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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Modern level for properties prediction of iodine-containing organic compounds: the halogen bonds formed by iodine

The modern concepts on specific features of anisotropy of the electron density of valence shells of bound atoms and chemical bonds providing the successful description of the properties of halogen bonds formed by the iodine molecule in compounds with useful physicochemical properties are generalized in the review. The prognoses of basicity by the diiodine basicity scale for the nitrogen-containing compounds are illustrated. The regularities and peculiarities of shifting bands in Raman spectra of iodine-containing organic crystals are considered. The methodical and specific problems of modeling appeared when the electronic characteristics of the iodine compounds are estimated and briefly discussed.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2010

A possible mechanism for the decrease in serum thyroxine level by phenobarbital in rodents

Effects of phenobarbital (PB) on the levels of serum thyroid hormones such as total thyroxine (T{sub 4}) and triiodothyronine were examined in male mice, hamsters, rats, and guinea pigs. One day after the final administration of PB (80 mg/kg, intraperitoneal, once daily for 4 days), significant decreases in the levels of the serum total T{sub 4} and free T{sub 4} occurred in mice, hamsters, and rats, while a significant decrease in the level of serum triiodothyronine was observed in hamsters and rats among the animals examined. In addition, a significant decrease in the level of serum thyroid-stimulating hormone was observed in only hamsters among the rodents examined. Significant increases in the level and activity of hepatic T{sub 4}-UDP-glucuronosyltransferase (UGT1A) after the PB administration occurred in mice, hamsters, and rats, while the increase in the amount of biliary [{sup 125}I]T{sub 4}-glucuronide after an intravenous injection of [{sup 125}I]T{sub 4} to the PB-pretreated animals occurred only in rats. In mice, rats, and hamsters, but not guinea pigs, PB pretreatment promoted the clearance of [{sup 125}I]T{sub 4} from the serum, led to a significant increase in the steady-state distribution volumes of [{sup 125}I]T{sub 4}, and raised the concentration ratio (Kp value) of the liver to serum and the liver distribution of [{sup 125}I]T{sub 4}. The present findings indicate that the PB-mediated decreases in the serum T{sub 4} level in mice, hamsters, and rats, but not guinea pigs, occur mainly through an increase in the accumulation level of T{sub 4} in the liver.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2011

A possible mechanism for 2,2',4,4',5,5'-hexachlorobiphenyl-mediated decrease in serum thyroxine level in mice

Serum total thyroxine (T{sub 4}) level was markedly decreased, without significant increases in the levels of hepatic T{sub 4}-UDP-glucuronosyltransferase (T{sub 4}-UGT) and serum thyroid-stimulating hormone, 3 days after treatment with 2,2',4,4',5,5'-hexachlorobiphenyl (CB153) (100 mg/kg, ip) in both 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-sensitive C57BL/6 and TCDD-resistant DBA/2 mice. Likewise, in either strain of mice, no CB153-mediated changes in the binding levels of [{sup 125}I]T{sub 4} to serum proteins, such as transthyretin, albumin, and thyroxine binding globulin, were observed, while in CB153-pretreated C57BL/6 mice, but not in CB153-pretreated DBA/2 mice, the levels of biliary [{sup 125}I]T{sub 4} and [{sup 125}I]T{sub 4}-glucuronide at 90-120 min after injection of [{sup 125}I]T{sub 4} slightly increased, as compared with those in the corresponding control mice. Concerning tissue distribution of [{sup 125}I]T{sub 4}, liver-selective increases in the [{sup 125}I]T{sub 4} accumulation by CB153-pretreatment were observed in both C57BL/6 and DBA/2 mice, and the hepatic levels of [{sup 125}I]T{sub 4} in the C57BL/6 and DBA/2 mice became more than 44% and 34% of the [{sup 125}I]T{sub 4} dosed, respectively. The present findings indicated that the CB153-mediated decreases in the level of serum total T{sub 4} in C57BL/6 and DBA/2 mice occur mainly through an increase in the accumulation of T{sub 4} in the liver.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2012

