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Numerous members of the Brassicaceae possess non-photoconvertible water-soluble chlorophyll (Chl)-binding proteins (Class II WSCPs), which function as Chl scavengers during cell disruption caused by wounding, pest/pathogen attacks, and/or environmental stress. Class II WSCPs have two extension peptides, one at the N-terminus and one at the C-terminus. The N-terminal peptide acts as a signal peptide, targeting the protein to the endoplasmic reticulum body, a unique defensive organelle found only in the Brassicaceae. However, the physiological and biochemical functions of the C-terminal extension peptide had not been characterized previously. To investigate the function of the C-terminal extension peptide, we produced expression constructs of recombinant WSCPs with or without the C-terminal extension peptide. The WSCPs used were of Brussels sprouts (Brassica oleracea), Japanese wild radish (Raphanus sativus) and Virginia pepperweed (Lepidium virginicum). The solubility of all of the WSCPs with the C-terminal extension peptide was drastically lower than that of the recombinant WSCPs without the C-terminal extension peptide. In addition, the stability of the reconstituted WSCPs complexes with the C-terminal extension peptide was altered compared with that of the proteins without the C-terminal extension peptide. These finding indicate that the C-terminal extension peptide affects not only the solubility, but also the stability of Class II WSCP. Furthermore, we characterized the Chl-binding properties of the recombinant WSCP from Japanese wild radish (RshWSCP-His) in a 40 % methanol solution. An electrophoretic mobility shift assay revealed that RshWSCP-His required a half-molar ratio of Chls to form a tetramer.

The title compound, C10H12O8, a prospective raw material for colourless polyimides which are applied to electronic and microelectronic devices, lies about an inversion centre and the cyclohexane ring adopts a chair conformation. Two crystallographycally independent carboxylic acid groups on adjacent C atoms are in equatorial positions, resulting in a mutually trans conformation. In the crystal, O—H...O hydrogen bonds around an inversion centre and a threefold rotoinversion axis, respectively, form an inversion dimer with an R 2 2(8) motif and a trimer with an R 3 3(12) motif.

Phosphorescence measurements were performed for 6H-benzo[cd]-pyren-6-one (l), 2-nitro-benzo[hi]chrysen- 13-one (2), 2-bromo-di-benzo[a, de]anthracen- 13-one (3), and 7H-benzo[hi]chrysen-7-one (4) in an ethanol-ether-toluene mixed solution and the character of their lowest excited triplet (T1) states were investigated. The phos horescence of the compounds appears at about 5,200 – 6,000 cm−1 to the red of their fluorescence, indicating that the T, states have ππ* character. On the other hand, the short phosphorescence lifetimes, 10 – 60 ms, suggest nπ* transitions. Such a duality of the T1 state seems to be characteristic of large polycyclic aromatic ketones. The polarized emission study revealed that the duality is ascribed to strong mixing of ππ* and nπ* natures.

Nitration of three isomeric dibenzanthrones, 13H-dibenzo[a,de]-anthracene-13-one(3), 7H-benzo[hi]chrysene-7-one(4), and 7H-dibenzo[a,kl]anthracene-7-one(5), with concentrated nitric acid was studied under various conditions. The nitration of (3) at 15 °C in 1,1,2,2-tetrachloroethane gave the 5-nitro derivative. The nitration of (4) in boiling acetic acid produced the 9-nitro derivative. The nitration of (5) at 70 °C in acetic acid gave the 5-nitro derivative. These nitro compounds are very useful in synthesizing undecacyclic aromatic hydrocarbons.

