Squirmers with swirl: a model for Volvox swimming.

Colonies of the green alga Volvox are spheres that swim through the beating of pairs of flagella on their surface somatic cells. The somatic cells themselves are mounted rigidly in a polymeric extracellular matrix, fixing the orientation of the flagella so that they beat approximately in a meridional plane, with axis of symmetry in the swimming direction, but with a roughly [Formula: see text] azimuthal offset which results in the eponymous rotation of the colonies about a body-fixed axis. Experiments on colonies of Volvox carteri held stationary on a micropipette show that the beating pattern takes the form of a symplectic metachronal wave (Brumley et al. Phys. Rev. Lett., vol. 109, 2012, 268102). Here we extend the Lighthill/Blake axisymmetric, Stokes-flow model of a free-swimming spherical squirmer (Lighthill Commun. Pure Appl. Maths, vol. 5, 1952, pp. 109-118; Blake J. Fluid Mech., vol. 46, 1971b, pp. 199-208) to include azimuthal swirl. The measured kinematics of the metachronal wave for 60 different colonies are used to calculate the coefficients in the eigenfunction expansions and hence predict the mean swimming speeds and rotation rates, proportional to the square of the beating amplitude, as functions of colony radius. As a test of the squirmer model, the results are compared with measurements (Drescher et al. Phys. Rev. Lett., vol. 102, 2009, 168101) of the mean swimming speeds and angular velocities of a different set of 220 colonies, also given as functions of colony radius. The predicted variation with radius is qualitatively correct, but the model underestimates both the mean swimming speed and the mean angular velocity unless the amplitude of the flagellar beat is taken to be larger than previously thought. The reasons for this discrepancy are discussed.

Intranasal sufentanil for cancer-associated breakthrough pain.

The objective of this study was to demonstrate the efficacy, safety and patient acceptability of the use of intranasal sufentanil for cancer-associated breakthrough pain. This was a prospective, open label, observational study of patients in three inpatient palliative care units in Australia. Patients on opioids with cancer-associated breakthrough pain and clinical evidence of opioid responsiveness to their breakthrough pain were given intranasal (IN) Sufentanil via a GO Medical patient controlled IN analgesia device. The main outcome measures were pain scores, need to revert to previous breakthrough opioid after 30 min, number of patients who chose to continue using IN sufentanil, and adverse effects. There were 64 episodes of use of IN sufentanil for breakthrough pain in 30 patients. There was a significant reduction in pain scores at 15 (P < 0.0001) and 30 min (P < 0.0001). In only 4/64 (6%) episodes of breakthrough pain did the participants choose to revert to their prestudy breakthrough medication. Twenty-three patients (77%) rated IN sufentanil as better than their prestudy breakthrough medication. The incidence of adverse effects was low and most were mild. Our study showed that IN sufentanil can provide relatively rapid onset, intense but relatively short lasting analgesia and in the palliative care setting it is an effective, practical, and safe option for breakthrough pain.

Community fluoridation status and caries experience in children.

OBJECTIVE: This study compares dental caries experience in fluoridated and nonfluoridated communities. METHODS: A dental health survey designed to collect data on caries experience and treatment needs for community-specific public health planning purposes was conducted in public elementary schools during the 1996-97 school year. Oral examinations of 17,256 children were completed, representing 93 percent of children residing in 62 East Tennessee communities. RESULTS: The analysis showed that water fluoridation was significantly related to caries experience in the primary (dfs) and permanent (DMFS) dentitions and to the proportion of caries-free children in the primary and permanent dentitions. When the data were adjusted for socioeconomic status, race, and age, caries levels were 21 percent lower in the primary dentition and 25 percent lower in the permanent dentition in fluoridated communities than in nonfluoridated communities. In addition, the proportion of children who were caries free was larger in fluoridated as compared with nonfluoridated communities by 19 percent in the primary dentition and 6 percent in the permanent dentition. CONCLUSION: Although the design of the study prevented the collection of individual fluoride and residency histories, findings suggest there was substantially lower caries experience in fluoridated communities than in nonfluoridated communities.

"Burst" ketamine for refractory cancer pain: an open-label audit of 39 patients.

