534 resultados para GEMINI SPECTROSCOPIC SURVEY


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Natural single-crystal specimens of the herderite-hydroxylherderite series from Brazil, with general formula CaBePO4(F,OH), were investigated by electron microprobe, Raman, infrared and near-infrared spectroscopies. The minerals occur as secondary products in granitic pegmatites. Herderite and hydroxylherderite minerals show extensive solid solution formation. The Raman spectra of hydroxylherderite are characterized by bands at around 985 and 998 cm-1, assigned to ν1 symmetric stretching mode of the HOPO33- and PO43- units. Raman bands at around 1085, 1128 and 1138 cm-1 are attributed to both the HOP and PO antisymmetric stretching vibrations. The set of Raman bands observed at 563, 568, 577, 598, 616 and 633 cm-1 are assigned to the ν4 out of plane bending modes of the PO4 and H2PO4 units. The OH Raman stretching vibrations of hydroxylherderite were observed ranging from 3626 cm-1 to 3609 cm-1. The infrared stretching vibrations of hydroxylherderites were observed between 3606 cm-1 and 3599 cm-1. By using a Libowitzky type function, hydrogen bond distances based upon the OH stretching bands were calculated. Characteristic NIR bands at around 6961 and 7054 cm-1 were assigned to the first overtone of the fundamental, whilst NIR bands at 10194 and 10329 cm-1 are assigned to the second overtone of the fundamental OH stretching vibration. Insight into the structure of the herderite-hydroxylherderite series is assessed by vibrational spectroscopy.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Raman and thermo-Raman spectroscopy have been applied to study the mineral formerly known as manasseite now simply renamed as hydrotalcite-2H Mg6Al2(OH)16[CO3]⋅4H2O. The mineral is a member of the homonymous hydrotalcite supergroup. Hydrogen bond distances calculated using a Libowitzky-type empirical function varied between 2.61 and 3.00 Å. Stronger hydrogen bonds were formed by water units as compared to the hydroxyl units. Raman spectroscopy enabled the identification of bands attributed to the hydroxyl units. Two Raman bands at 1059 and 1064 cm-1 are assigned to symmetric stretching modes of the carbonate anion. Thermal treatment shifts these bands to higher wavenumbers indicating a change in the strength of the carbonate bonding.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The mineral ettringite has been studied using a number of techniques, including XRD, SEM with EDX, thermogravimetry and vibrational spectroscopy. The mineral proved to be composed of 53% of ettringite and 47% of thaumasite in a solid solution. Thermogravimetry shows a mass loss of 46.2% up to 1000 °C. Raman spectroscopy identifies multiple sulphate symmetric stretching modes in line with the three sulphate crystallographically different sites. Raman spectroscopy also identifies a band at 1072 cm−1 attributed to a carbonate symmetric stretching mode, confirming the presence of thaumasite. The observation of multiple bands in the ν4 spectral region between 700 and 550 cm−1 offers evidence for the reduction in symmetry of the sulphate anion from Td to C2v or even lower symmetry. The Raman band at 3629 cm−1 is assigned to the OH unit stretching vibration and the broad feature at around 3487 cm−1 to water stretching bands. Vibrational spectroscopy enables an assessment of the molecular structure of natural ettringite to be made.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this report, a detailed FTIR fitting analysis was used to recognize Mg, Zn and Al homogeneous distribution in MgxZnyAl(x+y)/2-Layered double hydroxide (LDH) hydroxyl layer. In detail, OH-Mg2Al:OH-Mg3 ratios decreased from 95.2:4.8 (MIR) and 94.2:5.8 (NIR) to 58.9:41.1 (MIR) and 61.8:38.2 (NIR), when Mg:Al increased from 2.2:1.0 to 4.1:1.0 in MgAl-LDHs. These fitting results were similar with theoretical calculations of 94.3:5.7 and 59.0:41.0. In a further analysis of MgxZnyAl(x+y)/2-LDHs, OH bonded Zn2Mg, Zn2Al, MgZnAl, Mg2Al and Mg2Zn peaks were identified at 3420, 3430, 3445–3450, 3454 and 3545 cm-1, respectively. With the decrease of Mg:Zn from 3:1 to 1:3, metal-hydroxyl bands changed from OH-Mg2Al and MgZnAl (with a ratio of 49.4:50.6) to OH-MgZnAl and Zn2Al (with a ratio of 55.0:45.0). They were also similar with theoretical calculations of 47.6:52.4 and 54.6:45.4. As a result, these results show that there is an ordered cation distribution in MgxZnyAl(x+y)/2-LDH, and FTIR is feasible in recognizing this structure.