Transarterial Chemoembolization With Cisplatin as Second-Line Treatment for Hepatocellular Carcinoma Unresponsive to Chemoembolization With Epirubicin-Lipiodol Emulsion

Purpose: The purpose of this retrospective study was to investigate the efficacy of transarterial chemoembolization (TACE) using cisplatin as a second-line treatment for advanced hepatocellular carcinoma (HCC) unresponsive to TACE using epirubicin-Lipiodol emulsion at our institution. Materials and Methods: Between January 2006 and March 2009, 51 patients with unresectable HCC underwent TACE using cisplatin. All patients had shown persistent viable tumor or tumor progression after at least 2 sessions of TACE using epirubicin-Lipiodol emulsion. TACE procedures consisted of arterial injection of a mixture of Lipiodol and cisplatin (30-100 mg [mean 57 {+-} 21]) (n = 29) or arterial infusion of cisplatin (30-100 mg [mean 87 {+-} 19]) solution (n = 22) followed by injection of 1-mm porous gelatin particles. Early tumor response was assessed by contrast-enhanced computed tomography (CT) according to Response Evaluation Criteria in Solid Tumors (RECIST) and European Association for the Study of the Liver (EASL) criteria. Overall survival and progression-free survival was calculated using the Kaplan-Meier method. Toxicity was assessed according to NCI-CTCAE version 3 criteria. Results: Response rates were 11.8 and 27.5% by RECIST and EASL criteria, respectively. Overall survival rates were 61.9, 48.2, and 28.9% at 1, 2, and 3 years, respectively, and the median survival time was 15.4 months. Progression-free survival rate was 35.2% at 1 year, and median progression-free survival time was 3.1 months. No major complications were observed, and the occurrence of postembolization syndrome was minimal. Grade 3 to 4 toxicities included thrombocytopenia (5.8%), increased aspartate aminotransferase (AST) level (35.3%), and increased alanine aminotransferase (ALT) level (23.5%). Conclusions: witching the TACE anticancer drug from epirubicin to cisplatin might be the feasible option for advanced HCC, even when considered resistant to the initial form of TACE.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Endovascular Therapy of Bronchial Artery Aneurysm: Five Cases With Six Aneurysms

The objective of this study was to investigate the effect of transcatheter arterial embolization (TAE) with N-butyl-2-cyanoacrylate (NBCA)-Lipiodol mixture in patients with bronchial artery aneurysm (BAA). From January 2005 to January 2010, five patients presenting hemoptysis with six BAAs were treated with NBCA-Lipiodol mixture, including intra-aneurysm embolization (IAE) in one patient. Adjuvant embolization with spherical polyvinyl alcohol (PVA) embolic microparticles or NBCA was first performed to embolize the distal engorged bronchiectatic arteries. Bronchial arterial angiography showed six BAAs (four in the right lobe and two in the left lobe) and some engorged, tortuous bronchial arteries. TAE through microcatheter was successful in all cases. Postembolization angiogram demonstrated the NBCA cast and total occlusion of BAAs and bronchiectatic engorged vessels. After these procedures, hemoptysis completely disappeared in all patients. Follow-up computed tomography (CT) scan was performed at an average of 3 months (range 2 to 6), which showed no enhancement of BAAs and accumulation of NBCA. TAE is a minimally invasive, effective, and reliable approach for treatment for patients with BAA. NBCA-Lipiodol mixture provides a good choice for treatment of BAA, especially when catheterization of the efferent branches is impossible.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Hepatic Arterial Embolization with Doxorubicin-Loaded Superabsorbent Polymer Microspheres in a Rabbit Liver Tumor Model

