Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 19 de 19
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Data Brief ; 52: 109798, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38076480

RESUMO

The data reported here was prepared to study the effects of calendering process on NMC622 cathodes using a 3-3-2 full factorial design of experiments. The data set consists of 18 unique combinations of calender roll temperature (85 °C, 120 °C, or 145 °C), electrode porosity (30%, 35%, or 40%), and electrode mass loading (120 g/m² or 180 g/m²). The reported physical characteristics of the electrodes include thickness, coating weight, maximum tensile strength, and density. The electrochemical performances of the electrodes were obtained by testing coin cells. In this context, 54 half-cells were produced, 3 per each calendering experiment to ensure repeatability and reliability of the results. The responses of interest included, charge energy capacity at C/2, C/5, discharge energy capacity at C/20, C/5, C/2, C, 2C, 5C, 10C, gravimetric capacity (charge at C/2, C/5, discharge at C/20, C/5, C/2, C, 2C, 5C, 10C), volumetric capacity (charge at C/2, C/5, discharge at C/20, C/5, C/2, C, 2C, 5C, 10C), rate performance (5C:0.2C), area specific impedance (at 10% to 90% state of charge (SoC) in 10 breakpoints), long-term cycling capacity (charge at C/5 for 50 cycles, discharge at C/2 for 50 cycles), long-term cycling degradation (at C/2 during 50 cycles of charge and discharge), and cycling columbic efficiency (50 cycles of C/2 charge and discharge). The details of the experimental design that has led to this data as well as comprehensive statistical analysis, and machine learning-based models can be found in the recently published manuscripts by Hidalgo et al. and Faraji-Niri et al. [1,2].

2.
AAPS PharmSciTech ; 24(7): 208, 2023 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-37817001

RESUMO

Although nasal inhalation products are becoming more and more important for the delivery of medicines, characterization of these products for quality control and assessment of bioequivalence is complicated. Most of the problems encountered are associated with the assessment of aerodynamic droplet/particle size distribution (APSD). The droplets produced by the various nasal devices are large, and for suspension products, individual droplets may contain multiple drug particles or none at all. Assessment of suspension products is further complicated by the presence of solid excipient particles. These complications make it imperative that the limitations of the instruments used for characterization as well as the underlying assumptions that govern the interpretation of data produced by these instruments are understood. In this paper, we describe various methodologies used to assess APSD for nasal inhalation products and discuss proper use, limitations, and new methodologies on the horizon.


Assuntos
Inaladores Dosimetrados , Tamanho da Partícula , Aerossóis , Administração por Inalação , Suspensões
3.
Phys Chem Chem Phys ; 24(48): 29999-30009, 2022 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-36472147

RESUMO

Join counting, a standard technique in spatial autocorrelation analysis, has been used to quantify the clustering of carbon, fluorine and sodium in cross-sectioned anode and cathode samples. The sample preparation and EDS mapping steps are sufficiently fast for every coating from two Design of Experiment (DoE) test matrices to be characterised. The results show two types of heterogeneity in material distribution; gradients across the coating from the current collector to the surface, and clustering. In the cathode samples, the carbon is more clustered than the fluorine, implying that the conductive carbon component is less well distributed than the binder. The results are correlated with input parameters systematically varied in the DoE e.g. coating blade gap, coating speed, and other output parameters e.g. coat weight, and electrochemical resistance.

5.
J Aerosol Med Pulm Drug Deliv ; 33(4): 214-229, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32101074

RESUMO

Background: Determination of aerosol aerodynamic particle size distributions (APSD) from dry-powder inhalers (DPIs), following quality control procedures in the pharmacopeial compendia, requires that the flow through the measurement apparatus, comprising induction port, optional pre-separator, and cascade impactor, starts from zero on actuation of the inhaler, using a solenoid valve to apply vacuum to the apparatus exit. The target flow rate, governed by the inhaler resistance, is reached some time afterward. Understanding the behavior of the DPI design-specific flow rate-rise time curve can provide information about the kinetics of the initial powder dispersion in the inhaler and subsequent transport through the APSD measurement equipment. Accurate and precise measures of the internal volume of each component of this apparatus are required to enable reliable relationships to be established between this parameter and those defining the flow rate-rise time curve. Methods: An improved method is described that involves progressive withdrawal of an accurately known volume of air from the interior passageways of the apparatus-on-test that are closed to the outside atmosphere. This approach is applicable for determining internal volumes of components having complex internal geometries. Filling some components with water, along with volumetric or gravimetric measurement, has proven valuable for the induction port and for checking other measurements. Results: Values of internal volume are provided for the USP (United States Pharmacopeia)/PhEur (European Pharmacopoeia) induction port, the Next-Generation Impactor (NGI™) with and without its pre-separator, and various Andersen 8-stage cascade impactor configurations with and without their pre-separators. Conclusion: These data are more accurate and precise, and therefore update those reported by Copley et al.


