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In the current review of the journal Structural Chemistry, the contents of the issues 4-6 for the calendar year 2012 are related to thermochemistry. A brief thermochemical commentary is added to the summary of each paper. [ABSTRACT FROM AUTHOR]

An off-line solid-phase extraction procedure followed by high-performance liquid chromatography with ultraviolet detection for the determination of 16 priority polycyclic aromatic hydrocarbon pollutants in aqueous matrices was described. Diverse aspects determining extraction efficiency such as packing type (disk or cartridge), elution solvents and addition of organic modifiers to the sample were evaluated. Elution with acetonitrile yields the highest recoveries. Rinsing the sample bottle with acetonitrile and combining the rinse with the sample extract avoids the adsorption of polycyclic aromatic hydrocarbons on the walls of the water containers. The use of isopropanol or methanol 10 % (V/V) was the most appropriate amount for the enrichment of 2- to 6-ring aromatic compounds only on C18 cartridge. The recoveries for all studied polycyclic aromatic hydrocarbons are ranged from 71.4 to 95.2 % for a treated water samples of 500 mL. The proposed method gives very low detection limits (subnanograms per liter) and it has been applied to drinking water, surface water and industrial effluent (oil refinery) samples with good results. [ABSTRACT FROM AUTHOR]

Spatial heterogeneity can constrain the movement of individuals and consequently genes across a landscape, influencing demographic and genetic processes. In this study, we linked information on landscape composition, movement behavior, and genetic differentiation to gain a mechanistic understanding of how spatial heterogeneity may influence movement and gene flow of bobcats in the agricultural landscape of Iowa (USA). We analyzed movement paths of 23 animals to parameterize landscape resistance surfaces, applied least cost path analysis to generate measures of effective geographic distance between DNA collection locations of 625 bobcats, and tested the correlation between genetic distance and the different models of geographic distance. We found that bobcats showed a strong preference for forest over any other habitat type, and that incorporating information on habitat composition both along the path and in the surrounding landscape provided the best model of movement. Measures of effective geographic distance were significantly correlated with genetic distance, but not once the effects of Euclidean distance were accounted for. Thus, despite the impact of habitat composition on movement behavior, we did not detect a signature of a landscape effect in genetic structure. Our results are consistent with the issue of limiting factors: the high uniformity of forest fragmentation across southern Iowa, the primary study area, results in a landscape resistance pattern virtually indistinguishable from the isolation-by-distance pattern. The northern portion of the state, however, is predicted to pose a high level of resistance to bobcat movement, which may impede the regional genetic connectivity of populations across the Midwest. [ABSTRACT FROM AUTHOR]

Photodynamic therapy (PDT) has been demonstrated to be an effective minimally invasive treatment modality for early esophageal cancer. However, the molecular action in esophageal cancer during PDT is hardly known. EGFR has been known to downregulate in various cancer cells during PDT. In this study, we investigated the effects of Photofrin-mediated PDT on cell death and expression of EGFR in CE48T/VGH (CE48T) esophageal squamous cell carcinoma cells. We found that the photosensitizer Photofrin in the absence of light exposure can downregulate the expression of EGFR at both transcription and translation levels. Higher concentrations of Photofrin results in cytotoxicity whereas lower doses of Photofrin inhibit EGFR expression under dark control without inducing significant cell death. This Photofrin-associated inhibition of EGFR was repeated in lung cancer, cervical cancer, and glioblastoma cells. Another esophageal squamous cell carcinoma cell line CE81T/VGH (CE81T) was found to be resistant to Photofrin-induced inhibition of EGFR as well as to Photofrin-mediated dark toxicity compared with CE48T. The resistance to the cytotoxicity in CE81T cells became insignificant when the Photofrin-treated cells were further irradiated by red light (Photofrin-PDT). We suggest Photofrin modulates the expression of EGFR in cancer cells. However, efficient cell death still requires the combination of Photofrin and light irradiation in esophageal squamous cell carcinoma cells. [ABSTRACT FROM AUTHOR]

Papillary squamous cell carcinoma (PSCC) is a rare variant of SCC in the head and neck region. The role of human papillomavirus (HPV) infection in PSCC is still unclear. We retrospectively reviewed 11 PSCCs in our institute over a 21-year period and compared the HPV status of PSCCs with 26 squamous cell papillomas (SCPs). Polymerase chain reaction (PCR) amplification to detect HPV DNA and in situ hybridization (ISH) were performed to analyze the relationship between the papillary lesions and HPV infection. Immunohistochemical (IHC) staining for p16 protein expression was used to analyze the PSCC specimens. Nine of 11 (82 %), eight of 11 (73 %), and eight of 11 (73 %) PSCC samples were found to be HPV positive by PCR, ISH, and IHC staining for p16 protein expression, respectively. PSCC had a significantly higher rate of HPV infection than SCP by PCR ( p = 0.002) and ISH ( p = 0.001) analysis. This study presents different HPV status in two papillary neoplasms and may help to clarify the unique morphological and biological characteristics of head and neck PSCC. [ABSTRACT FROM AUTHOR]