Objectives: The pharmacokinetic profile after hepatic arterial embolization with superabsorbent microspheres (QuadraSpheres) loaded with doxorubicin was studied. Methods: Rabbits with hepatic VX2 tumors were treated with intra-arterial administration of QuadraSpheres loaded with doxorubicin, or transarterial chemoembolization (TACE) using doxorubicin, Lipiodol and Embospheres, or hepatic arterial infusion (HAI) of doxorubicin. Tumor specimens were evaluated by fluorescence microscopy, and plasma and tumor concentrations of doxorubicin were measured. Results: The peak plasma concentration of doxorubicin was lower in the QuadraSphere group (309.9 ng/ml) than in the HAI (673.4 ng/ml) or TACE (360.5 ng/ml) groups, suggesting higher tumor retention in the QuadraSphere group. Intratumoral doxorubicin levels declined to negligible levels at 1 and 3 days after treatment, respectively, in the HAI and TACE groups. In the QuadraSphere groups, intratumoral doxorubicin level declined after day 1, but was still detectable at 14 days after treatment and was higher than that in the other groups at 1, 3, and 7 days. Intratumoral doxorubicin fluorescence was detected at all time points in the QuadraSphere group, but only at 1 day after treatment in the TACE group. Conclusions: Hepatic arterial administration of doxorubicin-loaded QuadraSpheres enables the sustained release of doxorubicin to hepatic tumors.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2012

Comparison of the Anti-tumor Effects of Two Platinum Agents (Miriplatin and Fine-Powder Cisplatin)

Purpose: This study was designed to evaluate the anti-tumor effects of miriplatin-lipidol and fine-powder cisplatin-lipiodol suspensions. Methods: Assessment of the cytotoxicity of two drugs was performed: a soluble derivative of miriplatin (DPC) and fine-powder cisplatin. We randomly divided 15 rabbits with transplanted VX2 liver tumors into three equal groups. They were infused via the proper hepatic artery with a miriplatin-lipiodol suspension (ML), a fine-powder cisplatin-lipiodol suspension (CL), or saline (control) and the tumor growth rate was determined on MR images acquired before and 7 days after treatment. The concentration of platinum (PCs) in blood was assayed immediately, and 10, 30, and 60 min, and 24 h and 7 days after drug administration. Its concentration in tumor and surrounding normal liver tissues was determined at 7 days postadministration. Results: At high concentrations, fine-powder cisplatin exhibited stronger cytotoxicity than DPC. At low concentrations, both agents manifested weak cytotoxicity. While there was no difference between the tumor growth rate of the ML and the CL groups, the difference between the controls and ML- and CL-treated rabbits was significant. The blood PCs peaked at 10 min and then gradually decreased over time. On the other hand, no platinum was detected at any point after the administration of ML. There was no difference between the ML and CL groups in the PCs in tumor tissues; however, in normal hepatic tissue, the PCs were higher in ML- than CL-treated rabbits. Conclusions: We confirmed the anti-tumor effect of ML and CL. There was no significant difference between the anti-tumor effect of ML and CL at 7 days postadministration.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

Long-Term Outcome of Transcatheter Subsegmental and Segmental Arterial Chemoemobolization Using Lipiodol for Hepatocellular Carcinoma

