PHOTOSENSITIZED INHIBITION OF PHOTOSYNTHETIC 14 CO2 FIXATION BY α-TERTHIENYL and ULTRAVIOLET-A*

Abstract –A variety of naturally occurring photosensitizers of plant origin were tested for their ability to cause ultraviolet-A (UVA)-dependent inhibition of photosynthetic ¹⁴CO₂ fixation in leaf disks of Pisum sativum L. At 0.1 mM concentrations and 60 min UVA irradiation, α-terthienyl was strongly inhibitory, harmine and sanguinarine inhibited to a lesser degree, and curcumin, 8-methoxypsoralen and nordihydroguaiaretic acid had no effect under the conditions tested. Alpha-terthienyl + UVA treatments that fully inhibited ¹⁴CO₂ fixation had no effect on fresh weight, chlorophyll or protein content of the tissue. Chloroplast malate dehydrogenase and glyceraldehyde-3-phosphate dehydrogenase were inhibited 45% and 29%, respectively, by α-terthienyl + UVA treatment. Electron transport from H₂O to the reducing side of photosystem I was inhibited to a similar extent, suggesting interference with the reductive activation of chloroplast enzymes. Alpha-terthienyl + UVA-treated tissue exhibited a seven-fold increase in leakage of labeled photosynthate into the external medium. Treated leaf disks showed no ability to recover ¹⁴CO₂ fixing ability over a 24 h period. These results indicate photosensitized damage at the level of the thylakoid membranes resulting in partial loss of electron transport capability and more general damage to chloroplast and cell membranes.     

Decarboxylation of lndole-3-Acetic Acid and Inhibition of Growth in Avena sativa Seedlings by Plant-Derived Photosensitizers*

Abstract— A number of plant phototoxins, when supplemented with UVA (320–400 nm) radiation, are capable of sensitizing the decomposition of indole-3-acetic acid (IAA), as measured by release of ¹⁴CO₂ from carboxyl-labeled IAA. Alpha-terthienyl (αT) and harmine caused significant rates of IAA decarboxylation at concentrations as low as 1 nM and were approximately 80% as effective as riboflavin and flavin mononucleotide. Partial inhibition by sodium azide indicates that the aT-induced decarboxylation of IAA is predominately, but not entirely, a type II reaction mediated by singlet oxygen. Based on changes in UV ab sorption spectra, it appears that the hormones gibberellic acid, abscisic acid and 6-benzylaminopurine (a cytokinin) are less susceptible to photosensitized decomposition than is IAA. Alpha-terthienyl plus UVA also inhibited elongation growth and reduced endogenous IAA levels in Avena sativa L. coleoptile sections and promoted senescence in intact Avena seedlings. These results confirm the allelopathic potential of plant photosensitizers such as αT and indicate that the phytohormone IAA may represent an additional target for the action of photosensitizers.     

Antiviral properties of photosensitizers

Abstract— We have studied the antiviral properties of three different groups of photo-sensitizers, viz. (i) various furyl compounds; (ii) β-carboline alkaloids; (iii) thiophenes and their acetylene derivatives. In general the antiviral potency of the furyl compounds correlated with their ability to produce DNA photoadducts. Among the naturally occurring β-carboline alkaloids, harmine was considerably more potent (in the presence of long wavelength UV radiation, UVA) than several other harmane-related compounds. Slight alterations in chemical structure had profound effects on their antiviral activities. Harmine was shown to inactivate the DNA-virus murine cytomegalovirus (MCMV) by inhibiting viral gene expression, although other targets may also exist. Several eudistomins, carboline derivatives isolated from a tunicate, were also photoactive against viruses. Various plant thiophenes and polyacetylenes were studied in detail. These compounds also required UVA for antiviral activity, and some of them were extremely potent against viruses with membranes, e.g. α-terthienyl, which showed significant activity at only 10^-5μg/ml. When MCMV had been treated with α-terthienyl plus UVA, the virus retained its integrity and penetrated cells normally; but the virus did not replicate. More than 30 additional thiophenes have recently been evaluated, including many synthetic ones, and some of these are even more potent than a-terthienyl. We believe that certain thiophenes possess potential therapeutic value and should be tested against model virus infections in animals.     

