Axon morphology of rapid Golgistained pyramidal neurons in the prefrontal cortex in schizophrenia

Aim To analyze axon morphology on rapid Golgi impregnated pyramidal neurons in the dorsolateral prefrontal cortex in schizophrenia. Methods Postmortem brain tissue from five subjects diagnosed with schizophrenia and five control subjects without neuropathological findings was processed with the rapid Golgi method. Layer III and layer V pyramidal neurons from Brodmann area 9 were chosen in each brain for reconstruction with Neurolucida software. The axons and cell bodies of 136 neurons from subjects with schizophrenia and of 165 neurons from control subjects were traced. The data obtained by quantitative analysis were compared between the schizophrenia and control group with the t test. Results Axon impregnation length was consistently greater in the schizophrenia group. The axon main trunk length was significantly greater in the schizophrenia than in the control group (93.7±36.6 μm vs 49.8±9.9 μm, P=0.032). Furthermore, in the schizophrenia group more axons had visibly stained collaterals (14.7% vs 5.5%). Conclusion Axon rapid Golgi impregnation stops at the beginning of the myelin sheath. The increased axonal staining in the schizophrenia group could, therefore, be explained by reduced axon myelination. Such a decrease in axon myelination is in line with both the disconnection hypothesis and the two-hit model of schizophrenia as a neurodevelopmental disease. Our results support that the cortical circuitry disorganization in schizophrenia might be caused by functional alterations of two major classes of principal neurons due to altered oligodendrocyte development

Testing of welded butan: Propane gas container of AIMg3 alloy

U radu su prikazani rezultati ispiitvanja hidrostatičkim pritiskom do rasprskavanja zavarenih boca, izrađenih od legure AIMg3 debljine 4 mm. Mernim trakama je praćena deformacija boce na karakterističnim mestima da bi se odredilo naponsko stanje. Naponsko stanje boce je takođe proračunato primenom membranske teorije ljuski za tankozidne posude pod pritiskom. Usvajanje pritiska kao promjenjive izvedeni su osnovni izrazi za napone i deformacije. Proračunati naponi i deformacije su upoređeni sa izmerenim vrednostima.In the paper are presented results of testing by hydro­static pressure up to the bursting of welded container, produced of AIMg3 alloy, 4 mm in thickness. Strains on characteristic position had been recorded by strain gauges in order to determine stress state. Stress state of container is also calculated using membrane theory for shells for thin walled pressure vessels. Taking pressure as the variable the basic expressions for stresses and strains are developed. Calculated stresses and strains are compared with measured values

Testing of welded butan: Propane gas container of AIMg3 alloy

U radu su prikazani rezultati ispiitvanja hidrostatičkim pritiskom do rasprskavanja zavarenih boca, izrađenih od legure AIMg3 debljine 4 mm. Mernim trakama je praćena deformacija boce na karakterističnim mestima da bi se odredilo naponsko stanje. Naponsko stanje boce je takođe proračunato primenom membranske teorije ljuski za tankozidne posude pod pritiskom. Usvajanje pritiska kao promjenjive izvedeni su osnovni izrazi za napone i deformacije. Proračunati naponi i deformacije su upoređeni sa izmerenim vrednostima.In the paper are presented results of testing by hydro­static pressure up to the bursting of welded container, produced of AIMg3 alloy, 4 mm in thickness. Strains on characteristic position had been recorded by strain gauges in order to determine stress state. Stress state of container is also calculated using membrane theory for shells for thin walled pressure vessels. Taking pressure as the variable the basic expressions for stresses and strains are developed. Calculated stresses and strains are compared with measured values

External atmospheric influences on the mechanical properties of resin-bonded grinding wheels with aluminium oxide and silicon carbide grains

Ageing effects on resin-bonded grinding wheel properties are presented, including aluminium oxide and silicon carbide influence. Furthermore, humidity is examined as the most likely cause of significant downgrade in mechanical properties. Toward this aim a new system of accelerated ageing of grinding wheels (additional humidification) is used under special atmospheric conditions. The mechanisms for microstructural changes during ageing are analysed, based on the microstructure exposure to thermo-mechanical impacts

External atmospheric influences on the mechanical properties of resin-bonded grinding wheels with aluminium oxide and silicon carbide grains

Ageing effects on resin-bonded grinding wheel properties are presented, including aluminium oxide and silicon carbide influence. Furthermore, humidity is examined as the most likely cause of significant downgrade in mechanical properties. Toward this aim a new system of accelerated ageing of grinding wheels (additional humidification) is used under special atmospheric conditions. The mechanisms for microstructural changes during ageing are analysed, based on the microstructure exposure to thermo-mechanical impacts

Possibilities of predicting the behaviour of ferrite-austenite welded joints in pressure equipment during exploitation

