Micro-Change Process of Calcium–Magnesium Double Expansive Agent and Its Performance Characterization in Cement-Based Materials

With the increase of cement output, the demand for cement expansion agents increases, and composite expansion agents have become the development trend. The purpose of this study is to study the microscopic change process and expansion effect of calcium oxide and magnesium oxide double expansion agents. After calcination at different temperatures, the change process of microscopic morphology of calcined products was observed. Through calcining dolomite at 900 °C, the mixture D900 of calcium oxide and magnesium oxide was obtained. To prepare mixed cement, 10 wt %, 20 wt %, and 30 wt % of D900 were added into cement to prepare mixed cement. At the same time, the compressive strength, deformation, and porosity of mixed cement were measured. The results show that adding D900 improves the expansion rate of early cement paste and reduces the compressive strength. After 120 days, the compressive strength of 20 wt % cement paste is higher than that of blank cement paste, and the porosity of 20 wt % cement paste is the lowest among the three mixed cements. This shows that 20 wt % is a more suitable substitute.

Epithelial Alteration Associated With Recovery From Laryngeal Squamous Metaplasia in Rats: Kinetics of Recovery From a Test Item-Related Change

Squamous metaplasia is a nonspecific adaptive response to chronic irritation in the larynx and is often diagnosed as a test item-related change in rat inhalation studies. Investigating scientists are frequently asked to assess the adversity of laryngeal squamous metaplasia and to interpret its relevance to human risk. One factor in predicting relevance to human risk is the kinetics (degree and speed) of recovery following the cessation of exposure to the test item. Most reports describing recovery from squamous metaplasia in the rat larynx discuss the more severe end of the spectrum of metaplastic change (moderate to severe) and include relatively long (6 weeks or more) recovery periods. We conducted 2 studies to evaluate the toxicity and recovery from any potential effects of 4-(Chloro-2-methylphenoxy) butyric (MCPB) acid, a herbicide, when administered by inhalation to young male Sprague Dawley rats for 3 to 4 weeks. The studies resulted in minimal to moderate laryngeal squamous metaplasia for which we describe the kinetics of recovery over 1 to 4 weeks. We found that the microscopic change epithelial alteration, which is normally considered to be a precursor in the development of squamous metaplasia, can occur as a transitional stage between squamous and normal epithelium during recovery.

А Result of the histo-phatologic examination on edible organs of the livestock around the suspected mining area

In the last decade, there is growing concern about the increase in the number of unknown diseases of pasture livestock due to the natural and anthropogenic factors, such as heavy metals and dust exposure. Thus, it is necessary to measure the concentration of heavy metals in different organs of animals, as well as blood parameters assay and histopathology. We have collected samples from different suspected mining areas, using a random sampling method, and selected 15 goats and 15 sheep. The histopathologic study was performed in necropsy, also macroscopic and microscopic analysis were performed on the diseased animals comparing with healthy animals. In this study, 37.3 % of the sheep and 54.6% of the goat samples were found with gross lesions from different organs, while 24% of sheep and 18.6% of goat organs had microscopic change. Through histo-pathology study, small ruminant lungs of livestock from suspected mining areas were found with inflammatory nodules, while other edible organs were changed in a special transition. In conclusion, we assume the dust exposure from the mining area can be the reason behind the dysfunction. Уул уурхайн, хайгуул олборлолтын бүс орчимд бэлчээрлэж байсан малын эд, эрхтэнд эд судлалын шинжилгээ хийсэн дүнгээс Дэлхийн дулааралт, хуурайшилт болон хүний хүчин зүйлийн (байгаль орчинд халтай технологи бүхий уул уурхайн эрчимтэй үйлдвэрлэл, тээвэрлэлт, эмх замбараагүй олборлолт, хог хаягдал г.м) нөлөөлөлд Монгол орны бэлчээрийн мал өртсөний улмаас онош нь тодорхойгүй өвчин, төрөл бүрийн хүнд металлын хордлогот эмгэг илэрч, өвчлөх, үхэх, тоо толгой нь хорогдох зэрэг эдийн засгийн хохирол бүхий тохиолдол сүүлийн жилүүдэд нэмэгдэх хандлагатай болсон. Иймд мал амьтны эд эрхтэнд агуулагдаж буй хүнд металлын агууламжийг тодорхойлохын зэрэгцээ биохими болон эд судлалын шинжилгээ хийх шаардлага урган гарсан. Эд судлалын шинжилгээнд төв аймгийн Заамар сумын алтны хайгуул, олборлолт явуулж буй бүс нутаг орчим бэлчээрлэж байсан 6 хонь, 6 ямаа, Дорноговь аймгийн Улаанбадрах, Зүүнбаян сумын нутаг дэвсгэрт ураны хайгуул, туршилтын олборлолт явуулж буй бүс нутаг болон Айраг сумын жоншны уурхайн олборлолтын бүс нутаг орчим бэлчээрлэж байсан 9 хонь, 9 ямааны эд эрхтнүүдийг хамруулан шинжилгээ хийсэн. Түлхүүр үг: хонь, ямаа, эд судлалын эмгэгт өөрчлөлт, үлэмж ба бичил бүтэц

Microscopic Change in Hardened Cement Paste Due to High-Speed Impact

Impact load was applied to hardened cement paste (HCP) specimens using a gas gun to investigate microscopic changes in the specimens and develop a better response model of concrete subjected to impact load. Plasma emission was observed at the moment of impact at 420 m/s and the colour of the portion near the impact point turned brighter. This brighter portion was analysed, and it was observed that the pore structure was coarser compared to the other portion; however, the results of thermogravimetry and X-ray diffraction analysis were similar. A possible reason is that the generated heat was instantaneous and the rate of the temperature increase in the HCP decreased due to evaporation of water in the HCP. These results indicate that during impact at a few hundred m/s, porosity increase due to heat effect is more dominant than porosity decrease due to mechanical compaction.

