Ordered arrays of lead zirconium titanate nanorings

Periodic arrays of nanorings of morphotropic phase boundary lead zirconium titanate (PZT) have been successfully fabricated using a novel self-assembly technique: close-packed monolayers of latex nanospheres were deposited onto Pt-coated silicon substrates, and then plasma cleaned to form ordered arrays of isolated nanospheres, not in contact with each other. Subsequent pulsed laser deposition of PZT, high angle argon ion etching and thermal annealing created the arrays of isolated nanorings, with diameters of ∼100 nm and wall thicknesses of ∼10 nm. Energy dispersive x-ray analysis confirms that the rings are compositionally morphotropic phase boundary PZT, and high resolution transmission electron microscopy imaging of lattice fringes demonstrates some periodicities consistent with perovskite rather than pyrochlore material. The dimensions of these nanorings, and the expected 'soft' behaviour of the ferroelectric material from which they are made, means that they offer the most likely opportunity to date for observing whether or not vortex arrangements of electrical dipoles, analogous to those seen in ferromagnetic nanostructures, actually exist.

Role of prefrontal and parietal cortices in associative learning

Two studies were performed that compared a "Paired" condition in which participants studied paired associates with a "Generated" condition in which participants completed word fragments to produce paired associates. In both tasks, participants were responsible for memory of the material either studied or generated. The experiments revealed significant differences between the responses of a predefined prefrontal region and a predefined parietal region. The parietal region responded more in the Generated condition than the Paired condition, whereas there was no difference in the prefrontal region. On the other hand, the prefrontal region responded to the delay between study and test in both the Paired and Generated conditions, whereas the parietal region only responded to delay in the Generated condition. This pattern of results is consistent with the hypothesis that the parietal region is responsive to changes in problem representation and the prefrontal region to retrieval operations. An information-processing model embodying these assumptions was fit to the blood oxygen level-dependent responses in these regions.

Adhesive capsulitis: human fibroblast response to shoulder joint aspirate from patients with stage II disease

Abnormal fibroblast proliferation has been implicated in the pathogenesis of adhesive capsulitis. The aim of the study was to examine the effect of fluid aspirated from the glenohumeral joint of patients with adhesive capsulitis on human fibroblast cells. Shoulder aspirate from 15 patients with stage II adhesive capsulitis was obtained and diluted to concentrations of 10%, 25%, and 50%. Fifteen patients undergoing shoulder arthroscopy for instability comprised the normal control group. Human fibroblast cells were cultured from human volunteers. Cellular proliferation was determined by use of the Promega CellTiter 96 nonradioactive cell proliferation assay. Fibroblast proliferation was significantly increased in patients with adhesive capsulitis. The rate of increased fibroblast proliferation showed a dose-dependent relationship to aspirate concentration. There was a moderate increase in fibroblast apoptosis at higher aspirate concentrations (25% and 50%) as detected by the ability of apoptotic cells to bind annexin V and exclude propidium iodide. These findings demonstrate that fluid from shoulders with adhesive capsulitis contains growth factors that influence fibroblast activity.

Making the right connections

Advances in connector technology are supporting the requirements in medical electronics for greater speed, increased current handling and reduced size. A range of connector solutions are described.

Control of Bacterial Wilt of Geranium with Phosphorous Acid

Various bactericides were screened for efficacy in protecting geranium plants (Pelargonium hortorum) from Ralstonia solanacearum infection. Many of these bactericides were found to slow the disease progress; however, they were not able to protect the plants from infection and subsequent death. Potassium salts of phosphorous acid were found to be effective in protecting plants from infection when applied as a drench. The active portion of the potassium salts was found to be phosphorous acid (H₃PO₃). Phosphorous acid was found to inhibit in vitro growth of R. solanacearum. It is thought to be protecting plants from infection by acting as a bacteriostatic compound in the soil. The plants, however, are not protected from aboveground infection on wounded surfaces. Phosphorous acid drenches were shown to protect geranium plants from infection by either race 1 or 3 of R. solanacearum. Other phosphorous-containing products commonly used in the industry, such as phosphorus pentoxide (P₂O₅) and phosphoric acid (H₃PO₄), were not able to protect plants from bacterial wilt infection.

