Studying the aging of Laponite suspensions using extensional rheology.

The effect of aging on the break-up dynamics of Laponite suspensions was studied in an extensional geometry. It was found that samples of increased age undergo stronger necking at the midpoint. The thinning of samples, driven purely by motion of the plates, was compared with standard shear rheology to understand how the dynamics are related to the sample properties. The Laponite suspensions exhibit a growing stress overshoot with monotonically decreasing yield strain as they age. However, it is shown that the thinning curves in extension are only a good indicator of the sample's static yield stress, being insensitive to its yield strain. These measurements suggest that following an initial linear visco-elastic regime, samples accumulate significant plastic deformations prior to the complete yielding of the sample. The implications of this for the importance of assessing changes to the ductile-brittle nature of samples are also discussed.

Exploring the career experiences of Australian oral health therapists in different practice settings.

OBJECTIVE: To examine the reasons behind Australian oral health therapists (OHTs) pursuing different career pathways. BASIC RESEARCH DESIGN: Qualitative study with thematic analysis within an inductive realist approach. METHODS: A convenience sample of OHTs completed semi-structured interviews on Zoom. Participants discussed their experiences working as OHTs and commented on the future directions for the profession in Australia. RESULTS: Participants (n=21) chose clinical practice due to excellent job availability, good remuneration, and the opportunity to use their knowledge. Many indicated that non-clinical careers helped relieve the stress and fatigue of clinical practice. Some also enjoyed the variety that non-clinical jobs brought and viewed them as a means to advance their career. Participants indicated the need to better communicate the professional role and scope of practice of the OHT profession to other healthcare providers such as dentists and the general public. Some viewed independent practice as a way to serve the community. Others did not feel that they had the knowledge and skills to do so. CONCLUSION: These findings may help individual OHTs in career decision-making. OHTs could assume a major role in addressing oral healthcare inequality in Australia.

Slip in adhesion tests of a Kaolin clay.

Adhesion tests were performed on concentrated suspensions of Kaolin clay. At low concentrations samples formed conical deposits on both the top and bottom plates with the central region narrowing to a filament before undergoing breakup. In contrast high concentration samples deformed as a cylinder before apparently fracturing into two pieces. As the concentration of the samples was increased the samples underwent quite different forms of slip which it is shown can be deduced from their respective force distance curves. The type of slip behaviour for a given concentration of clay could be modified with changes to surface roughness, the initial compressive load prior to an experiment and with the separation velocity of the plates. The different slip characteristics appear to arise from the concentration dependent way in which particles interact with the rough surface topography.

Attitudes and barriers to providing dietary advice: perceptions of dental hygienists and oral health therapists.

OBJECTIVES: Effective dietary counselling in a dental setting can significantly reduce the risk of oral disease. However, studies suggest that dental professionals are not instigating dietary advice on a regular basis, and there is a lack of current information of the barriers experienced that limit the delivery of dietary advice. The aim of this study was to investigate the current attitudes and practice behaviours of dental hygienists and oral health therapists in NSW, Australia, regarding dietary advice, and identify the barriers that limit its delivery. METHODS: A convenience sample of dental hygienists and oral health therapists were surveyed using a mail-out questionnaire. The questionnaire investigated the demographic data of participants, the attitudes and practice behaviours of participants, the perceived barriers and current dietary resources accessed by participants. RESULTS: Of 987 dental hygienists and oral health therapists, 426 participants responded. The study results suggest that many dental hygienists and oral health therapists have positive beliefs regarding the importance of dietary counselling. However, there are a multitude of barriers preventing the delivery of dietary advice; these include time, patient compliance, patient knowledge of nutrition topics, personal counselling skills and practitioners' knowledge of nutrition. CONCLUSION: Whilst dental hygienists and oral health therapists recognize the importance of diet and have positive attitudes towards providing dietary advice to patients, this study identified many barriers preventing implementation in practice. This information may be used to develop targeted strategies aimed at overcoming these barriers and improving behaviours.

