Miracle-dz/UniFAR-FTUs huggingface dataset:
D-homo-steroids. Part III. The preparation of D-homoandrostane derivatives: a study of the reactions of steroidal C(17)-spiro-oxirans and their derivatives

The reaction of epoxides with azide ions, to give hydroxy-azides, proceeds smoothly in dimethylformamide containing boric acid. The resulting azides are conveniently reduced by zinc dust or chromium(II) ions in acidic media to give amine salts. Application of these reactions to the C(17)-spiro-oxirans (VI) afforded the hydroxy-amines (III), converted by nitrous acid into the D-homo-ketones (IV) and (V) in very high overall yield. The preparations of ‘D-homodehydroepiandrosterone’(IVa) and D-homo-5α-androstan-7-one (XVIIb) are described in detail. Other reactions of the C(17)-spiro-oxiran (VIa) were studied, including the addition of hydrogen halides, acid-catalysed rearrangement, and the reaction with guanidine, which gives an imino-oxazolidine derivative (XXIII). Sodamide, ammonia, and some carboxylic amides and imides, did not react usefully with the C(17)-spiro-oxiran. Benzylamine gave the 17-benzylaminomethyl derivative (XX), but this could not be reduced to the aminomethyl compound (III).
Highly Selective Epoxidation of Cycloaliphatic Alkenes with Aqueous Hydrogen Peroxide Catalyzed by [PO4{WO(O2)2}4]3−/Imidazole

In the presence of imidazole as an additive, a phosphorus‐containing tetranuclear peroxotungstate, THA3[PO4{WO(O2)2}4] (I, THA=tetra‐n‐hexylammonium), could act as an efficient catalyst for epoxidation of cycloaliphatic alkenes with 30 % aqueous hydrogen peroxide (H2O2). Compound I showed higher catalytic activity and selectivity to epoxide than other tungstates. By using the I/imidazole system, various kinds of cycloaliphatic alkenes could be highly selectively converted into the acid‐sensitive epoxides including industrially important diepoxides in high to excellent yields under the almost stoichiometric conditions. The 1H NMR spectroscopy showed that imidazole would work not only as a proton acceptor but also as a Lewis base to remarkably suppress the acid‐catalyzed ring opening of epoxides.
A thermal theory for flammability diagrams guiding purge and inertion of a flammable mixture

Recently, a thermal method was proposed to recheck the concept of flammability by manipulating the competition between heating and quenching. This method is further explored here to reconstruct flammability diagrams, explaining the contribution of each component toward flammability change for a mixture. Based on the assumption that a diluent will not change the flame temperature at the flammability limits, these isothermal processes lead to a conservative estimation of the flammable zone. Although rough near the inertion point, the theoretical flammability envelop has the potential to guide future purging and diluting operations. It will be a powerful tool for both educational purposes and practical utilities. © 2012 American Institute of Chemical Engineers Process Saf Prog 32: 42–48, 2013
Thermal and surface characterization of plasticized starch polyvinyl alcohol blends crosslinked with epichlorohydrin

Starch-polyvinyl alcohol (PVA) blends in 2:8 wt % were prepared with various plasticizers such as polyethylene glycol (PEG-200, PEG-400) and glycerol. The crosslinking of starch-PVA blends by epichlorohydrin was carried out in the presence of a plasticizer in situ. The obtained films were analyzed by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), dynamic mechanical and thermal analysis (DMTA), and X-ray photoelectron spectroscopy (XPS), and remarkable changes in thermal stability and glass-transition temperature have been observed on plasticizing and crosslinking in different concentrations. Different kinetic models such as Coats–Redfern, Broido, Friedman, and Chang were used to calculate the kinetic parameters of thermal decomposition. The results suggest that the thermal stability and activation energy of thermal decomposition passes through maxima at a critical concentration of plasticizer and increases with increasing crosslinker concentration. High-resolution C 1s XPS analysis was used to provide a method of differentiating the presence of various carbons associated with different environment in the films. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 25–34, 2006
Formation of Silicon-Based Thin Films Prepared by Catalytic Chemical Vapor Deposition (Cat-CVD) Method