Two kinds of water-soluble chlorophyll (Chl) proteins (WSCPs) have been found, e.g., a WSCP from Chenopodium, Atriplex, Polygonum, and Amaranthus species (class I) and that from Brassica, Raphanus, and Lepidium species (class II). Classes I and II WSCPs differ mainly in their photoconvertiblity. Class I WSCPs show a light-induced absorption change, whereas Class II WSCPs do not. The molecular and functional properties of Class I WSCP are largely uncertain. On the other hand, recent studies on the adaptation of plants to osmotic stress revealed the participation of drought-stress induced proteins with molecular masses of 20-22 kDa possessing a sequence similarity with class II WSCPs. This mini review focuses on the molecular signature of class II WSCPs. The physiological function of class II WSCPs has not been clarified either, but, their water-solubility, low Chl content, and stress-inducibility suggested little contribution to photosynthesis. Several molecular properties predicting its physiological role are as follows. The WSCP tetramer, may have only one or no Chl molecules in each subunit. All WSCPs possess a motif for Künitz-type proteinase inhibitor family in their sequence. WSCP is induced by drought- and heat-stresses suggesting its protective role during stress conditions. Monomeric recombinant apo-WSCP is able to remove Chls from the thylakoid membrane in aqueous solution and form into a tetramer. Brassica-WSCP contains a signal sequence targeted to endoplasmic reticulum. The highly conserved, C-terminal region is missing in the mature WSCP. Possible functions of class II WSCPs in plant tissues are discussed.

Background. Chorioamnionitis (CAM) may accelerate lung maturation in fetuses. It is possible that CAM prevents infant death after live birth.Methods. A retrospective study of live-born singletons at

Summary A water-soluble chlorophyll (Chl) protein (WSCP) from the main veins of the Japanese radish, Raphanus sativus L. var. hortensis , was purified and characterized. We sequenced 26 N-terminal residues of the Raphanus-WSCP and found a complete signature motif of Kunitz proteinase inhibitors, as in WSCPs from other Brassicaceae plants. The Raphanus-WSCP sequence shared 92% identity with that of a Lepidium-WSCP; however, the antibody against recombinant Lepidium-WSCP did not recognize the Raphanus-WSCP, indicating that the N-terminal region may not be a major antigenic epitope. On the other hand, while the absorption spectrum of the red band of the Raphanus-WSCP was distinct from that of the Lepidium-WSCP, it was similar to that of Brassica-WSCP. Spectrophotometric and spectrofluorometric analyses of Raphanus-WSCP from the main veins revealed that the red band was comprised of four Chl a and one Chl b forms. In addition, this WSCP contained an intense absorption component with a peak at 698 nm, which is not prominent in WSCP from Raphanus leaflets. As an initial step in determining its molecular structure, the Raphanus-WSCP was crystallized. A green, parallelepiped, single crystal was obtained. This is the first characterization and crystallization of WSCP from the genus Raphanus, which is the third documented genus possessing WSCP in Brassicaceae plants.

Shadow is something we experience in our daily lives and a significant obstacle to our work. So shadow has been considered one of the important factors in lighting design. In this paper, the illuminance distributions on a desk as the working plane when Task Ambient Lighting, which is one type of office lighting systems, and a globe as a shadow caster are set up in a model room containing fixtures are obtained by the Monte Carlo method and the characteristics of the shadow are examined. First, in order to carry out the illuminance calculation by the Monte Carlo method in the case of a light source with a non-uniform diffuse distribution, the relationship between the cumulative luminous flux and uniform random numbers was found by the use of division mensuration. Next, some experiments were made under the same conditions as the calculations. Comparing the experimental results with the calculated results, difference between them, confirms that the above method is suitable. Then, we obtained and examined the shadow characteristics on the surface of the desk when the position of the shadow caster was changed. As a result, we found that Task Ambient Light makes a weaker shadow than one of Task light or Ambient light, and variations in the shadow area by Task Ambient Light are similar to those by Task light.

We report a fetus with a giant neck hemangioma which was examined by MRI in utero. The initial diagnosis was made by ultrasonography. The sonolucent aspect of the mass, together with the presence of pulsating Doppler flow signals, was highly suggestive of a fetal hemangioma. In late pregnancy, fetal MRI revealed the location, size and characteristics of the neck tumor. Following prenatal corticosteroid treatment and premature delivery of the pregnancy due to fetal cardiac failure, the newborn received angiography and coil embolization of the tumor vessels. Despite vigorous treatments, the newborn died 12 h after birth. Evaluation of a fetal neck hemangioma by MRI is recommended late in pregnancy for precise information on the tumor and adjacent organs since the image is valuable for planning optimal perinatal treatment.

