees of crystal perfection, and on vitreous silica. The results for quartz show marked coherence effects, and it was possible to derive the form of the directionally averaged lowest‐energy acoustic branch of the spectrum. Coherence effects at higher energies are too complex to be interpreted in detail, but the results show the presence of a maximum in the vibrational frequency distribution [G(ω)] at ≈ 130 cm−1 and a broad maximum extending from ≈ 250–500 cm−1. These results are in excellent agreement with recent neutron scattering experiments on a single crystal and detailed calculations of the dispersion relations for a model of quartz. For cristobalite, the scattering was shown to be largely independent of crystal perfection so that the results obtained are characteristic of perfect cristobalite. The form of the direct.
Determination of the Surface Fractal Dimension of Active Carbons by Mercury Porosimetry

Abstract Mercury porosimetry has been used to characterize the macroporosity of several carbon materials activated by steam or carbon dioxide and their surface fractal dimension is determined. The first part is devoted to the analysis of the differential volume versus pressure curves in order to distinguish between mechanical effects resulting from the mercury pressure and true pore filling. It is shown, in the second part, that the macropore volume is not strongly affected by the activation process, but it depends mainly on the initial texture of the carbon. On the other hand, the fractal dimension varies largely with the activation conditions and burn-off. The experimental results suggest that the fractal dimension tends to increase with the degree of burn-off in steam, whereas the opposite occurs during activation by carbon dioxide. These observations are discussed in relation to the mechanisms of activation.
Kristall- und Molekülstruktur von Tetraaryl-3,7-diazabicyclo- [3.3.1]nonanen und Tetra- und Pentaaryl-1,3-diaza-adamantanen. Sessel/Boot-Konformation der Tetraaryl-3,7-diazabicyclo[3.3.1]nonane

Fur Struktur- und NMR-Untersuchungen wurden die 2,4,6,8-Tetrakis(3,5-dimethylphenyl)-3,7-diazabicyclo[3.3. 1]nonane 8c und 10c, die davon abgeleiteten 1,3-Diazaadamantane 11c und 13c sowie an einem (14b, 16b) oder an beiden Stickstoffatomen methylierte Tetraaryl-3,7-diazabicyclo[3.3. 1]nonane (15b, c, 17b, c, 19) synthetisiert. Die N-Methylierung erfolgte regioselektiv am Boot-Piperidinring und erst unter verscharften Bedingungen am Sessel-Piperidinring. 8b bildete mit 4-Methylbenzaldehyd unter Anderung der Konfiguration eines Benzylkohlenstoffatoms des Sessel-Piperidinrings langsam das Pentakis(4-methylphenyl)-1,3-diazaadamantanon 12b. Durch Rontgenstrukturbestimmung der 3,7-Diazabicyclononane 8c, 15b und 16b sowie der 1,3- Diazaadamantanone 12b und 20 wurden die Strukturen und die im Kristall bevorzugten Konformationen, insbesondere der Arylgruppen, aufgeklart. Alle Tetraaryl-3,7-diazabicyclononane liegen danach in der Sessel-Boot-Konformation mit aquatorialen Arylgruppen vor. Zwei der funf Arylsubstituenten von 12b besetzen eine 1,3-diaxiale Stellung, wahrend die drei benachbarten Arylgruppen eine unerwartete propellerahnliche Anordnung aufweisen. Crystal and Molecular Structure of Tetraaryl-3,7-diazabicyclo[3.3. 1]nonanes and Tetra- and Pentaaryl-1,3-diazaadamantanes. Chair-Boat Conformation of the Tetraaryl-3,7-diazabicyclo[3.3. 1]nonanes The 2,4,6,8-tetrakis(3,5-dimethylphenyl)-3,7-diazabicyclo[3.3. 1]nonanes 8c and 10c, the 1,3-diazaadamantanes 11c and 13c derived therefrom, and some tetraaryl-3,7-diazabicyclo[3.3. 1]nonanes methylated at one (14b, 16b) or both nitrogen atoms (15b, c, 17b, c, 19) have been synthesized for structure and NMR studies. N-Methylation occurred regioselectively at the piperidine ring existing in the boat conformation. The nitrogen atom of the piperidine ring in the chair conformation was methylated only under forced conditions. With 4-methylbenzaldehyde, 8b formed slowly the pentakis(4-methylphenyl)-1,3-diazaadamantanone 12b, in which the configuration of one of the benzylic carbon atoms of the piperidine ring in the chair conformation had changed. By means of X-ray analysis of the 3,7-diazabicyclononanes 8c, 15b, and 16b as well as of the 1,3-diazaadamantanones 12b and 20 the structures were determined and the preferred conformations, especially those of the aryl groups, in the crystalline state were established. Accordingly, all tetraaryl-3,7-diazabicyclononanes exist in the chair-boat conformation with equatorial aryl groups. Two of the five aryl substituents in 12b occupy a 1,3-diaxial position while the three neighbouring aryl groups exhibit an unexpected propeller-like arrangement.
Development of an ammonia sensor based on silver nanoparticles in a poly-methacrylic acid matrix