This paper is a review of the catalytic chemical vapor deposition (Cat-CVD) method and properties of silicon-based thin films, such as amorphous-silicon (a-Si), polycrystalline-silicon (p-Si) and silicon nitride (SiNx) films, prepared by the Cat-CVD method. In the Cat-CVD method, also known as the hot-wire CVD (HWCVD) method, deposition gases are decomposed by catalytic cracking reactions with a heated catalyzer placed near the substrates, so that films are deposited at low substrate temperatures around 300°C without any help from the plasma. After explaining the deposition system and deposition mechanism, the properties of Cat-CVD a-Si, p-Si and SiNx films are described and the results are compared with those obtained by the conventional plasma CVD (PCVD) method. The superiority of the Cat-CVD method over the PCVD method is demonstrated.
Determination of ammonia in low concentrations with Nessler's reagent by flow injection analysis

A turbidimetric procedure for the determination of ammonia in low concentrations with the use of Nessler's reagent is described. Both natural waters and soil extracts can be analysed at a rate of up to 120 samples per hour with good precision and accuracy. The effects of reagent composition, flow-rate, temperature and protective colloids in the flow injection system are discussed in detail.
Inexpensive and Reliable Monitoring of the Microdeposition of Biomolecules

Anti-C-reactive protein antibody is used to quantify C-reactive protein in diagnostic tests for assessing inflammation levels. In order to develop a practical chip for diagnostic tests, anti-C-reactive protein antibody was continuously ejected using a piezoelectric injector and microdeposition was monitored on a shot-by-shot basis using a 30 MHz quartz crystal microbalance. Background noise due to external sources such as air flow and temperature fluctuations were largely eliminated by covering the quartz crystal microbalance with a stainless-steel cover and maintaining a fixed distance between the optical microscope lamp and the piezoelectric injector. Each shot of a 1 mg ml−1 solution of anti-C-reactive protein antibody solution delivered approximately 30 pl to the quartz crystal microbalance. The frequency change per shot was 2.21 ± 0.97 Hz and the injected mass was estimated to be 44.2 pg using the Sauerbrey equation. This approach simplifies the experimental evaluation of inkjet bioprinting by allowing the sensitive determination of shot ejection mass and volume, and realizes label-free detection, continuous monitoring, and simple temperature control. Measurements can be performed at atmospheric pressure and at room temperature. Furthermore, the system uses only commercially available devices.
Electronic and atomic structure of liquid potassium via path integral molecular dynamics with non-local quantum exchange

We develop a novel first-principle molecular dynamics method based on the discretized path integral formalism of quantum mechanics. This method which includes quantum exchange is used to simulate the behavior of liquid potassium at high temperature. We compute the energy as well as the electronic and atomic structural properties of the liquid metal. These results compare favorably with previous calculations and experimental results.
Synthesis, experimental and theoretical characterization of Cu(II) complex of 2-chloropyrimidine

The new dimeric [Cu 2(OAc) 4(2-Clpym)2] complex of 2-chloropyrimidine (2-Clpym) ligand was synthesized, where 2-Clpym coordinated via the nitrogen atom and acts as monodentate ligand. The water molecules of dimeric Cu 2(OAc) 4(H 2O) 2 salt replaced by two 2-Clpym ligands producing the new complex. The nature of synthesized complex was determinated by elemental and spectrochemical (IR, UV-Vis) analysis. Also, the geometries of ligand and complex have been fully optimized using density functional theory (B3LYP) method. The obtained structural parameters are in good agreement with the experimental data, reported for the similar compounds. Also, the calculated and experimental wavenumbers confirm validity of the optimized structures for the ligand and Cu complex.
Polycyclitols Novel conduritol and carbasugar hybrids as new glycosidase inhibitors

