Radio frequency measurement and tuning of a 13 MeV Alvarez-type drift tube linac for a compact pulsed hadron source.

This paper describes the radio frequency (RF) measurement and tuning result of a 13 MeV Alvarez-type drift tube linac (DTL) for a compact pulsed hadron source (CPHS) at Tsinghua University. The design, machining, assembly, and alignment of the DTL are presented for integrity. The CPHS project consists of a high-current proton linac (13 MeV, 16 kW, peak current of 50 mA, 0.5 ms pulse width at 50 Hz), a neutron target station, a small-angle neutron scattering instrument, and a neutron imaging/radiology station. The linac contains an electron cyclotron resonance ion source, a low energy beam transport line, a four-vane radio frequency quadrupole (RFQ) accelerator, an Alvarez-type DTL, a high energy beam transport line, and a RF power supply and distributor. Construction on the CPHS started in June 2009, and the CPHS has provided 2000 h since 2013 to users with the neutrons produced by the 3 MeV proton beam from the radio frequency quadrupole bombarding on the beryllium target as an achievement of its mid-term objective. Presently, the tuning of the assembled DTL cavity has been completed successfully. The 4.3-m-long DTL consists of 40 accelerating cells, among which 39 full-length drift tubes (DTs) are suspended inside the cavity, and two half-length DTs are mounted inside the two end flanges of the cavity. Each DT contains a permanent magnet quadrupole. Thirteen post couplers and nine tuners are available for the tuning of the field. The relative error of the field after tuning is within ±1.6%, with a tilt sensitivity within ±33%/MHz in all cells. The beam energy will reach its designed value of 13 MeV after the DTL is installed in the beam line downstream the 3 MeV RFQ accelerator.

AIM2 contributes to the maintenance of intestinal integrity via Akt and protects against Salmonella mucosal infection.

The mechanism regulating the gastrointestinal epithelial barrier remains poorly understood. We herein demonstrate that Absent in melanoma-2 (AIM2) contributes to the maintenance of intestinal barrier integrity and defense against bacterial infection. AIM2-deficient mice displayed an increased susceptibility to mucosal but not systemic infection by Salmonella typhimurium, indicating a protective role for AIM2 in the gastrointestinal tract. In a Salmonella colitis model, compared with wild-type mice, AIM2(-/-) mice exhibited more severe body weight loss, intestinal damage, intestinal inflammation, and disruption of basal and activated epithelial cell turnover. In vivo and in vitro data showed that AIM2 restricted the early epithelial paracellular invasion of Salmonella and decreased epithelial permeability. The decreased epithelial barrier in AIM2(-/-) mice might be attributed to the altered expression of tight junction proteins that contribute to epithelial integrity. AIM2 promoted the expression of tight junction proteins through Akt activation. Together, these results suggest that AIM2 is required for maintaining the integrity of the epithelial barrier.

Patient delay in the diagnosis and treatment of tuberculosis in China: findings of case detection projects.

OBJECTIVE: 1) To assess patient delay among new smear-positive pulmonary tuberculosis (PTB) patients in accessing health services in seven FIDELIS (Fund for Innovative DOTS Expansion through Local Initiatives to Stop TB) projects from 2003 to 2008 in China; 2) to compare treatment delay by province; and 3) to assess factors associated with delay. METHOD: Records of new smear-positive PTB patients were reviewed. Data sources were the consultation book, laboratory register, patient record, treatment card and the PWLAHS (people with limited access to health services) evaluation form. Data were collected using a standard questionnaire, cross-checked by staff from the sites and by the International Union Against Tuberculosis and Lung Disease (The Union) and analysed by The Union. RESULTS: Of the 75 401 new smear-positive PTB patients included in the study, 63-89% were PWLAHS. The average gross domestic product of the project sites and at national level were respectively US$557 and US$998. The median patient delay was 93 days (range 68-128). Delays were longer among females, older patients, rural residents and PWLAHS. Delayed access to health services was significantly associated with a greater number of symptoms. CONCLUSION: Patient delay in accessing health care in China was lengthy; TB care and control needs to be improved.

Objectif : Evaluer le délai d'accès aux services des santé de nouveaux patients atteints de tuberculose pulmonaire (TBP) à frottis positif détectés au sein de sept projets FIDELIS (Fund for Innovative DOTS Expansion through Local Initiatives to Stop TB) exécutés en Chine entre 2003 et 2008 ; 2) comparer les retards du traitement par province ; et 3) évaluer les facteurs associés aux retards.Méthode : Les dossiers des patients TPB à frottis positif ont été revus. Les données émanaient du registre des consultations, de celui du laboratoire, des dossiers des patients, des cartes de traitement et des formulaires d'évaluation des personnes ayant un accès limité aux services de santé (PWLAHS). Les données ont été recueillies grâce à un questionnaire standard et vérifiées par le personnel des sites et de l'Union Internationale contre la Tuberculose et les Maladies Respiratoires (L'Union) et analysées par L'Union.Résultats : De 75 401 nouveaux patients atteints de TBP à frottis positif, 63­89% étaient des PWLAHS. Le produit intérieur brut moyen des sites du projet et du niveau national était de 557 et 998 $US respectivement. Le délai médian d'accès aux soins était de 93 jours (extrêmes 68­128). Ce délai était plus long pour les femmes, les patients âgés, les résidents ruraux et ceux estimés être des PWLAHS. Ce délai d'accès aux services était significativement associé à un nombre de symptômes plus élevé.Conclusions : Le délai d'accès aux services de santé en Chine est long et offre des opportunités d'amélioration en matière de lutte contre la TB et de traitement.

Objetivo: 1) Evaluar el retraso en el acceso a los servicios de salud de los pacientes en quienes se diagnosticó tuberculosis pulmonar (TBP) con baciloscopia positiva en siete centros del Proyecto FIDELIS (Fondo para la Expansión Innovadora de DOTS por conducto de Iniciativas Locales a fin de poner Alto a la Tuberculosis) del 2003 al 2008 en la China; 2) comparar el retraso en el tratamiento entre provincias; y 3) evaluar los factores asociados con estos retrasos.Método: Se analizaron las historias clínicas de los pacientes con TBP y baciloscopia positiva. Las fuentes de los datos fueron los libros de consulta, el registro de laboratorio, las historias clínicas, las tarjetas de tratamiento y el formulario de evaluación de las personas con acceso limitado a los servicios de salud. Se recogieron los datos mediante un cuestionario normalizado y verificado que analizaron profesionales de los centros locales y de la Unión contra la Tuberculosis y las Enfermedades Respiratorias.Resultados: Se incluyeron en el estudio 75 401 casos nuevos de TBP con baciloscopia positiva. El producto interno bruto promedio por habitante a escala de los centros del proyecto era 557 USD y a escala nacional era 998 USD. De los pacientes con TB, entre el 63% y el 89% contaban con un acceso limitado a los servicios de salud. La mediana del retraso de los pacientes en acceder a la atención fue 93 días (extremos 68 a 128 días). Los retrasos fueron más prolongados en las mujeres, los pacientes de mayor edad, los residentes en zonas rurales y las personas que se calificaron con un acceso limitado a los servicios sanitarios. El acceso tardío a los servicios de salud se asoció de manera significativa con una mayor cantidad de síntomas.Conclusión: Se observó un retraso considerable de los pacientes para acceder a la atención de salud; esta situación ofrece oportunidades para mejorar la atención y el control de la TB.