27 research outputs found
Evidence for distinct polymer chain orientations in KC60 and RbC60
The KC60 and RbC60 polymer phases exhibit contrasting electronic properties
while powder diffraction studies have revealed no definite structural
difference. We have performed single crystal X-ray diffraction and diffuse
scattering studies of these compounds. It is found that KC60 and RbC60 possess
different chain orientations about their axes, which are described by distinct
space groups Pmnn and I2/m, respectively. Such a structural difference will be
of great importance to a complete understanding of the physical properties.Comment: To be published in Phys. Rev. Let
High Temperature Thermopower in La_{2/3}Ca_{1/3}MnO_3 Films: Evidence for Polaronic Transport
Thermoelectric power, electrical resistivity and magnetization experiments,
performed in the paramagnetic phase of La_{2/3}Ca_{1/3}MnO_3, provide evidence
for polaron-dominated conduction in CMR materials. At high temperatures, a
large, nearly field-independent difference between the activation energies for
resistivity (rho) and thermopower (S), a characteristic of Holstein Polarons,
is observed, and ln(rho) ceases to scale with the magnetization. On approaching
T_c, both energies become field-dependent, indicating that the polarons are
magnetically polarized. Below T_c, the thermopower follows a law S(H) prop.
1/rho (H) as in non saturated ferromagnetic metals.Comment: 10 pages, 5 .gif figures. Phys. Rev B (in press
The New School Absentees Reporting System for Pandemic Influenza A/H1N1 2009 Infection in Japan
Objective: To evaluate the new Japanese School Absentees Reporting System for Infectious Disease (SARSID) for pandemic influenza A/H1N1 2009 infection in comparison with the National epidemiological Surveillance of Infectious Disease (NESID). Methods:We used data of 53,223 students (97.7%) in Takamatsu city Japan. Data regarding school absentees in SARSID was compared with that in NESID from Oct 13, 2009 to Jan 12, 2010. Results: Similar trends were observed both in SARSID and NESID. However, the epidemic trend for influenza in SARSID was thought to be more sensitive than that in NESID. Conclusion: The epidemic trend for influenza among school-aged children could be easily and rapidly assessed by SARSID compared to NESID. SARSID might be useful for detecting the epidemic trend of influenza
A Methodological Framework for the Evaluation of Syndromic Surveillance Systems: A Case Study of England
Background: Syndromic surveillance complements traditional public health surveillance by collecting and analysing health indicators in near real time. The rationale of syndromic surveillance is that it may detect health threats faster than traditional surveillance systems permitting more timely, and hence potentially more effective public health action. The effectiveness of syndromic surveillance largely relies on the methods used to detect aberrations. Very few studies have evaluated the performance of syndromic surveillance systems and consequently little is known about the types of events that such systems can and cannot detect. Methods: We introduce a framework for the evaluation of syndromic surveillance systems that can be used in any setting based upon the use of simulated scenarios. For a range of scenarios this allows the time and probability of to be determined and uncertainty is fully incorporated. In addition, we demonstrate how such a framework can model the benefits of increases in the number of centres reporting syndromic data and also determine the minimum size of outbreaks that can or cannot be detected. Here, we demonstrate its utility using simulations of national influenza outbreaks and localised outbreaks of cryptosporidiosis. Results: Influenza outbreaks are consistently detected with larger outbreaks being detected in a more timely manner. Small cryptosporidiosis outbreaks (<1000 symptomatic individuals) are unlikely to be detected. We also demonstrate the advantages of having multiple syndromic data streams (e.g. emergency attendance data, telephone helpline data, general practice consultation data) as different streams are able to detect different types outbreaks with different efficacy (e.g. emergency attendance data are useful for the detection of pandemic influenza but not for outbreaks of cryptosporidiosis). We also highlight that for any one disease, the utility of data streams may vary geographically, and that the detection ability of syndromic surveillance varies seasonally (e.g. an influenza outbreak starting in July is detected sooner than one starting later in the year). We argue that our framework constitutes a useful tool for public health emergency preparedness in multiple settings. Conclusions: The proposed framework allows the exhaustive evaluation of any syndromic surveillance system and constitutes a useful tool for emergency preparedness and response
Trends in parameterization, economics and host behaviour in influenza pandemic modelling: a review and reporting protocol.