Acridine orange (AO) was used as a fluorescent probe molecule to study the encapsulation of an alkylimidazolium cation from a water-soluble ionic liquid (IL) within two cavitand species, p-tetranitrocalix[4]arene ( 1) and calix[4]resorcinarene ( 2), both in alkaline aqueous media. The addition of IL to the preformed [ 1⋅AO] adduct resulted in significantly increased fluorescence due to the expulsion of AO from the inclusion complex to the aqueous phase by competitive recognition of the 1-alkyl-3-methylimidazolium cation ([Cmim], n = 4 and 6) by 1. Conversely, the fluorescence signal dropped upon the addition of IL to the [ 2⋅AO] host-guest complex due to unfavorable binding between [Cmim] and 2. The formation of these postulated adducts is corroborated using ab initio calculations, which also provide evidence for the location of [bmim] at the lower external rim of [ 2⋅AO], providing an explanation for the observed luminescence quenching in the latter case. These results point to a number of different paths for exploration, ranging from the fluorescence monitoring of IL contamination in groundwater to the 'daisy chaining' of macrocyles toward supramolecular ionic networks. They also broadly encourage the exploration of ILs in host-guest-based optical and mass spectrometric sensory systems. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Ionic liquids display an array of useful and sometimes unconventional, solvent features and have attracted considerable interest in the field of green chemistry for the potential they hold to significantly reduce environmental emissions. Some of these points have a bearing on the chemical reactivity of these systems and have also generated interest in the physical and theoretical aspects of solvation in ionic liquids. This review presents an introduction to the field of ionic liquids, followed by discussion of investigations into the solvation properties of neat ionic liquids or mixed systems including ionic liquids as a major or minor component. The ionic liquid based multicomponent systems discussed are composed of other solvents, other ionic liquids, carbon dioxide, surfactants or surfactant solutions. Although we clearly focus on fluorescence spectroscopy as a tool to illuminate ionic liquid systems, the issues discussed herein are of general relevance to discussions of polarity and solvent effects in ionic liquids. Transient solvation measurements carried out by means of time-resolved fluorescence measurements are particularly powerful for their ability to parameterize the kinetics of the solvation process in ionic liquids and are discussed as well. [ABSTRACT FROM AUTHOR]

In the current review of the journal Structural Chemistry, the content of the issues 4-6 for the calendar year 2011 is related to thermochemistry. To the summary of each paper, a brief thermochemical commentary is added. [ABSTRACT FROM AUTHOR]

Objective: To assess the impact of mammography capacity on appointment wait times.Methods: We surveyed by telephone all mammography facilities federally certified in 2008 in California, Connecticut, Georgia, Iowa, New Mexico, and New York using a simulated patient format. County-level mammography capacity, defined as the number of mammography machines per 10,000 women aged 40 and older, was estimated from FDA facility certification records and US Census data.Results: 1,614 (86%) of 1,882 mammography facilities completed the survey. Time until next available screening mammogram appointment was <1 week at 55% of facilities, 1-4 weeks at 34% of facilities, and >1 month at 11% of facilities. Facilities in counties with lower capacity had longer wait times, and a one-unit increase in county capacity was associated with 21% lower odds of a facility reporting a wait time >1 month (p < 0.01). There was no association between wait time and the availability of evening or weekend appointments or digital mammography.Conclusion: Lower mammography capacity is associated with longer wait times for screening mammograms.Impact: Enhancement of mammography resources in areas with limited capacity may reduce wait times for screening mammogram appointments, thereby increasing access to services and rates of breast cancer screening. [ABSTRACT FROM AUTHOR]

Copyright of Trauma und Berufskrankheit is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the paper, 2,4,5-tri(2-furyl)-1 H-imidazole (TFI) and 2-phenyl-4,5-di(2-furyl)-1 H-imidazole (PDFI), were chosen to investigate chemiluminescence (CL) properties of 2-substituted-4,5-di(2-furyl)-1 H-imidazoles. The directly oxidized CL of analytes by potassium permanganate (KMnO) was in detail studied. The KMnO could directly oxidize TFI/PDFI to produce strong CL emission in acidic solution. The effects of experimental conditions were investigated. Under the optimal conditions, the effect of albumin on the TFI/PDFI-KMnO system was investigated. It was found that the addition of albumin into the system could induce enhancement of CL signal, and the enhanced CL intensity is linearly related to the logarithm of concentration of albumin. Based on this study, a novel CL method has been developed for the determination of albumin with high sensitivity and good selectivity. The method was applied to the determination of albumin in human serum samples, and the results were in agreement with those obtained by the bromcresol green (BCG) method. The relative errors for the analytical results were from −5.8% to 4.2%. These new phenomena would further enable people to exploit more CL analytical application of the heterocyclic imidazole derivatives. [ABSTRACT FROM AUTHOR]

