bluuebunny/crossref_metadata_2025_split huggingface dataset:
Persistent infrared spectral hole burning of NO−2 ions in potassium halide crystals. I. Principle and satellite hole generation
Authors: Ambrose W. P. , Sethna J. P. , Sievers A. J. 
Published: July 2002

New features are resolved within the internal vibrational mode spectra of NO−2 defects in KCl, KBr, and KI crystals at low temperatures using high-resolution Fourier transform spectroscopy and persistent infrared spectral hole (PIRSH) burning separately and together. With interferometry it has been discovered that the vibrational linewidths of the different modes range over a factor of 300—from 0.01 cm−1 to ∼3 cm−1 and, with PIRSH burning, it has been demonstrated that the narrowest lines are inhomogeneously broadened while the broadest ones are homogeneously broadened. PIRSH’s have been found in some internal modes and combination bands of the NO−2 molecule when pumped with low-intensity single-mode lead salt diode lasers; however, detectable persistent holes are not produced in all of the modes because of a competition between hole production and relaxation by tunneling at low temperatures. This competition results in a hole burning intensity, below which hole relaxation overwhelms hole production and only small holes may be produced.
The most unusually shaped absorption features are the V-shaped notches in the reorientational tunneling fine structure at the NO−2 bending mode frequency in KCl and KBr. Of all the internal modes that do show pronounced PIRSH burning, these V-notched absorption bands exhibit the most striking behavior. Multiple satellite PIRSH’s are detected at frequencies away from the single-mode laser burn frequency with a broadband probe beam produced by a high-resolution Fourier transform interferometer. An explanation for these satellite holes is derived from temperature, plastic deformation, and uniaxial stress dependence measurements on the KCl:NO−2 absorption spectrum. We find that the inhomogeneous broadening of the KCl:NO−2 ν2 reorientational tunneling fine structure is dominated by degenerate rotor level splitting produced by random crystal strains. Degenerate perturbation theory of the rotor level splitting in the strain field is found to match very closely the V-shaped inhomogeneous distribution of levels associated with the KCl:NO−2 reorientational tunneling fine structure. The general conclusion is that whenever strain splitting of a doubly degenerate level dominates the inhomogeneous broadening, then the absorption spectrum displays zero strength in the distribution at zero splitting and a linear increase in absorption coefficient away from this frequency generating the observed V-shaped notch in the absorption profile.
Resonance Raman spectroscopy of the B1u region of benzene: Analysis in terms of pseudo-Jahn–Teller distortion
Authors: Sension Roseanne J. , Brudzynski Richard J. , Li Shijian , Hudson Bruce S. , Zerbetto Francesco , Zgierski Marek Z. 
Published: July 2002

Raman spectra of benzene and benzene-d6 vapor obtained with excitation in the range from 208 to 188 nm are presented and discussed in terms of vibronic coupling of the resonant B1u state and the nearby E1u electronic state. The Raman spectra show strong activity in the binary overtones and combinations of the e2g modes ν8, ν9, and ν6 with the ν8 activity being dominant. (The Wilson numbering scheme for the modes of vibration is used throughout.) These bands, plus a progression in ν1 alone or in combination transitions involving two quanta of e2g modes, constitute the major intensity bands in the spectra. A simple first-order vibronic coupling model can be constructed which accounts adequately for most of the intensity in the Raman spectra observed in resonance with the B1u state, but this model results in a calculated absorption spectrum that is qualitatively different from that observed. The nature of the discrepancy indicates a significant Duschinsky mode rotation in the B1u state relative to the ground state. An analysis of the vibronic coupling of the B1u state with the nearby E1u state is performed using semiempirical calculation methods to provide excited state geometries, vibrational frequencies, and vibronic coupling parameters.
This analysis confirms that there is strong vibronic coupling between these states resulting in a pseudo-Jahn–Teller effect. This results in a highly distorted potential surface for the B1u state with three D2h symmetry antiquinoidal minima lower in energy by ∼1000 cm−1 than the D6h symmetry geometry. The three minima of the threefold symmetric potential surface are separated by local maxima corresponding to the quinoidal geometry with a height of ∼300 cm−1. Three of the four e2g modes are calculated to have significant vibronic activity with mode 8 much stronger than modes 6 or 9. A small Jahn–Teller coupling is calculated. A strong Duschinsky rotation results from the vibronic activity of more than one mode. The absorption spectrum and the resonance Raman spectra calculated from this model are in good agreement with the experimental results. This analysis provides the first evidence for the expected pseudo-Jahn–Teller instability of the isolated 1B1u state of benzene.
Multiphoton ionization studies of C6H6–(CH3OH)n clusters. II. Intracluster ion–molecule reactions
Authors: Garrett Aaron W. , Zwier Timothy S. 
Published: July 2002