Assuntos
Aerossóis/administração & dosagem , Inaladores de Pó Seco , Tecnologia Farmacêutica/métodos , Administração por Inalação , Aerossóis/química , Desenho de Equipamento , Tamanho da Partícula , Farmacopeias como Assunto , Pós , Controle de Qualidade
6.
ACS Omega ; 4(7): 11338-11345, 2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31460237

RESUMO

Here, we report the use of Li2Mn(SO4)2 as a potential energy storage material and describe its route of synthesis and structural characterization over one electrochemical cycle. Li2Mn(SO4)2 is synthesized by ball milling of MnSO4·H2O and Li2SO4·H2O and characterized using a suite of techniques, in particular, ex situ X-ray diffraction, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy on the Mn and S K-edges to investigate the electronic and local geometry around the absorbing atoms. The prepared Li2Mn(SO4)2 electrodes undergo electrochemical cycles to different potential points on the charge-discharge curve and are then extracted from the cells at these points for ex situ structural analysis. Analysis of X-ray absorption spectroscopy (both near and fine structure part of the data) data suggests that there are minimal changes to the oxidation state of Mn and S ions during charge-discharge cycles. However, X-ray photoelectron spectroscopy analysis suggests that there are changes in the oxidation state of Mn, which appears to be different from the conclusion drawn from X-ray absorption spectroscopy. This difference in results during cycling can thus be attributed to electrochemical reactions being dominant at the surface of the Li2Mn(SO4)2 particles rather than in the bulk.

7.
AAPS PharmSciTech ; 15(5): 1126-37, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24871551

RESUMO

Compendial methods determining dry powder inhaler (DPI)-emitted aerosol aerodynamic particle size distribution (APSD) collect a 4-L air sample containing the aerosol bolus, where the flow, which propagates through the cascade impactor (CI) measurement system from the vacuum source, is used to actuate the inhaler. A previous article described outcomes with two CIs (Andersen eight-stage cascade impactor (ACI) and Next-Generation Pharmaceutical Impactor (NGI)) when the air sample volume was ≤4 L with moderate-resistance DPIs. This article extends that work, examining the hypothesis that DPI flow resistance may be a factor in determining outcomes. APSD measurements were made using the same CI systems with inhalers representing low and high flow resistance extremes (Cyclohaler® and HandiHaler® DPIs, respectively). The ratio of sample volume to internal dead space (normalized volume (V*)) was varied from 0.25 to 1.98 (NGI) and from 0.43 to 3.46 (ACI). Inhaler resistance was a contributing factor to the rate of bolus transfer; the higher resistance DPI completing bolus relocation to the NGI pre-separator via the inlet when V* was as small as 0.25, whereas only ca. 50% of the bolus mass was collected at this condition with the Cyclohaler® DPI. Size fractionation of the bolus from either DPI was completed within the ACI at smaller values of V* than within the NGI. Bolus transfer from the Cyclohaler® capsule and from the HandiHaler® to the ACI system were unaffected by the different flow rise time observed in the two different flow controller systems, and the effects the ACI-based on APSD measurements were marginal.


Assuntos
Aerossóis , Inaladores de Pó Seco , Desenho de Equipamento , Tamanho da Partícula
8.
J Aerosol Med Pulm Drug Deliv ; 25(4): 188-97, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22857270