Dibenzo[h,rst]naphtho[8,1,2-cde]pentaphcne (9) has been synthesized by the condensation of a mixture of 1-phcnalenone (1) and 13H-dibenz[a,de]anthracene-13-one (2) with zinc dust in the presence of ZnCl2 and NaCl. On the other hand, dibenz[a,lmn]anthra[1,2,9-hij]perylene (17) has been synthesized by Ullmann reaction of bromo derivative of benz[a]anthracene-7,12-dione (11).

The structure of the polycyclic aromatic hydrocarbon with the absorption maximum at 567 nm, synthesized by the condensation of naphth- anthrone (NT), was deduced to be benzo[rs]dinaphtho[2, 1, 8, 7-klmn:2, 3, 4, 5, 6-vwxyz]hexaphene (BDH) by semi-empirical molecular orbital calculation methods. The photooxygenation of BDH and benzo[op]naphtho[2, 1, 8, 7-hijk]anthra[2, 1, 9, 8-stuva]-pentacene (BNAP) due to irradiate to light with each absorption maximum was investigated by measurering the absorption spectra and applying semi-empirical molecular orbital calculation methods. BNAP is synthesized by the same reaction process together with dibenzo[de:op]dinaphtho[2, 1, 8, 7-hijk : 2′, 1′, 8′, 7′-syuv]pentacene (DDP). BNAP and BDH do not undergo photooxygenation. On the other hand, DDP undergoes photooxygenation. The empirical results were illustrated in terms of difference in heat of reaction, which were 25.5 and 30.2 kJ/mol for BDH and BNAP, respectively. Their values are considerably larger than -3....

The fluorescence spectra of three isomeric dibenzoanthrones, 13H-dibenzo[a, de]anthracen-13-one (1), 13H-benzo[hi]chrysen-13-one (2), and 7H-dibenzo[a, kl]anthracen-7-one (3), in an ethanol-ethertoluene mixed solution were measured as a function of the sample temperature (T). The three molecules provided individual T-dependences of fluorescence spectra. The spectra of 1 changed usually; as T was decreased, they were intensified, showing a vibrational structure more clearly. 2 fluoresced very weakly and the spectra were almost insensitive to T; it also phosphoresced at low temperatures. The spectra of 3 exhibited only a broad band and, strangely enough, it was reduced with decreasing T. The peculiar T-dependence of the fluorescence spectra of 2 and 3 was explained in terms of the results obtained by molecular orbital calculations.

1H NMR spectra of a series of high-spin (meso-tetraalkylporphyrinato)iron(III) chlorides, [Fe(TRP)Cl] where R = Me, Et, Pr, or iPr, have been measured at various temperatures in CD2Cl2 solution. In the case of the Et, Pr, and iPr complexes, either the methyl or the methylene signal split into two signals with equal integral intensities at low temperature. In contrast, the Me complex did not show any splitting even at −100 °C. The results have been ascribed to the hindered rotation of the meso-alkyl groups about Cmeso−Cα bonds. The activation free energies for rotation have been determined as 8.0 (−72 °C), 8.5 (−60 °C), and 8.9 (−62 °C) kcal·mol-1 for the Et, Pr, and iPr complexes, respectively, at coalescence temperatures given in parentheses. The small activation free energy for rotation of the isopropyl groups observed in the present system is explained in terms of the nonplanarity of the porphyrin ring, which has been verified both by the X-ray crystallographic analysis and by the EPR spectrum taken in...

BACKGROUND The effects of discrepancies in the birth weight and hemoglobin concentration ([Hb]) at the birth on infant outcome have not been fully investigated in monochorionic (MC) and dichorionic (DC) twins. METHODS A retrospective study of 95 twin pregnancies. All 190 neonates (68 MC twins and 122 DC twins) were admitted to the neonatal intensive care unit, and the [Hb] was determined soon after birth. The [Hb] discordance represents the [Hb] of the smaller twin expressed as a percentage of the [Hb] of the larger twin. Infants were followed-up until 1 year of corrected age and their psychomotor development was evaluated between 12 and 18 months. RESULTS One DC infant died by 1 year of age. Twelve MC infants and eight DC infants had disabilities by 1.5 year of age. In the MC group, 11 infants (28%) of 20 pairs with an intertwin [Hb] discordance >100 had disabilities compared with one (3.6%) of 14 pairs with an [Hb] discordance < or = 100 (p