Introducing loupes to clinical practice: dental hygienists experiences and opinions.

OBJECTIVES: Recent literature has identified a number of potential advantages in wearing loupes for dental hygienists, including improved quality of care and ergonomics. The aim of the study was to determine dental hygienists' opinions about wearing loupes. METHODS: A short online survey was distributed to all dental hygienists who had recently participated in a study investigating the efficacy of loupes on musculoskeletal disorders; all had only worn loupes for a 6-month period, and prior to the study had not worn loupes. All of those invited completed the survey (n = 12), achieving a 100% response rate. RESULTS: The majority of respondents noted that the loupes were adaptable to wear; however, only one-quarter of hygienists surveyed were wearing them often following the study. Respondents identified that the biggest advantage to loupes was calculus removal (91.7%), and most indicated that they felt the quality of their work increased when wearing loupes (75%). The biggest disadvantage to wearing loupes was the adjustment period (50%), with limited depth of vision, headache, vertigo and infection control noted by at least one-third of respondents. CONCLUSIONS: This study revealed that hygienists identify both benefits and limitations to wearing loupes, and therefore, ongoing support may be required for hygienists adopting their use in clinical practice.

The provision of dietary advice by dental practitioners: a review of the literature.

PURPOSE: The aim of this literature review was to examine the dietary advice practices of dentists and dental hygienists and to identify factors influencing whether practitioners provide dietary advice to patients. METHODS: A systematic search was carried out of the electronic databases CINHAL Plus, Medline via OVID and the Cochrane Library, using the search terms 'Diet', 'Nutrition', 'Dental hygienists' and 'Dentists'. Articles included in the review were all empirical studies and existing literature reviews examining the provision of dietary advice practices of dentists, dental hygienists and dental students. Only articles published after 1993 were included in the review to better reflect the current practices of dental practitioners. RESULTS: The literature revealed that dietary advice is rarely provided by dental practitioners, and that when dietary advice is provided it is often limited. The literature also established that provision of dietary advice is influenced by a number of factors, including financial considerations, time constraints and the dietary education of dental practitioners. CONCLUSIONS: Further research is required to strengthen the findings from the review and to investigate dietary advice specific to the prevention of dental erosion. Additional research is also required to examine dental curricula and assess the dietary advice practices of dental students.

The effect of wearing loupes on upper extremity musculoskeletal disorders among dental hygienists.

OBJECTIVES: It is well established that musculoskeletal disorders (MSD) are a significant occupational health issue for dentists and hygienists. Despite this, there has been little advancement in the application of ergonomic principles in the dental profession. While the use of loupes is often promoted as an ergonomic solution, there is little published research to robustly support this claim. The aim of the present study was to investigate the effect of the use of loupes on upper extremity MSD among dental hygienists. METHODS: The study was conducted using an exploratory pretest and post-test design, comparing musculoskeletal measures in practising dental hygienists wearing loupes with final-year dental hygiene students who did not wear loupes. Pre- and post-test measures included valid self-reported and objective outcome measures and were measured at baseline and 6 months following the intervention. Statistical analysis was conducted as a series of mixed anovas with time and treatment as the independent variables. RESULTS: The analysis revealed a significant interaction between time and treatment for the Disabilities of the Shoulder, Arm and Hand (DASH) scores (P < 0.04), indicating an improvement in symptoms for the treatment group but a reversed trend for the controls. There was also a significant mean increase in scapular position measures; however, this finding was evident in both groups, indicating that these were not a result of the intervention. CONCLUSIONS: Overall, this study suggests that wearing loupes appears to have both positive and negative effects on upper extremity MSD among dental hygienists. Ongoing research is required to determine the long-term effects of loupes wear, over an extended period of time.

Predictors of work-related musculoskeletal disorders among dental hygienists.