RESUMO

BACKGROUND: The Abbreviated Impactor Measurement (AIM) concept simplifies determination of aerodynamic size metrics for inhaler quality control testing. A similar approach is needed to compare in vitro particle size distribution metrics with human respiratory tract (HRT) deposition. METHODS: An abbreviated impactor based on the Andersen eight-stage cascade impactor (ACI) was developed having two size-fractionating stages with cut-points at 4.7 and 1.1 µm aerodynamic diameter at 28.3 L/min, to distinguish between coarse (CPM), fine (FPM), and extra-fine (EPM) mass fractions likely to deposit in the oropharynx, airways of the lungs, or be exhaled, respectively. In vitro data were determined for pressurized metered dose inhaler (pMDI)-delivered salbutamol (100 µg/actuation ex valve) with an "Alberta" idealized adult upper airway (throat) inlet (AIM-pHRT). Corresponding benchmark data for a full resolution Andersen eight-stage cascade impactor with "Alberta" idealized throat (ACI-AIT) and ACI-Ph.Eur./USP inlet were obtained with the same product. RESULTS: Mass recoveries (µg/actuation; mean ± SD) were equivalent at 100.5 ± 0.7; 97.2 ± 4.9 and 101.5 ± 9.5 for the AIM-pHRT, ACI-AIT, and ACI-Ph.Eur./USP induction port, respectively [one-way analysis of variance (ANOVA), p=0.64]. Corresponding values of CPM were 59.2 ± 4.2; 58.4 ± 2.4, and 65.6 ± 5.8; the AIT captured larger particles more efficiently than the Ph.Eur./USP induction port, so that less large particle mass was apparent in the upper stages of the ACI-AIT (p ≤ 0.037). Equivalent values of FPM were similar regardless of inlet/abbreviation at 41.3 ± 4.2; 38.7 ± 3.0, and 35.9 ± 3.8 (p=0.054), and EPM measures (1.7 ± 0.3; 2.0 ± 0.5; 2.1 ± 0.3) were also comparable (p=0.32). CONCLUSIONS: The AIT inlet significantly increased the capture of the coarse fraction compared with that collected by the Ph.Eur./USP induction port. Measures obtained using the AIM-pHRT apparatus were comparable with those obtained with the ACI-AIT.


Assuntos
Albuterol/administração & dosagem , Inaladores Dosimetrados/normas , Modelos Anatômicos , Sistema Respiratório/metabolismo , Administração por Inalação , Adulto , Aerossóis , Broncodilatadores/administração & dosagem , Desenho de Equipamento , Humanos , Modelos Biológicos , Tamanho da Partícula , Controle de Qualidade , Tecnologia Farmacêutica/instrumentação
9.
AAPS PharmSciTech ; 13(3): 875-82, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22678745

RESUMO

Current pharmacopeial methods for testing dry powder inhalers (DPIs) require that 4.0 L be drawn through the inhaler to quantify aerodynamic particle size distribution of "inhaled" particles. This volume comfortably exceeds the internal dead volume of the Andersen eight-stage cascade impactor (ACI) and Next Generation pharmaceutical Impactor (NGI) as designated multistage cascade impactors. Two DPIs, the second (DPI-B) having similar resistance than the first (DPI-A) were used to evaluate ACI and NGI performance at 60 L/min following the methodology described in the European and United States Pharmacopeias. At sampling times ≥2 s (equivalent to volumes ≥2.0 L), both impactors provided consistent measures of therapeutically important fine particle mass (FPM) from both DPIs, independent of sample duration. At shorter sample times, FPM decreased substantially with the NGI, indicative of incomplete aerosol bolus transfer through the system whose dead space was 2.025 L. However, the ACI provided consistent measures of both variables across the range of sampled volumes evaluated, even when this volume was less than 50% of its internal dead space of 1.155 L. Such behavior may be indicative of maldistribution of the flow profile from the relatively narrow exit of the induction port to the uppermost stage of the impactor at start-up. An explanation of the ACI anomalous behavior from first principles requires resolution of the rapidly changing unsteady flow and pressure conditions at start up, and is the subject of ongoing research by the European Pharmaceutical Aerosol Group. Meanwhile, these experimental findings are provided to advocate a prudent approach by retaining the current pharmacopeial methodology.


Assuntos
Inaladores de Pó Seco/métodos , Desenho de Equipamento/métodos , Tecnologia Farmacêutica/métodos , Inaladores de Pó Seco/instrumentação , Desenho de Equipamento/instrumentação , Tamanho da Partícula , Tecnologia Farmacêutica/instrumentação
10.
J Hazard Mater ; 185(1): 382-91, 2011 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-20934247

RESUMO

In this study, the application of ordered mesoporous silica (OMS) doped with various metal oxides (Zr, Ti, Fe and Al) were studied for the removal of (ortho) phosphate ions from water by adsorption. The materials were characterized by means of N(2) physisorption (BET), powder X-ray diffraction (PXRD) and transmission electron microscopy (TEM). The doped materials had surface areas between 600 and 700 m(2)g(-1) and exhibited pore sizes of 44-64 Å. Phosphate adsorption was determined by measurement of the aqueous concentration of orthophosphate using ultraviolet-visible (UV-vis) spectroscopy before and after extraction. The effects of different metal oxide loading ratios, initial concentration of phosphate solution, temperature and pH effects on the efficiency of phosphate removal were investigated. The doped mesoporous materials were effective adsorbents of orthophosphate and up to 100% removal was observed under appropriate conditions. 'Back extracting' the phosphate from the doped silica (following water treatment) was also investigated and shown to have little adverse effect on the adsorbent.