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Purpose Intensity modulated radiotherapy (IMRT) treatments require more beam-on time and produce more linac head leakage to deliver similar doses to conventional, unmodulated, radiotherapy treatments. It is necessary to take this increased leakage into account when evaluating the results of radiation surveys around bunkers that are, or will be, used for IMRT. The recommended procedure of 15 applying a monitor-unit based workload correction factor to secondary barrier survey measurements, to account for this increased leakage when evaluating radiation survey measurements around IMRT bunkers, can lead to potentially-costly over estimation of the required barrier thickness. This study aims to provide initial guidance on the validity of reducing the value of the correction factor when applied to different radiation barriers (primary barriers, doors, maze walls and other walls) by 20 evaluating three different bunker designs. Methods Radiation survey measurements of primary, scattered and leakage radiation were obtained at each of five survey points around each of three different radiotherapy bunkers and the contribution of leakage to the total measured radiation dose at each point was evaluated. Measurements at each survey point were made with the linac gantry set to 12 equidistant positions from 0 to 330o, to 25 assess the effects of radiation beam direction on the results. Results For all three bunker designs, less than 0.5% of dose measured at and alongside the primary barriers, less than 25% of the dose measured outside the bunker doors and up to 100% of the dose measured outside other secondary barriers was found to be caused by linac head leakage. Conclusions Results of this study suggest that IMRT workload corrections are unnecessary, for 30 survey measurements made at and alongside primary barriers. Use of reduced IMRT workload correction factors is recommended when evaluating survey measurements around a bunker door, provided that a subset of the measurements used in this study are repeated for the bunker in question. Reduction of the correction factor for other secondary barrier survey measurements is not recommended unless the contribution from leakage is separetely evaluated.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

BACKGROUND Chemotherapy-induced nausea and vomiting (CINV) remain prevalent among cancer patients despite pharmacological advances in CINV therapy. Patients can initiate nonpharmacologic strategies, which potentially play an important role as adjuncts to pharmacological agents in alleviating CINV. Some studies have explored nausea and vomiting self-management (NVSM) behaviors among patients in Western settings; however, little is known about the NVSM behaviors of patients in China. OBJECTIVES This study examines NVSM behaviors of Chinese cancer patients. METHODS A cross-sectional survey was conducted in a specialist cancer hospital in southeast China. RESULTS A sample of 255 cancer patients was recruited. A mean of 8.56 (±3.15) NVSM behaviors was reported. Most NVSM behaviors were rated as moderately effective and were implemented with moderate self-efficacy. Higher distress levels, better functional status, previous similar symptom experiences, receiving chemotherapy as an inpatient, and greater support from multiple levels were related to greater engagement in NVSM; higher self-efficacy levels pertaining to NVSM behaviors were associated with reports of more relief from specific NVSM behaviors. CONCLUSIONS A range of NVSM strategies was initiated by Chinese cancer patients and provided some relief. A range of individual, health status, and environmental factors influenced engagement with and relief from NVSM behaviors. IMPLICATIONS FOR PRACTICE To enhance Chinese patients' NVSM, patients should be supported to engage in behaviors including taking antiemetics, modifying their diet, using psychological strategies, and creating a pleasant environment. The findings highlight the importance of enhancing patients' self-efficacy in NVSM, alleviating symptom distress, and improving social support to achieve better outcomes.