Designing a new graphite illuminator for imaging facility of INUS to improve neutron beam uniformity and intensity.

A cylindrical graphite illuminator with a thickness of 6.5 cm and diameter of 18 cm was installed inside the collimator of INUS (Instalatie de Neutronografie UScata) neutron imaging facility in the past. The graphite illuminator is usually utilized inside the collimator of neutron imaging facility to provide an intense and approximately uniform beam of neutrons at the outlet of collimator. With the mentioned existing illuminator in INUS imaging facility, the thermal neutron flux at the exit of collimator was measured 7.2 × 104 n/cm2/s. Also the obtained neutron beam profile in this facility shows that it is not completely uniform at the imaging screen and the intensity of neutrons at the top and bottom of beam profile are not the same. Hence, in this paper a new graphite illuminator is proposed to improve the neutron beam characteristics in INUS imaging facility. Monte Carlo N-Particle (MCNP) code was implemented in this study for evaluating the proposed illuminator. The shape of proposed illuminator is a cylinder whose one side is inclined. Three quality factors of thermal neutron intensity, thermal neutron beam uniformity and gamma radiation dose rate were used to evaluate performance of the new illuminator. In order to obtain optimum illuminator shape, three effective parameters of thickness, angle of inclined side and position of the illuminator inside the collimator were investigated in this research. The investigation was carried out on thicknesses in the range of 5 to 25 cm with a step of 5 cm, angles in the range of 10 to 60° with a step of 10° and positions of -5, 0 and 5 cm with respect to center of reactor core. After investigating and interpolating the results, it was found that the proposed illuminator with a thickness of 10 cm, angle of 54.5° and position of 0 can produce a uniform beam profile, increase the thermal neutron intensity up to 7.1% and also decrease the neutron to gamma ratio up to 5% in comparison with the existing one.

Progressive preoperative pneumoperitoneum (PPP) as an adjunct for surgery of hernias with loss of domain.

BACKGROUND: forced repair of a giant abdominal wall defect end with unsatisfactory results despite development of prosthetics materials. The enlargement of abdominal wall dimensions could be realized altogether other methods with the aid of pneumo-peritoneum. The aim of the study is to evaluate early results of the method used for patients with giant incisional hernias. MATERIAL AND METHODS: between june 1998 - june 2013, 17 patients (4 males) with giant abdominal wall defects (incisional and inguinal hernias) were prepaired for radical surgery with pneumoperitoneum. Average age was 64.35 years. We reevaluated the standard constants of the pulmonary function,blood gases, and intra-vesical pressure in 3 moments: before the first gas insuflation, 24 hours before surgery and in the 7th daypost operatively. RESULTS: the method was free of accidents or incidents, no mortality was recorded. The respiratory function was significantly increased and also the intra-abdominal pressure. CONCLUSION: our results suggest that the method of progressive pneumoperitoneum is safe, costless of choice for creating a clear compatibility between the wall and abdominal content inpatients with giant abdominal wall defects. Also ensures a longterm and stable improvement of the respiratory function in all its components.

Cation exchange at the secondary building units of metal-organic frameworks.

Cation exchange is an emerging synthetic route for modifying the secondary building units (SBUs) of metal-organic frameworks (MOFs). This technique has been used extensively to enhance the properties of nanocrystals and molecules, but the extent of its applications for MOFs is still expanding. To harness cation exchange as a rational tool, we need to elucidate its governing factors. Not nearly enough experimental observations exist for drawing these conclusions, so we provide a conceptual framework for approaching this task. We address which SBUs undergo exchange, why certain ions replace others, how the framework influences the process, the role of the solvent, and current applications. Using these guidelines, certain trends emerge from the available data and missing experiments become obvious. If future studies follow this framework, then a more comprehensive body of observations will furnish a deeper understanding of cation exchange and inspire future applications.

[Pulmonary suppurations: etiologic profile]. / Supuratiile pulmonare--profil etiologic.

The goal of this study was to determine the pathogens of the necroses of pulmonary tissue. These debilitating diseases are usually diagnosed based on clinical and radiological findings, while the more difficult microbiological diagnosis often remains uncertain. The study involved 115 patients diagnosed with lung abscess or necrotizing pneumonia; the investigations were performed in the laboratory of the "Leon Daniello" Clinical Hospital of Pneumology, Cluj-Napoca, Romania, in the period 1999-2000. The laboratory samples (sputum, transtracheal aspiration, pleural fluid, blood samples) were studied by direct microscopy and in culture. Our results concerning the pathogens are as follows: aerobes - 20 patients (17%), mixed pathogens - 57 patients (50%). We found that the most dominant pathogens from those encountered are the anaerobes (83%), which were present either alone, or in mixed infections.

Evolution of osteopenia in inflammatory bowel disease.