Two kinds of model compounds for a bichromophoric ester, 2-(1-pyrenyl)ethyl p-cyanobenzoate (P2CN), were synthesized: 1-substituted 2-(1-pyrenyl)ethyl p-cyanobenzoates (RP2CN, R = Me, Et, and Ph) as flexible model compounds and trans-2-(1-pyrenyl)cyclohexyl p-cyanobenzoate (cyclo-P2CN) as a rigid model compound. P2CN and all the model compounds had an intramolecular exciplex emission (φEX ≈ 0.010) and efficient quenching of fluorescence from the locally excited pyrene part (φLE ≈ 0.001). The decay lifetimes of the locally excited pyrene were 365 ps for P2CN and 66 ps for cyclo-P2CN, which were respectively identical with the risetime for the exciplex formation. The 1H NMR of both P2CN and RP2CN showed the shifts of H2″ and H3″ of the p-cyanobenzoyl to the higher and H10′ of 1-pyrenyl signals to the lower magnetic field compared with those of the reference compounds, approaching towards those of cyclo-P2CN. NOE was observed between H10′ and H2″ of cyclo-P2CN, and, although very weak, between H2′ and H3″ of...

Objectives: We examined the effects of daily vaginal disinfection on the interval between premature rupture of the membranes (PROM) and delivery and on infant outcome. Methods: Daily vaginal disinfection with povidone iodine was performed on 43 women with PROM. The control group consisted of 59 women with PROM who did not undergo vaginal disinfection. In both groups, the infants born to these women were followed until 1 year of corrected age. Results: The degree of cervical dilatation, the leukocyte count, and the serum C-reactive protein level on admission did not differ between the 2 groups. Although there was no difference in the gestational week at delivery between the groups, the interval between PROM and delivery was significantly longer in the disinfectant group than among the control subjects (9.5 ±14.9 days vs. 3.9 ±5.1 days, p < 0.01). There was no difference in infant outcome between the 2 groups. Conclusions: These findings suggest that daily vaginal disinfection with povidone iodine prolongs the duration of gestation in women with PROM and dose not have an adverse effect on the fetus.

This paper describes a simulation model for estimating radical changes in the location of retail facilities that is applied to the Fukuoka metropolitan area of Japan. The model has three important characteristics. First, it clears the retail employment by applying multiple regression analysis and a modified Huff model incorporating distance and population. Secondly, it allocates retail employment for two types of retail stores: convenience-goods stores and shopping-goods stores. Thirdly, it computes commercial floor area for each retail type.

The crystal structure of an endoperoxide of tetrabenzo[de,hi,op,st]pentacene (TBPA-O2) was determined by X-ray crystallography. The unusually long OO and CO bonds were rationalized by the characteristic molecular structure of TBPA-O2. The photochromic behavior between TBPA-O2 and TBPA was discussed based on the enthalpy difference between TBPA-O2 and TBPA + O2 and the thermodynamic parameters of the extrusion reaction of oxygen from TBPA-O2.

Various plants possess hydrophilic chlorophyll (Chl) proteins known as water-soluble Chl-binding proteins (WSCPs). WSCPs exist in two forms: Class I and Class II, of which Class I alone exhibits unique photoconvertibility. Although numerous genes encoding Class II WSCPs have been identified and the molecular properties of their recombinant proteins have been well characterized, no Class I WSCP gene has been identified to date. In this study, we cloned the cDNA and a gene encoding the Class I WSCP of Chenopodium album (CaWSCP). Sequence analyses revealed that CaWSCP comprises a single exon corresponding to 585bp of an open reading frame encoding 195 amino acid residues. The CaWSCP protein sequence possesses a signature of DUF538, a protein superfamily of unknown function found almost exclusively in Embryophyta. The recombinant CaWSCP was expressed in Escherichia coli as a hexa-histidine fusion protein (CaWSCP-His) that removes Chls from the thylakoid. Under visible light illumination, the reconstituted CaWSCP-His was successfully photoconverted into a different pigment with an absorption spectrum identical to that of native CaWSCP. Interestingly, while CaWSCP-His could bind both Chl a and Chl b, photoconversion occurred only in CaWSCP-His reconstituted with Chl a.

