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Ensemble of single quadrupolar nuclei in rotating solids: sidebands in NMR spectrum.

A novel way is proposed to describe the evolution of nuclear magnetic polarization and the induced NMR spectrum. In this method, the effect of a high-intensity external static magnetic field and the effects of proper Hamiltonian left over interaction components, which commute with the first, are taken into account simultaneously and equivalently. The method suits any concrete NMR problem. This brings forth the really existing details in the registered spectra, evoked by Hamiltonian secular terms, which may be otherwise smoothed due to approximate treatment of the effects of the secular terms. Complete analytical expressions are obtained describing the NMR spectra including the rotational sideband sets of single quadrupolar nuclei in rotating solids.

Journal Article↗

Rural hospitals and volume standards in surgery.

BACKGROUND: We sought to understand the potential impact of volume-based referral policy on rural hospitals by estimating the proportion of low-volume operations occurring in rural versus urban hospitals. METHODS: We performed an observational study using the national Medicare population who underwent one of 12 high-risk operations from 1999-2001. Low-volume hospitals were considered those in the 2 lowest quintiles for each procedure. Hospitals were assigned to 1 of 3 types of geographic locations on the basis of Rural-Urban Commuting Area Codes: urban areas, rural large towns, or rural small towns. For each of the 12 operations, we estimated the proportion of patients undergoing operation in low-volume hospitals within each type of geographic area. RESULTS: For all 12 operations, the majority of surgical cases were performed in urban areas (ranging from a low of 76% for colectomy to 96% for heart valve operations). Evaluation of only operations performed in low-volume hospitals showed that the majority of surgical cases were still located in urban areas (varying from a low of 55% for colectomy to a high of 94% for heart valve operations). Operations with a stronger effect of volume on outcome (eg, pancreatic and esophageal resection) were more concentrated in urban areas, compared with operations with a weaker effect (eg, colectomy). CONCLUSIONS: Most low-volume operations take place in urban hospitals. Efforts to direct patients to high-volume hospitals can exempt rural hospitals and still realize most of the potential benefits.

Aged↗

Simulation and data reconstruction for NDT phased array techniques.

Phased array techniques are now widely employed for industrial NDT applications in various contexts. Indeed, phased array present a great adaptability to the inspection configuration and the application of suitable delay laws allows to optimize the detection and characterization performances by taking into account the component geometry, the material characteristics, and the aim of the inspection. In addition, the amount of potential information issued from the inspection is in general greatly enhanced. It is the case when the employed method involve sequences of shots (sectorial scanning, multiple depth focusing etc) or when signals received on the different channels are stored. At last, application of electronic commutation make possible higher acquisition rates. Accompanying these advantages, it is clear that an optimal use of such techniques require the application of simulation-based algorithms at the different stages of the inspection process: When designing the probe by optimizing number and characteristics of element; When conceiving the inspection method by selecting suitable sequences of shots, computing optimized delay laws and evaluating the performances of the control in terms of zone coverage or flaw detection capabilities; When analysing the results by applying simulation-helped visualization and data reconstruction algorithms. For many years the CEA (French Atomic Energy Commission) has been being greatly involved in the development of such phased arrays simulation-based tools. In this paper, we will present recent advances of this activity and show different examples of application carried out on complex situations.

Computer Simulation↗

Translating overactive bladder questionnaires in 14 languages.