Eksplotacijska sigurnost tlačne opreme zavisi, između ostalog, i od mogućnosti predviđanja ponašanja svakog njenog dijela toijekom eksploatacije. Ako se analiza sigurnosti odnosi na materijale od kojih su izrađeni pojedini delovi tlačne opreme, omotač, danca, prirubnice, predviđanje njihovog ponašanja je relativno jednostavno jer se radi o materijalima čija su svojstva uglavnom ujednačena u svim smjerovima. Međutim, predviđanje ponašanja zavarenih spojeva je, zbog kemijske i strukturne nehomogenosti, promjene geometrije stijenke na mjestu zavarenog spoja, zbog zaostalih naprezanja i grešaka formiranja šava, teže i time i manje pouzdano. Ponekad se, zbog optimizacije, različiti dijelovi tlačne opreme izrađuju od različitih vrsta čelika, zbog čega se pojavljuju zavareni spojevi između raznorodnih čelika. Zbog razlika u fizikalnim i mehaničkim svojstvima ovih čelika, njihovi spojevi imaju svoje specifičnosti koje u znatnoj mjeri otežavaju predviđanje njihovog ponašanja tijekom eksploatacije tlačne opreme.Exploitation safety of pressure equipment depends, among other factors, on the possibility of predicting the behaviour of each of its components during exploitation. If the safety of analysis is oriented towards materials which are used for manufacturing of individual parts of pressure equipment, such as mantle, lids and flanges, predicting their behaviour is relatively simple since the properties of these materials are generally similar in all directions. However, predicting the behaviour of welded joints is significantly harder and less reliable, due to a number of reasons, including chemical and structural non-homogeneity, changes in wall geometry at the welded joint site, as well as residual stresses and weld forming defects. Occasionaly, different pressure equipment parts are made of different types of steel, due to optimisation, which results in heterogeneous welded joints. Because of the difference in physical and mechanical properties of these steels, their joints have their own specificities, which make predicting their behaviour during exploitation much more complicated

Optimization of Nitrogen Use Efficiency in Cutting of Austenitic Stainless Steel by a Fiber Laser

In metallurgical processes, metal sheet cutting is usually a basic technological operation that needs to be performed. All other technological operations follow the procedure of metal sheet cutting, with the final aim of manufacturing a final product. Machines used for that basic metal cutting operation shall be reliable, efficient, fast, and relatively easy to work with. While working with a laser, the authors noticed the inefficiency of cutting with nitrogen. Nitrogen bottles got empty too quickly, which caused additional costs. Inefficient, i.e., excessive nitrogen consumption requires a more frequent supply of nitrogen. During the COVID-19 pandemic, nitrogen was not always available, as suppliers shifted to manufacture oxygen bottles for medical needs. Therefore, the authors engaged in finding solutions to reduce the consumption of nitrogen at cutting. The mentioned problem was studied within the experiment that focused on the optimization of nitrogen use during fiber laser cutting, the procedure, and results of which are described in this paper. Specimens of different cutting parameters were prepared and cut to measure their roughness and burr height. The collected data were used to create a mathematical model with an ANOVA table. The experiment resulted in the determination of optimal cutting parameters achieved by the lowest possible cutting gas pressure

Analysis of the effect of implant distance from the surrounding structure, in the PMMA block model

Strain analysis in the vicinity of the dental implants were the subject of many research papers. In this study, new experimental method was employed for strain determination in the surrounding area of the axially loaded dental implant, which was embedded in the resin block. This studies can improve understanding of strain distribution, and its possible effects on the surrounding structure. Dental Implant Branemark with dimensions of 14 x 3.75 mm was immersed into rectangular block of polymethil methacrylate in vertical position. Implant was distanced 2 mm and 4 mm from the block sides, and they were named as the surface 1 and surface 2, respectively. Axial load, in the range of 0 - 500 N, was applied using Universal testing machine Tinius Olsen. Digital Image Correlation method was used for measuring deformation. Results were presented in the form of horizontal and vertical strains. Horizontal strains were mostly tensile, with maximum value of 0.3 % on the bottom of the surface 1. This values decreased in the upper area of the block side. Vertical compressive strain were 2-3 times higher on the surface 1, when compared to the surface 2, with maximum values of 0.7 % located on the bottom of the surface 1, and 0.3 % on the bottom of the surface 2. Resin block models could be used for determination of strain distribution under axially loaded implants. Greatest strain concentration were located under the implants apex, in the bottom area of the block. It was concluded that, in this region, strain values decreased linearly with increase of distance from the implants surface

Optimization of nitrogen use efficiency in cutting of austenitic stainless steel by a fiber laser

In metallurgical processes, metal sheet cutting is usually a basic technological operation that needs to be performed. All other technological operations follow the procedure of metal sheet cutting, with the final aim of manufacturing a final product. Machines used for that basic metal cutting operation shall be reliable, efficient, fast, and relatively easy to work with. While working with a laser, the authors noticed the inefficiency of cutting with nitrogen. Nitrogen bottles got empty too quickly, which caused additional costs. Inefficient, i.e., excessive nitrogen consumption requires a more frequent supply of nitrogen. During the COVID-19 pandemic, nitrogen was not always available, as suppliers shifted to manufacture oxygen bottles for medical needs. Therefore, the authors engaged in finding solutions to reduce the consumption of nitrogen at cutting. The mentioned problem was studied within the experiment that focused on the optimization of nitrogen use during fiber laser cutting, the procedure, and results of which are described in this paper. Specimens of different cutting parameters were prepared and cut to measure their roughness and burr height. The collected data were used to create a mathematical model with an ANOVA table. The experiment resulted in the determination of optimal cutting parameters achieved by the lowest possible cutting gas pressure