928 research outputs found
Bond Orientational Order, Molecular Motion and Free Energy of High Density DNA Mesophases
By equilibrating condensed DNA arrays against reservoirs of known osmotic
stress and examining them with several structural probes, it has been possible
to achieve a detailed thermodynamic and structural characterization of the
change between two distinct regions on the liquid crystalline phase digram: a
higher-density hexagonally packed region with long-range bond orientational
order in the plane perpendicular to the average molecular direction; and a
lower-density cholesteric region with fluid-like positional order. X-rays
scattering on highly ordered DNA arrays at high density and with the helical
axis oriented parallel to the incoming beam showed a six-fold azimuthal
modulation of the first order diffraction peak that reflects the macroscopic
bond-orientational order. Transition to the less-dense cholesteric phase
through osmotically controlled swelling shows the loss of this bond
orientational order that had been expected from the change in optical
birefringence patterns and that is consistent with a rapid onset of molecular
positional disorder. This change in motion was previously inferred from
intermolecular force measurements and is now confirmed by NMR.
Controlled reversible swelling and compaction under osmotic stress, spanning a
range of densities between mg/ml to mg/ml, allows
measurement of the free energy changes throughout each phase and at the phase
transition, essential information for theories of liquid-crystalline states.Comment: 14 pages, 3 figures in gif format available at
http://abulafia.mgsl.dcrt.nih.gov/pics.html E-mail: [email protected]
Costs analysis of a population level rabies control programme in Tamil Nadu, India
The study aimed to determine costs to the state government of implementing different interventions for controlling rabies among the entire human and animal populations of Tamil Nadu. This built upon an earlier assessment of Tamil Nadu’s efforts to control rabies. Anti-rabies vaccines were made available at all health facilities. Costs were estimated for five different combinations of animal and human interventions using an activity-based costing approach from the provider perspective. Disease and population data were sourced from the state surveillance data, human census and livestock census. Program costs were extrapolated from official documents. All capital costs were depreciated to estimate annualized costs. All costs were inflated to 2012 Rupees. Sensitivity analysis was conducted across all major cost centres to assess their relative impact on program costs. It was found that the annual costs of providing Anti-rabies vaccine alone and in combination with Immunoglobulins was \$0.7 million (Rs 36 million) and \$2.2 million (Rs 119 million), respectively. For animal sector interventions, the annualised costs of rolling out surgical sterilisation-immunization, injectable immunization and oral immunizations were estimated to be \$ 44 million (Rs 2,350 million), \$23 million (Rs 1,230 million) and \$ 11 million (Rs 590 million), respectively. Dog bite incidence, health systems coverage and cost of rabies biologicals were found to be important drivers of costs for human interventions. For the animal sector interventions, the size of dog catching team, dog population and vaccine costs were found to be driving the costs. Rabies control in Tamil Nadu seems a costly proposition the way it is currently structured. Policy makers in Tamil Nadu and other similar settings should consider the long-term financial sustainability before embarking upon a state or nation-wide rabies control programme
Physikalische Parameter extrakorporaler Stoßwellen
Prerequisites for the successful investigation of the mechanism of action of ESWT (extracorporeal shockwave therapy) and the establishment of treatment standards, are the ability to measure, and a knowledge of, the physical parameters involved. The most accurate measurements are obtained with laser hydrophones. Various parameters (amplitude, rise time, pulse width, pressure pulse decay, rarification phase) of a typical shock wave can thus be determined. These can then be used to calculate energy flux density, focal extent, focal volume and as well as focal energy, effective energy in a defined area, and effective biological energy. These parameters can be utilized to work out a theoretical treatment protocol
Neuroactive steroids in depression and anxiety disorders: Clinical studies
Certain neuroactive steroids modulate ligand-gated ion channels via non-genomic mechanisms. Especially 3 alpha-reduced pregnane steroids are potent positive allosteric modulators of the gamma-aminobutyric acid type A (GABA(A)) receptor. During major depression, there is a disequilibrium of 3 alpha-reduced neuroactive steroids, which is corrected by clinically effective pharmacological treatment. To investigate whether these alterations are a general principle of successful antidepressant treatment, we studied the impact of nonpharmacological treatment options on neuroactive steroid concentrations during major depression. Neither partial sleep deprivation, transcranial magnetic stimulation, nor electroconvulsive therapy affected neuroactive steroid levels irrespectively of the response to these treatments. These studies suggest that the changes in neuroactive steroid concentrations observed after antidepressant pharmacotherapy more likely reflect distinct pharmacological properties of antidepressants rather than the clinical response. In patients with panic disorder, changes in neuroactive steroid composition have been observed opposite to those seen in depression. However, during experimentally induced panic induction either with cholecystokinine-tetrapeptide or sodium lactate, there was a pronounced decline in the concentrations of 3 alpha-reduced neuroactive steroids in patients with panic disorder, which might result in a decreased GABAergic tone. In contrast, no changes in neuroactive steroid concentrations could be observed in healthy controls with the exception of 3 alpha,5 alpha-tetrahydrodeoxycorticosterone. The modulation of GABA(A) receptors by neuroactive steroids might contribute to the pathophysiology of depression and anxiety disorders and might offer new targets for the development of novel anxiolytic compounds. Copyright (c) 2006 S. Karger AG, Basel
Cell-mediated immunity and its glucocorticoid-sensitivity after clinical recovery from severe major depressive disorder
Rabies Management Implications Based on Raccoon Population Density Indexes