Using a molecular genetic approach, we try to confirm the molecular alterations of inverted papilloma and clarify its status as a putative precursor lesion of sinonasal squamous cell carcinoma. To better understand its genetics, we investigated the immunohistochemical protein expression patterns of cell-cycle-regulators p53, p63, p21, p27 and proliferation marker Ki-67 in 22 inverted papilloma and 9 squamous cell carcinoma of the sinonasal tract. Significantly elevated levels of p53 and p63 in squamous cell carcinoma of sinonasal tract compared with inverted papilloma were revealed. Ki-67-stained neoplastic cell nuclei were found in a significantly higher percentage of squamous cell carcinoma of sinonasal tract than in inverted papilloma, whereas no variation of p21 and p27 expression was identified. This work first examined the immunohistochemical overexpression of p63 in sinonasal inverted papilloma and squamous cell carcinoma. In conclusion, this is a first study shedding light on the expression of p63 in tumors of paranasal sinuses. [ABSTRACT FROM AUTHOR]

In the paper, a chemiluminescence (CL) system was developed based on the catalytical effect of diperiodatocuprate (III) (DPC) on the 1,10-phenanthroline (phen)/hydrogen peroxide (HO) in the presence of cetyltrimethylammonium bromide (CTAB). The effects of experimental conditions were investigated. Meanwhile the increase of CL intensity of the DPC/phen/HO/CTAB system is proportional to the concentration of phen in the range of low concentration. The linear range of the calibration curve is 5.0 × 10-1.0 × 10 mol L, and the corresponding detection limit is 1.9 × 10 mol L. The effects of phenolic compounds (PCs) on the system were investigated. Hydroquinone was used as an example to investigate the application of the CL system to the determination of PCs. The quenched CL intensity is linearly related to the logarithm of concentration of hydroquinone. The linear range of the calibration curve is 2.5 × 10-1.0 × 10 g mL, and the corresponding detection limit is 1.8 × 10 g mL. This phen and hydroquinone can be synchronously determined. The method was applied to the determination of hydroquinone in water samples and the recoveries were from 92% to 106%. [ABSTRACT FROM AUTHOR]

All papers published in the Journal of Radioanalytical and Nuclear Chemistry (JRNC) in the period 2005–2009 (source dataset) and all papers citing these papers and published in other journals (target dataset) have been compiled. A scientometric analysis of the datasets has been performed using Hirsch-type statistics. A comprehensive bibliography of the citing papers is presented. [ABSTRACT FROM AUTHOR]

In their article, “New light on a dark subject: On the use of fluorescence data to deduce redox states of natural organic matter,” Macalady and Walton-Day () subjected natural organic matter (NOM) samples to oxidation, reduction, and photochemical transformation. Fluorescence spectra were obtained on samples, which were diluted “to bring maximum uvvisible absorbance values below 1.0.” The spectra were fit to the Cory and McKnight () parallel factor analysis (PARAFAC) model, and consistent variation in the redox state of quinone-like moieties was not detected. Based on these results they concluded that fitting fluorescence spectra to the Cory and McKnight () PARAFAC model to obtain information about the redox state of quinone-like moieties in NOM is problematic. Recognizing that collection and correction of fluorescence spectra requires consideration of many factors, we investigated the potential for inner-filter effects to obscure the ability of fluorescence spectroscopy to quantify the redox state of quinone-like moieties. We collected fluorescence spectra on Pony Lake and Suwannee River fulvic acid standards that were diluted to cover a range of absorbance wavelengths, and fit these spectra to the Cory and McKnight () PARAFAC model. Our results suggest that, in order for the commonly used inner-filter correction to effectively remove inner-filter effects, samples should be diluted such that the absorbance at 254 nm is less than 0.3 prior to the collection of fluorescence spectra. This finding indicates that inner-filter effects may have obscured changes in the redox signature of fluorescence spectra of the highly absorbing samples studied by Macalady and Walton-Day (). [ABSTRACT FROM AUTHOR]