OBJECTIVES: Overactive bladder (OAB) affects millions of people worldwide. Identifying patients and measuring OAB's impact on symptom severity and patients' health-related quality-of-life is necessary to ensure proper treatment and facilitate communication among patients, clinicians, and caregivers. To accomplish this, the Overactive Bladder questionnaire (OAB-q) and its subsets instruments, the OAB-q Short-Form and the OAB-V8, were developed in U.S. English. To measure the impact of OAB cross-culturally, we performed the linguistic validation of these instruments in Danish, English (Canada), French (Canada and France), Italian (Switzerland), German (Switzerland), Korean, Norwegian, Polish, Portuguese (Brazil), Romanian, Swedish, and Turkish. The linguistic validation was conducted following a rigorous method to ensure conceptual equivalence between the original and its translations. METHODS: In each country, a specialist monitored the process, which included six steps: (1) two forward translations; (2) comparison and reconciliation of the translations; (3) back-translation; (4) comparison of the source and back-translation; (5) review by one urologist or gynecologist; and (6) a comprehension test using patients. RESULTS: The translation of symptom-related adjectives such as "uncomfortable," "sudden," "accidental," "uncontrollable" proved challenging. The subtle differences in the meaning of symptomatic items increased the difficulties to find equivalents. Issues regarding the appropriateness of certain concepts and idiomatic terms emerged during cognitive debriefing. The terms "urge," "desire," "urination," "commute," "drowsy," and "escape routes" were not retained literally and were replaced by colloquial expressions. CONCLUSIONS: The 14 versions of the OAB-q, OAB-q Short-Form, and OAB-V8 were successfully validated linguistically to facilitate data collection cross-culturally and the international comparison of symptom bother and health-related quality of life in patients with OAB.

Language↗

A longitudinal study of the influence of smoking on the onset of obesity at a telecommunications company in Japan.

OBJECTIVE: To clarify the influence of smoking on the onset of obesity. METHODS.: A 5-year follow-up study was carried out on 25,312 workers at the time of their annual health check-up from 1992 to 1997. Pooled logistic regression analyses by sex were performed with age, working conditions and lifestyle as independent variables and the onset of obesity (BMI> or =26.4) as a dependent variable adjusted for the time period. RESULTS: In males, the following factors increased the risk of the onset of obesity: smoking equal to or more than 20 cigarettes per day (versus nonsmokers), monthly holidays fewer than 5 days (versus >7 days), one-way commute more than 90 min (versus< or =60 min), sleeping less than 5 h, moderate and high preference for fatty meals (versus little preference). In females, 30-39 years, 40-49 years and 50-59 years (versus 20-29 years), being an ex-smoker, smoking fewer than 20 cigarettes per day, smoking equal to or more than 20 cigarettes per day (versus nonsmokers, respectively) and high preference for fatty meals (versus little preference) increased the risk of the onset of obesity. CONCLUSION: This study revealed that smoking independently increases the risk of the onset of obesity regardless of sex.

Adult↗

Sleep debt, sleepiness and accidents among males in the general population and male professional drivers.

Men from the general population and male professional lorry and bus drivers were surveyed with regard to sleep habits and motor vehicle and other types of accidents. A random sample of 4000 men in the general population of Dalarna County in mid-Sweden were mailed a questionnaire and served as referents. A total of 1389 male professional lorry and bus drivers from this county responded to the same questionnaire. A total of 161 of the drivers also underwent a sleep study in their homes. The proportion of total accidents was higher among the professional drivers as compared with the males in the population, P=0.03. Reports on traffic accidents were the same in both groups, but the professional drivers reported more accidents at leisure compared with referents, P<0.0001. Accidents of any kind, traffic accidents included, among those affected by both snoring and apneas, were not reported more in either of the groups. At the sleep study, 17% of those examined received the diagnosis of obstructive sleep-apnea syndrome (OSAS). The professional drivers reported proportionally more sleep debt than the referents, P<0.001. Among referents, traffic accidents at leisure, traffic accidents while commuting and accidents at work increased in proportion to sleep debt (P<0.001, 0.006 and 0.002, respectively). The finding that self-perceived sleep debt may have an adverse effect on males in the general population and male professional drivers concerning accident likelihood should have an impact on prevention. These results stress the need to educate the general population on the importance of complying with our biological need of sleep.

Accidents, Traffic↗

Increased police enforcement: effects on speed.

Results of a field experiment in which a 35-km long stretch of road was subjected to an increase in police enforcement--mostly as stationary speed controls--are presented. A group of police officers was invited to plan and perform the enforcement based on their own experience and ideas. The level of enforcement reached a daily average of nine hours throughout an enforcement period of six weeks. Speed measurements were done in 60 and 80 km/h speed-limit zones before, during and after enforcement withdrawal, and were compared to another stretch of road. Average speeds were reduced by 0.9-4.8 km/h in both speed-limit zones and for all times of day. For some time intervals, the average speed and the percentage of speeding drivers were reduced for several weeks of the after-period, demonstrating a time-halo effect of eight weeks at most. The percentage of speeding drivers was reduced in both speed-limit zones for all hours of the day except the morning rush hours 6.00-9.00 A.M. It is suggested that commuting drivers in the morning rush hours are most resistant to speed reduction. These results were statistically significant at alpha = 0.01.

