KUAT TEKAN BETON GEOPOLYMER BERBAHAN DASAR ABU TERBANG (FLY ASH)

Beton merupakan material yang sangat penting dan banyak digunakan untuk membangun infrastruktur. Kebutuhan akan beton meningkat sejalan dengan meningkatnya kebutuhan sarana dan prasarana dasar manusia. Oleh karena itu produksi semen sebagai bahan pengikat beton meningkat pula. Dalam proses produksi semen terjadi pelepasan karbon dioksida (CO₂) yang sangat banyak ke atmosfer yang dapat merusak lingkungan. Untuk mengatasi efek buruk tersebut maka perlu dicari material lain sebagai bahan pengganti semen. Beton geopolymer merupakan salah satu alternatif untuk mengganti beton yang menggunakan semen yang kurang ramah lingkungan. Beton geopolymer dibuat tanpa menggunakan semen sebagai bahan pengikat, dan sebagai gantinya digunakan Abu Terbang (Fly Ash) yang kaya akan Silika dan Alumina dan dapat bereaksi dengan cairan alkalin untuk menghasilkan bahan pengikat (binder). Pada penelitian ini dilakukan pengujian kuat tekan beton terhadap sejumlah benda uji berbentuk kubus 15x15x15 cm3 dengan variasi curing time: 4 jam, 8 jam, 12 jam dan 24 jam menggunakan oven. Berdasarkan hasil penelitian dapat diperoleh grafik hubungan antara kuat tekan beton terhadap curing time. Trend menunjukkan bahwa semakin lama curing time maka semakin besar kuat tekan yang dihasilkan. Terlihat juga bahwa kuat tekan optimum dihasilkan pada curing time 24 jam.   Kata kunci : beton geopolymer, fly ash, ramah lingkungan, kuat teka

Gender differences in the perception of safety in public transport

Concerns over women's safety on public transport systems are commonly reported in the media. In this paper we develop statistical models to test for gender differences in the perception of safety and satisfaction on urban metros and buses using large-scale unique customer satisfaction data for 28 world cities over the period 2009 to 2018. Results indicate a significant gender gap in the perception of safety, with women being 10\% more likely than men to feel unsafe in metros (6% for buses). This gender gap is larger for safety than for overall satisfaction (3% in metros and 2.5% in buses), which is consistent with safety being one dimension of overall satisfaction. Results are stable across specifications and robust to inclusion of city-level and time controls. We find heterogeneous responses by sociodemographic characteristics. Data indicates 45% of women feel secure in trains and metro stations (respectively 55% in buses). Thus the gender gap encompasses more differences in transport perception between men and women rather than an intrinsic network fear. Additional models test for the influence of metro characteristics on perceived safety levels and find that that more acts of violence, larger carriages, and emptier vehicles decrease women's feeling of safety

First-principles modeling of the polycyclic aromatic hydrocarbons reduction

Density functional theory modelling of the reduction of realistic nanographene molecules (C42H18, C48H18 and C60H24) by molecular hydrogen evidences for the presence of limits in the hydrogenation process. These limits caused the contentions between three-fold symmetry of polycyclic aromatic hydrocarbon molecules and two-fold symmetry of adsorbed hydrogen pairs. Increase of the binding energy between nanographenes during reduction is also discussed as possible cause of the experimentally observed limited hydrogenation of studied nanographenes.Comment: 18 pages, 7 figures, accepted to J. Phys. Chem.

Значение герминальной BRCA-мутации при формировании опухолевого микроокружения Эффективность PARP-ингибирования в поздней линии терапии метастатического кастрационно-резистентного рака предстательной железы