The neutral C6H6–(CH3OH)n clusters, which have been spectroscopically characterized in Paper I, serve here as precursors for the study of intracluster ion chemistry initiated by resonant two-photon ionization. Resonant enhancement allows ion chemistry product yields to be determined as a function of cluster size by selective excitation of a single size cluster with the laser. Most of the work presented here uses one-color resonant ionization via the 610 transition of the C6H6 chromophore in the cluster. No ion chemistry is observed for the 1:n clusters with n≤2. At n=3, dissociative electron transfer (DET) to form C6H6+M+3 (M=CH3OH) is observed with a product yield of 6%. The remaining 94% of ionic products result from fragmentation of the 1:3 cluster by loss of a single CH3OH molecule. The unprotonated M+3 product ion is unusual in that electron bombardment or photoionization of pure methanol clusters yields exclusively protonated methanol cluster ions. The attachment of a C6H6 molecule to the methanol cluster provides an extremely gentle photoionization mechanism which produces M+3 with little enough internal energy to preclude its breakup to M2H++CH2OH (or CH3O ). The opening of this product channel at n=3 is consistent with estimates of the ionization potential of Mn clusters which predict an endothermic ET reaction at n=2 which becomes exothermic at n=3.
Despite the increasingly exothermic DET and dissociative proton transfer product channels, larger clusters (n≥4) continue to predominantly undergo unreactive fragmentation. For the 1:4 and 1:5 clusters, in addition to DET products, dissociative proton transfer (DPT) products are also observed. The MnH+ product arises from proton transfer from C6H+6, while Mn−1H+ probably occurs by DPT within the M+n cluster following loss of C6H6 in DET. Scans of the 1:2–1:5 clusters through their 610110 transitions yield a broader set of products which reflect the 5 kcal/mol increase in the reactant (1:n)+ cluster internal energies.
Modulation of the decrease in the seizure threshold of pentylenetetrazole in diazepam withdrawn mice by the neurosteroid 5αpregnan‐3α,21‐diol‐20‐one (alloTHDOC)
Authors: TSUDA MAKOTO , SUZUKI TSUTOMU , MISAWA MIWA 
Published: July 2002

AbstractThe effect of the neurosteroid 5α‐pregnan‐3α,21‐diol‐20‐one (alloTHDOC) on pentylenetetrazole (PTZ)induced diazepam‐withdrawal seizure was examined in mice. The threshold for PTZ‐induced seizure was markedly decreased by discontinuation of chronic diazepam treatment. The decrease in the seizure threshold of PTZ during diazepam withdrawal was significantly attenuated by pretreatment with alloTHDOC (10 and 20 mug/mouse, i.c.v.), which did not affect the seizure threshold of PTZ in chronically vehicle‐treated mice. However, the loss of the righting reflex (LRR) induced by other GABAA receptor activators (pentobarbital and propofol) did not differ between control and diazepam‐withdrawn mice. These findings provide the first demonstration that alloTHDOC may be able to suppress diazepam withdrawal signs, and that the sensitivity to the pharmacological effect of alloTHDOC via GABAA receptor may be enhanced in diazepam‐with‐ drawn mice.
Sleep, alcohol and alcohol abuse
Authors: VITIELLO MICHAEL V. 
Published: July 2002

AbstractAbstract Use and abuse of alcohol is extremely common in many countries. Sometimes alcohol may be used to self‐treat insomnia. However, alcohol consumption for any reason will affect an individual's sleep quality. The effects of alcohol use and abuse on sleep are complex and interactive. Anyone who consumes alcohol is likely to observe them, although the particular pattern and severity of the sleep impairment will differ with both the amount and duration of alcohol consumption. The fact that alcohol is a sedative and can induce rapid onset of sleep may contribute to its use, while the resultant disturbance of night‐time sleep quality and of respiration may possibly result in post‐consumptive daytime impairment. The persistent sleep disturbance that accompanies both acute and chronic alcohol abstinence syndromes may contribute to the continued craving and urge to resume drinking seen among chronic alcoholics. This review broadly examines the interaction of alcohol consumption and sleep disturbance. Beginning with a brief overview of normal sleep it examines the effects of modest acute alcohol consumption on sleep, sleepiness, night‐time respiration and cognitive function; examines the sleep patterns of chronic alcoholics both while drinking and during acute and chronic alcohol withdrawal; reviews what is known of the relationship between alcohol use and night‐time respiratory dysfunction; and concludes with some reflections on the implications of this information for drinking practices.
Identification of sequence-dependent DNA features correlating to activity of DNA sites interacting with proteins.
Authors: Ponomarenko M P , Ponomarenko J V , Frolov A S , Podkolodny N L , Savinkova L K , Kolchanov N A , Overton G C 
Published: July 2002

