Ultraviolet Absorption Spectra Research Articles

Epidermal growth factor receptor-targeted immunomagnetic liposomes for circulating tumor cell enumeration in non-small cell lung cancer treated with epidermal growth factor receptor-tyrosine kinase inhibitors

ObjectivesTo establish a circulating tumor cell (CTC) enrichment system for non-small cell lung cancer (NSCLC) patients who received first-line treatment with epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (EGFR-TKI), using EGFR magnetic liposomes (EGFR-ML). Materials and methodsAn inverted evaporation method was used to develop antibody modified EGFR-ML. Peripheral blood was collected from NSCLC patients who underwent first-line EGFR-TKI treatment for CTC enumeration. ResultsProtein electrophoresis, magnetic saturation curve, and ultraviolet absorption spectrum showed successful incorporation of the EGFR antibody on the surface of the magnetic microspheres, and the development of EGFR-ML was ascertained based on cell morphology and particle size. Using EGFR-ML, CTC were successfully enriched from blood samples and were identified in 77.3% (99/128) of the cohort. When compared to the 21L858R variant, EGFR-19del showed lower CTC counts by EGFR-ML (CTCEGFR). At one month after EGFR-TKI, a lower CTCEGFR was associated with partial response (PR) during treatment (CTCEGFR < 6 vs. ≥ 6/7.5 mL, 75% vs. 49%, P = 0.027). In addition, patients with a lower CTCEGFR at 3 months after EGFR-TKI achieved a longer progression-free survival (PFS) [CTCEGFR < 6 vs. ≥ 6/7.5 mL, 13 months vs. 10.4 months, HR = 2.4, P = 0.042]. CTCEGFR significantly increased at the time of RECIST-progressive disease (RECIST-PD). Representative cases showed that CTCEGFR might increase before and beyond RECIST-PD until no clinical benefit could be acquired from EGFR-TKI. ConclusionWe showed that establishing a CTC enrichment system by antibody modified EGFR-ML in NSCLC is feasible. CTC enumeration by EGFR-ML may have the potential to supplement RECIST in dynamically monitoring the response of NSCLC patients’ to first-line EGFR-TKI.

Synthesis and Investigations of Structural, Optical and AC Conductivity Properties of PANI/CeO2 Nanocomposites

This paper explains the details on the preparation of polyaniline/CeO2 (10 wt %) nanocomposites using the method of in situ polymerization. The formation of PANI/CeO2 nanocomposites were proposed via oxidation of aniline and reduction of CeO2, respectively. The effect of CeO2 concentration on AC conductivity, morphological, optical and structural properties of the prepared PANI/CeO2 nanocomposites material were examined. The structural studies show the presence of CeO2 nanoparticles were occurred in PANI of nanocomposites. The average grain size of PANI/CeO2 nanocomposites varied with increasing and decreasing concentration due to the process of nucleation during the polymerization. The average particle grain sizes were measured from HRTEM. The morphology analysis was carried out from SEM. The UV absorption spectrum showed that the absorption peak of CeO2 nanoparticle at 341 nm, shifted to lower wavelength side, the nanocomposite absorption peaks at about 324, 368 and 858 nm was confirmed by the formation of PANI/CeO2 nanocomposites. The electronic structure of the band gap of the nanocomposite materials were calculated using ultraviolet visible absorption spectrum. The band gap energy of nanocomposite is 3.36 eV. The FTIR spectrum clearly showed the strong presence of CeO2 nanoparticles in PANI chain. The AC conductivity varied with varying the temperature and depends on the concentration due to the formation of PANI/CeO2 nanocomposite.