The photooxygenation of tetrabenzo[a,cd,j,lm]perylene (TBP) and tribenzo[a,h,rst]phenanthra[10,1,2-cde]pentaphene (TBPP) due to exposure to visible-light was investigated by measuring the absorption spectra and applying semi-empirical molecular orbital methods. Regardless of similarity in molecular structure, TBPP undergoes photooxygenation, but TBP does not. The energy correlation diagrams were obtained by calculations of the heats of formation for TBP, TBPP and their endo-peroxides. The experimental results were explained in terms of difference in stabilization energy.

Dibenzo[def,i]naphtho[vwx-1,8,7]pyranthrene (12), a new dodecacyclic aromatic hydrocarbon is synthesized by the condensation reaction of a 1:1 mixture of 7H-benz[hi]chrysene-7-one (7) and 13H-dibenz[a,de]anthracene-13-one (8) with zinc dust in the presence of zinc chloride and sodium chloride. The reaction is selective and no condensation compounds of two identical ketones are produced at the 1:1 ratio; at other ratios, condensation of identical ketones (between 7 and 7, or 8 and 8) occurs. Compound 12 has a melting point of 402-403°C and a maximum absorption band at 538 nm in dichlorobenzenc, and its molecular structure is confirmed by X-ray analysis.

The phosphorescence spectra and lifetimes of ionic organic compounds, such as 4-hydroxy-3-methoxybenzaldehyde, 2-amino-1-naphthalene sulfonic acid, and 9-anthracenemethanol, adsorbed on filter paper were measured as a function of the substrate temperature (T) in the range of 93 – 373 K and the preparation concentration (c) of the solutions. The molecule-substrate interaction leading to room temperature phosphorescence is discussed on the basis of the experimental data.

The structures of morusin, 2-(2,4-dihydroxyphenyl)-5-hydroxy-8,8-dimethyl-3-(3-methyl-2-butenyl)- 4H,8H-benzo[1,2-b;3,4-b']dipyran-4-one (C25H24O6) (I) and morusin dimethyl ether, 2-(2,4-dimethoxyphenyl)-5-hydroxy-8,8-dimethyl-3-(3-methyl- 2-butenyl)-4H,8H-benzo[1,2-b;3,4-b']dipyran-4-one (C27H28O6) (II) are reported. In molecules (I) and (II), the benzopyranone moiety is planar. The dihedral angles between benzopyranone moiety and phenyl ring are 66.25 (10) and 85.32 (5)°, respectively. When the dihydroxyphenyl [dimethoxyphenyl for (II)] and 3-methyl-2-butenyl groups are fixed in the same positions to the benzopyranone plane, the pyrano rings of (I) and (II) are enantiomeric.

A water-soluble chlorophyll protein (WSCP) with a chlorophyll a:b ratio of 6:1 from Brassica oleracea L. var. acephala (kale) was purified and crystallized by the hanging-drop vapour-diffusion method using PEG 8000 and zinc acetate as precipitants. The crystal belongs to the hexagonal space group P6(4)22, with unit-cell parameters a = b = 162.2, c = 38.7 A. A native data set was collected to 2.80 A resolution at 293 K using Cu Kalpha radiation from a rotating-anode generator. Preliminary analysis via molecular replacement identified one kale WSCP monomer in the asymmetric unit. The crystal packing showed a tetrameric structure for kale WSCP, as suggested by previous biochemical studies of WSCPs from Brassicaceae plants.

The reactions of (±)-α-epoxy drimenol (4) and (±)-α-epoxy drimenyl cyanide (6) with acids (proton acid or Lewis acid) selectively gave the rearranged aldehyde (±)-13 and (±)-15 having the hydroindane skeleton, respectively, while the reactions of (±)-4 and (±)-6 with Dibal-H selectively afforded the allyl alcohol (±)-14 and (±)-16, respectively. The reactions of (8aR)-6 and (8aS)-6 with Dibal-H were applied for the determination of the absolute structure of natural 7β-acetoxy-ent-labda-8(17),13(14)E-dien-15-ol (18). The reaction of (±)-α-epoxy bicyclofarnesol (5) and (8aS)-5 with proton acid selectively provided the rearranged ketol (±)- and (8aS)-31 having the hydroindane skeleton, respectively. The optically active (8aS)-31 was converted to the natural (9S)-austrodoric acid (33).