Purpose: To clarify the efficacy of transcatheter hepatic sub-subsegmental, subsegmental, and segmental arterial chemoembolization using lipiodol (subseg/seg lip-TACE) for hepatocellular carcinoma (HCC), long-term outcomes of patients who had been treated using subseg/seg lip-TACE alone were retrospectively examined. Materials and Methods: Subjects comprised 199 patients with HCC (T1/2/{>=}3 = 30/108/61; Child-Pugh A/B/C = 115/52/32; Japan Integrated Staging [JIS] score {<=}1/2/{>=}3 = 88/64/47) who underwent subseg/seg lip-TACE using lipiodol mixed with an anticancer drug followed by injection of gelatin sponge particles. Each patient was followed-up every 3 months, and repeat subseg/seg lip-TACE and/or conventional lip-TACE was performed in cases showing recurrence. One-, 3-, 5-, 7-, and 10-year cumulative survival rates were calculated. Subgroup analyses were performed by stratifying the population according to T-factor, Child-Pugh classification, and JIS score. Results: Median duration of follow-up was 3.8 years (range 0.2 to 16.4). Median overall survival was 3.8 years. One-, 3-, 5-, 7- and 10-year survival rates were 91.5, 66.1, 38.8, 20.3, and 9.4% for all patients, and 95.5, 76.9, 51.9, 27.9 and 20.4% for patients with JIS {<=}1, respectively. Significant survival differences were found across two subgroups of staging systems (T2 vs. T3{<=} [P = 0.0012] and JIS score {<=}1 vs. 2 [P = 0.0036]). Conclusion: This study demonstrated that subseg/seg lip-TACE is a feasible treatment for obtaining prolonged survival in patients with localized HCC showing rich vasculature. Outcomes are influenced by both tumor stage and liver function, as seen in the best prolonged survival in patients with JIS score {<=}1.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Dependence of Cell Survival on Iododeoxyuridine Concentration in 35-keV Photon-Activated Auger Electron Radiotherapy

Purpose: To measure and compare Chinese hamster ovary cell survival curves using monochromatic 35-keV photons and 4-MV x-rays as a function of concentration of the radiosensitizer iododeoxyuridine (IUdR). Methods and Materials: IUdR was incorporated into Chinese hamster ovary cell DNA at 16.6 {+-} 1.9%, 12.0 {+-} 1.4%, and 9.2 {+-} 1.3% thymidine replacement. Cells were irradiated from 1 to 8 Gy with 35-keV synchrotron-generated photons and conventional radiotherapy 4-MV x-rays. The effects of the radiation were measured via clonogenic survival assays. Surviving fraction was plotted vs. dose and fit to a linear quadratic model. Sensitization enhancement ratios (SER{sub 10}) were calculated as the ratio of doses required to achieve 10% surviving fraction for cells without and with DNA-incorporated IUdR. Results: At 4 MV, SER{sub 10} values were 2.6 {+-} 0.1, 2.2 {+-} 0.1, and 1.5 {+-} 0.1 for 16.6%, 12.0%, and 9.2% thymidine replacement, respectively. At 35 keV, SER{sub 10} values were 4.1 {+-} 0.2, 3.0 {+-} 0.1, and 2.0 {+-} 0.1, respectively, which yielded SER{sub 10} ratios (35 keV:4 MV) of 1.6 {+-} 0.1, 1.4 {+-} 0.1, and 1.3 {+-} 0.1, respectively. Conclusions: SER{sub 10} increases monotonically with percent thymidine replacement by IUdR for both modalities. As compared to 4-MV x-rays, 35-keV photons produce enhanced SER{sub 10} values whose ratios are linear with percent thymidine replacement and assumed to be due to Auger electrons contributing to enhanced dose to DNA. Although this Auger effectiveness factor is less than the radiosensitization factor of IUdR, both could be important for the clinical efficacy of IUdR radiotherapy.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Effects of pre- and postnatal exposure to the UV-filter Octyl Methoxycinnamate (OMC) on the reproductive, auditory and neurological development of rat offspring