Assuntos
Metais/química , Óxidos/química , Fosfatos/química , Adsorção , Engenharia Química , Concentração de Íons de Hidrogênio , Microscopia Eletrônica de Transmissão , Nitrogênio/química , Fosfatos/isolamento & purificação , Porosidade , Dióxido de Silício/química , Espectrofotometria Ultravioleta , Temperatura , Eliminação de Resíduos Líquidos , Água/química , Difração de Raios X
11.
Langmuir ; 26(11): 7725-31, 2010 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-20148596

RESUMO

The influence of different solvent environments on the size, shape, and characteristics of surfactant micelles of Pluronic F127 and CTAB was investigated by small-angle neutron scattering (SANS). SANS experiments were undertaken on dilute micellar surfactant solutions of F127 and CTAB that between them were exposed to liquid and supercritical carbon dioxide, liquid propane, ethane, and heptane under various pressures and temperatures. Swelling of the surfactant micelles could be directly related to the solubility of the solvents within the micelles, especially within their cores. Carbon dioxide produced the largest swelling of the Pluronic F127 micelles, compared to propane and ethane, which mirrors the solubility of the gases in the PPO core of the micelles. Conversely, the extent of swelling of the cores of CTAB micelles was greater with propane compared to carbon dioxide, which again relates to the solubility of the solvents in the alkane core of the CTAB micelles.


Assuntos
Gases , Micelas , Pressão , Tensoativos , Cetrimônio , Compostos de Cetrimônio , Íons , Poloxâmero
12.
J Phys Condens Matter ; 22(7): 076001, 2010 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-21386398

RESUMO

Nanostructured NiS was prepared by inclusion into anodic alumina templates. The resultant particles were found to be stoichiometric and highly crystalline. The particles displayed small particle superparamagnetism, and a low temperature (at 48 K (T(sg))) spin-freezing phenomenon (a spin-glass) and higher temperature (170 K) thermal blocking of small particle magnetic moment fluctuations were both observed for the first time for a sulfide material. Very unusually, these NiS materials are quite distinct from antiferromagnetic nanoparticulate sulfide materials, as they display a high temperature ferromagnetic-like phase. The saturation magnetization, the remanent magnetization, the coercivity and the ferromagnetic mass susceptibility were measured as 0.58 emu g( - 1) (at 100 K), 0.19 emu g( - 1), 219.5 Oe (at 170 K) and ∼ 900 × 10( - 6) emu Oe( - 1) g( - 1) respectively and these are consistent with a moderately strong ferromagnetism. The materials had an unexpectedly high Curie temperature of 390 K. The decrease of the saturation magnetization value at 30 K suggests that the ferromagnetic response is a surface phenomenon and the high coercivity of the paramagnetic component well above T(sg) suggests that the core can be described as superparamagnetic.


Assuntos
Magnetismo , Nanopartículas/química , Nanotecnologia , Níquel/química
13.
Nature ; 455(7212): 528-31, 2008 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-18690215

RESUMO

The domestication of cattle, sheep and goats had already taken place in the Near East by the eighth millennium bc. Although there would have been considerable economic and nutritional gains from using these animals for their milk and other products from living animals-that is, traction and wool-the first clear evidence for these appears much later, from the late fifth and fourth millennia bc. Hence, the timing and region in which milking was first practised remain unknown. Organic residues preserved in archaeological pottery have provided direct evidence for the use of milk in the fourth millennium in Britain, and in the sixth millennium in eastern Europe, based on the delta(13)C values of the major fatty acids of milk fat. Here we apply this approach to more than 2,200 pottery vessels from sites in the Near East and southeastern Europe dating from the fifth to the seventh millennia bc. We show that milk was in use by the seventh millennium; this is the earliest direct evidence to date. Milking was particularly important in northwestern Anatolia, pointing to regional differences linked with conditions more favourable to cattle compared to other regions, where sheep and goats were relatively common and milk use less important. The latter is supported by correlations between the fat type and animal bone evidence.