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Spectroscopic studies of complex clinical fluids have led to the application of a more holistic approach to their chemical analysis becoming more popular and widely employed. The efficient and effective interpretation of multidimensional spectroscopic data relies on many chemometric techniques and one such group of tools is represented by so-called correlation analysis methods. Typical of these techniques are two-dimensional correlation analysis and statistical total correlation spectroscopy (STOCSY). Whilst the former has largely been applied to optical spectroscopic analysis, STOCSY was developed and has been applied almost exclusively to NMR metabonomic studies. Using a 1H NMR study of human blood plasma, from subjects recovering from exhaustive exercise trials, the basic concepts and applications of these techniques are examined. Typical information from their application to NMR-based metabonomics is presented and their value in aiding interpretation of NMR data obtained from biological systems is illustrated. Major energy metabolites are identified in the NMR spectra and the dynamics of their appearance and removal from plasma during exercise recovery are illustrated and discussed. The complementary nature of two-dimensional correlation analysis and statistical total correlation spectroscopy are highlighted.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Raman spectroscopy was used to characterize and differentiate the two minerals calcite and dolomite and the bands related to the mineral structure. The (CO3)2− group is characterized by four prominent Raman vibrational modes: (a) the symmetric stretching, (b) the asymmetric deformation, (c) asymmetric stretching and (d) symmetric deformation. These vibrational modes of the calcite and dolomite were observed at 1440, 1088, 715 and 278 cm−1. The significant differences between the minerals calcite and dolomite are observed by Raman spectroscopy. Calcite shows the typical bands observed at 1361, 1047, 715 and 157 cm−1, and the special bands at 1393, 1098, 1069, 1019, 299, 258 and 176 cm−1 for dolomite are observed. The difference is explained on the basis of the structure variation of the two minerals. Calcite has a trigonal structure with two molecules per unit cell, and dolomite has a hexagonal structure. This is more likely to cause the splitting and distorting of the carbonate groups. Another cause for the difference is the cation substituting for Mg in the dolomite mineral.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background Positive attitudes of healthcare staff towards people with dementia promote higher quality care, although little is known about important factors that underlie positive attitudes. Key aims of this project were to explore the relationships between staff attitudes towards dementia, self-confidence in caring for people with dementia, experience and dementia education and training. Method A brief online survey was developed and widely distributed to registered nurses and allied health professionals working in Queensland in 2012. Regression analyses were performed to identify important predictors of self-confidence in caring for people with dementia and positive attitudes towards people with dementia. Results Five hundred and twenty-four surveys were completed by respondents working in a range of care settings across Queensland. Respondents were predominantly female (94.1%), and most were registered nurses (60%), aged between 41 and 60 years (65.6%). Around 40% regularly worked with people with dementia and high levels of self-confidence in caring for this population and positive attitudes towards people with dementia were reported. The majority of respondents (67%) had participated in a dementia education/training activity in the past 12 months. More experience working with people with dementia predicted greater self-confidence while recent participation in a dementia education/training and higher self-confidence in caring for a person with dementia significantly predicted more positive attitudes towards people with dementia. Conclusion These results confirm the importance of self-confidence and dementia education in fostering positive attitudes and care practices towards people with dementia. Our results also indicate that the demand for ongoing dementia education is high amongst health care workers and it is recommended that regular dementia education/ training be provided and promoted for all healthcare personnel who work with people with dementia.