Octyl Methoxycinnamate (OMC) is a frequently used UV-filter in sunscreens and other cosmetics. The aim of the present study was to address the potential endocrine disrupting properties of OMC, and to investigate how OMC induced changes in thyroid hormone levels would be related to the neurological development of treated offspring. Groups of 14-18 pregnant Wistar rats were dosed with 0, 500, 750 or 1000 mg OMC/kg bw/day during gestation and lactation. Serum thyroxine (T{sub 4}), testosterone, estradiol and progesterone levels were measured in dams and offspring. Anogenital distance, nipple retention, postnatal growth and timing of sexual maturation were assessed. On postnatal day 16, gene expression in prostate and testes, and weight and histopathology of the thyroid gland, liver, adrenals, prostate, testes, epididymis and ovaries were measured. After weaning, offspring were evaluated in a battery of behavioral and neurophysiological tests, including tests of activity, startle response, cognitive and auditory function. In adult animals, reproductive organ weights and semen quality were investigated. Thyroxine (T{sub 4}) levels showed a very marked decrease during the dosing period in all dosed dams, but were less severely affected in the offspring. On postnatal day 16, high dose male offspring showed reduced relative prostate and testis weights, and a dose-dependent decrease in testosterone levels. In OMC exposed female offspring, motor activity levels were decreased, while low and high dose males showed improved spatial learning abilities. The observed behavioral changes were probably not mediated solely by early T{sub 4} deficiencies, as the observed effects differed from those seen in other studies of developmental hypothyroxinemia. At eight months of age, sperm counts were reduced in all three OMC-dosed groups, and prostate weights were reduced in the highest dose group. Taken together, these results indicate that perinatal OMC-exposure can affect both the reproductive and neurological development of rat offspring, which may be a cause of concern, as humans are systematically exposed to the compound through usage of sunscreens and other cosmetics.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2011

Altered cardiovascular reactivity and osmoregulation during hyperosmotic stress in adult rats developmentally exposed to polybrominated diphenyl ethers (PBDEs)

Polybrominated diphenyl ethers (PBDEs) and the structurally similar chemicals polychlorinated biphenyls (PCBs) disrupt the function of multiple endocrine systems. PCBs and PBDEs disrupt the secretion of vasopressin (VP) from the hypothalamus during osmotic activation. Since the peripheral and central vasopressinergic axes are critical for osmotic and cardiovascular regulation, we examined whether perinatal PBDE exposure could impact these functions during physiological activation. Rats were perinatally dosed with a commercial PBDE mixture, DE-71. Dams were given 0 (corn oil control), 1.7 (low dose) or 30.6 mg/kg/day (high dose) in corn oil from gestational day (GD) 6 through postnatal day (PND) 21 by oral gavage. In the male offspring exposed to high dose PBDE plasma thyroxine and triiodothyronine levels were reduced at PND 21 and recovered to control levels by PND 60 when thyroid stimulating hormone levels were elevated. At 14-18 months of age, cardiovascular responses were measured in four groups of rats: Normal (Oil, normosmotic condition), Hyper (Oil, hyperosmotic stress), Hyper PBDE low (1.7 mg/kg/day DE-71 perinatally, hyperosmotic stress), and Hyper PBDE high (30.6 mg/kg/day DE-71 perinatally, hyperosmotic stress). Systolic blood pressure (BP), diastolic BP, and heart rate (HR) were determined using tail cuff sphygmomanometry and normalized to pretreatment values (baseline) measured under basal conditions. Hyperosmotic treatment yielded significant changes in systolic BP in PBDE exposed rats only. Hyper PBDE low and high dose rats showed 36.1 and 64.7% greater systolic BP responses at 3 h post hyperosmotic injection relative to pretreatment baseline, respectively. No treatment effects were measured for diastolic BP and HR. Hyper and Hyper PBDE rats showed increased mean plasma osmolality values by 45 min after injection relative to normosmotic controls. In contrast to Hyper rats, Hyper PBDE (high) rats showed a further increase in mean plasma osmolality at 3 h (358.3 {+-} 12.4 mOsm/L) relative to 45 min post hyperosmotic injection (325.1 {+-} 11.4 mOsm/L). Impaired osmoregulation in PBDE-treated animals could not be attributed to decreased levels of plasma vasopressin. Our findings suggest that developmental exposure to PBDEs may disrupt cardiovascular reactivity and osmoregulatory responses to physiological activation in late adulthood. - Highlights: > We examined whether PBDE exposure could impact osmotic and cardiovascular regulation. > Hyperosmotic treatment yielded significant changes in systolic BP in PBDE exposed rats only. > PBDEs may disrupt cardiovascular and osmoregulatory responses to physiological activation.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2011