UVA-Potentiated Damage to Calf Thymus DNA by Fenton Reaction System and Protection by para-Aminobenzoic Acid

Abstract— Calf thymus DNA was irradiated with low-intensity UVA (main output at 365 nm, 2 mW cm^?2 or 36 kj m ² for 30 min), and the role of metal ions, hydrogen peroxide and reactive oxygen species (ROS) was examined. DNA damage was measured as thiobarbituric acid-reactive substances (possibly from degradation of deoxyribose) and as changes in ethidium bromide-DNA fluorescence due to unwinding from strand breaks. Under the present experimental conditions, UVA alone or in the presence of H₂0₂ had no effect on DNA but slightly enhanced the damage by iron/EDTA. Ultraviolet A strongly enhanced DNA damage (ca four- to five-fold) by the Fenton reaction system (50 μM Fe²⁺/100 μM EDTA + 0.5 mM H₂0₂). The results suggest that the Fenton reaction system was “photosensitized” to damage DNA by low-intensity UVA radiation. The enhanced damage by UVA was attributed in part to the reduction of Fe³⁺ to Fe²⁺. Ultraviolet A had no effect when iron (ferric or ferrous) ions were replaced by Cu²⁺, Zn²⁺, Mn²⁺ or Cd²⁺. The ROS involved in the UVA-enhanced damage to DNA by the Fenton reagents were OH and, to a lesser extent, superoxide anions. The UVA-potentiated DNA damage by the Fenton reaction system was then used to examine the protective effect of para-aminobenzoate (PABA), a UVB-absorbing sunscreen that protects against photocarcinogenesis in hairless mice. The results show that PABA and mannitol dose-dependently inhibited the damage with concentrations required for 50% inhibition at 0.1 mM and 3 mM, respectively. The protection by PABA was attributed to its radical-scavenging ability because PABA does not absorb light in the UVA region. These findings may be relevant to the biological damage by UVA and suggest that PABA is useful in protection against photocarcinogenesis by wide-range UV radiation.     

Effects of gamma-irradiation on CO2 fixation and

To investigate the possibility of ¹⁴CO₂ fixation using microorganisms in a high-dose area, the photosynthetic activity (specific production rate: SPR) and cellular proliferation (colony forming unit: CFU) of Euglena gracilis Z irradiated with gamma-rays at a dose of 0 to 500 Gy were determined. The dose responses of SPR and CFU suggested that it was possible to operate a CO₂ fixation system of Euglena up to 100 Gy. Even at a dose of 500 Gy, about half of the photosynthetic activity under non-irradiated condition was considered possible.     

Lethal Effect Induced in Pseudomonas aeruglnosa Exposed to Ultraviolet-A Radiation

Ultraviolet-A (365 nm, 120 kJ/m²/h) exposure caused cell death in Pseudomonas aeruginosa at doses at which Escherichia coli cell viability was not affected. We have not found that UVA induced growth delay or any other sublethal effect. Irradiated suspensions of P. aeruginosa showed a marked reduction in membrane-bound succinate dehydrogenase (SDH) and lactate dehydrogenase (LDH) activities. Succinate-driven respiration and several nutrient transport systems were also inhibited. Whereas SDH and LDH activities were independent of the irradiation conditions, cell viability, respiration and transport systems were protected when irradiation was performed in an N₂ atmosphere. A similar protective effect was observed when cells were grown in media containing glycerol or when preirradiation bacterial growth was carried out at 30°C (instead of 37°C). Results suggest that UVA induces a differential damaging effect on several biochemical functions of P. aeruginosa. The UVA induced photodamage may fall into two categories: indirect damage mediated by oxygen (cell killing and inhibition of respiration and transport systems) and direct damage to SDH and LDH (apparently not oxygen dependent). These enzymes and leucine transport appear not to be involved in the lethal effect described herein because they were altered despite viability-preserving conditions.     

