Quantum model of selective multiphoton processes: The role of external (field) and internal (anharmonic coupling) detunings

Quantum equations of motion describing the energy transfer dynamics via intramolecular anharmonic coupling are presented and solved numerically. Dynamical features of the average excitations of a homogeneous system (SF₆) and a heterogeneous system (H/W) are quantitatively discussed in terms of the intramolecular vibrational relaxation (IVR) rates. Possible mechanisms of surface-enhanced desorption via low-power laser radiation are proposed.This work was supported in part by the Office of Naval Research, the Air Force Office of Scientific Research (AFSC), United States Air Force, under Grant AFOSR-82-0046 and the National Science Foundation under Grant No. CHE-8022874Camille and Henry Dreyfus Teacher-Scholar (1975–82)     

The study and characterization of nucleosides by mass spectrometry—I: The mass spectra of pyrimidine 2,2′-anhydronucleosides and their derivatives

The mass spectra of 2,2′-anhydrouridine, 2,2′-anhydrothymidine and 2,2′-anhydro-4-thiouridine are reported. The acetyl, trifluoroacetyl, trityl, pivaloyl and trimethylsilyl ether derivatives were also studied. Deuterium labeling in acetyl and trimethylsilyl groups aided characterization of many ions in the spectra, as well as helping to clarify hydrogen migration processes. The anhydronucleosides and their derivatives are readily distinguished from natural nucleosides by the presence of an ion containing the base moiety plus the anhydro-ring plus one hydrogen atom from the rest of the molecule. As for natural nucleosides the [base + H]⁺ and [base + 2H]⁺ ions are usually prominent, but in contrast to natural nucleosides, ions characteristic of the sugar moiety do not retain the 2′-oxygen atom (i.e. the oxygen atom of the anhydro-ring). The mass spectra of deuterium labeled derivatives suggest a test for the presence of a 3′-O-acetyl function (the O-acetyl group is lost from the molecular ion much more readily from the 3′- than from the 5′-carbon atom). The trimethylsilyl derivatives showed evidence in their mass spectra for migration of trimethylsilyl groups in addition to hydrogen atoms.     

N(CH2CH2NH3)3][U3O2F13].2H2O: a novel organically templated mixed-valent uranium oxyfluoride with a hybrid network structure

The synthesis and characterization of a novel mixed-valent uranium oxyfluoride is described; the inorganic network consists of 2-D [U(2)F(10)](2)(-) sheets constructed from corner- and edge-sharing U(IV)F(9) tricapped trigonal prisms and 1-D [UO(2)F(3)](-) chains constructed from edge-sharing U(VI)O(2)F(5) pentagonal bipyramids with the organic cations and water molecules between the sheets. This is the first example with a hybrid network structure in the system of uranium fluoride or oxyfluoride. The variable-temperature magnetic susceptibility confirms the oxidation state of the uranium ions. Crystal data follow: C(6)H(25)N(4)O(4)F(13)U(3), monoclinic, space group P2(1) (No. 4); a = 8.6876(4) A, b = 7.3158(4) A, c = 16.3376(8) A, beta = 93.7285(9) degrees , V = 1036.2(2) A(3), and Z = 2.     

UV-ENHANCED REACTIVATION IN MAMMALIAN CELLS: INCREASE BY CAFFEINE

Abstract— It has been reported that caffeine decreases UV-enhanced reactivation of UV-irradiated Herpes simplex virus in CV-1 monkey kidney cells. That occurred when there was no delay between cell irradiation and virus infection. In the present study, virus infection was delayed following cell irradiation to allow an 'induction'period separate from the 'expression'period which occurs during the virus infection. Thus, the effects of caffeine on 'induction'and 'expression'could be determined separately. Caffeine increased the expression of UV-enhanced reactivation, while causing a small decrease in the 'induction'of enhanced reactivation.     