Abstract
MOTIVATION: The commonly accepted statistical mechanical theory is now multiply confirmed by using the weight matrix methods successfully recognizing DNA sites binding regulatory proteins in prokaryotes. Nevertheless, the recent evaluation of weight matrix methods application for transcription factor binding site recognition in eukaryotes has unexpectedly revealed that the matrix scores correlate better to each other than to the activity of DNA sites interacting with proteins. This observation points out that molecular mechanisms of DNA/protein recognition are more complicated in eukaryotes than in prokaryotes. As the extra events in eukaryotes, the following processes may be considered: (i) competition between the proteins and nucleosome core particle for DNA sites binding these proteins and (ii) interaction between two synergetic/antagonist proteins recognizing a composed element compiled from two DNA sites binding these proteins. That is why identification of the sequence-dependent DNA features correlating with affinity magnitudes of DNA sites interacting with a protein can pinpoint the molecular event limiting this protein/DNA recognition machinery. RESULTS: An approach for predicting site activity based on its primary nucleotide sequence has been developed. The approach is realized in the computer system ACTIVITY, containing the databases on site activity and on conformational and physicochemical DNA/RNA parameters. By using the system ACTIVITY, an analysis of some sites was provided and the methods for predicting site activity were constructed. The methods developed are in good agreement with the experimental data. AVAILABILITY: The database ACTIVITY is available at http://wwwmgs.bionet.nsc.ru/systems/Activity/ and the mirror site, http://www.cbil.upenn.edu/mgs/systems/acti vity/.
Strategies for the development of a peptide computer
Authors: Hug Hubert , Schuler Rainer 
Published: July 2002

Abstract
Motivation: We devise a computational model using protein–protein interactions.
Results: Peptide–antibody interactions can be used to perform a large number of small logical operations in parallel. We show for example how a sequence of operations can be used to compare the number of occurrences of an element in two sets and how to estimate the number of occurrences of an element in a set. Similar to DNA-computing, these techniques could in principle be extended to solve instances of NP-complete problems. We give as an example a procedure to solve examples of the satisfiability problem.
Contact: hubert.hug@medizin.uni-ulm.de; schuler@informatik.uni-ulm.de
* To whom correspondence should be addressed.
A comparative study of the in-vitro activity of levofloxacin against Streptococcus pneumoniae
Authors: Reinert R. R. , Lütticken R. , Lemperle M. , Bryskier A. 
Published: July 2002

Abstract
In this study, the in-vitroactivity of levofloxacin against Streptococcus pneumoniae was compared with the activities of a range of other antibiotics. In total, 320 penicillin-susceptible and 30 penicillin-intermediate clinical isolates of S. pneumoniae were collected in Germany between 1992 and 1994 from patients with bacteraemic pneumonia. MICs were determined using the agar dilution methodology recommended by the NCCLS and the results with levofloxacin compared with those with ofloxacin, d -ofloxacin, ciprofloxacin, amoxycillin, cefpodoxime, cefixime, cefuroxime, faropenem, erythromycin and tetracycline. Levofloxacin (MIC 50 1 mg/L) was approximately twice as active against the isolates as ofloxacin (MIC 50 2 mg/L). d -ofloxacin (MIC 90 32 mg/L) showed no activity, while β-lactam antibiotics showed elevated MIC 90 values against penicillin-intermediate strains (amoxycillin, 1 mg/L; cefpodoxime, 2 mg/L; cefixime, 32 mg/L; cefuroxime, 8 mg/L) in comparison with the MIC 90 obtained with penicillin-susceptible strains (amoxycillin, 0.015 mg/L; cefpodoxime, 0.03 mg/L; cefixime, 0.5 mg/L; cefuroxime, 0.03 mg/L). Faropenem showed good activity against pneumococcal isolates (penicillin-susceptible strains, MIC 90 0.016 mg/L; penicillin-intermediate strains, MIC 90 0.25 mg/L). Erythromycin (MIC 90 8 mg/L) and tetracycline (MIC 90 64 mg/L) were also less active against penicillin-intermediate pneumococcal isolates. In conclusion, levofloxacin and faropenem may be useful in the treatment of pneumococcal infections caused by organisms with decreased susceptibility to penicillin.
Structural studies of the pigeon cytosolic NADP+‐dependent malic enzyme
Authors: Yang Zhiru , Zhang Hailong , Hung Hui‐Chi , Kuo Chen‐Chin , Tsai Li‐Chu , Yuan Hanna S. , Chou Wei‐Yuan , Chang Gu‐Gang , Tong Liang 
Published: July 2002