OBJECTIVES: Work-related musculoskeletal disorders (MSD) have been recognized as a considerable problem for the dental hygiene profession, with the majority of professionals reporting musculoskeletal pain. The aim of this study was to investigate which risk factors may help predict MSD among Australian dental hygienists. METHODS: A modified version of the Standardised Nordic questionnaire was distributed to registered hygienists throughout Australia. RESULTS: Logistic regression analysis revealed a variety of work-related and psychosocial factors that correlate with reported MSD, including scaling tasks, type of practice and work interference in home life. Statistical predictors for non-reporting of MSD included wearing loupes, ergonomics education and wage satisfaction. Concerning is the impact on the profession, with an association between MSD and hygienists considering reducing working hours or even alternate careers. CONCLUSIONS: In general, it appears as though the causes of MSD among dental hygienists may be multifactorial, as may be the solutions to this problem. Further research is required to objectively examine whether controllable variables can be implemented as preventive strategies or interventions for MSD.

Saliva as a chemical cue in the development of social behavior.

Throughout development, Mongolian gerbils engage in conspicuous naso-oral investigations of their social partners' mouth areas. The behavioral contribution of saliva-related stimuli in regulating oral-directed responses was studied during several important phases of the gerbil's social life. Weanlings were preferentially attracted to their mother's saliva, subadults at puberty preferred saliva of littermates to that of nonlittermates, and sexually experienced males preferred the saliva of estrous females to that of nonestrous females. The use of saliva as a discriminative cue during various developmental periods suggests that oral chemostimuli have a perennial role in regulating social interchanges.

Prevalence and correlates of musculoskeletal disorders among Australian dental hygiene students.

INTRODUCTION: Although musculoskeletal disorders (MSD) have been identified as a significant occupational health issue for dental hygienists, few studies have explored this problem among the dental hygiene student population. AIM: The aim of this study was to investigate the prevalence and correlates of MSD among a selection of undergraduate dental hygiene students in Australia. METHODOLOGY: A self-reporting questionnaire was distributed to dental hygiene students at an Australian university during 2008, from which a response rate of approximately 72% was achieved. RESULTS: Musculoskeletal disorders were most commonly reported by students at the neck (64.29%), lower back (57.94%) and shoulder (48.41%) regions. Logistic regression indicated various correlations with MSD. Students who did not undertake regular exercise every week experienced an increased risk of lower back pain [Odds Ratio (OR): 4.88, 95% Confidence Interval (CI): 1.75-14.9]. Students undertaking 16-20 h of desk-based study per week were much more likely to report neck pain (OR: 19.7, 95% CI: 1.34-378.94). Working 6-10 h on a computer each week was a risk factor for shoulder (OR: 7.03, 95% CI: 1.42-39.49) and upper back pain (OR: 5.29, 95% CI: 1.21-25.56). CONCLUSIONS: Overall, this study suggests that MSD are a reasonably common problem for dental hygiene students in Australia. As such, further studies are required to establish epidemiological patterns of MSD, and our profession will need to carefully consider preventive strategies to help minimize the impact of this important occupational health issue on the next generation of dental hygienists.

Annexinopathies.

Annexins comprise a conserved family of proteins characterised by their ability to bind and order charged phospholipids in membranes, often in response to elevated intracellular calcium. The family members (there are at least 12 in humans) have become specialised over evolutionary time and are involved in a diverse range of cellular functions both inside the cell and extracellularly Although a mutation in an annexin has never been categorically proven to be the cause of a disease state, they have been implicated in pathologies as diverse as autoimmunity, infection, heart disease, diabetes and cancer. 'Annexinopathies' were first described by Jacob H. Rand to describe the pathological sequelae in two disease states, the overexpression of annexin 2 in a patients with a haemorrhagic form of acute promyelocytic leukaemia, and the under-expression of annexin 5 on placental trophoblasts in the antiphospholipid syndrome. In this chapter we will outline some of the more recent observations in regard to these conditions, and describe the involvement of annexins in some other major causes of human morbidity.

Epigenetic variation in OPRM1 gene in opioid-exposed mother-infant dyads.