Accidents, Traffic↗

Driver fatigue in the city.

The current survey investigates the features of driver fatigue incidents (accidents, near accidents and unintentional drifting-out-of-lane events) which occurred in cities. The results show similar patterns to previous surveys, with incident trips tending to be short, and prior sleep loss and late night driving featuring as factors. Work trips feature very strongly among city fatigue incident trips and work is also a common reason for sleep loss before a fatigue incident. Consistent with the high representation of work trips, there are peaks in incident occurrence at commuter travel times. Shiftworkers are prominent amongst fatigue incident-involved drivers. Social trips also feature amongst fatigue incident trips but are likely to be more difficult to address with countermeasures.

Accidents, Occupational↗

[Usefulness of the new classification for regional extension on CT of head and neck cancer].

OBJECTIVE: To present the usefulness of the new classification of neck nodes based in commuted tomography (CT). MATERIAL AND METHODS: We present several illustrative images showing neck nodes in each of the new levels (Ia, Ib, IIa, IIb, III, IV, Va, Vb, and VI) as an adjunct to nodal classifications. RESULTS AND CONCLUSION: An imaging-based classification for the cervical nodes allows to know much better their distribution along the neck, helping to find correlation between clinical, radiological and surgical findings.

Head and Neck Neoplasms↗

Modulation of Ca2+-activated K+ channels of human erythrocytes by endogenous protein kinase C.

Single IK(Ca) channels of human erythrocytes were studied with the patch-clamp technique to define their modulation by endogenous protein kinase C (PKC). The perfusion of the cytoplasmic side of freshly excised patches with the PKC activator, phorbol 12-myristate 13-acetate (PMA), inhibited channel activity. This effect was blocked by PKC(19-31), a peptide inhibitor specific for PKC. Similar results were obtained by perfusing the membrane patches with the structurally unrelated PKC activator 1-oleoyl-2-acetylglycerol (OAG). Blocking of this effect was induced by perfusion with PKC(19-31) or chelerythrine. Channel activity was not inhibited by the PMA analog 4alpha-phorbol 12,13-didecanoate (4alphaPDD), which has no effect on PKC. Activation of endogenous cAMP-dependent protein kinase (PKA), which is known to up-modulate IK(Ca) channels, restored channel activity previously inhibited by OAG. The application of OAG induced a reversible reduction of channel activity previously up-modulated by the activation of PKA, indicating that the effects of the two kinases are commutative, and antagonistic. Kinetic analysis showed that down-regulation by PKC mainly changes the opening frequency without significantly affecting mean channel open time and conductance. These results provide evidence that an endogenous PKC down-modulates the activity of native IK(Ca) channels of human erythrocytes. Our results show that PKA and PKC signal transduction pathways integrate their effects, determining the open probability of the IK(Ca) channels.

Adult↗

Identifying the residential location of rapists.

The spatial offence behaviour of 45 British serial rapists was examined in order to generate a predictive model, of use to criminal investigators. Two alternative hypotheses were explored. One predicted that rapists would commute into an area to carry out their offence. The second predicted that they would "maraud" out from a fixed location. Of the 45 offenders, 39 fitted the "maurader" hypothesis. However, the area covered by this model was an average of nearly 180 square miles. A second complementary theory, developed from facets of offenders' backgrounds, was therefore used to refine the predictions of distance travelled to and between offences. This enabled the size of the residential zone predicted from the marauder model to be reduced to a mean area of just over ten square miles. Tests of these models, combined into a small scale expert system, predicted the correct area for 82% of the cases. Suggestions for the further development of this expert system are discussed.

Adolescent↗

Sodium phosphate preparation for colonoscopy: onset and duration of bowel activity.