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Purpose Women who experience cancer treatment-induced menopause are at risk of long-term chronic morbidity. This risk can be prevented or offset with adherence to health promotion and risk reduction guidelines. The purpose of this study was to explore health behaviours in younger female survivors of cancer and the variables (quality of life and psychological distress) believed to moderate health behaviours. Design Cross-sectional survey of a convenience sample of women (n = 85) in southeast Queensland. Methods Health behaviour and health status were elicited with items from the Australian Health Survey and the Behavioural Risk Factor Surveillance System. The WHO Quality of Life (Brief) measured participants’ self-reported quality of life and their satisfaction with their health. The Brief Symptom Inventory-18 measured psychological distress. Findings Higher self-reported health status was associated with regular exercise and better quality of life. However, a substantial proportion of participants did not engage in the physical activity, dietary or cervical screening practices recommended by Australian guidelines. Conclusions The participants require education regarding the benefits of diet, exercise, weight loss and decreased alcohol intake, as well as information on future health risks and possible comorbidities. These education sessions could be addressed by a nurse-led health promotion model of care at the time of discharge or in the community.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Natural single-crystal specimens of althausite from Brazil, with general formula Mg2(PO4)(OH,F,O) were investigated by Raman and infrared spectroscopy. The mineral occurs as a secondary product in granitic pegmatites. The Raman spectrum of althausite is characterized by bands at 1020, 1033 and 1044 cm-1, assigned to ν1 symmetric stretching modes of the HOPO33- and PO43- units. Raman bands at around 1067, 1083 and 1138 cm-1 are attributed to both the HOP and PO antisymmetric stretching vibrations. The set of Raman bands observed at 575, 589 and 606 cm-1 are assigned to the ν4 out of plane bending modes of the PO4 and H2PO4 units. Raman bands at 439, 461, 475 and 503 cm-1 are attributed to the ν2 PO4 and H2PO4 bending modes. Strong Raman bands observed at 312, 346 cm-1 with shoulder bands at 361, 381 and 398 cm-1 are assigned to MgO stretching vibrations. No bands which are attributable to water were found. Vibrational spectroscopy enables aspects of the molecular structure of althausite to be assessed.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Adherence to behavioral weight loss strategies is important for weight loss success. We aimed to examine the reliability and validity of a newly developed compliance praxis-diet (COMPASS-diet) survey with participants in a 10-week dietary intervention program. During the third of five sessions, participants of the “slim-without-diet” weight loss program (n = 253) completed the COMPASS-diet survey and provided data on demographic and clinical characteristics, and general self-efficacy. Group facilitators completed the COMPASS-diet-other scale estimating participants’ likely adherence from their perspective. We calculated internal consistency, convergent validity, and predictive value for objectively measured weight loss. Mean COMPASS-diet-self score was 82.4 (SD 14.2) and COMPASS-diet-other score 80.9 (SD 13.6) (possible range 12–108), with lowest scores in the normative behavior subscale. Cronbach alpha scores of the COMPASS-diet-self and -other scale were good (0.82 and 0.78, respectively). COMPASS-diet-self scores (r = 0.31) correlated more highly with general self-efficacy compared to COMPASS-diet-other scores (r = 0.04) providing evidence for validity. In multivariable analysis adjusted for age and gender, both the COMPASS-diet-self (F = 10.8, p < 0.001, r2 = 0.23) and other (F = 5.5, p < 0.001, r2 = 0.19) scales were significantly associated with weight loss achieved at program conclusion. COMPASS-diet surveys will allow group facilitators or trainers to identify patients who need additional support for optimal weight loss.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We have studied the mineral olmiite CaMn\[SiO3(OH)](OH) which forms a series with its calcium analogue poldevaartite CaCa\[SiO3(OH)](OH) using a range of techniques including scanning electron microscopy, thermogravimetric analysis , Raman and infrared spectroscopy. Chemical analysis shows the mineral is pure and contains only calcium and manganese in the formula. Thermogravimetric analysis proves the mineral decomposes at 502°C with a mass loss of 8.8% compared with the theoretical mass loss of 8.737%. A strong Raman band at 853 cm-1 is assigned to the SiO stretching vibration of the SiO3(OH) units. Two Raman bands at 914 and 953 cm-1 are attributed to the antisymmetric vibrations.Two intense Raman bands observed at 3511 and 3550 cm-1 are assigned to the OH stretching vibration of the SiO3(OH) units. The observation of multiple OH bands supports the concept of the non-equivalence of the OH units. Vibrational spectroscopy enables a detailed assessment of the molecular structure of olmiite.