Neonatal abstinence syndrome (NAS) due to in-utero opioid exposure has significant variability of severity. Preliminary studies have suggested that epigenetic variation within the µ-opioid receptor (OPRM1) gene impacts NAS. We aimed to determine if DNA methylation in OPRM1 within opioid-exposed mother-infant dyads is associated with differences in NAS severity in an independent cohort. Full-term opioid-exposed newborns and their mothers (N = 68 pairs) were studied. A DNA sample was obtained and then assessed for level of DNA methylation at 20 CpG sites within the OPRM1 promoter region by next-generation sequencing. Infants were monitored for NAS and treated with replacement opioids according to institutional protocol. The association between DNA methylation level at each CpG site with NAS outcome measures was evaluated using linear and logistic regression models. Higher methylation levels within the infants at the -18 (11.4% vs 4.4%, P = .0001), -14 (46.1% vs 24.0%, P = .002) and +23 (26.3% vs 12.9%, P = .008) CpG sites were associated with higher rates of infant pharmacologic treatment. Higher levels of methylation within the mothers at the -169 (R = 0.43, P = .008), -152 (R = 0.40, P = .002) and +84 (R = 0.44, P = .006) sites were associated point-wise with longer infant length of stay. Maternal associations remained significant point-wise for -169 (ß = 0.07, P = .007) and on an experiment-wise level for +84 (ß = -0.10, P = .003) using regression models. These results suggest an association of higher levels of OPRM1 methylation at specific CpG sites and increased NAS severity, replicating prior findings. These findings have important implications for personalized treatment regimens for infants at high risk for severe NAS.

Apneic preterms and methylxanthines: arousal deficits, sleep fragmentation and suppressed spontaneous movements.

OBJECTIVE: To determine if apneic preterm infants currently treated with methylxanthines develop evidence of sleep deprivation from cumulative arousal and motor activational effects. STUDY DESIGN: Sleep, wake, arousal and actigraphic movements were monitored in extubated clinically stable premature infants (N=37). Neonates were free of other medications for >72 h and were grouped based on methylxanthine exposure: >5 days with caffeine (n=14), >5 days theophylline (n=13) or no prior exposure (n=10). RESULT: Duration of methylxanthine treatment predicted increased arousals, wakefulness and actigraphic movements, and decreased active sleep. Recording from 1200 to 0500 hours, methylxanthine-treated groups showed reductions in all arousal parameters: waking state, number of wake epochs, brief arousals and composite arousal index, and shorter fast-burst, sleep-related motility than untreated controls. CONCLUSION: In apneic preterms, chronic methylxanthine treatment appears to produce sleep deprivation secondary to the stimulatory action of methylxanthines on arousal and motor systems.

Dietary analysis and nutritional counselling for caries prevention in dental practise: a pilot study.

BACKGROUND: Dental practitioners agree that dietary counselling is essential for caries prevention; however, they provide advice infrequently due to a lack of confidence and competence. This study aimed to improve practises through an online training module exploring the use of a brief counselling method, and a diet assessment of caries risk form. METHODS: Dental practitioners (N = 41) completed a survey on current practises and confidence in providing dietary advice, followed by an online training module. Ten practitioners were involved in recruiting patients, eliciting a diet assessment of caries risk, and using brief counselling techniques with these patients. Patients were followed up at 6 months for a risk assessment review. Dental practitioners also completed a 6-month follow-up survey exploring changes in confidence and perceived barriers. RESULTS: Dental hygienists' confidence improved significantly following the intervention (P < 0.025). Patients showed a significant reduction in high-risk behaviour pertaining to quantity and timing of sugar intake, and significant trends in improvement of behaviours relating to frequency, exposure time and drinking style (P < 0.05). CONCLUSIONS: It appears that a simple online learning module can improve hygienists' confidence in dietary advice provision, and have a positive impact on patient behaviour change, within a relatively short time-frame.

An IgM class anti-neutrophil cytoplasm antibody inhibits neutrophil adhesion and apoptosis via a Syk dependent signaling cascade.