Abundances, emissions, and loss processes of the long-lived and potent greenhouse gas octafluorooxolane (octafluorotetrahydrofuran, &amp;lt;i&amp;gt;c&amp;lt;/i&amp;gt;-C&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt;F&amp;lt;sub&amp;gt;8&amp;lt;/sub&amp;gt;O) in the atmosphere

Abstract. The first atmospheric observations of octafluorooxolane (octafluorotetrahydrofuran, c-C4F8O), a persistent greenhouse gas, are reported. In addition, a complementary laboratory study of its most likely atmospheric loss processes, its infrared absorption spectrum, and global warming potential (GWP) are reported. First atmospheric measurements of c-C4F8O are provided from the Cape Grim Air Archive (41∘ S, Tasmania, Australia, 1978–present), supplemented by two firn air samples from Antarctica, in situ measurements of ambient air at Aspendale, Victoria (38∘ S), and a few archived air samples from the Northern Hemisphere. The atmospheric abundance in the Southern Hemisphere has monotonically grown over the past decades and leveled at 74 ppq (parts per quadrillion, femtomole per mole in dry air) by 2015–2018. The growth rate of c-C4F8O has decreased from a maximum in 2004 of 4.0 to &lt;0.25 ppq yr−1 in 2017 and 2018. Using a 12-box atmospheric transport model, globally averaged yearly emissions and abundances of c-C4F8O are calculated for 1951–2018. Emissions, which we speculate to derive predominantly from usage of c-C4F8O as a solvent in the semiconductor industry, peaked at 0.15 (±0.04, 2σ) kt yr−1 in 2004 and have since declined to &lt;0.015 kt yr−1 in 2017 and 2018. Cumulative emissions over the full range of our record amount to 2.8 (2.4–3.3) kt, which correspond to 34 Mt of CO2-equivalent emissions. Infrared and ultraviolet absorption spectra for c-C4F8O as well as the reactive channel rate coefficient for the O(1D) + c-C4F8O reaction were determined from laboratory studies. On the basis of these experiments, a radiative efficiency of 0.430 W m−2 ppb−1 (parts per billion, nanomol mol−1) was determined, which is one of the largest found for synthetic greenhouse gases. The global annually averaged atmospheric lifetime, including mesospheric loss, is estimated to be &gt;3000 years. GWPs of 8975, 12 000, and 16 000 are estimated for the 20-, 100-, and 500-year time horizons, respectively.

Electron-Induced Reactions in 3-Bromopyruvic Acid.

3-Bromopyruvic acid (3BP) is a potential anti-cancer drug, the action of which on cellular metabolism is not yet entirely clear. The presence of a bromine atom suggests that it is also reactive towards low-energy electrons, which are produced in large quantities during tumour radiation therapy. Detailed knowledge of the interaction of 3BP with secondary electrons is a prerequisite to gain a complete picture of the effects of 3BP in different forms of cancer therapy. Herein, dissociative electron attachment (DEA) to 3BP in the gas phase has been studied both experimentally by using a crossed-beam setup and theoretically through scattering and quantum chemical calculations. These results are complemented by a vacuum ultraviolet absorption spectrum. The main fragmentation channel is the formation of Br- close to 0 eV and within several resonant features at 1.9 and 3-8 eV. At low electron energies, Br- formation proceeds through σ* and π* shape resonances, and at higher energies through core-excited resonances. It is found that the electron-capture cross-section is clearly increased compared with that of non-brominated pyruvic acid, but, at the same time, fragmentation reactions through DEA are significantly altered as well. The 3BP transient negative ion is subject to a lower number of fragmentation reactions than those of pyruvic acid, which indicates that 3BP could indeed act by modifying the electron-transport chains within oxidative phosphorylation. It could also act as a radio-sensitiser.

Synthesis of modified carbon dots with performance of ultraviolet absorption used in sunscreen.

The research and development of non-toxic, broad-spectrum and environmentally friendly ultraviolet absorbers remains no significant progress in recent years. We found that the ultraviolet absorption spectra can be regulated through modification of functional groups on carbon dots surface, and the modified carbon dots exhibiting good stability and functions of sunscreen (Sun protection actor reaches to 22) and anti-aging properties were experimentally demonstrated. Moreover, we figured out the ultraviolet absorption mechanism of carbon dots for the first time and confirmed the existence of non-fluorescent radiation energy traps. Carbon dots are expected to be widely used and commercialized as ultraviolet absorbers.