The title acetone solvate, C42H28O2·C3H6O [systematic name: 1,3,10,12-tetraphenyl-19,20-dioxapentacyclo[10.6.2.02,11.04,9.013,18]icosa-2(11),3,5,7,9,13,15,17-octaene acetone monosolvate], is a photooxygenation product of rubrene (systematic name: 5,6,11,12-tetraphenyltetracene). The molecule bends at the bridgehead atoms, which are linked by the O—O transannular bond, with a dihedral angle of 49.21 (6)° between the benzene ring and the naphthalene ring system of the tetracene unit. In the crystal, the rubrene molecules are linked by C—H...O hydrogen bonds into a column along thecaxis. The acetone solvent molecules form a dimer around a crystallographic inversion centre through a carbonyl–carbonyl dipolar interaction. A C—H...O hydrogen bond between the rubrene and acetone molecules is also observed.

A water-soluble Chl-binding protein from Brussels sprouts (Brassica oleracea var. gemmifera), hereafter termed BoWSCP, is categorized into the Class II WSCPs (non-photoconvertible WSCPs). Previous studies on BoWSCP have focused mainly on its biochemical characterization. In this study, we cloned the cDNA encoding BoWSCP. Sequence analysis revealed that the BoWSCP gene was composed of a single exon corresponding to 654 bp of an open reading frame encoding 218 amino acid residues, including 19 residues of a deduced signal peptide targeted to the endoplasmic reticulum (ER). Matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis of native BoWSCP revealed that the molecular mass of the subunit was 19,008.523 Da, corresponding to a mature protein of 178 amino acids, indicating the removal of 21 residues in the C-terminal region. Functional BoWSCP was expressed in Escherichia coli as a hexa-histidine fusion protein (BoWSCP-His). When BoWSCP-His was mixed with thylakoid membranes in aqueous solution, BoWSCP-His was able to remove Chls from the thylakoid membranes. The absorption spectrum of the reconstituted BoWSCP-His was identical to that of the native BoWSCP. Chl binding analyses of BoWSCP-His revealed that the BoWSCP-His bound both Chl a and Chl b with almost the same affinity in 40% methanol solution, although the native BoWSCP had a higher content of Chl a. To reveal the intracellular localization of BoWSCP, we constructed a transgenic plant expressing the fluorescent protein fused with the N-terminal deduced signal peptide of BoWSCP. The fluorescence emitted from the chimeric protein was detected in the ER body, an ER-derived compartment observed only in Brassicaceae plants.

明石海峡大橋主塔基礎に代表される, 水中不分離性コンクリートの大規模・急速施工では, コンクリートの流動による合流・打継ぎ状態の把握が重要となる.本研究では, 水中不分離性コンクリートの長距離流動における構成材料の影響および打設方法の影響を検討し, その結果をふまえた大規模実験を実施して検討の妥当性を確認することができた. その結果, 適切な材料, 配合, 打設方法および打継目の処理により, 水中不分離性コンクリートの大規模・急速施工が可能なことが明らかとなった.

The photooxygenation of diphenanthro[5,4,3-abcd : 5′,4′,3′-jklm]perylene (DPP) due to visible-light irradiation was investigated by measuring the absorption spectra and applying semi-empirical molecular orbital methods. It was shown theoretically that molecular oxygen attaches to the central benzene ring of DPP to give an endo-peroxide. The oxygen gradually detaches from the endo-peroxide at room temperature, reproducing DPP. The activation energies for both the reactions of oxygen attachment and detachment were determined based on the temperature dependences of the reaction rates in benzene; 10.0 ± 5.5 kJ mol−1 for the attachment reaction and 83.8 ± 2.5 kJ mol−1 for the detachment reaction.

The title compound, C10H8O6, a promising raw material to obtain colorless polyimides which are applied to microelectronic and optoelectronic devices, adopts a folded conformation in which the dihedral angle between the two anhydro rings is 55.15 (8)°. The central six-membered ring assumes a conformation intermediate between boat and twist-boat. In the crystal, molecules are linked by weak C—H...O interactions, forming a layer parallel to the bc plane.

