A new method for measurement of moisture transport in porous media based on forward and backward scattering of epithermal neutrons.

We present a new method for determining the spatial distribution and transport of water in porous media. It is based on the detection of both forward and backward scattered neutrons from the wet regions of the samples under investigation. The experimental set-up is based on a Pu-Be neutron source and He-3 neutron detector assemblies. The results obtained showed that back scattered neutrons are more sensitive than the forward scattered neutrons to determine water content. Moreover, both forward and back scattered neutrons are more sensitive than either back or forward neutrons for determining water content. The method was used to measure moisture transport in sand columns and brick samples. Forward and backward scattered neutrons from different wet regions along the water flow path (x) are recorded as the sample absorbs water. Water saturates the regions of the samples tested near the inlet of water faster than the others. The water front positions were found to follow the square root behavior of the absorption time, and capillary penetration coefficients were determined for the samples investigated. The developed method can be used to investigate water absorption at various flow rates in porous samples of various sizes.

Determination of moisture distributions in porous building bricks by neutron radiography.

Water transport into construction building materials is an important subject since it may deteriorate them because it can carry harmful biological and chemical substances. Some of the reported results in literature for moisture transport in construction building materials follow Fick's law of diffusion while others show anomalous diffusion. There is not enough reliable and accurate data in the literature to discuss this issue. Therefore, in the present work moisture transport into four different kinds of brick samples was studied using the real time neutron radiography method. Neutron radiography images were registered continuously during the moisture absorption process. Simple procedures based on the Cd-umbrella method were used for the first time to correct for the neutron scattering during the water absorption process. The images showed clearly that the absorption process is different from one sample to another. The water content distribution along the flow direction, x (profiles) and positions of water front as the time of moisture absorption elapses were determined from the images obtained. The results obtained showed that the water front positions do not scale with the square root of the absorption time. It was shown that moisture diffusion processes in the samples investigated could be described by an anomalous diffusion approach of the sub-diffusive type. The moisture diffusivities were determined for every sample. The neutron radiography method and the neutron scattering correction procedures used are proven to be a powerful and effective for studying transport process in porous media.

Circulatory collapse in a parturient undergoing cesarean delivery: a diagnostic dilemma.

Embolic events including thromboembolism, air embolism, and amniotic fluid embolism can cause cardiovascular collapse during cesarean delivery. Differentiation between the three conditions is challenging because they share many of the initial clinical and echocardiographic findings, but an accurate, definitive diagnosis allows the administration of specific therapy that may help in saving the life of the mother and/or the fetus. We report a case of cardiovascular collapse during cesarean delivery under general anesthesia; massive pulmonary thromboembolism was suspected and unfractionated heparin was administered. Cardiac arrest followed and was managed with standard cardiopulmonary resuscitation, resulting in return of spontaneous circulation. Postoperatively, the patient remained hemodynamically unstable in spite of heparin, norepinephrine infusions and intravenous fluids. A transthoracic echocardiogram revealed right-sided pressure overload. Thrombolysis was initiated. Streptokinase (1,500,000IU over 2hours) was administered with no clinical response, followed by infusion (100,000IU/h) for 12hours. The patient's hemodynamics improved gradually and she was successfully weaned from norepinephrine and mechanical ventilation. Significant bleeding ensued, necessitating discontinuation of anticoagulation and transfusion of red blood cells. Eventually, the patient was discharged home, in good condition, and on oral warfarin therapy.

Thrombolysis for the management of massive pulmonary embolism in pregnancy.

Massive pulmonary embolism in pregnancy is a major cause of maternal mortality; the management is challenging, and often requires aggressive therapy. Thrombolysis has been used, often with favorable outcome, but has not been previously reported in a patient presenting with an intrauterine death. We present a 29-year-old nulliparous patient who had a massive pulmonary embolus associated with fetal death in the third trimester of pregnancy. Diagnosis of pulmonary embolus was aided by transthoracic echocardiography and the patient was successfully treated with streptokinase.

Increase urinary hepatocyte growth factor excretion in human acute renal failure.

Studies in animals suggest that hepatocyte growth factor (HGF) is an important mediator of kidney development, compensatory growth and tubule repair following acute injury, however, evidence for HGF action in human renal disease is scant. To determine whether increased renal production of HGF occurs in man, urine HGF excretion rate was measured in normals and in patients with a variety of acute and chronic renal diseases. Urine samples were collected from 9 healthy individuals, 25 individuals with acute tubular necrosis (ATN), 20 individuals with chronic glomerular disease, 9 patients with polycystic kidney disease and 10 individuals with severe chronic renal failure not yet receiving renal replacement therapy. Samples were initially frozen and then HGF content measured by ELISA and factored for creatinine concentration measured by autoanalyzer. Detectable but low levels of HGF were found in the urine of normals and in patients with chronic glomerular or polycystic disease. Levels were also not increased in patients with advanced, chronic renal insufficiency. In contrast, a marked increase in urine HGF was observed in patients with acute renal failure. In addition, HGF excretion tended to correlate with disease severity as higher levels were observed in patients with oliguric ATN. Urine HGF levels declined to control values in patients recovering from ATN, generally within one week. These findings are consistent with a role for HGF in promoting tubule cell proliferation, differentiation and recovery from acute tubular injury in man.

Professional perceptions of availability and quality of mental health services in Wisconsin.

Eighty-six county coordinators and psychiatrists from predominantly rural counties reported their perceptions of availability and quality of 21 types of inpatient, outpatient, and transitional living services in Wisconsin for five target populations: adult, children, adolescent, geriatric, and minority. Their ratings and priorities for addressing needs indicated (a) that transitional living services are insufficient and of inadequate quality for all populations; (b) that availability and quality of inpatient and outpatient services are better for adults; (c) that general needs across all populations for additional and higher quality services are for services that address specialized problems, both inpatient and outpatient; (d) that children, adolescent, minority, and geriatric populations have limited access to needed services; (e) that available services for these four groups are most often inadequate; and (f) that the needs of children and adolescents should be given highest priority, particularly their needs for transitional services and inpatient and outpatient services for special problems. Actions and recommendations are discussed for professionals and advocates to increase awareness of needs for quality services for children and adolescents, for expanding public information, and for design of local-county quality programs, including professional education and continuing outreach to important constituencies and advocates.