Optical properties of zinc-iridium oxide thin films

We present the results of an investigation of ultraviolet, visible, near-infrared (UV-Vis-NIR) and X-ray absorption spectroscopy absorption spectra for zinc-iridium oxide (Zn-Ir- O) thin films with various iridium concentrations deposited by reactive DC magnetron sputtering. It is found that the absorption spectra of zinc-iridium oxide thin films contain a broad band with maxima at 446 nm and 710 nm in the visible region, bands with maxima at about 1100 nm and 3300 nm, and a low-intensity absorption band at 1570 nm in the near-infrared region. The obtained absorption bands are associated with iridium ions at valences of Ir3+, Ir4+ and Ir5+. Changes in the oxidation state of iridium ions from 5+ to 4+ are observed.

Preparation and Photocatalyst Properties of Zinc Sulfide Using a Distinct Sulfur Source: 1-Benzylidenethiourea

Zinc sulfide nanostructures were prepared by hydro/solvothermal process via reaction of Zn(NO3)2 and a thio Schiff base ligand, 1-benzylidenethiourea (L) as new sulfuring agent in ethanol and water solvents. The obtained ZnS nanoparticles were studied structurally by XRD, EDX, FT-IR and UV–Vis spectroscopies and BET analysis. According to SEM and TEM images, it appears that the synthesized zinc sulfide have flower-like and sphere-like structures. Due to the quantum confinement effect in both structures, the ultraviolet absorption spectra show the blue shift in the band gap. From the results, it is obvious that the size and morphology of the obtained structures depend on solvent type, temperature and duration of reaction. The photocatalytic activities of the as-synthesized samples were evaluated by the color removal of methyl orange under UV irradiation.

A highly sensitive and selective chemosensor for 2,4,6-trinitrophenol based on L-cysteine-coated cadmium sulfide quantum dots

2,4,6-Trinitrophenol (TNP) is a common explosive and widely used in military, pharmaceutical, pesticide, printing and dyeing industries. TNP in the wastewater and waste residues will enter into the environment by various ways and lead to serious threat on the environment. It is urgent to develop simple and robust analytical methods for highly sensitive and selective determination of TNP. L-cysteine-coated cadmium sulfide quantum dots (L-Cy-CdS QDs) with strong fluorescence were synthesized at room temperature and characterized by ultraviolet visible absorption spectra, transmission electron microscopy and fourier transform infrared spectrometer. TNP could quench the fluorescence of quantum dots based on the favorable electronic energy transfer, fluorescence resonance energy transfer, and electrostatic interactions. The effects of pH, reaction time and L-Cy-CdS QDs concentration on the fluorescence response were optimized. It was found that the fluorescence quenching of the quantum dots was linear with the concentration of TNP in the range of 0.05–5 μg mL−1, and the limit of detection was as low as 39 ng mL−1. The method can be applied to the quantitative detection of TNP in environmental water samples.

Accurately measurement and efficiently recovery of ionic liquid in energy utilization of microalgae

Abstract Chlorella vulgais, a kind of micro-alagae, is an attracting feedstock for bioenergy production, such as biodiesel and biogas. But its tough cell wall structure is the main obstacle to efficiently extracting lipids and other biomass. Ionic liquid (IL) can be used to hydrolyze its cell-wall. However, due to its high cost and toxicity, it is important to recover IL as much as possible. Therefore, a method that can accurately measure the content of ILs, is urgently needed. In this work, two common methods that are used to measure the content of ILs: equimolar titration method and ultraviolet absorbance spectra were compared. The results show that equimolar titration method is not available for trace quantity analysis of ionic liquids as the endpoint of titration is hard to be identified at low IL content (