An estimate or index of target species density is important in determining oral rabies vaccination (ORV) bait densities to control and eliminate specific rabies variants. From 1997–2011, we indexed raccoon (Procyon lotor) densities 253 times based on cumulative captures on 163 sites from Maine to Alabama, USA, near ORV zones created to prevent raccoon rabies from spreading to new areas. We conducted indexing under a common cage trapping protocol near the time of annual ORV to aid in bait density decisions. Unique raccoons (n = 8,415) accounted for 68.0% of captures (n = 12,367). We recaptured raccoons 2,669 times. We applied Schnabel and Huggins mark‐recapture models on sites with ≥3 years of capture data and ≥25% recaptures as context for raccoon density indexes (RDIs). Simple linear relationships between RDIs and mark‐recapture estimates supported application of our 2 index. Raccoon density indexes ranged from 0.0–56.9 raccoons/km . For bait density decisions, we evaluated RDIs in the following 4 raccoon density groups, which were statistically different: (0.0–5.0 [n = 70], 5.1–15.0 [n = 129], 15.1–25.0 [n = 31], and \u3e25.0 raccoons/km2 [n = 23]). Mean RDI was positively associated with a higher percentage of developed land cover and a lower percentage of evergreen forest. Non‐target species composition (excluding recaptured raccoons) accounted for 32.0% of captures. Potential bait competitors accounted for 76.5% of non‐targets. The opossum (Didelphis virginiana) was the primary potential bait competitor from 27°N to 44°N latitude, north of which it was numerically replaced by the striped skunk (Mephitis mephitis). We selected the RDI approach over mark-recapture methods because of costs, geographic scope, staff availability, and the need for supplemental serologic samples. The 4 density groups provided adequate sensitivity to support bait density decisions for the current 2 bait density options. Future improvements to the method include providing random trapping locations to field personnel to prevent trap clustering and marking non‐targets to better characterize bait competitors
Evaluation of cost-effective strategies for rabies post-exposure vaccination in low-income countries
<b>Background:</b> Prompt post-exposure prophylaxis (PEP) is essential in preventing the fatal onset of disease in persons exposed to rabies. Unfortunately, life-saving rabies vaccines and biologicals are often neither accessible nor affordable, particularly to the poorest sectors of society who are most at risk and upon whom the largest burden of rabies falls. Increasing accessibility, reducing costs and preventing delays in delivery of PEP should therefore be prioritized.<p></p>
<b>Methodology/Principal Findings:</b> We analyzed different PEP vaccination regimens and evaluated their relative costs and benefits to bite victims and healthcare providers. We found PEP vaccination to be an extremely cost-effective intervention (from 60/death averted). Switching from intramuscular (IM) administration of PEP to equally efficacious intradermal (ID) regimens was shown to result in significant savings in the volume of vaccine required to treat the same number of patients, which could mitigate vaccine shortages, and would dramatically reduce the costs of implementing PEP. We present financing mechanisms that would make PEP more affordable and accessible, could help subsidize the cost for those most in need, and could even support new and existing rabies control and prevention programs.<p></p>
<b>Conclusions/Significance:</b> We conclude that a universal switch to ID delivery would improve the affordability and accessibility of PEP for bite victims, leading to a likely reduction in human rabies deaths, as well as being economical for healthcare providers.<p></p>
The feasibility of canine rabies elimination in Africa: dispelling doubts with data
<p><b>Background:</b> Canine rabies causes many thousands of human deaths every year in Africa, and continues to increase throughout much of the continent.</p>
<p><b>Methodology/Principal Findings:</b> This paper identifies four common reasons given for the lack of effective canine rabies control in Africa: (a) a low priority given for disease control as a result of lack of awareness of the rabies burden; (b) epidemiological constraints such as uncertainties about the required levels of vaccination coverage and the possibility of sustained cycles of infection in wildlife; (c) operational constraints including accessibility of dogs for vaccination and insufficient knowledge of dog population sizes for planning of vaccination campaigns; and (d) limited resources for implementation of rabies surveillance and control. We address each of these issues in turn, presenting data from field studies and modelling approaches used in Tanzania, including burden of disease evaluations, detailed epidemiological studies, operational data from vaccination campaigns in different demographic and ecological settings, and economic analyses of the cost-effectiveness of dog vaccination for human rabies prevention.</p>
<p><b>Conclusions/Significance:</b> We conclude that there are no insurmountable problems to canine rabies control in most of Africa; that elimination of canine rabies is epidemiologically and practically feasible through mass vaccination of domestic dogs; and that domestic dog vaccination provides a cost-effective approach to the prevention and elimination of human rabies deaths.</p>
Experimental study of pedestrian flow through a bottleneck
In this work the results of a bottleneck experiment with pedestrians are
presented in the form of total times, fluxes, specific fluxes, and time gaps. A
main aim was to find the dependence of these values from the bottleneck width.
The results show a linear decline of the specific flux with increasing width as
long as only one person at a time can pass, and a constant value for larger
bottleneck widths. Differences between small (one person at a time) and wide
bottlenecks (two persons at a time) were also found in the distribution of time
gaps.Comment: accepted for publication in J. Stat. Mec
ICZM and WTP of stakeholders for beach conservation: Policymaking suggestions from an Italian case study
In accordance with integrated coastal zone management (ICZM), private stakeholders could be asked to pay for the benefits from beach conservation projects. Since a private contribution is measured by the amount of other goods a person is willing to give up for beach quality, it can be solicited in monetary terms or, when possible, in other forms, such as specific works. In this paper, by analysing the results of two surveys in Italy concerning stakeholders' perceptions of ICZM and their willingness to pay for these benefits, suggestions for beach management are provided to policymakers. One survey focuses on beach visitors who are asked to pay in monetary terms, while the other focuses on sunbathing establishment managers, who are asked to pay not only in monetary terms but also through beach works. The results show that the majority of these stakeholders are fully or partially aware of what ICZM is, and are unwilling to pay. However, regression analysis of those willing to pay suggests that promoting an information and education campaign about ICZM may be important if stakeholders' probability of paying is to be increased
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