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Solid-state nuclear magnetic resonance (NMR) spectroscopy, thermal analysis, and X-ray powder diffraction data on the tubular, hydrous aluminosilicate imogolite were found to be fully consistent with a previously proposed crystal structure consisting of a rolled-up, 6-coordinate Al-O(OH) sheet, bonded to isolated orthosilicate groups. The calculated 29Si chemical shift of this structure agreed with the observed shift within 3 ppm. Thermal dehydroxylation of the Al-O(OH) sheet produced predominantly NMR-transparent 5-coordinate Al, but a few 4- and 6-coordinate sites and some residual hydroxyl groups may also have formed, as shown by NMR spectroscopy. Changes in the 29Si NMR spectrum on dehydroxylation suggest a condensation of the orthosilicate groups, but steric considerations rule out bonding between adjacent silicons. To account for these observations, an alternative mechanism to orthosilicate condensation has been proposed, involving the fracture and unrolling of the tubes, followed by the condensation of fragments to form a layer structure. The layer structure has a calculated 29Si chemical shift of -95.6 ppm, in good agreement with the observed value of -93 ppm.
To estimate the proportion of patients who acquire methicillin-resistant Staphylococcus aureus (MRSA) while in hospital and to identify risk factors associated with acquisition of MRSA.
Design.
Retrospective cohort study.
Patients.
Adult patients discharged from 36 general specialty wards of 2 Scottish hospitals that had implemented universal screening for MRSA on admission.
Methods.
Patients were screened for MRSA on discharge from hospital by using multisite body swabs that were tested by culture. Discharge screening results were linked to admission screening results. Genotyping was undertaken to identify newly acquired MRSA in MRSA-positive patients on admission.
Results.
Of the 5,155 patients screened for MRSA on discharge, 2.9% (95% confidence interval [CI], 2.43–3.34) were found to be positive. In the subcohort screened on both admission and discharge (n = 2,724), 1.3% of all patients acquired MRSA while in hospital (incidence rate, 2.1/1,000 hospital bed-days in this cohort [95% CI, 1.5–2.9]), while 1.3% remained MRSA positive throughout hospital stay. Three risk factors for acquisition of MRSA were identified: age above 64 years, self-reported renal failure, and self-reported presence of open wounds. On a population level, the prevalence of MRSA colonization did not differ between admission and discharge.
Conclusions.
Cross-transmission of MRSA takes place in Scottish hospitals that have implemented universal screening for MRSA. This study reinforces the importance of infection prevention and control measures to prevent MRSA cross-transmission in hospitals; universal screening for MRSA on admission will in itself not be sufficient to reduce the number of MRSA colonizations and subsequent MRSA infections.
Researchers evaluating voice disorder interventions currently have a plethora of voice outcome measurement tools from which to choose. Faced with such a wide choice, it would be beneficial to establish a clear rationale to guide selection. This article reviews the published literature on the three main areas of voice outcome assessment: (1) perceptual rating of voice quality, (2) acoustic measurement of the speech signal and (3) patient self-reporting of voice problems. We analysed the published reliability, validity, sensitivity to change and utility of the common outcome measurement tools in each area. From the data, we suggest that routine voice outcome measurement should include (1) an expert rating of voice quality (using the Grade-Roughness-Breathiness-Asthenia-Strain rating scale) and (2) a short self-reporting tool (either the Vocal Performance Questionnaire or the Vocal Handicap Index 10). These measures have high validity, the best reported reliability to date, good sensitivity to change data and excellent utility ratings. However, their application and administration require attention to detail. Acoustic measurement has arguable validity and poor reliability data at the present time. Other areas of voice outcome measurement (e.g. stroboscopy and aerodynamic phonatory measurements) require similarly detailed research and analysis.
