Nonlinear optical characteristics of N,N’-bis(salicylidene)-p-phenylenediamine: Z-scan technique and quantum mechanical calculations

ABSTRACT. In this work, we have characterized the linear and nonlinear optical properties of N,N′-bis(salicylidene)-p-phenylenediamine (BSP) in both macroscopic and microscopic modes by using Z-scan technique and quantum chemical calculations. The microscopic nonlinear optical properties of BSP were investigated by density functional theory with the basis set of 6-311G++dp. Electronic properties such as frontier molecular energies, band-gap energy, electron affinity, hardness, softness, and ionization potential were evaluated. The calculation of microscopic quantities included first-order hyperpolarizability and natural bond orbitals showed the electron delocalization, which confirmed the nonlinear optical properties in this compound. The results of the absorption spectrum of BSP in DMSO, DMF, CH3Cl solvents were shown that the dissolved sample in DMSO had better nonlinear properties than others. Then the macroscopic nonlinear properties of the sample were determined by the Z-scan technique. The values of the nonlinear refractive index (n2), nonlinear absorption coefficient (β), and third-order nonsusceptibility of the sample in DMSO were, 0.09250×10-10 cm2/W, -0.174×10–6 cm/W and 4.101× 10-5 esu, respectively. The two-photon absorption in this molecule has been enhanced by the donor–bridge–donor (D–π–D) architecture. The theoretical and experimental results concluded that BSP seems to be promising candidates for future photonic and optoelectronic devices.                 KEY WORDS: Azo dye, Nonlinear optic, Hyperpolarizability, One photon absorption, Two photon absorption, Schiff bases   Bull. Chem. Soc. Ethiop. 2022, 36(2), 465-477.                                                               DOI: https://dx.doi.org/10.4314/bcse.v36i2.18                                                       &nbsp

Enriching the Medical Student Radiology Clerkship: Simulating the Radiologist’s Experience

Background Current radiology training in medical schools is still predominantly limited to passively observing the radiologist at the workstation and through lectures, textbooks and online sources. Evaluation is also mainly limited on still image interpretation or knowledge-based multiple-choice questions. Furthermore, students may have specific interests based on their choice of residency. In order to create a tailored and active learning experience, and to evaluate students’ ability in image interpretation, we utilized an open-source web-based Picture archiving and communication system (PACS) named Weasis and integrated a report system. Method We establish a new PACS teaching system by utilizing the open-source PACS system “dcm4chee” and integrating Weasis as imaging viewing browser, MySQL as database and JBOSS as application server. The developmental environment is MyEclipse, developmental language is JAVA. We use WADO (Web Access to Digital Imaging and Communications in Medicine (DICOM) Object) to achieve web-client DICOM images access. Java applets are used via a browser to serve as a DICOM viewer without special software required, and all functions (window width and level, zoom, measurement, etc.) are provided as controls within the server application. Thus we built a reporting system using the same method for student reporting and preceptor commenting and grading. Following the establishing and implementation of a reporting system using the same way as a plug-in, students can write up very brief reports in the form of impression points. Result Attending radiologists can send desired anonymized studies from hospital PACS during read-out to a shared secure server on the hospital network. Cases can then be immediately accessed by trainees on any computer in the hospital. Students, even simultaneously, can simulate being a radiologist and independently formulate an opinion and write up a brief report, without the need for occupying an expensive PACS workstation. The cases can be categorized into different subspecialties, difficulty levels, and imaging modalities. In addition, this can be also used for examination purposes, both for radiology rotation evaluation of medical students and as part of the pre-call Objective Structured Clinical Examinations (OSCEs) of first year residents. Conclusion By implementing Weasis and add-on reporting system, a real-time, easy-access, sophisticated Image Database can be established. for learning, didactic and evaluation purposes. Teaching cases can easily accumulate, thus to provide a new opportunity for both versatile training and evaluation purposes for radiology programs

Patološka i biokemijska istraživanja pokusno izazvanoga hipotireoidizma u ovaca.