A family of novel carbasugar analogues (bicyclitols) based on cis-hydrindane and cis-decalin frameworks has been conceptualized. These novel entities can be regarded as conduritol and carbasugar hybrids. Syntheses of these polyhydroxylated entities have been achieved in stereo- and regioselective manners, starting from the readily available Diels-Alder adducts of 5,5-dimethoxy-1,2,3,4-tetrachlorocyclopentadiene and appropriate dienophiles like cyclopentadiene or p-benzoquinone, that embody a masked 7-ketonorbornenone moiety. Thermally induced chelotropic elimination of CO from the appropriately functionalized 7-ketonorbornenone derivatives to deliver annulated bicyclic 1,3-cyclohexadiene derivatives was the key step in this synthetic endeavor. Further oxy-functionalization of the 1,3- cyclohexadiene moiety delivered the targeted polycyclitols. A preliminary investigation of the glycosidase inhibitory potency of these bicyclitols, identified compounds 18 and 54 as potent and selective inhibitors of α-glucosidase (yeast).
Threshold Reduction in Polymer Lasers Based on Poly(9,9‐dioctylfluorene) with Statistical Binaphthyl Units

We introduce novel statistical copolymers of poly(9,9‐dioctylfluorene), PFO, which contain various concentrations of 6,6′‐(2,2′‐octyloxy‐1,1′‐binaphthyl) spacer groups. We demonstrate that, owing to the large dihedral angle (> 60°) between neighboring naphthalene units, we could hinder the formation of the highly ordered β‐phase in thin films of the copolymers. In low‐temperature photoluminescence measurements, the typical signature of the PFO β‐phase at 442 nm is no longer observed for copolymers with a binaphthyl concentration of about 12 %. Moreover, the optical properties of the copolymers resembled those of the glassy α‐phase PFO. Second‐order distributed feedback (DFB) lasers based on thin films of the homopolymer PFO showed a minimum lasing threshold of 11.7 μJ cm–2 (λmax = 452 nm, excitation at λ = 337 nm with 500 ps pulses). With increasing binaphthyl concentration in the copolymer backbone, the lasing threshold steadily decreased to 3 μJ cm–2 for a binaphthyl concentration of about 12 %. Therefore, our novel copolymers provide a vast improvement for PFO‐based optoelectronics.
Reweighted nonparametric likelihood inference for linear functionals

This paper is concerned with inference on finite dimensional parameters in semiparametric moment condition models, where the moment functionals are linear with respect to unknown nuisance functions. By exploiting this linearity, we reformulate the inference problem via the Riesz representer, and develop a general inference procedure based on nonparametric likelihood. For treatment effect or missing data analysis, the Riesz representer is typically associated with the inverse propensity score even though the scope of our framework is much wider. In particular, we propose a two-step procedure, where the first step computes the projection weights to approximate the Riesz representer, and the second step re-weights the moment conditions so that the likelihood increment admits an asymptotically pivotal chi-square calibration. Our re-weighting method is naturally extended to inference on treatment effects and data combination models, and other semiparametric problems. Simulation and empirical examples illustrate usefulness of the proposed method.
Functionalization of self‐assembled monolayers on glass and oxidized silicon wafers by surface reactions

Surface reactions were employed to introduce a variety of functional groups in self-assembled monolayers (SAMs) on hydroxylated surfaces such as glass and oxidized silicon wafers. The resulting layers were fully characterized by wettability studies, ellipsometry, Brewster angle infrared and x-ray photoelectron spectroscopy, UV-visible absorption and fluorescence measurements. Based on these measurements, it was concluded that the steric hindrance of the monolayer hampered the surface reactions, which generally led to sub-monolayer coverages. Detailed information concerning the interactions amongst adsorbates was obtained from fluorescence measurements. The characteristic excimer emission of pyrene-functionalized layers showed a large dependence on the solvent that was in contact with the SAM. Furthermore, efficient energy transfer could be observed in mixed monolayers that contained both fluorescein and lissamine groups.
Experimental study of the structure of laminar axisymmetric H2/air diffusion flames