Anti-neutrophil cytoplasm antibodies (ANCA) with specificity for myeloperoxidase (MPO) are implicated as pathogenic agents in pauci-immune systemic vasculitis. In agreement with previously published observations we show that human neutrophils incubated with an MPO-specific IgG class monoclonal antibody are pro-adhesive and undergo apoptosis more readily in vitro. If apoptotic neutrophils are incubated with this antibody they are readily phagocytosed by macrophages and we show that 'blocking' antibodies to FcgammaRIIa (CD32) on the macrophage inhibit this process. We also examined the effect of E3MPO, a monoclonal anti-MPO antibody derived from a patient with severe systemic vasculitis. E3MPO is closely related to the cold-agglutinins and bears an epitope recognized by the monoclonal antibody 9G4 which is expressed on antibodies derived from the V4-34 germ-line immunoglobulin gene. In previous studies, we have shown that anti-MPO antibodies present in sera from patients with vasculitis often bear this epitope. In contrast to the IgG-class antibody, incubation of neutrophils with E3MPO inhibited neutrophil adhesion and apoptosis. Apoptotic neutrophils however were phagocytosed more readily by macrophages in the presence of E3MPO. The effects of E3MPO on neutrophil adhesion and apoptosis were inhibited by piceatannol, an inhibitor of Syk-family kinases; activation of which is associated with cross-linking of the beta(2)-integrins. We show that surface-expressed MPO co-localizes with these beta(2)-integrins and suggest that cross-linking of beta(2)-integrin-bound MPO by polyvalent antibodies could result in signaling through these receptors. We have demonstrated that there are different consequences of Fcgamma-receptor-dependent and -independent signaling mediated by ANCA.

Methadone versus morphine for treatment of neonatal abstinence syndrome: a prospective randomized clinical trial.

OBJECTIVE: Compare duration of treatment of neonatal abstinence syndrome between methadone and morphine. STUDY DESIGN: A prospective, double-masked, randomized trial at a single site. Randomization of methadone or morphine was stratified for maternal treatment with methadone or buprenorphine. Inclusion criteria were (i) maternal treatment with prescribed methadone or buprenorphine, (ii) withdrawal treatment criteria, (iii) adjusted gestational age ⩾35(0/7) weeks and (iv) medically stable. Primary outcome was length of opioid treatment. RESULT: From January 2011 through October 2012, 78 infants were eligible for the study: 41 methadone-exposed and 37 buprenorphine-exposed. Consent was obtained from 31 mothers, 13/41 (32%) methadone-treated and 18/37 (49%) buprenorphine-treated. Length of opioid treatment was significantly shorter for methadone than morphine treatment, median 14 versus 21 days (P=0.008). CONCLUSION: Methadone had a shorter length of neonatal withdrawal treatment compared with morphine. Owing to the smaller sample size and single site, a larger randomized study is needed.

Isolation and structural identification of 1,25-dihydroxyvitamin D3 produced by cultured alveolar macrophages in sarcoidosis.

Hypercalcemia and hypercalciuria in sarcoidosis are thought to result from the endogenous overproduction of an active vitamin D metabolite. We employed primary cultures of pulmonary alveolar macrophages from two patients with biopsy-proven pulmonary sarcoidosis and a recent or current clinical abnormality in calcium metabolism to synthesize in vitro a 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3]-like metabolite from 25-hydroxyvitamin D3 (25OHD3). The macrophage metabolite cochromatographed with [3H]1,25-(OH)2D3 on normal phase and reverse phase high performance liquid chromatography and was bound with high affinity by the chick intestinal receptor for 1,25-(OH)2D3. On UV spectroscopy, the metabolite possessed the carbon-5,7,10 (19) cis-triene chromophore characteristic of a vitamin D sterol. Electron impact mass spectrometry of trimethylsilyl ether derivatives of the metabolite revealed a mass fragmentation pattern similar to that of the trimethylsilyl ether derivative of authentic 1,25-(OH)2D3. The incubation of cultured macrophages from two patients with idiopathic pulmonary fibrosis and two with scleroderma with [3H]25OHD3 did not result in production of a metabolite with the chromatographic identity of 1,25-(OH)2D3. These data indicate that the metabolite of 25OHD3 synthesized by sarcoid macrophages in vitro is 1,25-(OH)2D3 and that the macrophage is a synthetic source of the sterol metabolite in sarcoidosis.