Characteristics and Fouling Potential of Dissolved Organic Matter in a Stratified Source Water Reservoir

Quantity and quality of dissolved organic matter (DOM) in source water are critical factors affecting both the drinking water quality and operation of the water treatment process. As major water sources for many cities, deep reservoirs usually suffer seasonal thermal stratification, which has a significant influence on the fate and transport of many contaminants including iron, manganese, ammonia and DOM. This study focuses on the variation of properties and the fouling potential of DOM in a deep-source water reservoir during the thermal stratification period. Excitation-emission matrix (EEM) fluorescence spectra and ultraviolet absorption spectra were used to characterize the DOM. The results indicate that the quantity and quality of DOM vary with the water depth due to thermal stratification. The DOC of epilimnion is lower than that of the metalimnion and hypolimnion due to photochemical degradation. Moreover, organic matter released by phytoplankton, such as algae, play an important role in the DOM composition. Therefore, the DOM of the epilimnion exhibits a lower aromaticity, lower fluorescence intensities of Component 1 (i.e., fulvic-like substance) and Component 2 (i.e., humic-like substance), and higher fluorescence intensity of Component 3 (i.e., tryptophan-like substance). The DOM of the metalimnion is dominated by runoff input and therefore the concentration, aromaticity, and fluorescence intensities of Components 1 and 2 are higher. In terms of membrane fouling, total fouling caused by the DOM of the epilimnion is the largest, but its reversibility is better. The DOM of the metalimnion and hypolimnion results in lower total fouling but poor reversibility. The analysis of the fate of different fluorescence components during ultrafiltration suggests that the UF shows a relative high rejection rate for Component 3, which could be readily removed by backwash, whereas Component 1 and Component 2 retained by the membrane are difficult to be removed by backwash.

A hybridization chain reaction coupled with gold nanoparticles for allergen gene detection in peanut, soybean and sesame DNAs.

Food allergy is an abnormal immune response of the immune system to some foods, which has caused great harm to people's health. Therefore, it is particularly important to detect allergens in food. In this article, a hybridization chain reaction (HCR) was coupled with gold nanoparticles (AuNPs) to detect the allergen genes of peanut, soybean and sesame DNAs. Two hairpin probes (H1 and H2) were designed for the allergen target genes of peanut, soybean and sesame DNAs. In the presence of target DNA, the hybridization chain reaction was triggered by it producing long double-stranded DNA (dsDNA) products. In the gold nanoparticle system, long dsDNA couldn't be adsorbed on the surface of AuNPs. When the concentration of salt ions in the solution increased, gold nanoparticles accumulated and led to a decrease of ultraviolet absorption. In the absence of target DNA, no hybridization chain reaction occurred. The hairpin probes could be adsorbed on the surface of AuNPs and no accumulation happened for gold nanoparticles even if the concentration of salt ions in the solution was increased. This method required no enzymes and had a strong specificity, so it was very easy to distinguish target DNA from non-target DNA. The detection limit of three allergens detected by this method was as low as 0.5 nM. The feasibility of this method for the detection of commercial commodities had been demonstrated by the successful detection of the DNAs extracted from commercial commodities, which were treated with extreme thermostable single-stranded binding protein (ET SSB).