Small bowel obstruction in a twin pregnancy due to fibroid degeneration

Small bowel obstruction in pregnancy is unusual. It is a difficult diagnosis to make, as vomiting and abdominal distension are commonly associated with pregnancy, and x-rays are avoided if possible. We present a case of small bowel obstruction caused by uterine fibroid degeneration in a 37 year old with a twin pregnancy. Following a period of observation an x-ray was performed which prompted surgical exploration, relief of the obstruction and myomectomy. This case highlights that x-ray is essential if there is a clinical suspicion of small bowel obstruction in pregnancy as delay in diagnosis can be catastrophic. As childbearing is increasingly delayed into later life it is possible that pregnancy complicated by fibroids will be seen more frequently.

The influence of some different factors on the accuracy of shade selection

The purpose of this study was to elucidate some of the factors on which accurate shade taking depends. Custom shade tabs (0.5, 1.0 and 1.5 mm porcelain thickness) were fabricated from selected Vita and Shofu porcelains. Four main factors were investigated, namely, the difference between the two types of porcelain used, the effect of light quality, the effect of porcelain thickness and the experience of the observer. The chi-square test for independence at a probability level of P <0.05 was used to analyse the results. The results indicated that in ideal light there was no difference between the two porcelains (P=0.58). The experienced observers proved better than the novice observers in ideal light conditions (P=0.003). Thickness was also significant in the overall results (P=0.0001), in that thicker samples gave more accurate results. The results indicate that in adverse light, there was an overall difference between the two porcelains (P=0.046), but no difference between the experienced and novice observers. The thickness made no difference to the experienced or the novice observer in adverse light. These results indicate that the most influential factor on shade taking was the light quality (P <0.0001); better results were obtained overall for the ideal light situation. In ideal light thicker samples gave better results (P=0.0001).

Participation in screening for colorectal cancer based on a faecal occult blood test is improved by endorsement by the primary care practitioner

OBJECTIVES

To investigate the influence of general practitioner (GP) endorsement on participation in screening for colorectal cancer based on a faecal occult blood test (FOBT).

SETTING

South Australian residents (n=2400), in 1999, aged >50 years.

METHODS

Random selection of three groups (GP1, GP2, GP3) from two general practices and of one group (ER) from the federal electoral roll; n=600 per group. Without previous communication or publicity, subjects were posted an offer of screening by immunochemical FOBT. The GP1 and ER groups were invited without indication that their GP was involved; GP2 received an invitation indicating support from the practice; and GP3 received an invitation on practice letterhead and signed by a practice partner. A reminder was posted at 6 weeks. Participation was defined as return of correctly completed FOBT sample cards within 12 weeks.

RESULTS

Participation rates were: GP1 192/600 (32.0%), GP2 228/600 (38.0%), and GP3 244/600 (40.7%); chi(2)=10.2, p=0.006. Both GP2 and GP3 differed significantly from GP1 (odds ratio (OR) 0.77, 95% confidence interval (95% CI) 0.60 to 0.98 and relative risk (RR)=0.69, 95% CI 0.54 to 0.87 respectively). ER (193/600 (32.2%)) and GP1 were not significantly different. Age but not sex was significantly associated with participation. Overall test positivity rate was 4.6%; five malignancies were found in the 918 who performed FOBT.

CONCLUSIONS

Association of a GP of recent contact with a screening offer in the form of a personalised letter of invitation achieves better participation than does the same letter from a centralised screening unit that does not mention the GP. Thus, GP enhanced participation is achievable without their actual involvement. Additional strategies are needed to further improve participation.

Predictive testing for BRCA1 and 2 mutations: a male contribution

BACKGROUND

Management strategies for women carrying BRCA1 and 2 mutations are becoming clearer and predictive testing for a known family mutation is commonly undertaken. Implications for men are not as clear and they participate less frequently.

PATIENTS AND METHODS

Twenty-six men from 10 extended families underwent predictive testing. Their motivation, reaction and outcome were studied. Subjects had appropriate pre- and post-test counselling. Informed consent was obtained before predictive testing for known deleterious mutations. DNA analysis followed standard procedures.

RESULTS

Eighteen tested positive and eight negative. Four had adverse psychological reactions and three reneged on their commitments to impart results. The spouse of another man had an adverse psychological reaction to the disclosure of his positive result. Two, already suffering from prostate cancer, were phenocopies and paternal lineage transmission was unexpectedly determined in another. Risk was removed from 33 offspring and confirmed for 56.

CONCLUSIONS

Complex themes associated with genetic testing are confirmed and the spectrum extended. Men appear to understand the importance of participating in this process. Methods of avoiding adverse reactions merit further study along with other aspects of the process.