Levothyroxine rescues the lead-induced hypothyroidism and impairment of long-term potentiation in hippocampal CA1 region of the developmental rats

Lead (Pb) exposure during development has been associated with impaired long-term potentiation (LTP). Hypothyroidism happening upon subjects with occupational exposure to Pb is suggestive of an adverse effect of Pb on thyroid homeostasis, leading to the hypothesis that Pb exposure may alter thyroid hormone homeostasis. Hippocampus is one of the targets of Pb exposure, and is sensitive to and dependent on thyroid hormones, leading us to explore whether levothyroxine (L-T{sub 4}) administration could alter the thyroid disequilibrium and impairment of LTP in rat hippocampus caused by Pb exposure. Our results show that Pb exposure caused a decrease in triiodothyronine (T{sub 3}) and tetraiodothyronine (T{sub 4}) levels accompanied by a dramatic decrease of TSH and application of L-T{sub 4} restored these changes to about control levels. Hippocampal and blood Pb concentration were significantly reduced following L-T{sub 4} treatment. L-T{sub 4} treatment rescued the impairment of LTP induced by the Pb exposure. These results suggest that Pb exposure may lead to thyroid dysfunction and induce hypothyroidism and provide a direct electrophysiological proof that L-T{sub 4} relieves chronic Pb exposure-induced impairment of synaptic plasticity. - Highlights: > Lead may interfere with thyroid hormone homeostasis and induce hypothyroidism. > Levothyroxine decreases the hippocampal and blood Pb concentration. > Levothyroxine amends the T{sub 3}, T{sub 4} and TSH levels in blood. > Levothyroxine rescues the impaired LTP in CA1.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2010

Experimental measurement of the van der Waals binding energy of X-O{sub 2} clusters (X=Xe,CH{sub 3}I,C{sub 3}H{sub 6},C{sub 6}H{sub 12})

Van der Waals binding energies for the X-O{sub 2} complexes (X=Xe,CH{sub 3}I,C{sub 3}H{sub 6},C{sub 6}H{sub 12}) are determined by analysis of experimental velocity map imaging data for O({sup 3}P{sub 2}) atoms arising from UV-photodissociation of the complex [A. V. Baklanov et al., J. Chem. Phys. 126, 124316 (2007)]. Several dissociation pathways have been observed, we focus on the channel corresponding to prompt dissociation of X-O{sub 2} into X+2O({sup 3}P) fragments, which is present for complexes of O{sub 2} with all partners X. Our method is based on analysis of the kinetic energy of all three photofragments, where the O atom kinetic energy was directly measured in the experiment and the kinetic energy of the X partner was calculated using momentum conservation, along with the measured angular anisotropy for O atom recoil. We exploit the fact that the clusters are all T-shaped or nearly T-shaped, which we also confirm by ab initio calculations, along with knowledge of the transition dipole governing radiative absorption by the complex. The effect of partitioning the kinetic energy between translation along the X-O{sub 2} and O-O coordinates on the angular anisotropy of the O atom recoil direction is discussed. Van der Waals binding energies of 110{+-}20 cm{sup -1}, 280{+-}20 cm{sup -1}, 135{+-}30 cm{sup -1}, and 585{+-}20 cm{sup -1} are determined for Xe-O{sub 2}, CH{sub 3}I-O{sub 2}, C{sub 3}H{sub 6}-O{sub 2}, and C{sub 6}H{sub 12}-O{sub 2} clusters, respectively.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2011

Hyperfine-resolved 3.4-{mu}m spectroscopy of CH{sub 3}I with a widely tunable difference frequency generation source and a cavity-enhanced cell: A case study of a local Coriolis interaction between the v{sub 1}=1 and (v{sub 2},v{sub 6}{sup l})=(1,2{sup 2}) states