AbstractMalic enzymes are widely distributed in nature, and have important biological functions. They catalyze the oxidative decarboxylation of malate to produce pyruvate and CO2 in the presence of divalent cations (Mg2+, Mn2+). Most malic enzymes have a clear selectivity for the dinucleotide cofactor, being able to use either NAD+ or NADP+, but not both. Structural studies of the human mitochondrial NAD+‐dependent malic enzyme established that malic enzymes belong to a new class of oxidative decarboxylases. Here we report the crystal structure of the pigeon cytosolic NADP+‐dependent malic enzyme, in a closed form, in a quaternary complex with NADP+, Mn2+, and oxalate. This represents the first structural information on an NADP+‐dependent malic enzyme. Despite the sequence conservation, there are large differences in several regions of the pigeon enzyme structure compared to the human enzyme. One region of such differences is at the binding site for the 2′‐phosphate group of the NADP+ cofactor, which helps define the cofactor selectivity of the enzymes. Specifically, the structural information suggests Lys362 may have an important role in the NADP+ selectivity of the pigeon enzyme, confirming our earlier kinetic observations on the K362A mutant. Our structural studies also revealed differences in the organization of the tetramer between the pigeon and the human enzymes, although the pigeon enzyme still obeys 222 symmetry.
Atomic Layer Deposition of CoxOy Films: Oxidants versus Composition
Authors: Wan Zhixin , Zhang Teng Fei , Zeng Zhihao , Xi Bin 
Published: April 2022

AbstractCobalt oxides (CoxOy) have shown great potential for applications in catalysts, sensors, and energy storage fields, and their performance remarkably depends on their oxidation states. Herein, CoxOy films with precisely controlled composition are first introduced by atomic layer deposition (ALD) using bis(N,N0‐di‐iso‐propylacetamidinato)cobalt(II) (Co(iPr2‐Me‐AMD)2) as Co precursor and H2O/O3 as oxidants. The results show that the ALD processes using both oxidants exhibit typical self‐limiting characteristic, where cubic‐CoO films, with growth rate of 0.045 nm per cycle, are obtained at 150–200 °C using H2O oxidant, while cubic‐Co3O4 films, with growth rate of 0.05 nm per cycle, can be deposited at 200–225 °C using O3 oxidant. Both CoO and Co3O4 films show dense, smooth microstructure, and good crystallinity with typical columnar crystal feature, where the Co3O4 film shows smaller columnar size because the O3 promotes rapid nucleation with relatively higher density of nucleation sites. The thermodynamic growth mechanism of ALD process is established via density functional theory calculations, which demonstrates that the exothermic reaction path of O3 is more energetically than that of H2O. Both films possess relatively low resistivity of ≈10−1 Ω cm−1 with p‐type semiconductor behavior, which shows promising application potentials of these films.
Printed Chalcogenide/Metal Heterostructured Photodetectors for Flexible Near‐Infrared Sensing
Authors: Wang Jianyang , Pan Qi , Xie Hongfei , Ma Ying , Su Meng , Chen Binda , Wang Huadong , Xue Tangyue , Zhang Zeying , Chi Jimei , Li Siyi , Song Yanlin 
Published: April 2022