Temperature-dependent properties of metastable graphene oxide

Monolayer of graphene oxide has great potential applications in ion and molecular screening, desalination and purification of water, gas separation, biosensing, proton conductors, lithium batteries, super capacitors and other fields, due to its excellent physical and chemical properties. However, the graphene oxide prepared by chemical and physical methods, such as the commonly used Hummers method is a metastable material. The transformation and regulation of the physical and chemical properties of the final morphology are essential, and systematic research is urgently needed. In this paper, the thermostat treatment method is used to control the metastable transformation of graphene oxide. The relationship of content, type, and morphology with temperature of oxygen-containing graphene oxide are detected by X-ray photoelectron absorption spectroscopy, Fourier infrared absorption spectroscopy, scanning electron microscope, etc.; and the effects of temperature on the stability of solution suspension stability, photon energy band and tensile strength of graphene oxide in the transformation process are analyzed by using Zeta potential, ultraviolet absorption spectrum, tensile force. The quantitative test results show that there exists a phenomenon in which the epoxy phase decreases, the hydroxyl group increases and the overall oxygen content decreases in the metastable transition process of graphene oxide, and the monolayer morphology of graphene oxide does not change significantly in this process. This structural transformation, however, greatly enhances the viscosity and hydrophilicity of the suspension, and remarkably reduces the energy band and considerably raises the tensile strength enhancement effect. When the transformation process is long enough, the hydrophilicity of the graphene oxide will decrease and precipitate. It is indicated that a further dehydration transition occurs between the hydroxyl groups. In addition, in the paper we also analyze the effect of constant temperature treatment time and concentration of suspension on this transformation process. The relevant research results are helpful in understanding the performance change of metastable graphene oxide suspension with temperature, and have certain reference value for the specific application of graphene oxide.

Индуцированный квазидинамический беспорядок в структуре имплантированного ионами рения кварцевого стекла

The ultraviolet (UV) absorption spectra of quartz KUVI glasses (type IV) irradiated with rhenium ions with an energy of 30 keV are studied. It was found that with increasing ion fluence (510^15 – 510^17 cm^ 2), a characteristic fan-shaped broadening of the optical absorption edge of glasses is observed. The results are interpreted within the framework of the generalized Urbach rule (approximation of quasidynamic disorder induced by ion irradiation). Based on the dose dependence of the characteristic Urbach energy, an estimate was made of the effective cross section for the process of radiative disordering of the glass matrix. It was found that this value varies within 1.0710^-17 cm^2 –1.210^-18 cm^2 with increasing fluence. The optical gap width of the implanted samples was determined by the Tauts method for direct allowed interband transitions. Based on the principle of equivalence of static and dynamic structural disorder, a ratio of the constants of second-order deformation potentials was found, which determines the relationship between the Urbach energy and the optical gap width of silica glass matrix SiO2. This work was supported by the Ministry of Education and Science of the Russian Federation (Government Task No. 3.1485.2017 / 4.6) and the Russian Government (Act 211, Contract No. 02.A03.21.0006).

Nickel ion detection by imidazole modified carbon dots.

Nickel ions (Ni2+) were detected by a new imidazole modified carbon dots (CDs) based on fluorescence quenching method. Structural characterization of CD-imidazole quantum dots were accomplished by transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR). Spectroscopic properties were characterized by ultraviolet absorption spectrum and fluorescence spectrum. Ni2+ concentration showed good linear relationship with fluorescence quenching efficiency in the range of 6-100 mM (R = 0.99) and the limit of detection (LOD) was 0.93 mM. Imidazole modified CDs have strong selectivity of Ni2+ compared with other metal ions in aqueous solution. These results demonstrated that the fluorescence sense platform based on imidazole modified CDs can be applied to Ni2+ detection in environment.

Photofragment Translational Spectroscopy Studies of H Atom Loss Following Ultraviolet Photoexcitation of Methimazole in the Gas Phase.

The ultraviolet (UV) photodissociation of gas-phase methimazole has been investigated by H Rydberg atom photofragment translational spectroscopy methods at many wavelengths in the range of 222.5-275 nm and by complementary electronic structure calculations. Methimazole is shown to exist predominantly as the thione tautomer, 1-methyl-2(3 H)-imidazolinethione, rather than the commonly given thiol form, 2-mercapto-1-methylimidazole. The UV absorption spectrum of methimazole is dominated by the S4 ← S0 transition of the thione tautomer, which involves electron promotion from an a' (p y) orbital localized on the sulfur atom to a σ* orbital localized around the N-H bond. Two H atom formation pathways are identified following UV photoexcitation. One, involving prompt, excited-state N-H bond fission, yields vibrationally cold but rotationally excited methimazolyl (Myl) radicals in their first excited (Ã) electronic state. The second yields H atoms with an isotropic recoil velocity distribution peaking at low kinetic energies but extending to the energetic limit allowed by energy conservation given a ground-state dissociation energy D0(Myl-H) ∼24 000 cm-1. These latter H atoms are attributed to the unimolecular decay of highly vibrationally excited S0 parent molecules. The companion electronic structure calculations provide rationales for both fragmentation pathways and the accompanying product energy disposals and highlight similarities and differences between the UV photochemistry of methimazole and that of other azoles (e.g., imidazole) and with molecules like thiourea and thiouracil that contain similar N-C═S motifs.