OBJECTIVE: Our aim was the assessment of frequency and evolution of osteopenia in patients with inflammatory bowel disease and identification of related factors. METHODS: Bone mineral density (BMD) of the lumbar spine was measured in 54 patients with Crohn's disease (CD) and in 49 patients with ulcerative colitis (UC) and was repeated after a mean observation period of 21 (range, 8-50) months in 30 CD and 14 UC patients. Eighteen age-matched healthy subjects served as controls. Serum biochemistry (parathyroid hormone, osteocalcin, alkaline phosphatase, insulin-like growth factor 1, minerals, and markers of inflammation) was assessed at the time of the second BMD measurement. RESULTS: Reduced BMD values were found in 48% of CD, and in 38% of UC patients. Compared with control subjects, the mean BMD was significantly lower in CD (p < 0.003) and UC (p < 0.0001) patients. BMD was positively correlated with the body mass index (p < 0.05) and inversely correlated with the lifetime steroid dose (p < 0.03). After 21 months the BMD of CD patients was virtually unchanged, with an annual variation (%deltaBMD/yr) of -0.31 +/- 0.49, whether treated with steroids or not, whereas in UC patients the BMD decreased significantly (p < 0.02) with a %deltaBMD/yr of -2.47 +/- 0.82 (p < 0.02 vis CD). This decrease can be attributed to steroid treatment. No biochemical alterations were detected in patients with rapid bone loss, compared with those with stable BMD. CONCLUSIONS: Low bone density is frequent in both CD and UC, but apparently stable in CD. The evolution of BMD suggests that low bone density is associated with the pathogenesis of CD, whereas in UC it seems to be correlated with the side effects of corticosteroid treatment.

Calcaneal ultrasound bone densitometry in inflammatory bowel disease--a comparison with double x-ray densitometry of the lumbar spine.

OBJECTIVE: The aim of this study was to measure ultrasound (US) densitometric parameters [Broadband Ultrasound Attenuation (BUA), Speed of Sound (SOS), and stiffness of the os calcis] in patients with inflammatory bowel disease (IBD) and to compare the results with those obtained with conventional x-ray absorptiometry (DXA) of the lumbar spine. METHODS: Twenty-two patients with Crohn's disease (13 with ileal and nine with ileocolonic disease), 11 patients with ulcerative colitis (eight with left-sided and three with pancolitis), and 18 healthy controls. US densitometry of the right heel and DXA of the lumbar spine were performed within the same day. RESULTS: Compared to controls, IBD patients had significantly lower values with both methods, US and DXA. Forty-nine percent of patients had a lumbar T score below -1. Calcaneal SOS and stiffness of these patients were significantly reduced (p < 0.03 and p < 0.05, respectively). Positive significant correlations were found between lumbar DXA and calcaneal US parameters. Lumbar bone density and calcaneal US stiffness correlated inversely with the lifetime prednisone intake (p < 0.03 andp < 0.05, respectively), but not with age or duration of disease. A cut-off level of 80 dB/MHz for calcaneal BUA predicted axial osteopenia correctly in 74%, but some underestimation of spinal BMD was observed, especially in female patients with Crohn's disease. CONCLUSION: US evaluation of the os calcis gives results similar to those of conventional DXA and therefore may be used for screening IBD patients for axial osteoporosis. Because US does not expose patients to radiation, repeated measurements are possible and may be used to assess short term variations and the effect of treatment of IBD-associated bone disease.

Quality of life after proctocolectomy and ileo-anal anastomosis for severe ulcerative colitis.

OBJECTIVE: Impaired quality of life (QOL) in patients with ulcerative colitis (UC) may be a prominent feature of the disease, and in some cases, may become an indication for surgical treatment. The objective of this study was to assess QOL in patients who underwent proctocolectomy with ileo-anal anastomosis with a J pouch for severe UC and to compare it with patients with UC of different severity who were under medical treatment. METHODS: We used a validated, disease-specific research instrument (a 29 item, self-administered questionnaire) that examines the following four functions: intestinal (score 0-24) and systemic symptoms (0-21), and emotional (0-27) and Social Function (0-15). High scores indicate an impairment of the function examined and the sum of the four scores (maximal total score = 87) reflects the patient's QOL. We studied 29 operated patients (22 men, mean age 35 yr, mean time after intervention 3.8 yr) and compared their scores with those of 57 UC patients (39 men, mean age 36 yr) with different degrees of disease activity, and with those of 72 healthy controls (38 men, mean age 31 yr). RESULTS: In UC, scores were significantly higher than in controls, increasing with the severity of the disease. Even patients in remission had higher scores than controls in the "systemic" (4.6 vs. 2.0) and emotional (5.6 vs. 2.5) functions. Patients who underwent surgical treatment had much better scores than patients with severe disease (total score 20.1 vs. 38.2), with values comparable to those of patients in remission or with mild disease activity. There was no significant gender difference, either for UC and ileo-anal anastomosis patients, or in healthy controls. CONCLUSION: In patients with UC, even in remission, there is a measurable impairment of QOL, which increases with the severity of disease. Operated patients have a QOL that is comparable to that of patients in remission or with mild disease, and proctocolectomy with ileo-anal anastomosis may restore an acceptable QOL in patients with moderate/severe UC.