Metastatic castration-resistant prostate cancer is a difficult problem for a clinical oncologist. In addition, mutations in genes of homologous DNA recombination, including BRCA1/2, suggest an aggressive behavior and therapy resistance. Treatment options for such patients were significantly limited until new drugs - PARP inhibitors have been registered. Nevertheless, there is evidence that BRCA1/2 gene mutations are associated with increased mutational load, neoepitopes formation, increased number of tumor-infiltrating lymphocytes and a response to the immune response checkpoints blockade. Studies have shown that BRCA2-mutated prostate cancer demonstrates high level of immune cells infiltration compared to tumors without mutation, in particular with respect to CD4+, CD8+ and FOXP3+ T-lymphocytes. It should be noted that studies have shown a tendency of CD8+ T-lymphocytes/FOXP3+ T-cells ratio decreasing in BRCA2-mutated tumors. Thus, the mutational status of BRCA2 presumably forms the immune phenotype of prostate cancer with an increase of intratumoral immune cells, but with immunosuppressive properties. At the same time, the use of immune checkpoint blockers in advanced prostate cancer has been unsuccessful in terms of overall survival. Despite the fact that immune checkpoint blocker's efficacy is often associated with a high intracellular CD4+ and CD8+ T lymphocytes, their presence is clearly insufficient for response. Studies showed that PARP inhibitors effect tumor microenvironment significantly. Anti-PD-1/PD-L1 combination with PARP inhibitors is being actively studied due to their properties of modulating the tumor microenvironment. Thus, future immunooncological strategies for primary prostate cancer therapy may include not only an increase in mutational load, but also an impact on the immunosuppressive microenvironment. The article presents clinical cases of 3 brothers, carriers of the germinal BRCA2 c.9371A>T mutation, suffering from prostate cancer with a burdened family history. The disease development under standard therapies was studied and markers of the tumor microenvironment were immunohistochemically evaluated. PARP inhibitor Olaparib efficacy in prostate cancer of older brother in late-line therapy for metastatic castration-resistant disease was analyzed.Метастатический кастрационно-резистентный рак предстательной железы является сложной проблемой для клинического онколога. Кроме этого, наличие мутации в генах гомологичной рекомбинации ДНК, в том числе BRCA1/2, предполагает агрессивное течение и резистентность к проводимой терапии. До регистрации новой группы препаратов - PARP-ингибиторов - опции лечения таких больных были существенно ограниченны. Тем не менее есть данные о том, что мутации генов BRCA1/2 связаны с повышенной мутационной нагрузкой, образованием неоэпитопов, увеличением количества инфильтрирующих опухоль лимфоцитов и ответом на блокаду контрольных точек иммунного ответа. В исследованиях показано, что BRCA2-мутированный рак предстательной железы обладает высоким уровнем инфильтрации иммунными клетками по сравнению с опухолями без мутации, в частности в отношении Т-лимфоцитов, экспрессирующих CD4, CD8 и FOXP3. Следует отметить, что в исследованиях наблюдалась тенденция к снижению отношения CD8+-Т-лимфоцитов к FOXP3+-Т-клеткам в BRCA2-мутированных опухолях. Таким образом, мутационный статус BRCA2 предположительно формирует иммунный фенотип рака предстательной железы с увеличением количества интратуморальных иммунных клеток, но с иммуносупрессивными свойствами. При этом использование блокаторов контрольных точек иммунитета при распространенном раке предстательной железы до сих пор было в значительной степени безуспешным в отношении показателей общей выживаемости пациентов. Несмотря на то что эффективность блокаторов контрольных точек иммунитета зачастую связана с высоким содержанием внутриопухолевых CD4+- и CD8+-Т-лимфоцитов, их присутствия явно недостаточно для ответа. Как показано в исследованиях, ингибиторы PARP способны оказывать существенное влияние на микроокружение опухоли. Активно изучается комбинация анти-PD-VPD-Lt с ингибиторами PARP за счет их свойств модулирования микроокружения опухоли. Таким образом, будущие онкоиммунологические стратегии первичной терапии рака предстательной железы могут включать не только повышение мутационной нагрузки, но и воздействие на иммуносупрессивное микроокружение. В статье представлены случаи развития рака предстательной железы у 3 братьев, носителей герминальной мутации гена BRCA2 c.9371A>T с отягощенным семейным анамнезом. Изучено клиническое течение заболевания при применении стандартных методов терапии, иммуногистохимически оценены маркеры микроокружения опухоли. Проанализирована эффективность использования PARP-ингибитора олапариба у одного из братьев в поздней линии терапии при метастатическом кастрационно-резистентном заболевании