Gambaran makroskopik dan mikroskopik otak besar pada hewan coba postmortem

Most brain cells belong to pyramidal cells which are very sensitive toward conditions that cause cell death. This study was aimed to obtain macroscopic and microscopic postmortem changes of the brain according to time variations up to 48 hours. This study was conducted at Histology Laboratorium, Medical Faculty of Sam Ratulangi University, Manado. Two domestic pigs weighing 20 kg were used as models. Macroscopic and microscopic observations were done at certain interval times. The results showed that at 16 hours postmortem, the brain looked pale, its consistency became softer and watery, and the inner part would crumble under touch. At 44 hours postmortem most of the brain became watery which was complete at 48 hours postmortem. Microscopic observations were done on brain samples at time intervals, as follows: 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 9 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours, and 24 hours postmortem. The earliest microscopic change was observed at 3 hours postmortem as the enlargement of clear zones around the pyramidal cells. At 7 hours postmortem, the pyramidal cells became flattened, darker, and shorter. At 18 hours postmortem, the pyramidal cells underwent fragmentation, and at 24 hours postmortem they became lysis leaving empty spaces. Conclusion: All parts of the brain became watery at 48 hours postmortem. The microscopic changes were the enlargemnet of clear zones around the pyramidal cells, the cells became darker, flattened, and shorter, underwent fragmentation and lysis leaving empty spaces.Keywords: postmortem, macroscopic and microscopic changed, pyramidal cell Abstrak: Sebagian besar sel penyusun otak ialah sel piramidal yang sangat peka terhadap keadaan yang dapat menyebabkan kematian sel. Penelitian ini bertujuan untuk mendapatkan perubahan makroskopik dan mikroskopik postmortem dari otak besar berdasarkan variasi waktu sampai 48 jam pada hewan coba. Penelitian dilaksanakan di Laboratorium Histologi Fakultas Kedokteran Universitas Sam Ratulangi Manado. Hewan coba ialah dua ekor babi domestik, berat badan sekitar 20 kg. Pengamatan makroskopik dan mikroskopik dilakukan pada interval waktu tertentu. Hasil penelitian mendapatkan pada 16 jam postmortem otak besar tampak pucat, konsistensi melunak, berair, dan bagian dalam akan hancur bila disentuh. Pada 44 jam postmortem sebagian besar bagian otak besar telah mencair yang menjadi lengkap pada 48 jaam postmortem. Pengamatan mikroskopik dilakukan terhadap sediaan otak besar dengan interval waktu 1 jam, 2 jam, 3 jam, 4 jam, 5 jam, 6 jam, 9 jam, 10 jam, 12 jam, 14 jam, 16 jam, 18 jam, 20 jam, 22 jam, 24 jam postmortem. Perubahan mikroskopik paling awal terlihat pada 3 jam postmortem berupa zona jernih mengelilingi sel-sel piramidal. Pada 7 jam postmortem sel-sel piramidal tampak gelap, memipih, dan memendek. Pada 18 jam postmortem sel-sel piramidal mengalami fragmentasi dan lisis pada 24 jam postmortem dengan meninggalkan ruang-ruang kosong. Simpulan: Seluruh otak besar telah mencair pada 48 jam postmortem. Perubahan mikroskopik yang teridentifikasi ialah pelebaran zona jernih sekeliling sel piramidal, sel-sel piramidal tampak gelap, memipih, dan memendek, fragmentasi, dan lisis pada 24 jam postmortem dengan meninggalkan ruang-ruang kosong. Kata kunci: postmortem, perubahan makroskopik and mikroskopik, sel piramidal

Clinical correlation with pathology of placenta in medical disorders of pregnancy and its comparison in normal pregnancy

Background: Healthy placenta is responsible for maintaining pregnancy and promoting normal foetal development. It reflects the intrauterine status of the foetus.Methods: In the present prospective study, total 50 Placentae from Medical Disorders of Pregnancies were studied and compared with equal number of Placentae from normal Pregnancies.Results: The significant macroscopic changes were calcification and infarction seen in Hypertensive Disorder. Extensive placental infarction was associated with high incidence of low APGAR (82%) and perinatal deaths (66.67%). No significant gross macroscopic changes were seen in Anaemia, Diabetes Mellitus and Heart Disease. Increased syncytial knots, fibrinoid degeneration, vasculo-syncytial membrane paucity were significant microscopic changes in Hypertensive Disorder. In Anaemia stromal fibrosis, increased syncytial knots were seen, whereas in Diabetes Mellitus villous edema was the most significant microscopic finding. No significant microscopic change was found in Heart Disease. Increased syncytial knots, fibrinoid degeneration, vasculo-syncytial membrane paucity, stromal fibrosis were associated with increased perinatal mortality.Conclusions: Gross and microscopic examination of placenta is strongly recommended in cases where maternal co-morbid conditions is likely to have an adverse perinatal outcome.