Two new limonoids, brownin D ( 1 ) and E ( 2 ), were isolated from the bark of Harrisonia brownii (Simaroubaceae). Their relative stereostructures were established by specific methods and X-ray diffraction analysis of 1 .

The photooxygenation of diphenanthro[5,4,3-abcd:5′,4′,3′-jklm]perylene (DPP) is investigated by using semi-empirical molecular orbital methods. It was shown theoretically that molecular oxygen (O2) attaches to the central part of DPP, causing a large bend of the molecular plane. The experimental observation was reasonably explained on the basis of the calculated oscillator strengths of optically allowed transitions in DPP and photooxygenated DPP.

Crystal structures of title compounds have been determined by single crystal x-ray analysis. Crystal data. 4′-Hexyloxy-4-cyanobiphenyl (6OCB), Molecular structures in both crystals are very similar with twisted biphenyl moieties and fully extended paraffin chains. Dimers are formed by close contacts of CN groups between neighboring molecules (C-N: 3.56 and 3.40 A for 6OCB and 3.55 and 3.39 A for 7OCB). The neighboring dimers in 6OCB are overlapped half-and-half, while those in 7OCB are arranged in a smectic-like layer structure.

The structure determination of the title compound, C 31 H 54 OSi, based on single-crystal X-ray diffraction, shows that the absolute configuration at C22 is R

The structures of morusin, 2-(2,4-dihydroxyphenyl)-5-hydroxy-8,8-dimethyl-3-(3-methyl-2-butenyl)- 4H,8H-benzo[1,2-b;3,4-b']dipyran-4-one (C25H24O6) (I) and morusin dimethyl ether, 2-(2,4-dimethoxyphenyl)-5-hydroxy-8,8-dimethyl-3-(3-methyl- 2-butenyl)-4H,8H-benzo[1,2-b;3,4-b']dipyran-4-one (C27H28O6) (II) are reported. In molecules (I) and (II), the benzopyranone moiety is planar. The dihedral angles between benzopyranone moiety and phenyl ring are 66.25 (10) and 85.32 (5)°, respectively. When the dihydroxyphenyl [dimethoxyphenyl for (II)] and 3-methyl-2-butenyl groups are fixed in the same positions to the benzopyranone plane, the pyrano rings of (I) and (II) are enantiomeric.

The crystal structure of an endoperoxide of tetrabenzo[de,hi,op,st]pentacene (TBPA-O2) was determined by X-ray crystallography. The unusually long OO and CO bonds were rationalized by the characteristic molecular structure of TBPA-O2. The photochromic behavior between TBPA-O2 and TBPA was discussed based on the enthalpy difference between TBPA-O2 and TBPA + O2 and the thermodynamic parameters of the extrusion reaction of oxygen from TBPA-O2.

We have reconstituted human mitochondrial transcription in vitro on DNA oligonucleotide templates representing the light strand and heavy strand-1 promoters using protein components (RNA polymerase and transcription factors A and B2) isolated from Escherichia coli. We show that 1 eq of each transcription factor and polymerase relative to the promoter is required to assemble a functional initiation complex. The light strand promoter is at least 2-fold more efficient than the heavy strand-1 promoter, but this difference cannot be explained solely by the differences in the interaction of the transcription machinery with the different promoters. In both cases, the rate-limiting step for production of the first phosphodiester bond is open complex formation. Open complex formation requires both transcription factors; however, steps immediately thereafter only require transcription factor B2. The concentration of nucleotide required for production of the first dinucleotide product is substantially higher than that required for subsequent cycles of nucleotide addition. In vitro, promoter-specific differences in post-initiation control of transcription exist, as well as a second rate-limiting step that controls conversion of the transcription initiation complex into a transcription elongation complex. Rate-limiting steps of the biochemical pathways are often those that are targeted for regulation. Like the more complex multisubunit transcription systems, multiple steps may exist for control of transcription in human mitochondria. The tools and mechanistic framework presented here will facilitate not only the discovery of mechanisms regulating human mitochondrial transcription but also interrogation of the structure, function, and mechanism of the complexes that are regulated during human mitochondrial transcription.