Acute choroidal ischemia as a complication of photocoagulation

Acute choroidal vascular insufficiency as a complication of photocoagulation has been little noticed. In 17 eyes of 16 patients photocoagulated with either xenon or argon sources for proliferative sickle cell retinopathy, gray lesions of the fundus developed peripheral to the photocoagulation sites. Histologic examination of similar gray lesions produced in monkeys showed necrosis and atrophy of the outer half of the retina. Intense photocoagulation of the human fundus, even with smaller spot sizes, may occlude a choroidal artery, producing separate gray lesions of distinctive shape. The lesions in both the patients and the monkeys progressed to granular hyperpigmentation by two to three weeks after photocoagulation.     

Ultrasonic blood flow measurements: transcutaneous compared with implanted cuff

Experiments were undertaken in our laboratory to establish relationships between flow parameters calculated from implanted ultrasonic cuff signals and those obtained with a transcutaneous probe. Analog signals were received from crystals surgically implanted on the right carotid, right femoral, and abdominal aorta of a mature male beagle dog. Near these locations, transcutaneous measurements were made using a prescribed technique. From these ultrasonic signals, the following time dependent flow parameters were calculated: spatial velocities, velocity profiles, diameters, flows, and velocity frequency distributions. Using these measurements, a comparison between the implanted cuff and transcutaneous probe was made. In addition to high reproductibility, results confirm a strong correlation between the two techniques; consequently, the validity of the less traumatic transcutaneous method is substantiated.     

Effect of staphylococcal alpha-toxin pancreatitis on glucose tolerance in the dog

Acute pancreatitis was experimentally produced in dogs to study the effect of the disease on glucose tolerance. The k value (glucose disappearance coefficient measured in percentage decrease of glucose/min) calculated from the high-dose intravenous glucose-tolerance test was used to evaluate the glucose tolerance of each dog. Thirty dogs were allotted to 3 groups of 10 dogs each as follows: group I--nonsurgical control dogs; group II--surgical control dogs; and group III--pancreatitis-affected dogs. To increase their susceptibility to diabetes, 50% partial pancreatectomies and ductal catheterizations were performed on group II and III dogs. Saline solution was infused into the ductal systems of group II dogs, and staphylococcal alphatoxin was infused into the ductal systems of group III dogs to produce pancreatitis. The results indicated that (1) high-dose intravenous glucose-tolerance test was an effective tool for determining decreased glucose tolerance in dogs; (2) glucose tolerance of group III dogs was markedly decreased compared with that of group I and II dogs; (3) staphylococcal alpha-toxin produced signs of moderately severe pancreatitis; and (4) 50% partial pancreatectomy and saline solution infusion produced clinical and clinicopathologic signs of mild pancreatitis. To determine if a simplified k value (calculated using 2 or 3 blood samples) could closely approximate the standard k value (calculated using 6 blood samples), simplified k values were derived from the 5- and 60-minute blood sample values. These values closely approximated the standard k values, indicating the simplified value may be used in the clinical situation. The standard k value, however, is preferred for investigative work.     

The prevalence of diabetes mellitus in three population groups in the Republic of Mali

A new method of estimating intracranial decompensation in man is described. An on-line computer system is connected to an intracranial pressure (ICP) monitoring system to compute regression plots of mean ICP vs standard deviation; standard deviation is used as a measure of ICP instability. Two zones with distinctly different slopes are a characteristic feature of these plots. It is thought that the changes of slope signify intracranial decompensation.     

Solution calorimetry: A novel perspective into the dissolution process of food powders

The enthalpy of dissolution of two food powders, maltodextrin and skim milk, was studied by means of isothermal solution calorimetry. The effects of the moisture content and the physical state of the samples were investigated. A reduced exothermic response was found as the moisture content of the samples increased. It was shown that this effect is reversible upon re-drying of the solid, unless crystallization occurs. In the skim milk powder, crystallization of lactose occurred, leading to a less exothermic response. In addition, the dissolution kinetics of single particles was followed in situ with real time video acquisition and a novel image analysis technique. The data showed a significant effect of the physical state of the powder on the dissolution kinetics. Fully amorphous skim milk powder dissolved significantly faster than the recrystallized counterpart. A clear relation was observed between the physical state of the powders, their thermodynamic response and the dissolution kinetics.     

Shrinkage, density, porosity and shape changes during dehydration of pumpkin (Cucurbita pepo L.) fruits

The aim of this work was to study the changes in volume, density, porosity and shape factors of pumpkin tissue during osmotic dehydration (OD) and air drying (AD). Pumpkin cylinders with length/diameter ratio of 5/3 were used. OD experiments were carried out with solutions of sucrose, sodium chloride and mixtures of both solutes at different temperatures. AD experiments were conducted at 70 °C. Volume of samples decreased linearly with weight reduction (WR). Bulk density varied in a restricted range (5-13%) during dehydration and for all the methods maximum values were found. Particle density increased during both processes. Porosity increased at advanced degrees of dehydration, showing a minimum value at the beginning of OD and AD. The proposed models to evaluate shrinkage, bulk and particle densities and porosity from WR were satisfactorily applied. Image analysis showed that shrinkage of samples during OD was isotropic. Pumpkin cylinders increased elongation and decreased roundness and compactness during osmotic dehydration.     

Microstructure and mechanical performance examination of 3D printed acrylonitrile butadiene styrene thermoplastic parts

Fused filament fabrication (FFF) is a process where thermoplastic materials are heated to its melting point and then extruded, layer by layer, to create a three dimensional printed part. Printing occurs in a layered manner, which leads to creation of voids (air gaps) in the 3D printed parts. These voids act as centers for crack initiation, propagation and therefore resulting bulk mechanical properties are lower. This paper focuses on microstructural characterization and analysis of fused filament fabricated tensile test coupons made from acrylonitrile butadiene styrene polymer, at various design conditions. Comparable tensile modulus with injection molded specimens was obtained for FFF design condition that is, slice height (0.1778 mm), raster width (0.4064 mm), raster to raster air gap (−0.0015 mm), contour to raster air gap (−0.0508 mm) and raster angle (0°). Scanning electron microscope studies provided an understanding as to why FFF processed specimens yielded lower failure strain and an insight into the presence of intralayer voids in specimens having lower tensile modulus. The study confirmed that though bulk mechanicals were affected by the combined effect of inter, intra and interfacial voids, intravoids had a predominant influence.     

Undifferentiated X-linked oligophrenias

In the course of investigation of 262 families with non-differentiated forms of oligophrenias it is established that in 48 families (18.3%) mental deficiency in sibs is caused by pathological mutations in the X-chromosome. Besides, it is not excluded that in certain inbred families oligophrenia in female persons is also, due to mutations linked with X-chromosome. This is supported by the dependence established between the frequency of the cases of oligophrenia among female persons and the inbreeding coefficient for the X-linked loci. The possibility of manifestation of the recessive genes of oligophrenia linked with X-chromosomes in heterozygous state is discussed.