The standard ( p° = 0.1 MPa) energies of combustion in oxygen, at T = 298.15 K, for the solid compounds 2-methylpyridine- N-oxide (2-MePyNO), 3-methylpyridine- N-oxide (3-MePyNO) and 3,5-dimethylpyridine- N-oxide (3,5-DMePyNO) were measured by static-bomb calorimetry, from which the respective standard molar enthalpies of formation in the condensed phase were derived. The standard molar enthalpies of sublimation, at the same temperature, were measured by Calvet microcalorimetry. From the standard molar enthalpy of formation in gaseous phase, the molar dissociation enthalpies of the N–O bonds were derived, and compared with values of the dissociation enthalpies of other N–O bonds available for other pyridine- N-oxide derivatives. [ABSTRACT FROM AUTHOR]

The absorption and fluorescence spectra of 1,5-diaminoanthraquinone(1,5-DAAQ) have been investigated in organic solvents-Benzene(BZ), Ethanol (ETOH), Acetonitrile (AN), Dimethylformamide (DMF) and Dimethyl sulfoxide (DMSO). There is an intra molecular hydrogen bond formed between quinoid oxygen and the substituents NH2 [C = O…H-N]. The interaction of the hydrogen atom of - NH2 leads to red shift in both absorption and fluorescence spectra. The dipole moment ratio of 1,5 DAAQ in ground and excited states was calculated from stokes shift obtained from optical absorption and fluorescence spectra. Photo physical properties of 1,5-DAAQ dye was studied using this absorption and fluorescence spectroscopy techniques in binary liquid mixtures(AN + DMF, AN + DMSO, AN + ETOH and BZ + ETOH). [ABSTRACT FROM AUTHOR]

Abstract  HeLa 229 cells were treated with methotrexate (MTX) and doxorubicin (DOX), utilizing fourth generation (G4), amine terminated poly(amidoamine) {PAMAM} dendrimer as the drug carrier. In vitro kinetic studies of the release of both MTX and DOX in presence and absence of G4, amine terminated PAMAM dendrimers suggest that controlled drug release can be achieved in presence of the dendrimers. The cytotoxicity studies indicated improved cell death by dendrimer-drug combination, compared to the control experiments with dendrimer or drug alone at identical experimental conditions. Furthermore, HeLa 229 cells were imaged for the first time utilizing the intrinsic emission from the PAMAM dendrimers and drugs, without incorporating any conventional fluorophores. Experimental results collectively suggest that the decreased rate of drug efflux in presence of relatively large sized PAMAM dendrimers generates high local concentration of the dendrimer-drug combination inside the cell, which renders an easy way to image cell lines utilizing the intrinsic emission properties of PAMAM dendrimer and encapsulated drug molecule. [ABSTRACT FROM AUTHOR]

Heavy metal accumulation of lead (Pb), chromium (Cr), and cadmium (Cd) in the muscle of the catfish Eremophilus mutisii was studied in 47 specimens, captured by anglers in the Bogotá River at two sampling sites (Chocontá and Suesca) during May–October 2005. Water samples were processed for physicochemical and metal analyses. Metal accumulation in muscle (wet weight) of specimens at Chocontá and Suesca showed high levels of Pb (3.4 and 3.1 ppm, respectively), Cr (1.8 and 2.1 ppm, respectively), and Cd (0.35 and 0.48, respectively). Metal levels in waters (ppm) indicated that average Pb (0.028 Chocontá, 0.029 Suesca), Fe (0.462 Chocontá, 1.1 Suesca), and Cr (0.113 Chocontá) were above the maximum levels (MCLs) allowed in drinking waters. No extreme average values were found for pH, nitrites, alkalinity, and hardness in the waters. This study showed the importance of benthic and nonmigratory species like the capitán to evaluate the effects of heavy metals pollution. Further public health implications could be derived in the region where this investigation took place due to consumption of capitán by people in the area. [ABSTRACT FROM AUTHOR]

Supercritical carbon dioxide has attracted attention as a potential replacement for traditional organic solvents due to its simplified workup procedures and reduced environmental impact—providing a green chemistry approach for organic solvent-free functionalisation. In addition to the environmental benefits, the enhanced diffusivity observed in supercritical solvents can often enhance reaction rates. We have applied these valuable features to the preparation of silica-bonded stationary phases and examined their potential in liquid chromatography. We report the successful preparation and characterisation of polyether silica based on Frechet dendrimers—this significantly enhances the range of stationary-phase chemistries that can be prepared in supercritical fluids. First- and second-generation polyether silicas were prepared, characterised, end-capped and evaluated for use as stationary phases for liquid chromatography. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Abstract  In this study, we relate the contents of the journal Structural Chemistry for the calendar year 2007 and thermochemistry. The year’s articles were briefly summarized and a thermochemical comment written to supplement them. Frequently questions were asked and future research was suggested. [ABSTRACT FROM AUTHOR]