The results of a novel approach to the use of ketamine in refractory cancer pain are reported. In this prospective, multicenter, unblinded, open-label audit, 39 patients (with a total of 43 pains) received a short duration (3 to 5 days) ketamine infusion. The initial dose of 100 mg/24 hr was escalated if required to 300 mg/24 hr and then to a maximum dose of 500 mg/24hr. The overall response rate was 29/43 (67%). Analysis of results according to pain mechanisms showed that 15/17 somatic and 14/23 neuropathic pains responded. In 5 patients who appeared to respond, it is possible that another concurrent intervention may have contributed in whole or part for the pain relief observed. After cessation of ketamine, 24/29 maintained good pain control, with a maximum documented duration of eight weeks. However, 5 of the initial 29 responders experienced a recurrence of pain within 24 hours, and ketamine was recommenced. Of these, 2 underwent another intervention for pain control while 3 continued on ketamine until their deaths between two and four weeks later. Twelve patients reported adverse psychomimetic effects, with the incidence rising with increasing dose. Four of these were non-responders and the ketamine was stopped. Eight were responders, and in 3 the adverse effects were rendered acceptable with dose reduction; the other 5 rejected a dose reduction. The results reported suggest the need for further investigation of the place of ketamine in cancer pain management.

Successful implementation of community water fluoridation via the community diagnosis process.

OBJECTIVES: This paper describes the community diagnosis process and how it was used to implement community water fluoridation in Tennessee. METHODS: Public health dental staff developed a survey instrument to collect community-specific data on the oral health status of schoolchildren. Key survey findings were presented to county health councils who were determining and prioritizing the health needs of their communities. RESULTS: Community-specific data showed higher caries levels in children without access to an optimally fluoridated community water supply. Presentation of local survey findings to county health councils resulted in fluoridation being a high-priority health issue in several counties. With health council support, opposition to fluoridation by utility district officials was overcome when decision makers were challenged with local survey findings. The community diagnosis process resulted in the successful fluoridation of six community water systems serving a total of 33,000 residents. CONCLUSIONS: The community diagnosis approach was successful in implementing community water fluoridation in geographic areas historically opposed to this public health measure. The success of these fluoridation initiatives was attributed to: (1) current, community-specific assessments of children's oral health; (2) identification of communities with disparate oral health needs, problems, and resources; and (3) effective presentation of community-specific oral health survey data to community leaders, stakeholders, and decision makers.

Community socioeconomic status and children's dental health.

BACKGROUND: Although a substantial decline in dental caries has occurred among U.S. children, not everyone has benefited equally. The first-ever surgeon general's report on oral health in America indicates that the burden of oral diseases is found in poor Americans. This study investigates the relationship between community socioeconomic status, or SES, and dental health of children. METHODS: An oral health survey of 17,256 children, representing 93 percent of children residing in 62 Tennessee communities, was conducted in public elementary schools during the 1996-1997 school year. Portable dental equipment was used for examinations, and data from each examination were entered directly into a laptop computer. The authors performed analyses of covariance to examine the relationship between community SES (low/medium/high) and dental health, controlling for community fluoridation. RESULTS: Community SES was significantly related to caries experience in the primary teeth, the proportion of untreated caries in the primary and permanent teeth, dental treatment needs, dental sealants and incisor trauma. Overall, dental health was significantly worse for low-SES communities than for medium- and high-SES communities. CONCLUSION: The authors conclude that all specific dental indexes used to measure children's dental health in this study, with the exceptions of caries experience in the permanent teeth and sealant presence, were inversely related to the communities' SES. The percentage of children with dental sealants was directly related to the community's SES. PRACTICE IMPLICATIONS: Further improvements in oral health will necessitate that community-based preventive programs and access to quality dental care be made available to children who are identified as being at highest risk of experiencing oral disease.

Death certification by doctors in non-metropolitan Victoria.

OBJECTIVE: To examine the completeness and accuracy of death certification by general practitioners, specialists and resident medical officers (RMOs) in non-metropolitan Victoria. DESIGN: An examination of the death certificates written by a representative sample of community and hospital doctors and comparison with the clinical history. SETTING: The Ballarat statistical district. RESULTS: Eighteen percent of the death certificates at initial assessment, were unsatisfactory (the percentage for those written by RMOs were significantly higher). After review of the clinical record, 27% of certificates were found to inaccurately represent the cause of death, (again the percentage for RMOs was higher) Eighteen percent of certificates required a change of code. CONCLUSION: Monitoring the health of the public relies in part on information gained from death certificates. It is thus of concern that such a high percentage of death certificates are inaccurate to the extent that they are incorrectly coded. Consideration should be given to new educational initiatives and to the promotion of the existing toll free telephone advice service to doctors.