Target separation of flavonoids from Saxifraga tangutica using two-dimensional hydrophilic interaction chromatography/reversed-phase liquid chromatography.

An orthogonally (80.3%) preparative two-dimensional hydrophilic interaction chromatography/reversed-phase liquid chromatography method has been established for the isolation and purification of flavonoids from Saxifraga tangutica. Initially, flavonoids were enriched by means of a middle-pressure chromatographic tower (containing middle chromatogram isolated gel). In the first dimension, a XION preparative column was used to separate the flavonoid fractions under the guidance of characteristic ultraviolet absorption spectra of flavonoids and nine flavonoid fractions were obtained. Then, the coeluted flavonoid fractions were selected for further purification via reversed-phase liquid chromatography with the parent ion peak of quercetin (303), kaempferol (287), or isorhamnetin (317). Several flavonoids could be separated from each hydrophilic interaction chromatography fraction; furthermore, flavonoids with poor resolution in one-dimensional liquid chromatography were isolated in two-dimensional liquid chromatography due to the orthogonality. In addition, this technique was valuable for trace flavonoids, which were concentrated in the first stage and separated in the second stage. In total, 18 flavonoids with either quercetin, kaempferol, or isorhamnetin parent nuclei were targetedly obtained, and 15 flavonoids were obtained for the first time from S. tangutica. These results established that the off-line two-dimensional hydrophilic interaction chromatography/reversed-phase liquid chromatography technique was efficient for the isolation of flavonoids from Saxifraga tangutica.

Effect of substituents on the UV spectra of supermolecular system: Silver nanoparticles with bi‐aryl Schiff bases containing hydroxyl

AbstractEffect of substituents on the ultraviolet (UV) spectra of supermolecular system involving silver nanoparticles (AgNPs) and Schiff bases was investigated. AgNPs and 49 samples of model compounds (MC), bi‐aryl Schiff bases containing hydroxyl (XBAY, involving 4‐OHArCHNArY, 2‐OHArCHNArY, XArCHNAr‐4′‐OH, and XArCHNAr‐2′‐OH), were synthesized. The size of AgNPs was characterized by transmission electron microscopy (TEM), and the UV absorption spectra of AgNPs, XBAYs, and MC‐AgNPs mixed solutions were measured, respectively. The results show that (1) the size of AgNPs is larger in MC‐AgNPs solutions than that in AgNPs solution due to the distribution of MC molecules on the surface of AgNPs; (2) the UV absorption wavelength of XBAYs changes in the action of AgNPs and their wavelength shift exists limitation between XBAY and MC‐AgNPs solutions; and (3) the wavelength shift limit of MC‐AgNPs (λWSL) is influenced by the substituents X and Y and the position of hydroxyl OH. The wavenumber ΔνWSL of λWSL can be quantified by employing the excited‐state substituent constant and Hammett constant σ of substituents X and Y. Comparing with the 4‐OH, the 4′‐OH makes the ΔνWSL a red shift, whereas the 2′‐OH, comparing with the 2‐OH, makes the ΔνWSL a blue shift.

Theoretical investigation of auxiliary electronic acceptors in modifying D-D-π-A sensitizers for dye-sensitized solar cells.