Abstract  Strongly fluorescent dipyrrinones can be prepared by bridging the pyrrole and lactam nitrogens with a carbonyl group, from reaction with N,N′-carbonyldiimidazole in the presence of a strong, non-nucleophilic base. The yellow, N,N′-carbonyl-bridged dipyrrinones typically have fluorescent quantum yields (φF) approaching 1.0. Thus, in chloroform, N,N′-bridged 9H-dipyrrinones with β-alkyl substituents: 2,3-diethyl-7,8-dimethyl has φF = 0.90 (λem = 465 nm) and 2,3-dimethyl-7,8-dimethoxy has φF = 0.84 (λem = 482 nm). In contrast, 2,3-dimethoxy-7,8-dimethyl and 2,3,7,8-tetramethoxy show red-shifted λem but with strongly reduced φF: φF = 0.10 (λem = 511 nm) and 0.08 (λem = 511 nm), respectively. Methoxy substituents on the lactam, but not the pyrrole ring act to quench the fluorescence and shift the emission and excitation wavelengths bathochromically. The first X-ray crystal structure of an N,N′-carbonyl-bridged dipyrrinone was obtained from 7,8-dimethoxy-2,3-dimethyl-10H-dipyrrin-1-one. [ABSTRACT FROM AUTHOR]

Imprinting analyses of IGF2 and H19, loss of heterozygosity (LOH) analyses of IGF2R and CTCF and Helicobacter pylori detection, were performed on 35 human laryngeal squamous cell carcinomas (LSCC). Forty-six percent of the tumors were heterozygous for IGF2, and 54% were informative for the H19. Biallelic expression of IGF2 was observed in 33% (5 out of 15) of the tumors and in 27% (4 out of 15) of adjacent non-tumorous laryngeal tissues. H19 loss of imprinting (LOI) was observed in 24% (4 out of 17) of the tumors. For IGF2R and CTCF, 71% (25 out of 35) and 50% (17/34), respectively, of the samples were heterozygous, and LOH was detected in 12% (3 out of 25) and 6% (1 out of 17), respectively, of the tumors. H. pylori was found in 26% (9/35) of these tumors. Among them, four were informative for the imprinting analysis. The presence of H. pylori had no effect on IGF2/H19 imprinting. Only the H. pylori detection was further broadened with an additional 47 laryngeal tumors, resulting in a total final positivity of close to 16% (13 out of 82). This study represents the largest comprehensive IGF2/H19 imprinting study done to date on well-defined samples of human laryngeal carcinomas and corresponding non-tumorous tissue. For the first time, the analyses of IGF2/H19 imprinting have been broadened with LOH analyses of IGF2R and CTCF, with both of these genes acting as modulators of IGF2 and H19 activity. Although there were indications that H. pylori may be present in LSCC, we are the first to show its presence in LSCC by two direct techniques: Giemsa staining and nested-PCR. [ABSTRACT FROM AUTHOR]

Abstract  Poly(ethyleneimine) (PEI) dendrimers up to the third generation (G3) were prepared by a divergent synthesis method from an ethylenediamine (EDA) core. The amine terminals were bonded with vinylbromide by a Michael addition reaction. Then, the bromide terminals were converted to amine groups using a Gabriel amine synthesis method. PEI dendrimers displayed pH-dependent luminescence, and their emission intensities at pH 6 increased over time. Fluorescence intensities also increased with increasing dendrimer generation from G1 to G3. Air-bubbling in aqueous solutions of dendrimers made to incorporate detectable amount of oxygen in dendrimers. EDA also behaved similarly in luminescence and oxygen incorporation. Figure Synthesis and Characterization of Poly(ethyleneimine) Dendrimers Omprakash Yemul and Toyoko Imae* [ABSTRACT FROM AUTHOR]