The effects of cigarette smoking on the incidence of epidemic influenza and on the serological response to influenza vaccination with killed subunit and live attenuated vaccines have been investigated during comparative vaccine trials in Western Australia. It was found that cigarette smokers with no pre-epidemic haemagglutination-inhibiting (HI) antibody (titres of ≤ 12) were significantly more susceptible to epidemic influenza than non-smokers. Smokers were no more susceptible however, if they had possessed detectable pre-epidemic HI antibody. A significantly higher proportion of smokers sero-converted after receiving the live virus vaccine than their non-smoking counterparts, but this could not be correlated with pre-vaccination HI antibody titres. The longevity of the immune response to the subunit vaccine was severely depressed 50 weeks post-vaccination in smokers who had possessed little or no immunity before vaccination (titres of ≤ 12). This antibody deficit was not observed in live virus vaccinees or subunit vaccinees with pre-vaccination HI antibody (titres of ≥ 24). Post-vaccinal symptoms were similar regardless of vaccine group or smoking history.
Deafness is the hidden disability of childhood, and leads to poor educational and employment prospects. There is little published information on deafness in Pakistan. Profound hearing impairment is more prevalent in countries where consanguineous marriages are common, such as Pakistan. This study aimed to assess causes of childhood deafness and association with parental consanguinity, within deaf and hearing children in the Peshawar district of Pukhtoonkhwa Province, Pakistan.
Methods:
One hundred and forty deaf children were identified from two schools for deaf children within the Peshawar district. These children were assessed via audiology, otoscopic examination, case note review and parental history, in order to attempt to ascertain the cause of their deafness. Two hundred and twenty-one attendees at a local immunisation clinic (taken as representative of the local childhood population) were also screened for hearing impairment. Parents of both groups of children were assessed by interview and questionnaire in order to ascertain the mother and father's family relationship (i.e. whether cousins or unrelated).
Results:
Of the 140 deaf school pupils, 92.1 per cent were profoundly hearing impaired and 7.9 per cent were severely hearing impaired. All these children had bilateral sensorineural hearing loss. A possible cause of deafness was identified in only six of these children. Parental consanguinity (i.e. first or second cousins) was established for 86.4 per cent of deaf school pupils and 59.7 per cent of immunisation clinic attendees. None of the control children were identified as having a hearing problem.
Conclusion:
The prevalence of parental consanguinity was significantly higher in deaf children compared with non-hearing impaired children. However, the study also confirmed a high rate of consanguinity within the general Peshawar community. In this setting, prevention of consanguineous unions is the only means of reducing levels of congenital hearing impairment. The current levels of hearing disability represent both a prominent public health problem and an important, potentially preventable childhood disability.
A wide range of well validated instruments is now available to assess voice quality and voice-related quality of life, but comparative studies of the responsiveness to change of these measures are lacking. The aim of this study was to assess the responsiveness to change of a range of different measures, following voice therapy and surgery.
Design:
Longitudinal, cohort comparison study.
Setting:
Two UK voice clinics.
Participants:
One hundred and forty-four patients referred for treatment of benign voice disorders, 90 undergoing voice therapy and 54 undergoing laryngeal microsurgery.
Main outcome measures:
Three measures of self-reported voice quality (the vocal performance questionnaire, the voice handicap index and the voice symptom scale), plus the short form 36 (SF 36) general health status measure and the hospital anxiety and depression score. Perceptual, observer-rated analysis of voice quality was performed using the grade–roughness–breathiness–asthenia–strain scale. We compared the effect sizes (i.e. responsiveness to change) of the principal subscales of all measures before and after voice therapy or phonosurgery.
Results:
All three self-reported voice measures had large effect sizes following either voice therapy or surgery. Outcomes were similar in both treatment groups. The effect sizes for the observer-rated grade–roughness–breathiness–asthenia–strain scale scores were smaller, although still moderate. The roughness subscale in particular showed little change after therapy or surgery. Only small effects were observed in general health and mood measures.
