Al Quran dan Ruang Angkasa

Peluncuran satelitbumi buatan yang pertama, SPUTNIK I, oleh yang pertama, SPUTNIK I, oleh Uni Soviet, padatangga14 Oktober Uni Soviet, padatangga14 Oktober 1957 ~erupakan peristiwabersejacab yang membuka pintu gerbang 1957 ~erupakan peristiwabersejacab yang membuka pintu gerbang sejarah kebudayaan manusia dan sejarah kebudayaan manusia dan mengantarkannya ke abadsatelit. mengantarkannya ke abadsatelit. Sejak peristiwa itu, demam Sejak peristiwa itu, demam angkasa luar (Outer Space Fever) angkasa luar (Outer Space Fever) telah menyerang manusia dengan telah menyerang manusia dengan hebatnya, mempengaruhi cara berpikir sehari-hari dan mengubah pandangan mereka yang sebelumnya hebatnya, mempengaruhi cara berpikir sehari-hari dan mengubah pandangan mereka yang sebelumnya merupakan khayalan dan .impian merupakan khayalan dan .impian belaka. belaka

A porcine model of heart failure with preserved ejection fraction:magnetic resonance imaging and metabolic energetics

Aims A significant proportion of heart failure (HF) patients have HF preserved ejection fraction (HFpEF). The lack of effective treatments for HFpEF remains a critical unmet need. A key obstacle to therapeutic innovation in HFpEF is the paucity of pre-clinical models. Although several large animal models have been reported, few demonstrate progression to decompensated HF. We have established a model of HFpEF by enhancing a porcine model of progressive left ventricular (LV) pressure overload and characterized HF in this model including advanced cardiometabolic imaging using cardiac magnetic resonance imaging and hyperpolarized carbon-13 magnetic resonance spectroscopy. Methods and results Pigs underwent progressive LV pressure overload by means of an inflatable aortic cuff. Pigs developed LV hypertrophy (50% increase in wall thickness, P <0.001, and two-fold increase in mass compared to sham control, P <0.001) with no evidence of LV dilatation but a significant increase in left atrial volume (P = 0.013). Cardiac magnetic resonance imaging demonstrated T1 modified Look-Locker inversion recovery values increased in 16/17 segments compared to sham pigs (P <0.05-P <0.001) indicating global ventricular fibrosis. Mean LV end-diastolic (P = 0.047) and pulmonary capillary wedge pressures (P = 0.008) were elevated compared with sham control. One-third of the pigs demonstrated clinical signs of frank decompensated HF, and mean plasma BNP concentrations were raised compared with sham control (P = 0.008). Cardiometabolic imaging with hyperpolarized carbon-13 magnetic resonance spectroscopy agreed with known metabolic changes in the failing heart with a switch from fatty acid towards glucose substrate utilization. Conclusions Progressive aortic constriction in growing pigs induces significant LV hypertrophy with cardiac fibrosis associated with left atrial dilation, raised filling pressures, and an ability to transition to overt HF with raised BNP without reduction in LVEF. This model replicates many aspects of clinical HFpEF with a predominant background of hypertension and can be used to advance understanding of underlying pathology and for necessary pre-clinical testing of novel candidate therapies

Metodologi Perhitungan Koefisien Perpindahan Panas Konveksi Paksa Fluida Organik Propana pada Kondisi Superkritik

Penelitian tentang siklus Rankine organik superkritis mulai giat dilakukan sebagai salah satu usaha untuk meningkatkan efisiensi termal dari siklus Rankine organik. Pada kondisi superkritik, sifat-sifat termodinamika dan fisika dari fluida organik berubah dengan sangat drastis disekitar titik kritisnya. Sehingga perhitungan koefisien perpindahan panas konveksi paksa tidak dapat lagi dilakukan dengan asumsi sifat-sifat fluida konstan. Dalam penelitian ini diusulkan sebuah metodologi untuk menghitung nilai koefisien perpindahan panas pada kondisi superkritis. Propana digunakan sebagai fluida organiknya. Tipe alat pemindah panas yang dipakai adalah jenis pipa ganda aliran berlawanan arah dan perhitungan bilangan Nusselt menggunakan korelasi Dittus-Boetler dan Gnielinski. Hasil perhitungan koefisien perpindahan panas dengan menggunakan metodologi ini dapat digunakan untuk menghitung luas daerah perpindahan panas dari alat pemindah panas tipe double pipe counter flow. Selanjutnya hasil perhitungan ini perlu dibandingkan dengan nilai koefisien perpindahan panas yang diperoleh dari hasil eksperimen