AbstractNear‐infrared (NIR) photodetectors can be fabricated for various applications, such as imaging, military tracking, and medical diagnosis. However, achieving miniaturization and high responsivity for NIR photodetector arrays is still a challenge. In this study, a high‐density NIR photodetector array with a micro/nano chalcogenide and silver nanoparticle heterostructure is achieved using a low‐cost printing strategy. The Ag/Ge2Sb2Te5(GST)/Ag heterostructure is fabricated using a template‐assisted sequential printing strategy. At an absorption wavelength of λ = 980 nm, the NIR photodetector has a high light responsivity of 6.7 × 104 A W−1 owing to the high crystallinity of the GST microwire and refined GST/Ag heterointerface during the printing process. In addition, the sensing pixel interval can be reduced to 25 µm, corresponding to the highest resolution of NIR photodetectors achieved thus far (resolution: 1.0 × 103 dpi). In addition, the NIR photodetector printed on soft substrates exhibits flexibility. Thus, a simple and effective strategy for the fabrication of NIR photodetectors is demonstrated, and precise flexible infrared sensing is achieved.
Theoretical Study on Thermoelectric Performance of N‐Type Mg3(Sb,Bi)2 Single Crystal for Cooling or Power Generation
Authors: Li Juan , Zhang Shuai , Zheng Shuqi , Han Kai , Sun Bing , Bi Zuozhang , Wang Xinle 
Published: April 2022

AbstractMg3Sb2‐based Zintl compounds have been paid much attention in recent years because of their high peak figure of merit (zT), however, there is room for the improvement of the average zT. In this work, the thermoelectric performance of Mg3(Sb,Bi)2 single crystal by using density functional theory is investigated. The optimal carrier concentration (n) of Mg3SbBi is 2 × 1019 to 3 × 1020 cm–3 at 100−700 K. At the n of 3 × 1019 cm–3, it can exhibit a high average zT of ≈1.27 at cold‐side temperature (Tc) of 300 K and hot‐side temperature (Th) of 700 K, and the electrical transport performance can be further improved by increasing the n. When the optimal n is reached, the maximum average zT of Mg3SbBi at Tc of 100 K and Th of 300 K can be up to 0.54, which is comparable to that of state‐of‐the‐art Bi2(Te,Se)3. Because the decreasing trend of the optimal n with temperature, the maximum low‐temperature thermoelectric performance is easier to be achieved by less extrinsic doping. This work reveals the great potential of Mg3(Sb,Bi)2 single crystal for thermoelectric cooling or power generation, which is expected to provide useful guidance for thermoelectric devices.
Artificial Olfactory Neuron for an In‐Sensor Neuromorphic Nose
Authors: Han Joon‐Kyu , Kang Mingu , Jeong Jaeseok , Cho Incheol , Yu Ji‐Man , Yoon Kuk‐Jin , Park Inkyu , Choi Yang‐Kyu 
Published: April 2022

AbstractA neuromorphic module of an electronic nose (E‐nose) is demonstrated by hybridizing a chemoresistive gas sensor made of a semiconductor metal oxide (SMO) and a single transistor neuron (1T‐neuron) made of a metal‐oxide‐semiconductor field‐effect transistor (MOSFET). By mimicking a biological olfactory neuron, it simultaneously detects a gas and encoded spike signals for in‐sensor neuromorphic functioning. It identifies an odor source by analyzing the complicated mixed signals using a spiking neural network (SNN). The proposed E‐nose does not require conversion circuits, which are essential for processing the sensory signals between the sensor array and processors in the conventional bulky E‐nose. In addition, they do not have to include a central processing unit (CPU) and memory, which are required for von Neumann computing. The spike transmission of the biological olfactory system, which is known to be the main factor for reducing power consumption, is realized with the SNN for power savings compared to the conventional E‐nose with a deep neural network (DNN). Therefore, the proposed neuromorphic E‐nose is promising for application to Internet of Things (IoT), which demands a highly scalable and energy‐efficient system. As a practical example, it is employed as an electronic sommelier by classifying different types of wines.
RETRACTED: Research on the mechanism and efficiency of agricultural products logistics transportation based on big data
Authors: Liu Huiyi 
Published: April 2022

AbstractIn order to improve the efficiency of agricultural product logistics transportation, based on big data technology, this paper starts from the factors that affect the efficiency of agricultural product logistics and combines big data technology to conduct the research on the mechanism and efficiency of agricultural products logistics transportation. Moreover, this paper analyzes how to improve the efficiency of agricultural product logistics by studying the dynamic relationship between influencing factors and the efficiency of agricultural product logistics. At the same time, this paper takes the efficiency evaluation of agricultural product logistics transportation network as the research object to improve the agricultural product data analysis algorithm, and constructs the system model from the perspective of the supply chain. In addition, this paper constructs system function modules according to the actual needs of agricultural product logistics transportation, and analyzes agricultural product transportation logistics by factor analysis. Finally, this paper verifies the effect of the model proposed in this paper through experimental research. From the test results, it can be seen that the model proposed in this paper basically meets the actual needs.