In light of the performance of the SD2 pigments in DSSC, in order to expand the absorption spectral scope, decrease the energy difference between the highest occupied and the lowest unoccupied molecular orbitals, with SD2 dye molecular electron donor and electron acceptor as the fundamental framework, the indole fragment and thiophene derivative in the prototype dye molecule were replaced by the two π-bridges (labeled PA, PB, respectively) and the four auxiliary electron acceptors (labeled A1, A2, A3, A4, respectively). For the sake of characterizing dye molecules as thoroughly as possible in DSSC, the frontier orbital energy levels, ultraviolet absorption spectra, natural bond orbital analysis, intramolecular charge transfer, charge and hole reorganization energies, parameters influencing the short-circuit current density and the open-circuit photovoltage for these eight individual dye molecules are carried out to try to fully characterize the properties of these dye molecules. According to these computational results of physical quantities and based on the performance of these dye molecules in the above aspects, in this paper, six free molecular models were picked out to combine with titanium dioxide cluster to calculate their geometrical structures, frontier orbital distributions, electron excitation energies, ultraviolet absorption spectra and the composition of the electronic transitions in chloroform solvent with polarizable continuum model. The results of these calculations show that the PA-A2 and PB-A4 dye molecule has better properties in electron transfer and spectral absorption range before and after the adsorption on the titanium dioxide.

Absolute Infrared Absorption Cross Section of the Simplest Criegee Intermediate Near 1285.7 cm-1.

The ν4 fundamental of the simplest Criegee intermediate, CH2OO, has been monitored with high-resolution infrared (IR) transient absorption spectroscopy under total pressures of 4-94 Torr. This IR spectrum provides an unambiguous identification of CH2OO and is potentially useful to determine the number density of CH2OO in various laboratory studies. Here we utilized an ultraviolet (UV) and IR coupled spectrometer to measure the UV and IR absorption spectra of CH2OO simultaneously; the absolute IR cross section can then be determined by using a known UV cross section. Due to significant pressure broadening in the studied pressure range, we integrated the IR absorption spectra between 1285.2 and 1286.4 cm-1 (covering the Q branch), and then we converted this integrated absorbance to the absolute integral IR cross section of CH2OO (for the Q branch); its absolute value is (3.7 ± 0.6) × 10-19 cm·molecule-1 or 2.2 ± 0.4 km·mol-1. The whole rotational band (P, Q, and R branches) can be adequately simulated by using the precise spectroscopic parameters from the literature, yielding the absolute integral IR cross section (full ν4 band) to be 19.2 ± 3.5 km·mol-1. For a practical detection of CH2OO, this work also reports the peak cross section as a function of total pressure (4-94 Torr O2). At low pressure (≤4 Torr), where the pressure broadening is insignificant, the absorption cross section of the highest peak is (6.2 ± 0.9) × 10-18 cm2·molecule-1 (at the system line width of 0.004 cm-1 fwhm).

Fabrication and Luminescence Properties of Flower-Like Cadmium Sulfide Using 1-Benzylidenethiourea as Sulfur Source and Capping Agent

A thio Schiff base ligand, 1-benzylidenethiourea (L), was used as sulfur source and capping agent together for preparation of CdS nanostructures via solvothermal method in glycerol solvent. The Schiff base was characterized by elemental analysis as well as FT-IR and 1H, 13CNMR spectroscopies. Structure characterization of obtained CdS nanoparticles were studied by XRD, EDX, FT-IR and UV–Vis spectroscopies. SEM and TEM images were showed that the synthesized CdS have flower-like structures contain of several nanorods. The optical properties of the product was characterized by photoluminescence (PL) spectroscopy measurements. The PL spectrum of CdS nanoparticles shows a blue visible spectrum. The ultraviolet absorption spectrum shows the blue shift in the band gap due to the quantum confinement effect. The effect of some parameter such as solvent type, temperature and duration of reaction on size and morphology of CdS nanostructure was investigated as well.