BACKGROUND: Two doses of sodium phosphate are recommended for colonic cleansing before colonoscopy. Patients need information about the onset and duration of activity of the preparation. This study was designed to develop practical prescribing information to patients to reduce anxiety concerning bowel accidents. METHODS: Two hundred patients were requested to take a liquid diet the day before colonoscopy, to take 45 mL sodium phosphate with water or juice the evening before and the morning of the procedure, and to complete a questionnaire. RESULTS: Bowel activity began 1.7 hours (range 0.5 to 13) after the first dose and continued for 4.6 (1 to 14) hours. For the second dose the time to onset was 0.7 hours (0.25 to 4), and bowel activity continued for 2.9 hours (0.5 to 6.5). Bowel activity was completed 4 hours after ingestion of the second dose in 83% of patients and within 5 hours in 87%. Three of 200 patients reported the need for bowel evacuation during transit. CONCLUSIONS: The activity from the second dose of sodium phosphate starts and ends sooner than that from the first dose. When advising patients on when to take the second dose of sodium phosphate, 4 hours for most and 5 hours for those with long commutes, should provide adequate time for almost all patients to avoid bowel activity during travel.

Cathartics↗

Caribbean skilled international migration and the transnational household.

"This paper briefly outlines the occupational profile of Caribbean migrants and raises questions concerning the extent to which migrant outflow represents absolute loss.... It is argued that circulation is not confined to commuter-type mobility but in the Caribbean it is also a feature of long-stay migration and the establishment of what are effectively transnational households. Though the characteristics and spatial behaviour of the household vary with the specific migration type, the transnational household provides a more appropriate model for analysing Caribbean migration and its implications than does the model based on migration as displacement."

Americas↗

Effects of cyclic changes in muscle length on force production in in-situ cat soleus.

Muscle shortening and stretch are associated with force depression and force enhancement, respectively. Previously, we have investigated the effect of combined dynamic contractions (i.e. a single shortening-stretch and stretch-shortening cycle) on force production (Herzog and Leonard, 2000). In order to investigate the relationship between force depression and force enhancement systematically, we studied the effects of a single as well as multiple stretch-shortening and shortening-stretch cycles on the ascending limb of the force-length relationship. Furthermore, by systematically varying the speed and magnitude of stretch preceding shortening and the speed and magnitude of shortening preceding stretch, we investigated the influence of these varying contractile conditions on force depression and force enhancement, respectively. Test contractions were performed on cat soleus (n=6) by electrical stimulation using four conceptually different protocols containing a single or repeated stretch-shortening and shortening-stretch cycles. The results of this study showed that: (1) force depression was not influenced by stretch preceding shortening independent of the speed and amount of stretch; (2) force enhancement was influenced in a dose-dependent manner by the amount of shortening preceding stretch but was not affected by the speed of shortening; (3) repeated stretch-shortening (shortening-stretch) cycles showed cumulative effects; (4) the number of shortening steps over a given distance did not influence the amount of force depression. The findings of this study support the idea that the mechanism of force depression associated with muscle shortening is different from that of force enhancement associated with muscle stretch. Furthermore, they support and extend our previous findings that stretch-shortening and shortening-stretch cycles are not commutative.

Analysis of Variance↗

The history dependence of force production in mammalian skeletal muscle following stretch-shortening and shortening-stretch cycles.