Friends with Benefits: Social Coupons as a Strategy to Enhance Customers’ Social Empowerment

Businesses often seek to leverage customers’ social networks to acquire new customers and stimulate word-of-mouth recommendations. While customers make brand recommendations for various reasons (e.g., incentives, reputation enhancement), they are also motivated by a desire for social empowerment—to feel an impact on others. In several multi-method studies, we show that facilitating sharing of social coupons (i.e., coupon sets that include one for self-use and one to be shared) is a unique marketing strategy that facilitates social empowerment. Firms benefit from social coupons because customers who share spend more and report greater purchase intentions than those who do not. Furthermore, we demonstrate that social coupons are most effective when the sharer’s brand relationship is new versus established. For customers with an established relationship, sharing with a receiver who also has an established relationship maximizes potential impact. Together, these studies connect social empowerment to relationship marketing and provide guidance to managers targeting social coupons

Bedmap2: improved ice bed, surface and thickness datasets for Antarctica

We present Bedmap2, a new suite of gridded products describing surface elevation, ice-thickness and the seafloor and subglacial bed elevation of the Antarctic south of 60° S. We derived these products using data from a variety of sources, including many substantial surveys completed since the original Bedmap compilation (Bedmap1) in 2001. In particular, the Bedmap2 ice thickness grid is made from 25 million measurements, over two orders of magnitude more than were used in Bedmap1. In most parts of Antarctica the subglacial landscape is visible in much greater detail than was previously available and the improved data-coverage has in many areas revealed the full scale of mountain ranges, valleys, basins and troughs, only fragments of which were previously indicated in local surveys. The derived statistics for Bedmap2 show that the volume of ice contained in the Antarctic ice sheet (27 million km3) and its potential contribution to sea-level rise (58 m) are similar to those of Bedmap1, but the mean thickness of the ice sheet is 4.6% greater, the mean depth of the bed beneath the grounded ice sheet is 72 m lower and the area of ice sheet grounded on bed below sea level is increased by 10%. The Bedmap2 compilation highlights several areas beneath the ice sheet where the bed elevation is substantially lower than the deepest bed indicated by Bedmap1. These products, along with grids of data coverage and uncertainty, provide new opportunities for detailed modelling of the past and future evolution of the Antarctic ice sheets

Comperetive analysis of minimal mearsurable disease monitoring by flow cytometry and real-time quantitative pcr results in infants with acute lymphoblastic leukemia

The article contains qualitative and quantitative assessment of relation of monitoring MRD results in infants with B-cell acute lymphoblastic leukemia by FCM and quantitative RT-PCR.В статье приведена оценка качественной и количественной зависимости между результатами определения МОБ методами ПЦ и ОТ-ПЦР-РВ у детей первого года жизни с острым лимфобластным лейкозом из В-линейных предшественнико

Bedmap2: improved ice bed, surface and thickness datasets for Antarctica

We present Bedmap2, a new suite of gridded products describing surface elevation, ice-thickness and the seafloor and subglacial bed elevation of the Antarctic south of 60 S. We derived these products using data from a variety of sources, including many substantial surveys completed since the original Bedmap compilation (Bedmap1) in 2001. In particular, the Bedmap2 ice thickness grid is made from 25 million measurements, over two orders of magnitude more than were used in Bedmap1. In most parts of Antarctica the subglacial landscape is visible in much greater detail than was previously available and the improved datacoverage has in many areas revealed the full scale of mountain ranges, valleys, basins and troughs, only fragments of which were previously indicated in local surveys. The derived statistics for Bedmap2 show that the volume of ice contained in the Antarctic ice sheet (27 million km3) and its potential contribution to sea-level rise (58 m) are similar to those of Bedmap1, but the mean thickness of the ice sheet is 4.6% greater, the mean depth of the bed beneath the grounded ice sheet is 72m lower and the area of ice sheet grounded on bed below sea level is increased by 10 %. The Bedmap2 compilation highlights several areas beneath the ice sheet where the bed elevation is substantially lower than the deepest bed indicated by Bedmap1. These products, along with grids of data coverage and uncertainty, provide new opportunities for detailed modelling of the past and future evolution of the Antarctic ice sheets