Experimental investigation of interface states in photonic crystal heterostructures.

Optical Tamm states, a kind of interface modes, are also called Tamm plasmon-polaritons. They are experimentally observed in photonic heterostructures based on microstrip transmission lines. The position of optical Tamm states can be designed exactly under effective impedance match and effective phase shift match conditions. Our results show that the photonic band gaps can have the effect of negative-permittivity or negative-permeability media in constructing the interface modes. The simulations and experimental results agree with each other quite well.

Evaluation of control measures implemented in the severe acute respiratory syndrome outbreak in Beijing, 2003.

CONTEXT: Beijing, China, experienced the world's largest outbreak of severe acute respiratory syndrome (SARS) beginning in March 2003, with the outbreak resolving rapidly, within 6 weeks of its peak in late April. Little is known about the control measures implemented during this outbreak. OBJECTIVE: To describe and evaluate the measures undertaken to control the SARS outbreak. DESIGN, SETTING, AND PARTICIPANTS: Data were reviewed from standardized surveillance forms from SARS cases (2521 probable cases) and their close contacts observed in Beijing between March 5, 2003, and May 29, 2003. Procedures implemented by health authorities were investigated through review of official documents and discussions with public health officials. MAIN OUTCOME MEASURES: Timeline of major control measures; number of cases and quarantined close contacts and attack rates, with changes in infection control measures, management, and triage of suspected cases; and time lag between illness onset and hospitalization with information dissemination. RESULTS: Health care worker training in use of personal protective equipment and management of patients with SARS and establishing fever clinics and designated SARS wards in hospitals predated the steepest decline in cases. During the outbreak, 30 178 persons were quarantined. Among 2195 quarantined close contacts in 5 districts, the attack rate was 6.3% (95% confidence interval [CI], 5.3%-7.3%), with a range of 15.4% (95% CI, 11.5%-19.2%) among spouses to 0.36% (95% CI, 0%-0.77%) among work and school contacts. The attack rate among quarantined household members increased with age from 5.0% (95% CI, 0%-10.5%) in children younger than 10 years to 27.6% (95% CI, 18.2%-37.0%) in adults aged 60 to 69 years. Among almost 14 million people screened for fever at the airport, train stations, and roadside checkpoints, only 12 were found to have probable SARS. The national and municipal governments held 13 press conferences about SARS. The time lag between illness onset and hospitalization decreased from a median of 5 to 6 days on or before April 20, 2003, the day the outbreak was announced to the public, to 2 days after April 20 (P<.001). CONCLUSIONS: The rapid resolution of the SARS outbreak was multifactorial, involving improvements in management and triage in hospitals and communities of patients with suspected SARS and the dissemination of information to health care workers and the public.

[Re-survey on epidemiological history of 1 091 probable cases with severe acute respiratory syndrome in Beijing].

OBJECTIVE: To know their real epidemiological histories in 1,091 probale cases of severe acute respiratory syndrome (SARS) without definite history of contact with SARS patients in the first survey. METHODS: All the probable SARS cases until June 9, 2003 without definite history of contact with SARS patients in the first epidemiological survey were included in a re-survey with questionnaire. The second survey was carried out during June 9 to 30, 2003. RESULTS: The results showed that history of contact with other SARS patients was obtained in 15.9% of 1 091 probale SRAS cases in the second survey, transmission of SARS to others was found in 10.5% of them, and source of infection in hospital was found in 46.5%. Comprehensive judgement based on epidemiological history showed that probale history of contact with SARS patients could be found in 72.9% of 1,091 probale cases of SARS in the second survey. CONCLUSION: Source of infection could be found through additional survey in part of probale cases of SARS without it in initial epidemiological survey.

Severe acute respiratory syndrome, Beijing, 2003.

The largest outbreak of severe acute respiratory syndrome (SARS) struck Beijing in spring 2003. Multiple importations of SARS to Beijing initiated transmission in several healthcare facilities. Beijing's outbreak began March 5; by late April, daily hospital admissions for SARS exceeded 100 for several days; 2,521 cases of probable SARS occurred. Attack rates were highest in those 20-39 years of age; 1% of cases occurred in children <10 years. The case-fatality rate was highest among patients >65 years (27.7% vs. 4.8% for those 20-64 years, p < 0.001). Healthcare workers accounted for 16% of probable cases. The proportion of case-patients without known contact to a SARS patient increased significantly in May. Implementation of early detection, isolation, contact tracing, quarantine, triage of case-patients to designated SARS hospitals, and community mobilization ended the outbreak.