Methods for Determining Rates of Protein Synthesis via Dark CO2 Fixation by Marine Prokaryote

Methods were developed to determine rates of particulate and dissolved protein synthesis via dark CO₂ fixation by marine prokaryotic assemblages. The methods are based on incorporation of [¹⁴C]-bicarbonate and separation of proteins as TCA-insoluble materials. Results indicated that particulate protein constitutes a significant fraction (～67%) of cellular organic matter produced via prokaryotic dark CO₂ fixation. The microcentrifuge method allowed us to estimate the rate of total protein synthesis via CO₂ fixation. Time-series data proved useful for determining the optimum incubation period, and for estimating the rate of protein synthesis by regression analysis. The total prokaryotic dark CO₂ fixation rate (10.3 ng C l^?1 h^?1) estimated by these methods was 2.7-times the rate of particulate CO₂ fixation, which was comparable to the CO₂ fixation rate estimated by methods used in previous studies. Thus, total prokaryotic dark CO₂ fixation appears to be more important in the marine carbon cycle than previously thought.     

Mg-induced vesicles of tetradecyldimethylamine oxide and magnesium dodecyl sulfate

A Mg²⁺-induced vesicle phase was prepared from a mixture of tetradecyldimethylamine oxide (C₁₄DMAO) and magnesium dodecyl sulfate [Mg(DS)₂] in aqueous solution. Study of the phase behavior shows that at the appropriate mixing ratios, Mg²⁺–ligand coordination between C₁₄DMAO and Mg(DS)₂ results in the formation of molecular bilayers, in which Mg²⁺ can firmly bind to the head groups of the two surfactants. The area of the head group can be reduced because of the complexation. In this case, no counterions exist in aqueous solution because of the fixation of Mg²⁺ ions to the bilayer membranes. Therefore, the charges of the bilayer membranes are not shielded by salts. The birefringent solutions of Mg(DS)₂ and C₁₄DMAO mixtures consist of vesicles which were determined by transmission electron microscopy (TEM) images and rheological measurements. Magnesium oxide (MgO) nanoplates were obtained via the decomposition of Mg(OH)₂ which were synthesized in Mg²⁺-induced vesicle phase which was used as the microreactor under the existence of ammonia hydroxide. The morphologies and structures of the obtained MgO nanoplates have been characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicate that the crystal growth is along the (1 1 1) direction which can be affected by the presence of a vesicle phase having a fixation of Mg²⁺ ions to the bilayer membranes.     

Designing GO Channels with High Selectivity for CO2/N2 Separation via Incorporating Metal Ions

Graphene oxide (GO) membranes holds great potential for high-performance CO₂ capture. Aiming at enhancing the CO₂ separation performance and structural stability of GO membranes, functionalizing GO channels with metal ions confers a promising strategy. In this study, we reported the fabrication of metal ion-incorporated GO membranes with remarkably improved CO₂/N₂ separation performance. The metal ions within GO channels contribute to facilitating CO₂ transport, decreasing N₂ solubility, hindering N₂ diffusion, and form multiple interactions with GO nanosheets. After introducing Mg²⁺ ions, the CO₂/N₂ separation factor of GO membrane is remarkably increased from 4 to 48.8 with the CO₂ permeance increases 1.5 times. Moreover, the separation performance of the GO-Mg²⁺ membranes shows an excellent long-term stability owing to the structural robustness. This study could provide insights into the regulation of the microstructure of metal ion-functionalized GO membranes for highly selective transport of specific molecules.     

Effects of Ultraviolet Radiation (UVA+UVB) on Young Gametophytes of Gelidium floridanum: Growth Rate,Photosynthetic Pigments,Carotenoids, Photosynthetic Performance,and Ultrastructure