This thesis presents an experimental study of the structure of laminar axisymmetric coflow hydrogen diffusion flames. The motivation behind studying these flames is the current drive towards sustainable energy and strict pollution norms. In this regard, hydrogen as a fuel is one such candidate, which burns clean and possesses the capability as a future sustainable energy carrier. In addition, hydrogen flames are known to have many interesting properties arising mainly from finite-rate chemistry, thermal diffusion, and large differences in diffusion coefficients between H2 and other molecules. Considerable research will be needed to understand H2 diffusion flame structure in practical devices, which often possess multidimensional turbulent flow and complex chemical kinetics. Studying flame structure using the model flames discussed in this thesis can provide insight into the behavior of practical systems. The study of steady laminar flames also allows direct comparison of measurements with theoretical predictions.
Different Sensitivities of Whitefish (Coregonus Lavaretus) and Northern Pike (Esox Lucius) Eleutheroembryos to Photoinduced Toxicity of Polycyclic Aromatic Hydrocarbons

The photoinduced toxicity of two polycyclic aromatic hydrocarbons (PAHs), retene (RET) and pyrene (PYR), to the eleutheroembryos of whitefish and northern pike was studied. Fish were exposed to three concentrations of RET and PYR, and irradiated with ultraviolet radiation (UVR) or visible light for 3 h on two consecutive days. UVR covered the absorption maxima of RET and PYR at UVB and UVA, the daily UVR doses were 30 and 28 kJ m−2, respectively. After 72 h, mortality and behavioral abnormalities were observed. Survivors were analyzed for the proteins of CYP1A, CYP3A, Hsp70, and the activity of glutathione reductase (GR). While neither PAHs nor UVR on their own were lethal, simultaneous exposure caused mortality. The whitefish were more sensitive than the pike to the photoinduced toxicity, and PYR was much more phototoxic than RET. RET induced Hsp70 in both species, and PYR induced GR without UVR in pike.
Relationship of Demographic Traits and Situational Factor Determinants with the Tech Readiness of Self-Service Consumers

Over the past 20 years, self-service technology (SST) has become prevalent as a service delivery option. To ensure that SST options reach full potential, firms need to understand what customer traits and situational factors are related to the propensity to use SSTs. From a subset of data and independent determinants from an original dissertation model on SST adoption, this study uses linear regression to examine: H1) the relationship between: H1) consumers’ tech readiness (TR) and the consumer demographics of age (AG), gender (GN), income (IN), education (ED), and ethnicity (ET) (H1), and H2) the relationship between consumer’s tech readiness and the situational factors of wait time (WT) and crowding (CR). The study finds both hypotheses partially supported; the demographic determinants of age, income, education, gender, and ethnicity, and both situational factor determinants of wait time (WT) and crowding (CR), all have one or more significant relationships with some, but not all, tech readiness facets (OPT, INN, DIS, INS). However, none of the determinants independently or in combination explain more than 10% of TR’s’ variance; these demographic and situational variables appear to be relatively weak and somewhat fragmented predictors of consumer tech readiness. INTRODUCTION In recent years technology advances have combined with a rising prominence of service-based products to have a dramatic impact on service delivery businesses (Bitner, Brown, & Meuter, 2000; Bitner, Ostrom & Meuter, 2002; Lin & Hsieh, 2007; Parasuraman, 2000). Consumers now have the option of using ATMs, kiosks, scanners, touch screens, automated phone systems, and the Internet in self-served modes for a variety of tasks, including booking flights and seat assignments, vending boarding passes, entering fast-food orders, preparing taxes, self-checkin/out, shopping, and account management (Meuter, et al., 2000). These SST options, by removing the need for human service encounters and personnel and actively allowing the consumer to self-serve and control the service, have the potential of providing time savings, convenience, and service quality to the consumer while leveraging cost reduction and effective service delivery for firms (Bhappu & Schultze, 2006; Dabholkar, 1996; Parasuraman, 2000). While SSTs often provide a more flexible and consumer-controlled alternative to traditional service to customers, SSTS can be a “double edged sword” regarding service benefits. Almost any consumer can recant horror stories of automated phone systems that do not address or provide selections for their service needs or of electronic screens and web pages where precise data entry and/or user unfriendly links have stalled their self-service progression and results. While there is much research and data regarding traditional face-to-face service encounters, SSTs have created the need for an entirely new understanding of consumer behaviors and
New decline pattern of filtrate flux in cross-flow microfiltration of dilute suspension