The insulin-like growth factor-II (IGF-II) gene has four promoters that produce distinct transcripts which vary by tissue type and developmental stage. Dysregulation of normal promoter usage has been shown to occur in cancer; DNA methylation regulates promoter use. Thus, we sought to examine if DNA methylation varies among IGF-II promoters in ovarian cancer and if methylation patterns are related to clinical features of the disease. Tumor tissue, clinical data, and follow-up information were collected from 215 patients diagnosed with primary epithelial ovarian cancer. DNA extracted from tumor tissues was analyzed for IGF-II promoter methylation with seven methylation specific PCR (MSP) assays: three for promoter 2 (P2) and two assays each for promoters 3 and 4 (P3 and P4). Methylation was found to vary among the seven assays: 19.3% in P2A, 45.6% in P2B, 50.9% in P2C, 48.4% in P3A, 13.1% in P3B, 5.1% in P4A, and 6.1% in P4B. Methylation in any of the three P2 assays was associated with high tumor grade ( P = 0.043), suboptimal debulking ( P = 0.036), and disease progression [hazards ratio (HR) = 1.73, 95% confidence interval (CI) 1.09–2.74]. When comparing promoter methylation patterns, differential methylation of P2 and P3 was found to be associated with disease prognosis; patients with P3 but not P2 methylation were less likely to have disease progression (HR = 0.39, 95% CI 0.17–0.91) compared to patients with P2 but not P3 methylation. This study shows that methylation varies among three IGF-II promoters in ovarian cancer and that this variation seems to have biologic implications as it relates to clinical features and prognosis of the disease. [ABSTRACT FROM AUTHOR]

Abstract??The relative thermodynamics of 12 isomers of both cyanophenol and cyanothiophenol have been computed by DFT and composite approaches. It is shown that these methodologies are capable of correctly reproducing the energetics of the three cyanophenols, anthranil, and phenylisocyanate but have a fair behavior when dealing with benzoxazole and benzothiazole compounds. The estimated values for the latter two species are always less positive than the experimental results, indicating that the theoretical approaches predict a much too stable compound. [ABSTRACT FROM AUTHOR]

The use of organized supramolecular systems—including micellar media and cyclodextrin inclusion complexes—combined with luminescence techniques in the study and determination of compounds and elements of environmental interest from 1990 to 2005 is reviewed. Analyses of environmental samples performed using fluorescence, photochemically induced fluorescence and phosphorescence spectroscopy as well as liquid chromatography, capillary electrophoresis and flow injection with luminescence detection in the presence of these organized media are described in detail. [ABSTRACT FROM AUTHOR]

A fluorescence signal amplification mechanism allowing detection limits for DNA in the zeptomolar range was investigated. Photophysical properties of the molecular system were studied in order to better explain the signal amplification that is observed. We show that the confinement of a fluorescent DNA hybridization transducer in aggregates improves its quantum yield and photostability. Furthermore, we show that the combination of the resonance energy transfer occurring within the aggregates with the use of a conjugated polymer as the hybridization transducer and donor allows ultrafast and efficient energy coupling to the aggregates and can lead to the excitation of a large number of acceptors by only one donor. [ABSTRACT FROM AUTHOR]

Signaling from the endothelin-A (Ednra) receptor is responsible for initiating multiple signaling pathways within neural crest cells (NCCs). Loss of this initiation is presumably the basis for the craniofacial defects observed inEdnra-/- embryos. However, it is not known whether continued Ednra signaling in NCC derivatives is required for subsequent development of the lower jaw. To address this question, mice containingloxP recombination sequences flanking a portion of theEdnragene were bred with transgenic mice that expressCrerecombinase under control of aDlx5/6enhancer element. We find that whileEdnragene inactivation within the mandibular arch of these Ednra conditional knockout embryos is detectable by embryonic day (E) 10.5, mandibular arch-specific gene expression is normal, as is overall mandible development. These results suggest that while Ednra receptor signaling is crucial for early NCC patterning, subsequent Ednra signaling is not essential for mandible bone development. [ABSTRACT FROM AUTHOR]

In this paper we propose a mean-field theory to calculate the solvation free energy of a charged solute imbedded in a complex multi-component solvent. We considered a solvent made up of a mixture of small (electrolyte solution) and large (polymer) components. The presence of macromolecules ensures reduced mixing entropy among the different solvent components, an effect due to polymer connectivity. The reduced entropy favours strong preferential distribution of a particular solvent even in the presence of weak preferential solute–solvent interactions. In addition, two energy terms must be considered: (a) the interaction between the solute electrostatic potential and the electrolyte solution and (b) the formation of a polymer–solute interface. Because of the different dielectric permittivity of the solvent components, the electrolyte and polymer distribution functions are strongly coupled: ions, indeed, are more solvated in regions of higher local dielectric permittivity arising from the inhomogeneous mixing of solvent and polymer. We combined together the different energy terms in the framework of the de Gennes free energy functional for polymer solutions along with a generalised Poisson–Boltzmann equation developed for inhomogeneous dielectric media. Moreover, the preferential electrolyte solvation in regions of greater polarity was considered by an extension of the Born equation. Setting the polymer dielectric permittivity smaller than the solvent one and making null the specific polymer–solute interactions, we calculated enhanced electrolyte concentration and reduced polymer concentration near the solute surface on raising the solute surface charge density. The theory shows also the breakdown of the widely used separation between electrostatic and surface tension-dependent contributions to solvation energy when non-ideal mixed solvents are considered. In fact, according to the model, the surface tension of such mixed solvents strongly depends on the solute surface charge density: at high potentials the interfacial tension may increase rather than decrease on raising the polymer volume fraction. The theoretical results have been compared with experimental data on polymer+electrolyte solution surface tension and with solubility data of colloidal particles. The comparison evidences the complex behaviour of multi-component solvents going well beyond the trivial weighted average of the dielectric permittivity and surface tension of the isolated chemical components. Deviations from the simple behaviour predicted by an average picture of multi-component solvents could be understood by developing more sophisticated, but still simple, approaches like that proposed in this paper. [ABSTRACT FROM AUTHOR]