Skin Necrosis due to Photodynamic Action of Benzoporphyrin Depends on Circulating Rather than Tissue Drug Levels: Implications for Control of Photodynamic Therapy

In an ideal world, photodynamic therapy (PDT) of abnormal tissue would reliably spare the surrounding normal tissue. Normal tissue responses set the limits for light and drug dosimetry. The threshold fluence for necrosis (TFN) was measured in normal skin following intravenous infusion with a photosensitizer, benzoporphyrin derivative monoacid ring A (BPD-MA) Verteporfin as a function of drug dose (0.25-2.0 mg/kg), wavelength of irradiation (458 and 690 nm) and time interval (0–5h) between drug administration and irradiation. The BPD-MA levels were measured in plasma and skin tissue to elucidate the relationship between TFN, drug kinetics and biodistribution. The PDT response of normal skin was highly reproducible. The TFN for 458 and 690 nm wavelengths was nearly identical and the estimated quantum efficiency for skin response was equal at these two wavelengths. Skin phototoxicity, quantified in terms of 1/ TFN, closely correlated with the plasma pharmacokinetics rather than the tissue pharmacokinetics and was quadratically dependent on the plasma drug concentration regardless of the administered drug dose or time interval between drug and light exposure. This study strongly suggests that noninvasive measurements of the circulating drug level at the time of light treatment will be important for setting optimal light dosimetry for PDT with liposomal BPD-MA, a vascular photosensitizer.     

一些金属氧化物在TiO_2(锐钛矿)载体上的分散 嵌入模型的应用

一些金属氧化物在ＴｉＯ２（锐钛矿）载体上的分散＊嵌入模型的应用徐斌董林陈懿（南京大学化学系亚微观固态化学研究所，南京２１００９３）关键词嵌入模型，金属氧化物，分散容量，锐钛矿我们曾以γ－Ａｌ２Ｏ３，ＣｅＯ２和ＳｉＯ２为载体研究了离子化合物的分散，认为...     

Sesquiterpenoids and Phenylpropane Derivatives from Sonchus uliginosus

Six new compounds were isolated from the whole plant of Sonchus uliginosus, including three eudesmane‐type sesquiterpenoids (1β,6α)‐1,6,14‐trihydroxyeudesm‐3‐en‐12‐oic acid γ‐lactone ( 1 ), (1β,6α)‐1,6,14‐trihydroxyeudesma‐3,11(13)‐dien‐12‐oic acid γ‐lactone ( 2 ), and (1β,6α)‐1,6‐dihydroxy‐14‐O‐[(4‐hydroxyphenyl)acetyl]eudesma‐3,11(13)‐dien‐12‐oic acid γ‐lactone ( 3 ), and three phenylpropane derivatives, 4‐hydroxy‐γ,3,5‐trimethoxybenzenepropanol ( 6 ), γ,3,4,5‐tetramethoxybenzenepropanol ( 7 ), and γ,3,4,5‐tetramethoxybenzenepropanol acetate ( 8 ), together with the two known compounds 4 and 5 . The new structures were elucidated by means of spectroscopic methods, such as IR, EI‐MS, HR‐ESI‐MS, 1D‐ and 2D‐NMR, and by comparison of the spectroscopic data with those reported for structurally related compounds.     

铁电体爆-电换能的实验研究

使用掺铌PZT97.5/2.5铁电陶瓷样品在垂直工作模式下,进行了爆-电换能的实验研究。在电感-电容并联负载上获得了1360安的峰值电流;在电阻负载上获得了145×10³伏的峰值电压。实验结果与理论预计符合得比较好。 关键词：     

纤维素基磁性聚偕氨肟树脂吸附Mn（Ⅶ）

用酸处理的纤维素基磁性聚偕氨肟树脂（AMAO）在溶液中吸附KMnO4，发生氧化还原反应的几率在2％以下；用碱处理的树脂（BMAO）作吸附剂，KMnO4还原为Mn（OH）4的比例剧增，达到或超过10％，并且与溶液的pH有关。但是，Mn（Ⅶ）被还原为Mn（Ⅳ）的量基本上不受KMnO4起始浓度、吸附剂添加量和吸附时间变化的影响。BMAO树脂吸附KMnO4的量是树脂偕氨肟基含量的5倍以上。超当量吸附现象反映了物理吸附的本质。     

The Synthesis of Alanine Oligopeptides

The oligopeptides of alanine (penta-, deca-, and pentadeca-) were synthesized by solid phase method and new peptide-resin cleaving reagent TFA-BBr₃ was used to cleave the peptides from resin-support. Penta-alanine was also synthesized by liquid phase for the comparision and FAB-Mass method was used to determine the molecular weight of penta-alanine. HPLC separation of these new oligopeptides were described.