Samples of Ag nanoparticles (AgNPs) in a poly-methacrylic acid (PMA) matrix have been prepared by a photo-induced reduction process. They have been widely characterized by SEM, EDX-mapping, TEM, XRD and XPS measurements. The results have shown that the morphological and microstructural characteristics of AgNPs formed in a PMA matrix depend on the Ag/PMA molar ratio. Thick films of these samples deposited on ceramic substrates have also been prepared. The formation of Ag dendritic structures has been evidenced in samples with a low Ag/PMA ratio, whereas at a higher Ag/PMA ratio the film surface was found to be highly heterogeneous, along with an increase in Ag species in the ionic form. Loading AgNPs/PMA samples with multi-walled carbon nanotubes (MWCNTs) allowed production of conductive films suitable for sensing applications. The samples synthesized were investigated as sensing materials for fabricating ammonia (NH3) gas resistive sensors. The novel sensors developed are active at low temperature, exhibiting fast response/recovery times in a wide range of detection levels from ppm to v/v (%).
Particle sizes and electrophoretic mobilities of poly(N-isopropylacrylamide) latex

Les dimensions des particules et les mobilites electrophoretiques ont ete mesurees en fonction de la temperature. Les diametres des particules diminuent de 788 nm pour une temperature de 10°C a 380 nm pour une temperature de 50°C. Inversement, la mobilite electrophoretique augmente avec la temperature
Reactions of osmium tetraoxide with protein side chains and unsaturated lipids

The reactions of OsO4 with derivatives or model systems (L) for the side chains of tissue proteins have been studied, alone and in the presence of unsaturated lipids (R). The following new complexes have been isolated and their structures studied by vibrational and 1H n.m. r. spectroscopy: Os2O6L4(L =α-N-benzoyl-L-histidine isobutyl ester, imidazole, 1-methylimidazole, 5,6-dimethylbenzimidazole, n-butylamine, or α-N-benzoyl-DL-methionine); OsL2(L = glutathione or L-cysteine); the mixed species Os2O6L3L′(L = 1-methylimidazole, L′=L-proline methyl ester or α-N-benzoyl-L-arginine ethyl ester) and OsLL′n(L = 1-methylimidazole, L′=α-N-benzoyl-L-cysteine or α-N-acetyl-L-cysteine); OsO2(O2R)L2(R = cyclohexene, oleic acid, methyl oleate, or cholesteryl acetate; L = 1-methyl- and 5,6-dimethyl-benzimidazole, α-N-benzoyl-L-histidine isobutyl ester, or pyridine); Os2O4(O4R)L4 and Os3O6(O6R′)L6(R = methyl linoleate, R′= methyl linolenate; L = 1-methylimidazole). A possible role for OsO4 in cross-linking proteins and lipids in biological tissue fixation is discussed.
A New and Reproducible Surface-Enhanced Resonance Raman Scattering Method for the Determination of Trace Au(III) in Solution Using 4-Mercaptopyridine as Molecular Probe

In pH 6.5 Na2HPO4-NaH2PO4 buffer solution and in the presence of stable reagent PEG10000 and aggregation reagent NaCl, nanosilvers were aggregated to form stable aggregated-nanosilvers (ANS). The molecular probe of 4-mercaptopyridine (MP) adsorbed on the surface of ANS to form MP-ANS conjugates that produce strongest surface-enhanced resonance Raman scattering (SERRS) peak at 1097 cm-1. When Au(III) was added, the SERRS intensity at 1097 cm-1 decreased. The decreased SERRS intensity was linear to Au(III) concentration in the range of 5-50 ×10-10 mol/L, with a detection limit of 2.0×10-10 mol/L Au(III).
A Study of Pt Dissolution during Formic Acid Oxidation

The studies on Pt or Pt-alloy based catalysts for formic acid oxidation (FAO) have been focused mostly on their activity with little analysis of durability and long-term performance. While durability of Pt-based FAO catalysts has been associated with CO poisoning, recent studies have brought evidence of correlation between catalyst performance and dissolution of Pt. Aimed at assessing the impact of that correlation, a detailed quantitative durability analysis of Pt ultrathin films grown on Au by surface limited redox replacement of a Pb underpotentially deposited layer is presented in this work. Long-term catalytic performance of those films featuring well-defined thickness and structure has been examined by potential cycling in 2 M HCOOH+0.1 M HClO4 solution at sweep rate of 0.050 V s–1 over an extended potential range limited positively by the onset of Pt oxidation. A clear proportionality between overall life and thickness of the catalyst observed in the tests emphasizes the dissolution of Pt as the ke.
Catalytic Mechanism of the Enzyme Papain: Predictions with a Hybrid Quantum Mechanical/Molecular Mechanical Potential