Assuntos
Bovinos/fisiologia , Indústria de Laticínios/história , Leite/história , Leite/estatística & dados numéricos , Animais , Cerâmica/análise , Europa (Continente) , Europa Oriental , Ácidos Graxos/análise , Cabras , História Antiga , Humanos , Carne , Leite/química , Ovinos
14.
Langmuir ; 24(13): 6959-64, 2008 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-18512872

RESUMO

The influence of liquid and supercritical carbon dioxide and liquid propane on the structural properties of both ionic and nonionic surfactant-based liquid crystal films is discussed in this paper. Swelling of the films, measured using in situ small-angle neutron scattering (SANS), was found to be dependent on the solubility of the propane/carbon dioxide in the micelles of the respective liquid crystals. Additionally, under certain pressure conditions the structural properties of some of the films were observed to change, ultimately leading to a loss of order in the micellar arrays of the liquid crystals.


Assuntos
Cristais Líquidos/química , Dióxido de Carbono , Espalhamento a Baixo Ângulo
15.
Langmuir ; 21(9): 4163-7, 2005 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-15835989

RESUMO

In this paper we investigate the use of supercritical carbon dioxide (sc-CO(2)) for synthesizing calcined mesoporous silicas with tunable pore sizes, wall thickness, and d spacings. Small angle neutron scattering was used to probe the controlled swelling of the triblock copolymer surfactant templating agents, P123 (PEO(20)PPO(69)PEO(20)), P85 (PEO(26)PPO(39)PEO(26)), and F127 (PEO(106)PPO(70)PEO(106)), as a function of CO(2) pressure. The transition from the liquid crystal phase to the calcined mesoporous silicas, formed upon condensation and drying, was also studied in detail. Powder X-ray diffraction, transmission electron microscopy, and nitrogen adsorption techniques were used to establish pore diameters, silica wall widths, and the hexagonal packing of the pores within the calcined silicas. Using a direct templating method, the diameters of mesopores and the spacing between the pores could be tuned with a high level of precision. The swelling process was observed to have no detrimental effects on the quality of silica formed, a distinct advantage over conventional swelling techniques, and all of the silicas synthesized in this study were highly ordered over distances of at least 2000 A.


Assuntos
Dióxido de Carbono/química , Dióxido de Silício/química , Tensoativos/química , Adsorção , Hidróxido de Alumínio/química , Hidróxido de Magnésio/química , Microscopia Eletrônica de Transmissão , Nitrogênio/química , Transição de Fase , Porosidade , Propriedades de Superfície , Difração de Raios X
16.
Analyst ; 129(3): 270-5, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-14978532

RESUMO

The chemical analyses of "bog butters" recovered from peat bogs of Scotland were performed with the aim of determining their origins. Detailed compositional information was obtained from "bog butter" lipids using high temperature gas chromatography (HTGC) and GC-mass spectrometry (GC-MS). The results indicate the degree to which "bog butters" have undergone diagenetic alterations during burial to form an adipocere like substance, consisting predominantly of hexadecanoic (palmitic) and octadecanoic (stearic) acids. GC-combustion-isotope ratio MS (GC-C-IRMS) was used to determine delta13C values for the dominant fatty acids present, revealing for the first time that "bog butters" were derived from both ruminant dairy fats and adipose fats. The results are compared and contrasted with modern reference fats and adipoceres produced in vitro.

17.
Rapid Commun Mass Spectrom ; 17(20): 2283-9, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-14558127

RESUMO

This study investigates the effects of hydrolysis on the delta13C values of individual amino acids (IAAs) derived from polypeptide standards, and modern and ancient bone collagen. All IAAs were derivatised to their trifluoroacetyl/isopropyl (TFA/IP) esters for delta13C determination using gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). Firstly, authentic single poly amino acid standards (SPAAs; n = 5) were hydrolysed for 4, 10, 24 and 48 h. As expected, IAA yields increased as a function of hydrolysis time. Significantly, it was only after 24 h of hydrolysis that IAA delta13C values were statistically identical to bulk SPAA values for all five standards. The accuracy of IAA delta13C values was thus shown to be a function of yield; however, poly phenylalanine demonstrated accurate IAA delta13C values with yields of only 1.4 and 4.3%, after 24 and 48 h of hydrolysis time, respectively. Authentic mixed poly amino acid standards (MPAAs; n = 5) comprising two different amino acids were then hydrolysed for 24 h. Percentage recoveries ranged from 36-95%. Estimates of bulk MPAA delta13C values calculated from measured IAA delta13C values agreed within experimental error with measured bulk MPAA values for three out of the five standards. Finally, the experimental procedure was applied to modern rat (MBCs; n = 20) and ancient ovi-caprine and bovine (ABCs; n = 27) bone collagen samples where the delta13C values of 12 out of its 18 constituent amino acids were determined. Estimated bulk MBC and ABC delta13C values were calculated from constituent amino acid delta13C values using mass balance. With the exclusion of three ABC samples, calculated bulk bone collagen delta13C values (delta13C(BCcal)) were shown to correlate extremely well with measured bone collagen values (delta13C(BCmes)) for both modern and ancient samples, where R2 = 0.91 and 0.84, respectively. Significantly, the variation between calculated and measured bone collagen values (Delta13C(BCcal-BCmes)) exhibited similar ranges for both MBC (from -2.6 to +1.2 per thousand ) and ABC (from -2.7 to +2.2 per thousand ) samples, providing evidence for the preservation of intact collagen in the ancient samples. These results demonstrate that the experimental procedures employed in the acid hydrolytic cleavage of peptides or proteins to their constituent amino acids does not involve significant isotopic fractionation.