The cross-flow microfiltration flux is assumed to fall smoothly with a decreasing slope from startup to the steady state. Under actual operating conditions beyond a critical level, however, an anomalous decline pattern arises; initially cross-flow medium filtration occurs and then thin-cake filtration. At the earlier stage, fine particles in polydispersed suspensoids are filtered out on the surface of the membrane and/or captured within the latter, clogging the membrane pores gradually. After the membrane surface is covered by the deposit, further filtration occurs by the buildup of filter cake on the initial deposit. Among the many operating variables, three major controlling factors for the earlier stage are confirmed: solids concentration, relative size of solids and pores, and relative force of sweeping and capturing of suspensoids. Because suspended solids are separated by medium- and cake-law filtration in a series, a method for evaluating the time dependence of flux with the new pattern is derived. Reliable flux analysis is achieved for the transient flux of the dilute suspension forming a low compressibility fouling layer, which helps understand efficient flux performance.
Heterocyclic inflammation inhibitors

Non steroidal anti-inflammatory drugs are the most widely used medicines for relief of pain. These drugs have some side effects, particularly toxicity in the gastrointestinal tract and kidneys. Various approaches have been used for obtaining safer anti-inflammatory drugs. In this review we have summarized the recent developments in the following areas; (i) mode of action of NSAIDs (ii) Role of COX-1 & COX-2 in inflammation, (iii) Different approaches used to improve gastric tolerance i.e. chemical manipulation, formulation & co-administration, development of non specific (COX-1 & COX-2 inhibitors) and specific (COX-2 inhibitors) inflammation inhibitors, and development of inflammation inhibitors having a mode of action other than COX-1 & COX-2 inhibition. We have also focused on the safety of COX-2 inhibitors and the synthesis of heterocyclic compounds and their role as inflammation inhibitors.
Cryogenic Core Collection and Preservation of Subsurface Samples for Biomolecular Analysis

A cryogenic coring system for the collection and preservation of biomolecules in unconsolidated subsurface solid samples is presented here. The sampler is based on existing direct‐push coring technology, with the addition of a cryogenic step to freeze the sample in situ. Once brought to the surface, the frozen cores can be packed in dry ice and shipped to the laboratory for further processing and analysis. The approach prevents redistribution of fluids during sample recovery and shipping, and because the cores are frozen in situ there is little loss of solid material during retrieval to ground surface. To evaluate the performance of the approach, DNA analyses of samples collected by cryogenic coring in a very large physical model are compared with results from water samples and horizontal core samples taken in close proximity. The data indicate that the vertical distribution of DNA within the cryogenic core can be measured at the centimeter scale, providing unprecedented characterization of subsurface biogeochemical interfaces.
Definitions of terms relating to reactions of polymers and to functional polymeric materials (IUPAC Recommendations 2003)

Abstract The document defines the terms most commonly encountered in the field of polymer reactions and functional polymers. The scope has been limited to terms that are specific to polymer systems. The document is organized into three sections. The first defines the terms relating to reactions of polymers. Names of individual chemical reactions are omitted from the document, even in cases where the reactions are important in the field of polymer reactions. The second section defines the terms relating to polymer reactants and reactive polymeric materials. The third section defines the terms describing functional polymeric materials.
Supercritical Fluid Extraction and Enzyme Immunoassay for Pesticide Detection in Meat Products

Two techniques supercritical fluid extraction (SFE) and enzyme immunoassay (EIA) were integrated into an analytical method for the rapid detection of pesticide residues in meat samples. The pesticides of interest were extracted from meats using supercritical CO2• A pumpless SFE system, which was designed in our laboratory, and commercial equipment were used in SFE experiments. The presence of pesticide residues in the extract was quantitatively determined using the magnetic bead-based EIA kits. Several types ofpesticides (alachlor, carbofuran, atrazine, benomyl, and 2,4-D) , spiked in the meat samples (bovine liver, ground beef, and lard), were extracted and analyzed. Interferences caused by the coextracted substances from these complex sample matrices required the use of a cleanup step prior to the EIA test. The described techniques are potentially portable and could be used for the rapid screening of meat samples in plant environments.