Haematuria investigation based on a standard protocol: emphasis on the diagnosis of urological malignancy

OBJECTIVE

To audit the findings of a standard investigation protocol for haematuria with emphasis on the diagnosis of urological malignancy.

METHODS

Data were prospectively collected on haematuria referrals to one centre over a 5 year period. The standard protocol of investigation included flexible cystoscopy, urine cytology and culture, upper tract imaging, consisting of a renal tract ultrasound scan and a radiograph of kidney-ureter-bladder (KUB), proceeding to an intravenous urogram (IVU) in selected patients.

RESULTS

1046 patients were examined; 63% (n = 657) had microscopic haematuria and 37% (n = 389) had frank haematuria. No malignancy was found in patients with microscopic haematuria below 50 years of age. The findings of malignancy were not associated with either the sex or duration of symptoms in either groups. No association between the presence of symptoms and the finding of malignancy was observed in the microscopic haematuria group. Twenty five percent of patients presenting with frank haematuria had malignancy compared with 3.7% of patients with microscopic haematuria (p < 0.0001). The type of haematuria (frank or microscopic) was not predictive of grade or stage of malignancy. Of patients under 70 years with frank haematuria, males were more likely than females to have malignancy. This higher risk was not observed in older patients. Urine cytology had a poor predictive value for detection of malignancy with a sensitivity of only 25%.

CONCLUSION

Full investigation of all patients with frank haematuria and those with microscopic haematuria above 50 years of age, is well justified. Patients under 50 years with microscopic haematuria should have a lower priority for investigation.

Children's amplification needs--same or different from adults?

Hearing aid fitting strategies for children have largely developed separately from those for adults. There has, however, been little consideration of whether children's amplification requirements are different, except for the physical effects of differences in ear canal size. This paper summarizes the fitting strategies for children, and examines whether children require more (or less) gain for high-, medium- or low-level sounds, or a different frequency response, compared with adults with similar hearing loss. Research relating to the above questions is reviewed. The gain that children require for high-level sounds is not different than for adults because loudness discomfort levels are similar. The gain children prefer for medium-level sounds is the same, or only slightly more, than is preferred by adults. Children may require greater gain for low-level sounds because they do require higher signal levels to achieve the same level of speech understanding as adults do. There are, however, arguments why more gain for low-level sounds may not be desirable. The frequency response children prefer is the same as that preferred by adults. New methods for evaluating individual fittings are briefly discussed.

Bioterrorism: crime and opportunity

The unprecedented and tragic terrorist attacks in the United States (US) have sent shock waves through national administrations that have grown accustomed to fighting expenditure wars in the health area and had relegated public health vigilance and emergency preparedness to the back burner. It was obvious from the immediate reaction to the horrors and menaces of the autumn of 2001 that, insofar as health and safety is concerned, governments continued to measure success by the degree of quietness, remoteness and uneventful normality that is achieved by those entrusted with the responsibility to protect health. The paradox of health and safety is that you are winning when you hear nothing: any publicity is bound to be bad publicity.

Winter excess morbidity: is it a summer phenomenon?

BACKGROUND

It was hypothesized that winter excess mortality is a feature of ill health produced by exposure to ambient low temperatures, and will be matched by winter excess morbidity. The aim of the study was to test the prediction that winter excess morbidity would be observable and would show a social class gradient with greater excesses in less affluent groups, who are less able to heat their houses or whose lack of a car exposes them more frequently to outdoor cold exposure.

METHODS

The study was set in the Metropolitan Borough of Stockport and documented, from routine health services hospital admissions data, winter and summer differences in ACORN-specific, age- and sex-standardized hospital admission rates and ratios, for ischaemic heart disease, directly and indirectly standardized using the Stockport population as the standard.

RESULTS

The expected social class gradient in ischaemic heart disease admissions was more clearly observable in the summer than in the winter. Affluent groups showed winter excess morbidity, less affluent groups showed summer excess morbidity.

CONCLUSION

The data serendipitously indicate an alternative hypothesis - that winter excess morbidity is a feature of health benefits derived in the summer and differentially available to the more affluent, such as opportunities for outdoor leisure. This hypothesis deserves testing in a study designed for that purpose, although it is not entirely satisfactory as an explanation of existing data.