This study investigated the effects of radiation (PAR+UVA+UVB) on the development and growth rates (GRs) of young gametophytes of Gelidium floridanum. In addition, photosynthetic pigments were quantified, carotenoids identified, and photosynthetic performance assessed. Over a period of 3 days, young gametophytes were cultivated under laboratory conditions and exposed to photosynthetically active radiation (PAR) at 80 μmol photons m^?2 s^?1 and PAR+UVA (0.70 W m^?2)+UVB (0.35 W m^?2) for 3 h per day. The samples were processed for light and electron microscopy to analyze the ultrastructure features, as well as carry out metabolic studies of GRs, quantify the content of photosynthetic pigments, identify carotenoids and assess photosynthetic performance. PAR+UVA+UVB promoted increase in cell wall thickness, accumulation of floridean starch grains in the cytoplasm and disruption of chloroplast internal organization. Algae exposed to PAR+UVA+UVB also showed a reduction in GR of 97%. Photosynthetic pigments, in particular, phycoerythrin and allophycocyanin contents, decreased significantly from UV radiation exposure. This result agrees with the decrease in photosynthetic performance observed after exposure to ultraviolet radiation, as measured by a decrease in the electron transport rate (ETR), where values of ETRmax declined approximately 44.71%. It can be concluded that radiation is a factor that affects the young gametophytes of G. floridanum at this stage of development.     

Characterization of xylitol dehydrogenase from debaryomyces hansenii

The xylitol dehydrogenase (EC 1.1.1.9) from xylose-grown cells ofDebaryomyces hansenii was partially purified in two Chromatographic steps, and characterization studies were carried out in order to inves tigate the role of the xylitol dehydrogenase-catalyzed step in the regu lation of D-xylose metabolism. The enzyme was most active at pH 9.0–9.5, and exhibited a broad polyol specificity. The Michaelis con stants for xylitol and NAD⁺ were 16.5 and 0.55 mM, respectively. Ca²⁺, Mg²⁺, and Mn²⁺ did not affect the enzyme activity. Conversely, Zn²⁺, Cd²⁺, and Co²⁺ strongly inhibited the enzyme activity. It was concluded that NAD⁺-xylitol dehydrogenase from D.hansenii has similarities with other xylose-fermenting yeasts in respect to optimal pH, substrate specificity, and K_m value for xylitol, and therefore should be named L-iditol:NAD⁺-5-oxidoreductase (EC 1.1.1.14). The reason D.hansenii is a good xylitol producer is not because of its value of K_m for xylitol, which is low enough to assure its fast oxidation by NAD⁺ xylitol dehydrogenase. However, a higher K_m value of xylitol dehydro genase for NAD⁺ compared to theK _m values of other xylose-ferment ing yeasts may be responsible for the higher xylitol yields.     

Stereoselective Effects in Reactions of Metal Complexes III. Asymmetric hydrogenation of 5, 7, 7, 12, 14, 14-hexamethyl-1, 4, 8, 11-tetraazacyclotetradeca-4, 11-diene-nickel (II)

The catalytic hydrogenation in acidic solution (pH ～ 2) of the title compound

1 In order to represent this and the related compounds by meaningful abbreviations, we shall adopt the numerotation system proposed in the literature [8] [12]. The complete abbreviation of the title compound is [Ni(5, 7, 7, 12, 14, 14-Me₆-[14]-4, 11-diene-1, 4, 8, 11-N₄)]²⁺. As in the present work the 14-membered ring system with six methyl groups remains unchanged, we shall use [Ni(4, 11-dieneN₄)]²⁺ and [Ni(4, 11-aneN₄)]²⁺ and [Ni(4, 11-aneN₄)]²⁺ for the complex with the unsaturated and saturated ligand, respectively.

[Ni(4, 11-dieneN₄)]²⁺ (I) has been studied. The reaction yields only C-meso- 5, 7, 7, 12, 14, 14-hexa-methyl-1, 4, 8, 11-tetraaza-cyclotetradecane-nickel (II) (C-meso-[Ni(4, 11-aneN₄)]²⁺), when meso-[Ni(4, 11-dieneN₄)]²⁺ is the starting material. Rac-[Ni(4, 11-dieneN₄)]²⁺ yields the unstable α-C-rac-[Ni(4, 11-aneN₄)]²⁺. When optically active [Ni(4, 11-dieneN₄)]²⁺ is reduced, optically active α-[Ni(4, 11-aneN₄)]²⁺ is obtained, which in neutral or basic solution shows mutarotation due to conversion into optically active β-[Ni(4, 11-aneN₄)]²⁺ no racemization is observed. Reaction with cyanide ions yields the optically active free tetramine ligand. The reaction mechanism of this asymmetric synthesis is discussed.     