BACKGROUND: The volume of influenza pandemic modelling studies has increased dramatically in the last decade. Many models incorporate now sophisticated parameterization and validation techniques, economic analyses and the behaviour of individuals. METHODS: We reviewed trends in these aspects in models for influenza pandemic preparedness that aimed to generate policy insights for epidemic management and were published from 2000 to September 2011, i.e. before and after the 2009 pandemic. RESULTS: We find that many influenza pandemics models rely on parameters from previous modelling studies, models are rarely validated using observed data and are seldom applied to low-income countries. Mechanisms for international data sharing would be necessary to facilitate a wider adoption of model validation. The variety of modelling decisions makes it difficult to compare and evaluate models systematically. CONCLUSIONS: We propose a model Characteristics, Construction, Parameterization and Validation aspects protocol (CCPV protocol) to contribute to the systematisation of the reporting of models with an emphasis on the incorporation of economic aspects and host behaviour. Model reporting, as already exists in many other fields of modelling, would increase confidence in model results, and transparency in their assessment and comparison
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Inflammatory pseudotumor secondary to urachal cyst: A challenging clinical case report
•Inflammatory pseudotumor are non-neoplastic tumors of the abdomen.•They may be large and invasive.•They may cause significant morbidity and mortality.•There is limited information in the literature about management.
There is a wide differential diagnosis for intraabdominal tumors. Surgical resection and microscopic analysis of tissue structure can identify tumor origin in most cases. Most rapidly growing invasive tumors are neoplastic. Inflammatory pseudotumors are a subcategory of intraabdominal tumors that are non-neoplastic and can be rapidly growing. Urachal cysts originate from the dome of the bladder; however they are typically not invasive. There is limited literature on the appropriate management of these tumors.
A 37-year-old female presenting with symptoms of abdominal pain was found to have a large intraabdominal mass invading multiple organs. Core biopsies demonstrated inflammation. The mass grew significantly over the course of a year and patient's abdominal pain worsened. The patient was taken to the operating room for resection. Final pathology revealed reactive fibrous tissue with acute and chronic inflammation invading bladder, urethra, abdominal wall, appendix, and ovary. Intraoperative frozen section demonstrated low grade spindle cells with concern for inflammatory pseudotumor but final pathology demonstrated inflammation.
Although benign, these tumors cause significant morbidity due to their size and level of organ invasion. Management should involve surgical resection as well as potential post-operative chemotherapy or NSAIDs based off clinical picture. We demonstrate the importance of close follow up for residual disease or recurrence of patients with inflammatory pseudotumors of the abdomen.
This case highlights difficulties in diagnosis of a tumor that has potential to cause significant morbidity. There is need for further research to discover the best management after surgical resection of these tumors
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Effectiveness and cost-effectiveness of vaccination against pandemic influenza (H1N1) 2009
Pandemic (H1N1) 2009 has caused 182 166 confirmed infections and 1799 deaths in more than 150 countries to date (1). Both the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC) have declared public health emergencies in response to global circulation of this virus, and the WHO has raised the influenza pandemic alert level from 3 to 6 (2).
As a result of the strain's novelty, most people lack innate immunity to pandemic (H1N1) (3); currently available vaccines do not protect against the virus; and the time needed to manufacture, test, and distribute a matched vaccine is several months (4–5).
In the absence of a matched vaccine, infections and deaths from pandemic (H1N1) will continue globally until a sufficient proportion of the population has developed immunity through infection and recovery, inducing “herd immunity” (population immunity that decreases the effective reproductive rate of the virus below 1, ending the pandemic by epidemiologic definitions [6]). Public health officials were planning to begin vaccination campaigns in mid-October 2009 (7); however, the National Biodefense Science Board, a group of advisors to the U.S. Department of Health and Human Services, recommended moving large-scale vaccine administration to mid-September 2009 (8). Decisions on vaccination timing and distribution are complicated: It is unclear how many individuals would require vaccination to substantially reduce transmission once vaccine is available (some scientists note that the first epidemic wave may in fact already be complete by this time [9]), and it could be expensive to manufacture and administer the vaccine and to treat its side effects.
To help guide policymakers in advising vaccine manufacturers, we developed a model of progression of the 2009 (H1N1) pandemic to determine how vaccination in October or November 2009 would affect the course of the pandemic. We compared the effectiveness and cost-effectiveness of no vaccination, vaccination in mid-October, and vaccination in mid-November