The objective of this experiment was to determine pathological and biochemical changes in hypothyroid sheep. Experiments were carried out using 12 Iranian crossbred sheep aged between 3-3.5 years old and weighing 45-65 kg. The animals were divided into two groups, 4 sheep as control and 8 as the experimental group. Hypothyroidism was induced in experimental animals by giving thiourea 50 mg/kg body mass daily for 4 weeks. Blood samples were taken weekly for T3 and T4 measurements. There was a highly significant decrease (P<0.01) in values of T3 and T4 in experimental animals as compared to the control group. At the end of the experiment all the animals of control and experimental groups were sacrificed and necropsied. Tissue samples were collected from the thyroid, kidney, liver, skin and spleen and stained by hematoxylin and eosin and sudan 3 and 4. In the experimental group the following changes were observed: the thyroid gland was moderately enlarged and firm in texture and darker in color. Histopathologically, the epithelial lining of the thyroid follicles showed hypertrophy and hyperplasia which projected into the lumen. The lumens of the follicles were empty of colloid. Kidneys were apparently normal but microscopically showed glomerular lipidosis and tubular changes including mild congestion and lipidosis. The liver was pale, anemic, friable and enlarged. The hepatocytes exhibited fatty change and some inclusion bodies in their nuclei. Moreover, hyperplasia of bile ducts and mononuclear cell infiltration of liver were seen. The skin was mainly normal in the majority of the cases but histologically one case showed hyperkeratosis of the epidermis, associated with excessive keratin formation within the hair follicles. In the spleen, the number and size of macrophages were increased and one case showed some petechial hemorrhages on its surface. The treated ewes showed significant hyperlipidemia (P<0.01) and hypercholesterolemia (P<0.01). A significant decline (P<0.01) was detected in HDL as well as a significant increase (P<0.01) in LDL serum levels of the treated ewes.Svrha pokusa bila je istražiti patološke i biokemijske promjene u ovaca s hipotireoidizmom. U pokus je uzeto 12 iranskih križanih ovaca u dobi od 3 do 3,5 godine tjelesne mase 45 do 65 kg. Ovce su bile podijeljene u dvije skupine: četiri su uzete u kontrolnu, a osam u pokusnu skupinu. Hipotireoidizam je u pokusnih životinja bio potaknut davanjem 50 mg/kg tjelesne mase tioureje dnevno u tijeku četiri tjedna. Uzorci krvi uzimani su tjedno za mjerenje T3 i T4. Ustanovljeno je značajno smanjenje (P<0,01) vrijednosti T3 i T4 u pokusnih životinja u odnosu na kontrolnu skupinu. Na kraju pokusa sve su životinje pokusne i kontrolne skupine bile žrtvovane i razuđene. Uzeti su uzorci tkiva štitnjače, bubrega, jetre, kože i slezene te su pripremljeni histološki preparati obojeni hematoksilin-eozinom i sudan 3 i 4 postupkom. U pokusnoj skupini štitasta žlijezda bila je blago povećana, čvrste strukture i jače obojena. Epitel tireoidnoga folikula je hipertrofirao, a uočena je i hiperplazija projicirana u lumen. U lumenu folikula nije ustanovljen koloid. Bubrezi su makroskopski bili nepromijenjeni, ali je mikroskopski ustanovljena glomerularna lipidoza i tubularne promjene uključujući blagu kongestiju i lipidozu. Jetra su bila blijeda, anemična, prhka i povećana. U hepatocitima je ustanovljena masna degeneracija i inkluzijska tjelešca u jezgrama. Povrh toga ustanovljena je hiperplazija žučovoda i mononuklearna infiltracija jetrenoga tkiva. Koža je makroskopski bila normalna u većine životinja, ali je patohistološki u jednom slučaju ustanovljena hiperkeratoza epidermisa povezana s obilnom tvorbom keratina unutar dlačnih folikula. U slezeni je bio povećan broj makrofaga i njihova veličina, a u jednom slučaju ustanovljena su petehijalna krvarenja na površini. Pokusne ovce pokazivale su značajnu hiperlipidemiju (P<0,01) i hiperkolesterolemiju (P<0,01). Ustanovljen je značajan pad razine (P<0,01) lipoproteina velike gustoće kao i značajno povećanje (P<0,01) razine lipotroteina male gustoće u pokusnih ovaca

Epidemiology of Gastroesophageal Reflux Disease in Asia: A Systematic Review

Ethnic and geographical differences are important factors in studying disease frequencies, because they may highlight the environmental or genetic influences in the etiology. We retrieved the studies which have been published regarding the epidemiologic features of gastroesophageal reflux disease (GERD) in Asia, based on the definitions of GERD, study settings, publication years and geographical regions. From the population-based studies, the prevalence of symptom-based GERD in Eastern Asia was found to be 2.5%-4.8% before 2005 and 5.2%-8.5% from 2005 to 2010. In Southeast and Western Asia, it was 6.3%-18.3% after 2005, which was much higher than those in Eastern Asia. There were robust epidemiologic data of endoscopic reflux esophagitis in medical check-up participants. The prevalence of endoscopic reflux esophagitis in Eastern Asia increased from 3.4%-5.0% before 2000, to 4.3%-15.7% after 2005. Although there were only limited studies, the prevalence of extra-esophageal syndromes in Asia was higher in GERD group than in controls. The prevalence of Barrett's esophagus was 0.06%-0.84% in the health check-up participants, whereas it was 0.31%-2.00% in the referral hospital settings. In summary, the prevalence of symptom-based GERD and endoscopic reflux esophagitis has increased in Asian countries. However, the prevalence of Barrett's esophagus in Asia has not changed and also still rare