We report the case of a 58-year-old man who presented with a squamous cell carcinoma pT1a G2 of the left vocal cord. Six months after histologically verified complete resection, the patient experienced an endolaryngeal and extralaryngeal local recurrence pT4 pN2b G2. We applied DNA flow cytometry (FCM) and comparative genomic hybridization (CGH) on both primary and recurrent tumor. The primary tumor and the endolaryngeal compartment of the relapse was an aneuploid cell clone with a FCM DNA index of 1.42 and 1.44, respectively. The extralaryngeal compartment showed a shift featuring a DNA index of 2.78. In the primary tumor and in both compartments of the recurrence there was an identical pattern of complex chromosomal imbalances as detected in CGH (CGH karyotype: rev ish enh [8q24.2-q24.3, 10q26.1-q26.3, 11q24-q25, 12q24.2-q23.33,X], dim [4q, 13q14.3-q31], amp[1p36.1-p36.2]). Hence, the recurrence was not associated with further gains and losses of chromosomal material. However, in the anterior part of the recurrence, the aneuploid tumor cell genome had completely doubled, obviously due to endoreduplication. Immunohistochemical analysis of several cell-cycle regulators revealed altered expression of checkpoint proteins, pointing to a complex disturbance in cell-cycle regulation. [ABSTRACT FROM AUTHOR]

Purpose: The p16/cyclin D1/pRb pathway plays a critical role in tumourigenesis. We recently reported alterations in expression of tumour suppressor gene products, p16 and pRb in esophageal cancer. Knowledge of alterations in cyclin D1, a vital component of this pathway in esophageal carcinomas from the Indian subcontinent, where the etiology and pathogenesis may be confounded by various unique dietary and environmental factors, is presently scanty. In order to bridge the gap between the accentuating incidence of esophageal cancer and aberrations in the components of this vital pathway, we analysed cyclin D1 expression in esophageal squamous cell carcinoma in the Indian population. Method: Immunohistochemical analysis of cyclin D1 expression was carried out in paraffin-embedded sections of surgically resected esophageal squamous cell carcinomas (ESCC) (70 patients) and matched with histopathologically normal esophageal tissues from a distant site. The findings were correlated with clinicopathological parameters. Results: Overexpression of cyclin D1 was observed in the tumour nuclei in 41 out of 70 (59%) patients. We found concomitant alterations in 16 and cyclin D1 (p16−/CycD1+ phenotype) in 16 of the 70 patients (23%), while alterations of pRb and cyclin D1 (pRb−/CycD1+) were observed in 36 of the 70 (51%) patients of ESCCs. Cyclin D1 overexpression was significantly associated with the loss of p16 immunoreactivity ( P=0.005). The pRb− and p16−/pRb−/Cyc D+ phenotypes showed significant association with differentiation of the tumour ( P=0.005, 0.05, respectively). Kaplan-Meier analysis for disease recurrence showed increased disease recurrence in cyclin D1 overexpressed patients. Median time to disease recurrence in the cyclin D1+ group was 15 months as against 18 months observed in the cyclin D1− patients ( P=0.067; log-rank test). Conclusion: Alterations in at least one of the components of the p16/cyclin D1/pRb pathway in majority of the 70 patients analysed herein, and concomitant alterations in all the three proteins in 19 patients (35%) underscore the critical role of this pathway in esophageal tumourigenesis. The results of the present study taken together with our previous findings on p16 and pRb alterations in ESCCs suggest that these alterations are not mutually exclusive and may cooperatively provide greater tumour growth advantage. The prognostic significance of alterations in the expression of these components cyclin D1, p16, and pRb remains to be established in a larger cohort. [ABSTRACT FROM AUTHOR]