A hybrid quantum mechanical/molecular mechanical approach is used to elucidate structural and energetic features of amide hydrolysis by the enzyme papain. The role of the enzyme in stabilizing the thiolate−imidazolium ion pair is examined and the potential energy pathway for the subsequent attack of the cysteine anion and proton transfer from the imidazolium cation is determined. The reaction is found to be concerted rather than stepwise, and the transition state for the reaction is located. The effect of residue mutations both on the ion pair stability and on the barrier to amide hydrolysis is explored and found to be in agreement with experiment. In this work both high-level electronic structure and semiempirical MO methods are used, with location and characterization of stationary structures. Rearrangement of the enzyme in response to the changing electronic structure of the active site is also considered.
Vapor-liquid equilibiriums of the trifluoromethane-trifluorochloromethane system

A specified composition of trifluoromethane and trifluorochloromethane, particularly 49-51 mol % trifluoromethane, is patented (I) and marketed as Refrigerant 503. An investigation of Refrigerant 503 has been published (IO) in which the equimolar mixture was treated as a pure material. In our continuing program of studies of the thermodynamic properties of mixtures of the more volatile fluorocarbons, it became of interest to determine the vapor-liquid equilibria of the trifluoromethane-trifluorochloromethane binary over the complete composition range. The temperature range covered was as wide as could be conveniently handled in our experimental apparatus. The highest temperature (32'F) was limited by the apparatus design which requires that equilibrium temperatures be lower than ambient temperature, and the lowest temperature (- 100°F) was limited by the requirement that the associated equilibrium pressures be large enough to permit extraction of sufficient phase samples for analysis.
Atomic Layer Deposition preparation of Pd nanoparticles on a porous carbon support for alcohol oxidation

To reduce the loading of noble metals on fuel cell catalysts a synthesis method providing evenly distributed nanoparticles on the support surface is needed. Narrow size distribution palladium nanoparticles were prepared on a porous carbon support by atomic layer deposition (ALD), and their activity for ethanol and isopropanol oxidation was studied electrochemically in alkaline media. Palladium particles had smaller average particle sizes on the support material resulting in ∼50 mV lower onset potential and 2.5 times higher mass activity for alcohol oxidation compared with a commercial catalyst. The results indicate that the use of ALD allows the preparation of a noble metal nanoparticle catalyst, and this catalyst can provide similar mass activity with lower catalyst loading than current commercial fuel cell catalysts. This would significantly reduce the cost of the cell and provide a competitive advantage compared with other power sources.
Solution Properties of Polymacromonomers Consisting of Polystyrene V. Effect of Side Chain Length on Chain Stiffness

Light scattering and viscosity measurements were made on cyclohexane and toluene solutions of a series of polymacromonomer samples consisting of polystyrene with 65 monomer units in each side chain to determine the z-average mean-square radius of gyration ‹s2›z and the intrinsic viscosity [η] as functions of the weight average molecular weight in a range from 2.9×105 to 8.6×106. The theta temperature for the polymacromonomer in cyclohexane was determined to be 34.5°C. The ‹s2›z data in this solvent at 34.5°C and toluene at 15°C (a good solvent) were quantitatively described by the wormlike chain with λ−1 (the Kuhn segment length)=36 nm and ML (the molecular weight per unit contour length)=25000 nm−1 in the former and with λ−1=75 nm and ML=25000 nm−1 in the latter. The molecular weight dependence of [η] in each solvent was also explained by this model chain when the end effect arising from side chains near the main-chain ends was taken into account. The above λ−1 values in the two solvents and the previous estimates for polystyrene polymacromonomers with shorter side chains were used to examine the dependence of the backbone stiffness on side chain length. It was found that λ−1 increases almost linearly with the side-chain molecular weight for both solvents but with a larger slope in toluene than in cyclohexane.
The coupled‐cluster method in high sectors of the Fock space

The coupled-cluster method is applied to high sectors of the Fock space (up to five electrons outside a closed shell). Ionization potentials and excitation energies are calculated for atomic N, O, F, P, and S and their ions. The effect of virtual triple excitations is included, exactly or at several levels of appoximation. These terms are important for accurate results in the high sectors. © 1995 John Wiley & Sons, Inc.