Effect of groove placement on the retention/resistance of resin-bonded retainers for maxillary and mandibular second molars

STATEMENT OF PROBLEM

Lack of retention/resistance form in the clinical preparation of teeth for resin-bonded retainers may lead to clinical failure.

PURPOSE

This study investigated the effect of proximal grooves on the retention/resistance of cast resin-bonded retainers for maxillary and mandibular second molar teeth.

MATERIAL AND METHODS

Two ivorine teeth (a maxillary and a mandibular second molar) were prepared for resin-bonded retainers. Twenty metal replicas of the prepared teeth were made (10 for each tooth morphotype). Resin-bonded retainers 0.5 mm thick were made for the 40 replicas and luted with Panavia EX cement. Forces for dislodgment of the retainers were applied along the long axes of the teeth. Forces recorded at the time of dislodgment were analyzed with 2-way analysis of variance and the post hoc Scheffé test.

RESULTS

Grooves resulted in substantial increases in debonding forces for maxillary molars (P<.001). The effect of grooves on mandibular second molars was not significant (P=.13).

CONCLUSION

Grooves placed in tooth preparations of maxillary molar teeth for resin-bonded retainers had a significant effect on retention/resistance. The effect of grooves on mandibular second molars was less pronounced.

Molecular identification and sequence analysis of Hillarin, a novel protein localized at the axon hillock

The monoclonal antibody Lan3-15 identifies a novel protein, Hillarin, that is localized to the axon hillock of leech neurons. Using this antibody we have identified a full length cDNA coding for leech Hillarin and determined its sequence. The gene encodes a 1274 residue protein with a predicted molecular mass of 144013 Da. Data base searches revealed that leech Hillarin has potential orthologues in fly and nematode and that these proteins share two novel protein domains. The W180 domain is characterized by five conserved tryptophans whereas the H domains share 21 invariant residues. In contrast to the arrangement in fly and nematode the cassette containing the W180 and H domains is repeated twice in leech Hillarin. This suggests that the leech Hillarin sequence originated from a duplication event of an ancestral protein with single cassette structure.

Maximizing effective audibility in hearing aid fitting

OBJECTIVE

This paper examines why more audibility is not always better than less audibility if hearing-impaired people are to best understand speech.

DESIGN

We used speech perception data from 14 normally hearing and 40 hearing-impaired people to quantify the contribution of audibility to speech intelligibility. The quantification revealed that the effectiveness of audibility decreased with hearing loss, and the decrement was greater at high frequencies than at lower frequencies. To apply the Speech Intelligibility Index (SII) model to predict speech intelligibility for hearing-impaired people, we modified the model to take account of effective audibility rather than physical audibility.

RESULTS

The modified SII model provided an adequate description of speech performance of people with a wide range of hearing threshold levels. We applied the model to the evaluation of two prescriptions for a sloping audiogram at prescribed levels and at equated loudness levels to demonstrate the necessity of considering loudness and effective audibility in prescribing amplification. Effective audibility is defined as audibility corrected for the effects of level distortion and hearing loss desensitization, and this paper proposes a method of estimating effective audibility from hearing threshold level at different frequencies.

CONCLUSIONS

The practical implication of considering effective audibility in prescribing hearing aids is that for a given listening level, less gain is provided at frequencies where the hearing is most impaired to allow more gain at frequencies where audibility is most useful. In developing the NAL-NL1 prescription for nonlinear hearing aids, we adopted the modified SII model together with a loudness model to derive optimal gain-frequency response characteristics that maximize predicted speech intelligibility for people with different degrees of hearing losses.

The Australian experience: global system for mobile communications wireless telephones and hearing aids

A digital, wireless telephone system, the Global System for Mobile Communications (GSM), was introduced in Australia in 1993. Studies were conducted at the National Acoustic Laboratories to determine how the use of GSM mobile telephones (i.e., wireless telephones) causes interference in hearing aids and how hearing aids could be made more immune to such interference. A measurement system was developed, and measurements are presented for a variety of standard and treated hearing aids. Effective treatments include the addition of shunt capacitors to the hearing aid circuit and shielding by applying a conductive coating to the hearing aid case. Some recently produced microphones also increase immunity. High immunity levels can be achieved in future hearing aids, sufficient to prevent interference from other people's use of a wireless telephone and that often permit use of digital mobile telephones by hearing aid users. Audiologists will have an increasing role in advising hearing aid wearers on the use of wireless telephones or other communications equipment.