Commercially available, replaceable sieving matrices and their solvent modulated forms were evaluated for use in on-the-fly fluorescence lifetime detection of dye-labeled DNA fragments in capillary electrophoresis. The fragments were labeled with dyes that can be excited by the 488 nm line of an argon ion laser and have lifetimes in the range of 0.8 ns to 3.8 ns. The sieving matrices and buffer systems included poly(vinylpyrrolidone) (PVP), poly(ethyleneoxide) (PEO), hydroxyethylcellulose (HEC), Tris-borate-EDTA (TBE) and Tris-TAPS-EDTA buffers modified with DMSO and formamide. Selection of the optimal sieving matrix is based on the separation efficiency and the enhancement of lifetime resolution of DNA fragments. Best results for both electrophoretic resolution and lifetime detection were obtained using a poly(ethyleneoxide)/TBE gel buffer in the presence of 10% formamide. [ABSTRACT FROM AUTHOR]

Simultaneous measurements of acetylene reduction by Anabaena variabilis and the concentration of dissolved oxygen in the suspension were made using a specially designed vessel which allowed measurements under steady-state conditions. The rate of acetylene reduction in the dark increased with increasing oxygen concentrations until a maximum value was reached at 300 μM O (corresponding to 30% O in the gas phase at 35°C). This presumably results from a requirement for energy provided by respiration. Measurements of the dependence of respiration rate on dissolved oxygen concentration were made under comparable conditions using an open system to allow conditions close to steady-state to be obtained. The respiration rate of diazotrophically grown Anabaena variabilis had a dependence on oxygen concentration corresponding to the sum of two activities. These had K values of 1.0 μM and 69 μM and values of V of similar magnitude. Only the high affinity activity was observed in nitrate-grown cyanobacteria lacking heterocysts, and this presumably represent activity in the vegetative cells. The oxygen concentration dependence of the low affinity activity resembled that for the stimulation of acetylene reduction. We interpret this as the result of oxygen uptake by the heterocysts. The results are consistent with the idea that in intact filaments of cyanobacteria O enters heterocysts much more slowly than it enters the vegetative cells. [ABSTRACT FROM AUTHOR]

Using a model reaction, we recently investigated the thermochemistry and aromaticity systematics of nitrogen, oxygen and sulfur-containing heterocycles that are isoelectronic to the carbocyclic indane and its unsaturated counterpart indene. In this study all of the benzo-annelated species, e.g. indole, indoline, phthalic anhydride, phthalan and benzothiazole, all corresponding to annelation on a formal double bond of the 5-membered ring of the single ring species. In that study we asked 'What is to be done about the so-called iso-species?' such as isobenzofuran, anthranil, benzofurazan and 2,1,3-benzothiadiazole, wherein it is annelation of the formal single bond in the 5-membered ring. A modified model reaction is suggested in the current paper where we admit that it is quantitatively untested. [ABSTRACT FROM AUTHOR]

Obtaining reliable population density estimates for pumas (Puma concolor) and other cryptic, wide-ranging large carnivores is challenging. Recent advancements in spatially explicit capture-recapture models have facilitated development of novel survey approaches, such as clustered sampling designs, which can provide reliable density estimation for expansive areas with reduced effort. We applied clustered sampling to camera-traps to detect marked (collared) and unmarked pumas, and used generalized spatial mark-resight (SMR) models to estimate puma population density across 15,314 km2 in the southwestern USA. Generalized SMR models outperformed conventional SMR models. Integrating telemetry data from collars on marked pumas with detection data from camera-traps substantially improved density estimates by informing cryptic activity (home range) center transiency and improving estimation of the SMR home range parameter. Modeling sex of unmarked pumas as a partially identifying categorical covariate further improved estimates. Our density estimates (0.84-1.65 puma/100 km2) were generally more precise (CV = 0.24-0.31) than spatially explicit estimates produced from other puma sampling methods, including biopsy darting, scat detection dogs, and regular camera-trapping. This study provides an illustrative example of the effectiveness and flexibility of our combined sampling and analytical approach for reliably estimating density of pumas and other wildlife across geographically expansive areas. [ABSTRACT FROM AUTHOR]

Research into stimuli-responsive controlled self-assembly and reversible transformation of molecular architectures has received much attention recently, because it is important to understand and reproduce this natural self-assembly behavior. Here, we report two coordination nanocapsules with variable cavities: a contracted octahedral V24 capsule and an expanded ball-shaped V24 capsule, both of which are constructed from the same number of subcomponents. The assemblies of these two V24 capsules are solvent-controlled, and capable of reversible conversion between contracted and expanded forms via control of the geometries of the metal centers by association and dissociation with axial water molecules. Following such structural interconversions, the magnetic properties are significantly changed. This work not only provides a strategy for the design and preparation of coordination nanocapsules with adaptable cavities, but also a unique example with which to understand the transformation process and their structure-property relationships. [ABSTRACT FROM AUTHOR]