Assuntos
Aminoácidos/análise , Aminoácidos/química , Peptídeos/química , Proteínas/química , Animais , Osso e Ossos , Isótopos de Carbono , Bovinos , Cromatografia Gasosa , Colágeno/química , Cromatografia Gasosa-Espectrometria de Massas , Hidrólise , Ratos , Fatores de Tempo
18.
Acc Chem Res ; 35(8): 660-8, 2002 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12186571

RESUMO

Animal fats are preserved at archaeological sites in association with unglazed pottery, human and animal remains, and other deposits or hoards. High-temperature gas chromatography (HT-GC) and combined HT-GC/mass spectrometry (HT-GC/MS) has confirmed the presence of animal fats in lipid extracts of artifacts. Degradation products and pathways have been discerned through the analyses of archaeological finds and the products of laboratory and field-based decay experiments. The origins of preserved fats have been determined through detailed compositional analysis of their component fatty acids by GC, by GC/MS of dimethyl disulfide derivatives of monoenoic components, and by GC-combustion-isotope ratio-MS (GC-C-IRMS), to derive diagenetically robust delta(13)C values. Regiospecific analysis of intact triacylglycerols by high-performance liquid chromatography/MS (HPLC/MS), with atmospheric pressure chemical ionization, provides a further criterion for establishing the origin of fats. Preparative GC has been employed to isolate individual fatty acids from archaeological pottery in sufficient amounts for (14)C dating.


Assuntos
Arqueologia , Gorduras/análise , Gorduras/química , Animais , Cromatografia Gasosa , Cromatografia Líquida de Alta Pressão , Cromatografia Gasosa-Espectrometria de Massas
19.
Sex Transm Dis ; 29(4): 216-21, 2002 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11912463

RESUMO

BACKGROUND: To assess the prevalence and increase awareness of Neisseria gonorrhoeae and Chlamydia trachomatis infections among men who have sex with men, a screening program was conducted at three inner-city homosexual entertainment venues and one community function. STUDY DESIGN: Each venue was accessed twice over a 3-month period between March and June 2000. First-catch urine specimens were collected for analysis by polymerase chain reaction (PCR), and throat swabs were collected for culture and PCR. RESULTS: A total of 202 men were tested during the 7 screening nights, including 16 who were tested more than once. From the 186 men tested for the first time, 184 urine specimens were collected, of which 8 (4.3%; 95% CI, 1.9-7.8%) were PCR-positive for C trachomatis and 1 (0.5%; 95% CI, 0-2.1%) was PCR-positive for N gonorrhoeae. Of the 161 throat swabs collected, none were positive for C trachomatis or N gonorrhoeae. CONCLUSIONS: C trachomatis is a potentially significant pathogen in this population of urban homosexual men. Screening programs such as these are valuable as health-promotion exercises.


Assuntos
Infecções por Chlamydia/epidemiologia , Gonorreia/epidemiologia , Homossexualidade Masculina/estatística & dados numéricos , Adulto , Infecções por Chlamydia/prevenção & controle , Infecções por Chlamydia/urina , Chlamydia trachomatis/genética , Chlamydia trachomatis/isolamento & purificação , DNA Bacteriano/genética , Gonorreia/prevenção & controle , Gonorreia/urina , Humanos , Masculino , Programas de Rastreamento/métodos , Neisseria gonorrhoeae/genética , Neisseria gonorrhoeae/isolamento & purificação , Faringe/microbiologia , Reação em Cadeia da Polimerase , Prevalência , Queensland/epidemiologia , Recreação , Saúde da População Urbana
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...