UVA II Exposure of Human Skin Results in Decreased Immunization Capacity, Increased Induction of Tolerance and a Unique Pattern of Epidermal Antigen-Presenting Cell Alteration

Abstract— The risks incurred from increased exposure to UVA II (320-340 nm) (i.e. during sunscreen use and extended outdoor exposure, tanning parlors) are not well understood. Therefore, we explored the effects of UVA II on skin immune responses in humans. After a single local exposure (4 minimum erythemal dose [MED]) using a xenon arc lamp filtered with a narrow bandpass filter (335 ± 5 nm full width at half maximum), individuals were contact-sensitized with dinitrochlorobenzene (DNCB) through a UVA II exposure site or through normal skin. UVA II induced a marked decrease in the magnitude of skin immune responses (P < 0.0001). The UVA II group had only 29% successful sensitizations, as compared to 83% in the control group. The percentage of individuals who remained tolerant to DNCB after two sensitizations was 23.6% for the UVA II-exposed group, as compared to 3.8% in the controls (P= 0.006). UVA II also uniquely altered the type of antigen-presenting cells present in the epidermis. Human leukocyte antigen (HLA)-DR+ cells in control epidermal cell suspensions (C-EC) comprised a single, homogeneous population of Langerhans cells (LC) with the phenotype: CD1a^hi DR^mid CD11b^? CD36^? (1.5 ± 0.3% of EC). UVA II irradiation reduced the number of such LC to 0.6 ± 0.2% of EC. Although cells expressing the macrophage phenotype: CD1a DR^hi CD11b+ CD36+ were increased in UVA II skin, relative to C-EC, these comprised only 10.1 ± 6.1% of the DR+ cells, which is less than that after UVB exposure. Also distinct from UVB, a third population was found in UVA II-EC, which exhibited a novel phenotype: CD1a+ DR+ CD36+ CDllb+; these comprised 11.1 ± 6.9% of the DR+ UVA II-EC. In conclusion, despite the above differences in infiltrating DR cells, both UVB and UVA II reduce the skin's ability to support contact sensitization, induce active suppression (tolerance) and induce a reduction in LC.     

Lignocellulose degradation by actinomycetes

A collection of actinomycetes including fresh isolates was initially screened for the ability to degrade ball-milled straw or utilize lignin-related aromatic compounds. Selected strains were tested for ligninolytic activity by measuring the amount of¹⁴CO₂ released from [¹⁴C-lignin] wheat lignocellulose. Two actinomycetes,Thermomonospom mesophila and aStreptomyces sp., were particularly effective, degrading up to 8% of the radiolabeled substrate to¹⁴CO₂ in 10 d at 37‡C.¹⁴CO₂ evolution was not significantly affected by flushing flasks with air rather than 100% O₂, or growing the actinomycetes in shake-flask rather than stationary broth cultures. Solubilization of radioactivity paralleled¹⁴CO₂ evolution and was greatest during the first 72 h of growth, after which no further increase in water-soluble¹⁴C was detected although¹⁴CO₂ evolution continued at a reduced rate. The regulation of ligninolytic activity in these actinomycetes thus differs from that in white-rot fungi, and HPLC analyses of the degradation products suggest that their mode of attack on grass lignin is distinct. Xylanolytic strains from four thermophilic actinomycete taxa were also obtained. These strains produced inducible extracellular xylanases that were active over a broad pH and temperature range and were relatively thermostable. TLC analysis suggested that endoxylanases were the predominant components and gel electrophoresis provided further information on the nature of the xylanase complex. The activity of these enzymes against native lignocellulose was also studied. We thank the Agricultural Research Council and the British Petroleum Venture Research Unit for support.     

