State University of Semarang

About: State University of Semarang is a education organization based out in Semarang, Indonesia. It is known for research contribution in the topics: Population & Curriculum. The organization has 7737 authors who have published 7790 publications receiving 38055 citations. The organization is also known as: Universitas Negeri Semarang.

Recurrent SARS-CoV-2 RNA positivity after COVID-19: a systematic review and meta-analysis

Abstract: Present study aimed to estimate the incidence of recurrent SARS-CoV-2 RNA positivity after recovery from COVID-19 and to determine the factors associated with recurrent positivity. We searched the PubMed, MedRxiv, BioRxiv, the Cochrane Library, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry for studies published to June 12, 2020. Studies were reviewed to determine the risk of bias. A random-effects model was used to pool results. Heterogeneity was assessed using I2. Fourteen studies of 2568 individuals were included. The incidence of recurrent SARS-CoV-2 positivity was 14.8% (95% confidence interval [CI] 11.44–18.19%). The pooled estimate of the interval from disease onset to recurrence was 35.4 days (95% CI 32.65–38.24 days), and from the last negative to the recurrent positive result was 9.8 days (95% CI 7.31–12.22 days). Patients with younger age and a longer initial illness were more likely to experience recurrent SARS-CoV-2 positivity, while patients with diabetes, severe disease, and a low lymphocyte count were less likely to experience. Present study concluded that the incidence of recurrent SARS-CoV-2 positivity was 14.8% suggesting further studies must be conducted to elucidate the possibility of infectious individuals with prolonged or recurrent RNA positivity.

Implementasi LKS Dengan Pendekatan STEM (Science, Technology, Engineering, And Mathematics) Untuk Meningkatkan Kemampuan Berpikir Kritis Siswa

Abstract: The purpose of this study is to overcome the increased of critical thinking’ students after they used worksheet with STEM approach. This research method is experiment method that consist of preparing, implementation, and data processing. Increasing of critical thinking can be measured by pretest-posttest problems. The result of data normalization show that data have normal distributed so next test is n-gain test. Result of the n-gain test pretest-posttest scores around 0.5 ( medium level categorized). The highest improvement is 0.9 at evaluation aspect and lowest increase is 0.3 at interpretation aspect.

Antioxidant activity in vitro of two aromatic compounds from Caesalpinia sappan L.

Abstract: Two antioxidant compounds were isolated from C. sappan L by multiple steps of column chromatography and thin layer chromatography in succession with superoxide scavenging assay as activity monitor. Structures of the two compounds were determined by spectroscopic methods as 1',4'-dihydro-spiro[benzofuran-3(2H),3'-[3H-2]benzopyran]-1',6',6',7'-tetrol (compound 1) and 3-[[4,5-dihydroxy-2(hydroxymethyl) phenyl]-methyl]-2,3-dihydro-3,6-benzofurandiol (compound 2). Characterization of antioxidant properties of these two compounds was done by determining the inhibitory effect on xanthine oxidase activity as well as scavenging effect on superoxide anion and hydroxyl radicals. Our results indicated that compounds 1 and 2 inhibited xanthine oxidase activity and scavenged superoxide anion and hydroxyl radicals. Compounds 1 and 2 possessed similar radical scavenging activities as ascorbic acid, and they were more effective than other well-known antioxidants such as alpha-tocopherol, beta-carotene, and BHT. As inhibitors of free radical formation, compounds 1 and 2 were more effective than all the other antioxidants tested. In conclusion, compounds 1 and 2 can be regarded as primary antioxidants with radical-scavenging and chain-breaking activities as well as secondary antioxidants with inhibitory effect on radical generation.

Penerapan model discovery terbimbing pada pembelajaran fisika untuk meningkatkan kemampuan berpikir kreatif

Abstract: Penelitian ini bertujuan untuk mengetahui penerapan model pembelajaran discovery terbimbing pada materi kalor terhadap peningkatan kemampuan berpikir kreatif siswa MTs Matholi’ul Huda Troso. Penelitian eksperimen ini menggunakan Design Control Group Pre-test – Post-test . Populasi pada penelitian ini adalah siswa kelas VII MTs Matholi’iul Huda Troso tahun ajaran 2010/2011. Pengambilan sampel melalui teknik simple random sampling dengan mengambil dua kelas secara acak dari populasi sebagai kelas kontrol dan kelas eksperimen. Analisis uji gain ternormalisasi memberikan hasil peningkatan rendah untuk siswa yang diajar menggunakan model discovery terbimbing dan kecil untuk siswa yang diajar menggunakan metode diskusi. Hasil penelitian dapat disimpulkan bahwa penerapan model pembelajaran discovery terbimbing dapat meningkatkan kemampuan berpikir kreatif siswa. This research was aimed to determine the application of guided discovery learning applied in heat topic in increasing the ability of Matholi’ul Huda Islamic Secondary School students’ creative thinking skills. The design of this research was experimental research with the Control Group Pre-test Post-test Design . The population of this research were the students grade of VII Matholi’ul Huda Islamic Secondary School year 2010/2011. Sampling technique of this research were used simple random sampling technique by taking two classes from the population as a control class and an experimental class. The data analysis using gain normalized test showed that the result is medium category for class which was taught by guided discovery model, and low category for class which was taught by discussion method. The conclusion of this research is that the application of guided discovery learning can increase the students’ creative thinking skills.

Methyl violet dye removal using coal fly ash (CFA) as a dual sites adsorbent

Abstract: It has become a trend to use cheap adsorbents like coal fly ash (CFA) for removal of dyes. CFA is a solid waste produced from coal-based power plant. CFA is mainly composed of minerals containing some oxides such as Al2O3 and SiO2 having active sites and mesoporous unburned carbon. The existence of active sites in the CFA's minerals and carbon pores was considered to have roles in the adsorption process with different adsorption mechanisms, namely chemisorption for the minerals and physisorption for the unburned carbon. This allows the CFA to become a dual sites adsorbent. As the result, isothermal models such as Langmuir and Freundlich may not be appropriate. The objectives of this study are to develop appropriate dual sites isotherm models for methyl violet dye adsorption onto the CFA, and to compare the models with single site models including Langmuir and Freundlich. The CFAs having [Si + Al]/C ratio of 0.5, 2.0 and 90, namely CFA-1, CFA-2, and CFA-3, respectively were used in this study. X-Ray Fluorescence (XRF) analysis results showed that the major components of the original CFA are SiO2 (36.47%) and Al2O3 (19.27%), while the unburned carbon content is 19.11%. Additionally, the adsorption test results showed that CFA with high unburned carbon contents (i.e. CFA-1 and CFA-2) were well fitted with the dual sites isotherm model, i.e. Freundlich–Langmuir isotherm model. Whereas, CFA with low unburned carbon contents (i.e. CFA-3) was well fitted with the single site isotherm model, i.e. Langmuir isotherm model.