Chemoimmunotherapy of cancer. 3. Analytical measurement of chemical half-lives of monofunctional alkylators.

The objective of this study is the measurement of the rates of hydrolysis of a series of chloroethyl sulfide derivatives, under stimulated physiological conditions. Interferences encountered with the conventional spectrophotometric method prompted the use of a rapid-response, chloride selective electrode. This probe was readily capable of monitoring the hydrolytic rate, which is identical with the rate of chloride ion formation. Since the desired subsecond half-lives were not achieved by any of the compounds, factors influencing the rates were investigated. The results suggest that the rate-controlling cyclization step may be inhibited, due to coordination of undissociated protonic functional groups on the aromatic portions of the structures with the lone-pair electrons on sulfur.

In vivo quantification of human pulmonary beta-adrenoceptor density using PET: comparison with in vitro radioligand binding.

UNLABELLED: A new method has recently been developed to quantify pulmonary beta-adrenergic receptors in vivo using PET. This study used in vitro radioligand binding assay (RLBA) as the gold standard to validate in vivo PET measurements. METHODS: Five male patients with lung cancer aged 57 yr (range 42-67 yr) were studied. PET scanning was performed the day before thoracotomy to determine regional pulmonary beta-receptor density. RLBA was carried out on cell membranes prepared from specimens of lung tissue obtained at the thoracotomy to measure beta-receptor density in vitro. In both cases, the hydrophilic nonselective beta-antagonist radioligand (S)-CGP-12177 was used. For PET studies, this was labeled with 11C and for RLBA with 3H. RESULTS: In the PET study, beta-receptor density (Bmax) was 9.43 +/- 1.32 pmole g-1 tissue. In the RLBA study, Bmax was 99.0 +/- 15.5 fmole mg-1 protein, equivalent to 9.90 +/- 1.55 pmole mg-1 tissue. These values are in good agreement with previously reported in vitro measurements on human lung membranes using 125I-iodocyanopindolol. A correlation was found between beta-adrenergic density obtained using PET and beta-adrenergic density obtained using RLBA (r = 0.92; p < 0.05). CONCLUSION: The results support the use of PET as a new method for imaging and the way for studies of physiological and pharmacological regulation of beta-adrenergic receptors through noninvasive serial measurements.

Bedsharing, temperament, and sleep disturbance in early childhood.

STUDY OBJECTIVE: Temperament was explored as a factor in both night-waking and bedsharing in preschool-aged children. DESIGN: Bedsharers and solitary sleepers were categorized based on the frequency of current bedsharing. MANOVA was used to examine associations among temperament and sleep measures. SETTING: Two preschools affiliated with a rural university in the Northeast United States. Participants. 67 children between 2.4-5.6 years of age from two University-affiliated preschools were studied. INTERVENTION: Child temperament was rated by parents and teachers using the Carey Temperament Scale and compared to night-waking, current sleep habits, and the circumstances in which bedsharing occurred MEASUREMENTS AND RESULTS: Parents and preschool teachers completed the Carey Temperament Scale for 3-7 year olds. Parents also scored the Sleep Habits Inventory and the Sleeping Arrangements Inventory, which provided a current and retrospective history of the child's sleep location and sleep patterns. Parents' ratings showed that bedsharers have less regular bedtimes; difficulty with sleep onset; more night-waking; and seek out the parents following awakening during the night. Temperamentally, bedsharers were found to be more intense and exhibit less adaptability and rhythmicity. However, teachers' temperament ratings did not predict bedsharing and were not concordant with parental ratings. CONCLUSIONS: These findings suggest that bedsharing at preschool age is a complex phenomenon related to parents' ratings of child temperament, sleep habits, and disturbances such as night waking. Implications for the clinical assessment of sleep disorders are discussed.