Thioredoxin Reductase Activity may be More Important than GSH Level in Protecting Human Lens Epithelial Cells against UVA Light

This study compares the abilities of the glutathione (GSH) and thioredoxin (Trx) antioxidant systems in defending cultured human lens epithelial cells (LECs) against UVA light. Levels of GSH were depleted with either L‐buthionine‐(S,R)‐sulfoximine (BSO) or 1‐chloro‐2,4‐dinitrobenzene (CDNB). CDNB treatment also inhibited the activity of thioredoxin reductase (TrxR). Two levels of O₂, 3% and 20%, were employed during a 1 h exposure of the cells to 25 J cm^?2 of UVA radiation (338–400 nm wavelength, peak at 365 nm). Inhibition of TrxR activity by CDNB, combined with exposure to UVA light, produced a substantial loss of LECs and cell damage, with the effects being considerably more severe at 20% O₂ compared to 3%. In contrast, depletion of GSH by BSO, combined with exposure to UVA light, produced only a slight cell loss, with no apparent morphological effects. Catalase was highly sensitive to UVA‐induced inactivation, but was not essential for protection. Although UVA light presented a challenge for the lens epithelium, it was well tolerated under normal conditions. The results demonstrate an important role for TrxR activity in defending the lens epithelium against UVA light, possibly related to the ability of the Trx system to assist DNA synthesis following UVA‐induced cell damage.     

Electrospray ionization multiple-stage linear ion-trap mass spectrometry for structural elucidation of triacylglycerols: Assignment of fatty acyl groups on the glycerol backbone and location of double bonds

Linear ion-trap multiple-stage mass spectrometric approach (MS ⁿ ) towards nearly complete structural elucidation of triacylglycerol (TAG) including (1) assignment the fatty acid substituents on the glycerol backbone and (2) location of the double bond(s) on the unsaturated fatty acyl groups is reported. The characterization is established by the findings that MS² on the [M+Li]⁺ ions of TAG yields more abundant ions reflecting losses of the outer fatty acid substituents either as free acids (i.e., [M+Li-R₁CO₂H]⁺ and [M+Li-R₃CO₂H]⁺ ions) or as lithium salts (i.e., [M+Li-R₁CO₂Li]⁺ and [M+Li-R₃CO₂Li]⁺ ions) than the ions reflecting the similar losses of the inner fatty acid substituent (i.e., [M+Li-R₂CO₂Li]⁺ and [M+Li-R₂CO₂Li]⁺ ions). Further dissociation (MS³) of [M+Li-R _n CO₂H]⁺ (n=1, 2, or 3) gives rise to the ion series locating the double bonds along the fatty acid chain. These ions arise from charge-remote fragmentations involving β-cleavage with γ-H shift, analogous to those seen for the unsaturated long-chain fatty acids characterized as initiated ions. Significant differences in abundances in the ion pairs reflecting the additional losses of the fatty acid moieties, respectively, were also seen in the MS³ spectra of the [M+Li-R _n CO₂H]⁺ and [M+Li-R _n CO₂Li]⁺ ions, leading to confirmation of the fatty acid substituents on the glycerol backbone. MS ⁿ on the [M+Na]⁺ and [M+NH₄]⁺ adduct ions also affords location of fatty acid substituents on the glycerol backbone, but not the position of the double bond(s) along the fatty acid chain. Unique ions from internal losses of the glycerol residues were seen in the MS³ spectra of [M+Alk-R _n CO₂H]⁺ (n=1, 2, 3) and of [M+Alk-R _n CO₂Alk]⁺ (Alk=Li, Na, NH₄; n=1, 3). They are signature ions for glycerides and the pathways leading to their formation may involve rearrangements.     

Negative ion chemical ionization mass spectrometry of some nitroso compounds with CO2 as reagent gas

Summary Mass spectra of seven N-nitrosamines and five alkyl nitrites, the O-nitroso compounds, have been obtained by low pressure negative chemical ionization with CO₂ as reagent gas. Intense anions were observed at m/z M–32 for N-nitrosamines and at m/z M–30 for alkyl nitrites. Addition products were found at m/z M+12 and M+43 for N-nitrosamines and at m/z M+14 for alkyl nitrites. By using isotopically labeled CO₂, it could be shown that the anions at m/z M+12, M+14 and M+43 correspond to [M - H₂NO + CO₂ ^–, [M – NO + CO₂]^–, and [M – H + CO₂]^–, respectively.