Saturated absorption spectra of the {nu}{sub 1} fundamental band of CH{sub 3}I are recorded with a cavity-enhanced cell and a tunable difference frequency generation source having an 86-cm{sup -1} range. The recorded spectral lines are 250 kHz wide, and most of them are resolved into the individual hyperfine components. The Coriolis interaction between the v{sub 1}=1 and (v{sub 2},v{sub 6}{sup l})=(1,2{sup 2}) states locally perturbing the hyperfine structures is analyzed to yield the Coriolis and hyperfine coupling constants with uncertainties similar to those in typical microwave spectroscopy. The spectrometer has demonstrated the potential for precisely determining the energy structure in the vibrational excited states.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2011

Resonant inelastic x-ray scattering at the limit of subfemtosecond natural lifetime

We present measurements of the resonant inelastic x-ray scattering (RIXS) spectra of the CH{sub 3}I molecule in the hard-x-ray region near the iodine L{sub 2} and L{sub 3} absorption edges. We show that dispersive RIXS spectral features that were recognized as a fingerprint of dissociative molecular states can be interpreted in terms of ultrashort natural lifetime of {approx}200 attoseconds in the case of the iodine L-shell core-hole. Our results demonstrate the capacity of the RIXS technique to reveal subtle dynamical effects in molecules with sensitivity to nuclear rearrangement on a subfemtosecond time scale.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Electron attachment and positive ion chemistry of monohydrogenated fluorocarbon radicals

Rate coefficients and product branching fractions for electron attachment and for reaction with Ar{sup +} are measured over the temperature range 300–585 K for three monohydrogenated fluorocarbon (HFC) radicals (CF{sub 3}CHF, CHF{sub 2}CF{sub 2}, and CF{sub 3}CHFCF{sub 2}), as well as their five closed-shell precursors (1-HC{sub 2}F{sub 4}I, 2-HC{sub 2}F{sub 4}I, 2-HC{sub 2}F{sub 4}Br, 1-HC{sub 3}F{sub 6}I, 2-HC{sub 3}F{sub 6}Br). Attachment to the HFC radicals is always fairly inefficient (between 0.1% and 10% of the Vogt–Wannier capture rate), but generally faster than attachment to analogous perfluorinated carbon radicals. The primary products in all cases are HF-loss to yield C{sub n}F{sub m−1}{sup −} anions, with only a minor branching to F{sup −} product. In all cases the temperature dependences are weak. Attachment to the precursor halocarbons is near the capture rate with a slight negative temperature dependence in all cases except for 2-HC{sub 2}F{sub 4}Br, which is ∼10% efficient at 300 K and becomes more efficient, approaching the capture rate at higher temperatures. All attachment kinetics are successfully reproduced using a kinetic modeling approach. Reaction of the HFC radicals with Ar{sup +} proceeds at or near the calculated collisional rate coefficient in all cases, yielding a wide variety of product ions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

Low resistivity ZnO-GO electron transport layer based CH{sub 3}NH{sub 3}PbI{sub 3} solar cells

Perovskite based solar cells have demonstrated impressive performances. Controlled environment synthesis and expensive hole transport material impede their potential commercialization. We report ambient air synthesis of hole transport layer free devices using ZnO-GO as electron selective contacts. Solar cells fabricated with hole transport layer free architecture under ambient air conditions with ZnO as electron selective contact achieved an efficiency of 3.02%. We have demonstrated that by incorporating GO in ZnO matrix, low resistivity electron selective contacts, critical to improve the performance, can be achieved. We could achieve max efficiency of 4.52% with our completed devices for ZnO: GO composite. Impedance spectroscopy confirmed the decrease in series resistance and an increase in recombination resistance with inclusion of GO in ZnO matrix. Effect of temperature on completed devices was investigated by recording impedance spectra at 40 and 60 {sup o}C, providing indirect evidence of the performance of solar cells at elevated temperatures.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