The purpose of this study was to determine the history dependence of force production during and following stretch-shortening and shortening-stretch cycles in mammalian skeletal muscle. Thirty-three different isometric, stretch, shortening, stretch-shortening and shortening-stretch experiments were preformed in cat soleus (n=8) using previously established methods. Stretch-shortening and shortening-stretch cycles are not commutative with respect to the isometric forces following the length changes. Whereas force depression following shortening is virtually unaffected by previous stretching of the muscle, force enhancement following stretch depends in a dose-dependent manner on the amount of muscle shortening preceding the stretch. The history dependence of isometric force following shortening-stretch cycles can conveniently be modelled using an elastic (compressive and tensile) element that engages at the length of muscle activation. Such an "elastic" mechanism has been proposed by Edman and Tsuchiya (1996) (Edman, K.A. P., Tsuchiya, T., 1996. Strain of passive elements during force enhancement by stretch in frog mucle fibres. Journal of Physiology 490. 1, 191-205) based on experimental observations, and has been implemented theoretically in a rheological model of muscle (Forcinito et al., 1997) (Forcinito, M., Epstein, M., Herzog, W., 1997. Theoretical considerations on myofibril stiffness. Biophysics Journal 72, 1278-1286). The history dependence of isometric force following stretch-shortening cycles appears independent of the stretch preceding the shortening, except perhaps, if stretching occurs at very high speeds (i.e. 6-10 times fibre length per second). The results of this study are hard to reconcile with the two major mechanisms associated with history dependence of force production: sarcomere length non-uniformity (Edman et al., 1993) and stress-induced cross-bridge inhibition (Maréchal and Plaghki, 1979) (Maréchal, G., Plaghki, L., 1979. The deficit of the isometric tetanic tension redeveloped after a relase of frog muscle at a constant velocity. Journal of General Physiology 73, 453-467). It appears that studying the history dependence of force production under more functionally relevant conditions than has been done to date may provide new information that contributes to our understanding of possible mechanisms associated with force depression and force enhancement following muscular length changes.

Animals↗

A simple design for a small fixed four-electrode brain stimulation array.

Anatomical studies of intracranial self-stimulation (ICSS) reward in rats often use the lesion method and, therefore, require repeated behavioral testing before and after the lesion. Other anatomical studies on unlesioned rats use a moveable electrode to permit testing at a number of ICSS sites. Combining these methods would yield still more information, but repeated testing is not possible due to the damage created by lowering the electrode. To meet this need, an array of 4 fixed vertically-spaced electrodes was devised. Electrodes are constructed from strands of 0.14-mm (0.0045'') Teflon-insulated stainless-steel wire, 4 of which are glued into an implantable bundle. A 4-channel IC rotary switch is implanted on the rat's head to permit the use of an inexpensive 2-channel electrode lead and commutator. In our laboratory, electrodes were vertically spaced at 0.3 mm, spanning the dorsoventral extent of the lateral hypothalamus and yielded stable rate-frequency curves over the usual 3-4 month period of behavioral testing.

Animals↗

Room oxygen enrichment improves sleep and subsequent day-time performance at high altitude.

We carried out a randomized, double-blind trial at 3800 m altitude to test whether a small degree of room oxygen enrichment at night improves sleep quality, and performance and well-being the following day. Eighteen sea-level residents drove from sea level to 3800 m in one day, and then slept one night in ambient air, and another night in 24% oxygen, the order being randomized. With oxygen enrichment the subjects had fewer apneas (P < 0.01) and spent less time in periodic breathing with apneas (P < 0.01) than when they slept in ambient air. Subjective assessments of sleep quality were also significantly improved. There was a lower acute mountain sickness score during the morning after oxygen-enriched sleep (P < 0.01) and a greater increase in arterial oxygen saturation from evening to morning (P < 0.05). The larger increases in arterial oxygen saturation from evening to morning suggest that the control of breathing may have been altered. Installing an oxygen-enriched room at high altitude is relatively simple and inexpensive, and shows promise for improving well-being of both commuters and residents.

Adult↗

Aedes aegypti in Ho Chi Minh City (Viet Nam): susceptibility to dengue 2 virus and genetic differentiation.

Aedes aegypti is the principal vector of dengue viruses, responsible for a viral infection that has become a major public health concern in Asia. In Viet Nam, dengue haemorrhagic fever was first detected in the 1960s and is now a leading cause of death in childhood. We studied the variability in competence of Ae. aegypti as a vector for dengue 2 virus and genetic differentiation in this mosquito species. Twenty mosquito samples collected in 1998 in Ho Chi Minh City were subjected to oral infection and isoenzyme polymorphism analysis by starch gel electrophoresis. Ae. aegypti populations from the centre of Ho Chi Minh City were genetically differentiated and their infection rates differed from those of populations from the commuter belt. These results have implications for insecticidal control during dengue outbreaks.

Aedes↗