---

Negativionen-CI-Massenspektrometrie einiger Nitrosoverbindungen mit CO₂ als Reagensgas

Zusammenfassung Die Massenspektren von sieben N-Nitrosaminen und fünf Alkylnitriten (O-Nitrosoverbindungen) wurden durch negative chemische Ionisation bei niederem Druck mit CO₂ als Reagensgas erhalten. Intensive Anionen wurden bei m/z M–32 für N-Nitrosamine und bei m/z M–30 für Alkylnitrite beobachtet. Additionsprodukte fanden sich bei m/z M+12 und M+43 für N-Nitrosamine sowie bei m/z M+14 für Alkylnitrite. Mit Hilfe von Isotopen-markiertem CO₂ konnte gezeigt werden, daß die Anionen bei m/z M+12, M+14 und M+43, [M – H₂NO + CO₂]^–, [M – NO + CO₂]^– bzw. [M – H + CO₂]^– entsprechen.

---

---

A full account of this work including the negative chemical ionization mass spectra obtained with other reagent gases will be submitted to the Journal of Mass Spectrometry.     

Contracted well-tempered Gaussian basis sets in SCF calculations on the ground and excited electronic states of neutral and ionized diatomic molecules containing first-row atoms

Summary Calculations were done on ground and excited states of C₂, C ₂ ⁺ , C ₂ ^– , N₂, N ₂ ⁺ , O₂, O ₂ ⁺ , O ₂ ^– , CO, CO⁺, CO²⁺, and CO^– using contracted well-tempered basis sets. The (14s 10p) basis sets were augmented with threed, one or twof, and oneg functions. Total energies, orbital energies, and spectroscopic constants were compared with the best available computational data.     

Electron-Rich Bi Nanosheets Promote CO2⋅− Formation for High-Performance and pH-Universal Electrocatalytic CO2 Reduction

Electrochemical CO₂ reduction reaction (CO₂RR) to chemical fuels such as formate offers a promising pathway to carbon-neutral future, but its practical application is largely inhibited by the lack of effective activation of CO₂ molecules and pH-universal feasibility. Here, we report an electronic structure manipulation strategy to electron-rich Bi nanosheets, where electrons transfer from Cu donor to Bi acceptor in bimetallic Cu−Bi, enabling CO₂RR towards formate with concurrent high activity, selectivity and stability in pH-universal (acidic, neutral and alkaline) electrolytes. Combined in situ Raman spectra and computational calculations unravel that electron-rich Bi promotes CO₂⋅⁻ formation to activate CO₂ molecules, and enhance the adsorption strength of *OCHO intermediate with an up-shifted p-band center, thus leading to its superior activity and selectivity of formate. Further integration of the robust electron-rich Bi nanosheets into III–V-based photovoltaic solar cell results in an unassisted artificial leaf with a high solar-to-formate (STF) efficiency of 13.7 %.     

Synthesis,characterization, and biological studies of lanthanide complexes with 2,6-pyridine dicarboxylic acid and α-picolinic acid

Four new solid ternary complexes of lanthanide with 2,6-pyridine dicarboxylic acid and α-picolinic acid [Ln(DPA)(L^α)(H₂O)] · 2H₂O (Ln = La³⁺, Ce³⁺, Eu³⁺, or Gd³⁺; DPA = 2,6-pyridine dicarboxylic acid; HL^α = α-picolinic acid) have been synthesized and characterized by elemental analysis, molar conductance, FT-IR, UV–Vis, and TG–DTA. The antibacterial activities indicate that all the complexes exhibit antibacterial ability against Escherichia coli and Staphylococcus aureus with broad antimicrobial spectra. The anticancer activity of the La complex against K562 tumor cell in vitro is measured using methyl thiazolyl tetrazolium (MTT) colorimetry and flow cytometry. The La complex can induce K562 tumor cell apoptosis, presenting the best apoptosis effect by acting on the S period after inducing K562 tumor cell for 72 h.