Conclusion:
The results suggest that the use of a voice-specific questionnaire is essential for assessing the effectiveness of voice interventions. All three self-reported measures tested were capable of detecting change, and scores were highly correlated. On the basis of this evaluation of different measures' sensitivities to change, there is no strong evidence to favour either the vocal performance questionnaire, the voice handicap index or the voice symptom scale.
There is an increasing choice of voice outcome research tools, but good comparative data are lacking.
Objective:
To evaluate the reliability and validity of three voice-specific, self-reported scales.
Design:
Longitudinal, cohort comparison study.
Setting:
Two UK voice clinics: the Freeman Hospital, Newcastle upon Tyne, and the Glasgow Royal Infirmary.
Participants:
One hundred and eighty-one patients presenting with dysphonia.
Main outcome measures:
All patients completed the vocal performance questionnaire, the voice handicap index and the voice symptom scale. For comparison, each patient's voice was recorded and assessed perceptually using the grade–roughness–breathiness–aesthenia–strain scale. The reliability and validity of the three self-reported vocal performance measures were assessed in all subjects, while 50 completed the questionnaires again to assess repeatability.
Results:
The results of the 170 participants with completed data sets showed that all three questionnaires had high levels of internal consistency (Cronbach's alpha = 0.81–0.95) and repeatability (voice handicap index = 0.83; vocal performance questionnaire = 0.75; voice symptom scale = 0.63). Concurrent and criterion validity were also good, although, of the grade–roughness–breathiness–aesthenia–strain subscales, roughness was the least well correlated with the self-reported measures.
Conclusion:
The vocal performance questionnaire, the voice handicap index and the voice symptom scale are all reliable and valid instruments for measuring the patient-perceived impact of a voice disorder.
The weight distribution and postural sway was measured in diabetic subjectswith, and without, neuropathy, and then compared with age and sex matched non-diabetic subjectsusing a cheap and highly portable sway plate – SwayWeigh. The SwayWeigh was found to be very practical and the results obtained confirmed the increased postural sway in the absence of proprioceptive information in neuropathy subjects. The study shows that peripheral neuropathy increases the postural sway especially in the absence of visual clues but this did not result inpostural strategies causing significant limb load asymmetry.
We present a patient with established histiocytosis who developed dysphagia, retching, regurgitation, hoarseness and stridor. These symptoms were managed with carbon dioxide laser vaporization, electively on three occasions, and once as an urgent procedure, while awaiting radiotherapy, to control her airway.
Histiocytosis is a rare cause of a number of otolaryngological syndromes, but there has been no previous record of this disease causing laryngopharyngeal symptoms. This paper discusses the classification of histiocytosis, and describes our management of this rare and intriguing case.
All laser interferometers rely on measuring the strain in space caused by a gravitational wave, sensitivities of the order of 10–22 over millisecond timescales being required to allow a good probability of detection.
In principle the strain as monitored by the change in separation of two test masses hung as pendulums can be measured against the wavelength of light from a stable source, but the degree of wavelength or frequency stability required of the source is unreasonably high. It is much more conceivable to measure the distance between test masses along an arm with respect to the distance between similar masses along a perpendicular arm. This is particularly appropriate since the interaction of a gravitational wave is quadrupole in nature and so can cause an opposite sign of length change in the two arms. The measurement of a differential length change of this type when performed by interferometry puts much less demand in principle on the frequency stability of the illuminating laser light – since a Michelson interferometer is insensitive to changes in the wavelength of the light used if the path lengths are equal. However, in practice a fairly high degree of frequency stability is required. In the case of optical delay lines in the arms of a Michelson interferometer this is a result of the difficulty in achieving equal path lengths and of some light being scattered back early without completing the full number of reflections (Billing et al, 1983).
Rhabdomyosarcoma is a diagnostic and therapeutic problem in the management of childhood tumours. A case of embryonal rhabdomyosarcoma affecting the sphenoid sinus and involving the cavernous sinus is presented. It has become evident that modern combined modality therapy, including surgery when required, radiation and adjuvant multi-drug chemotherapy offers the best chance of survival.