Quantitative 1H MRI, 19F MRI, and 19F MRS of cell-internalized perfluorocarbon paramagnetic nanoparticles

In vivo molecular imaging with targeted MRI contrast agents will require sensitive methods to quantify local concentrations of contrast agent, enabling not only imaging-based recognition of pathological biomarkers but also detection of changes in expression levels as a consequence of disease development, therapeutic interventions or recurrence of disease. In recent years, targeted paramagnetic perfluorocarbon emulsions have been frequently applied in this context, permitting high-resolution 1H MRI combined with quantitative 19F MR imaging or spectroscopy, under the assumption that the fluorine signal is not altered by the local tissue and cellular environment. In this in vitro study we have investigated the 19F MR-based quantification potential of a paramagnetic perfluorocarbon emulsion conjugated with RGD-peptide to target the cell-internalizing a¿ß3-integrin expressed on endothelial cells, using a combination of 1H MRI, 19F MRI and 19F MRS. The cells took up the targeted emulsion to a greater extent than nontargeted emulsion. The targeted emulsion was internalized into large 1-7µm diameter vesicles in the perinuclear region, whereas nontargeted emulsion ended up in 1-4µm diameter vesicles, which were more evenly distributed in the cytoplasm. Association of the targeted emulsion with the cells resulted in different proton longitudinal relaxivity values, r1, for targeted and control nanoparticles, prohibiting unambiguous quantification of local contrast agent concentration. Upon cellular association, the fluorine R1 was constant with concentration, while the fluorine R2 increased nonlinearly with concentration. Even though the fluorine relaxation rate was not constant, the 19F MRI and 19F MRS signals for both targeted nanoparticles and controls were linear and quantifiable as function of nanoparticle concentration. © 2010 John Wiley &amp; Sons, Ltd

In vivo mouse myocardial (31)P MRS using three-dimensional image-selected in vivo spectroscopy (3D ISIS): technical considerations and biochemical validations

Item does not contain fulltext(31)P MRS provides a unique non-invasive window into myocardial energy homeostasis. Mouse models of cardiac disease are widely used in preclinical studies, but the application of (31)P MRS in the in vivo mouse heart has been limited. The small-sized, fast-beating mouse heart imposes challenges regarding localized signal acquisition devoid of contamination with signal originating from surrounding tissues. Here, we report the implementation and validation of three-dimensional image-selected in vivo spectroscopy (3D ISIS) for localized (31)P MRS of the in vivo mouse heart at 9.4 T. Cardiac (31)P MR spectra were acquired in vivo in healthy mice (n = 9) and in transverse aortic constricted (TAC) mice (n = 8) using respiratory-gated, cardiac-triggered 3D ISIS. Localization and potential signal contamination were assessed with (31)P MRS experiments in the anterior myocardial wall, liver, skeletal muscle and blood. For healthy hearts, results were validated against ex vivo biochemical assays. Effects of isoflurane anesthesia were assessed by measuring in vivo hemodynamics and blood gases. The myocardial energy status, assessed via the phosphocreatine (PCr) to adenosine 5'-triphosphate (ATP) ratio, was approximately 25% lower in TAC mice compared with controls (0.76 +/- 0.13 versus 1.00 +/- 0.15; P < 0.01). Localization with one-dimensional (1D) ISIS resulted in two-fold higher PCr/ATP ratios than measured with 3D ISIS, because of the high PCr levels of chest skeletal muscle that contaminate the 1D ISIS measurements. Ex vivo determinations of the myocardial PCr/ATP ratio (0.94 +/- 0.24; n = 8) confirmed the in vivo observations in control mice. Heart rate (497 +/- 76 beats/min), mean arterial pressure (90 +/- 3.3 mmHg) and blood oxygen saturation (96.2 +/- 0.6%) during the experimental conditions of in vivo (31)P MRS were within the normal physiological range. Our results show that respiratory-gated, cardiac-triggered 3D ISIS allows for non-invasive assessments of in vivo mouse myocardial energy homeostasis with (31)P MRS under physiological conditions