Diffusion tensor imaging and fiber tractography of the median nerve at 1.5T: optimization of b value

Objective: The objective of this study was to systematically assess the optimal b value for diffusion tensor imaging and fiber tractography of the median nerve at 1.5T. Materials and methods: This is a prospective study which was carried out with institutional review board approval and written informed consent from the study subjects. Fifteen healthy volunteers (seven men, eight women; mean age, 31.2years) underwent diffusion tensor imaging of the wrist. A single-shot spin-echo-based echo-planar imaging sequence (TR/TE, 7000/103ms) was performed in each subject at eight different b values ranging from 325 to 1,550s/mm2. Number and length of reconstructed fiber tracts, fiber density index (FDi), fractional anisotropy (FA), and apparent diffusion coefficient (ADC) were calculated for the median nerve. Signal-to-noise ratio (SNR) was also calculated for each acquisition. The overall image quality was assessed by two readers in consensus by ranking representative fiber tract images for each subject using a scale range from 1 to 8 (1 = best to 8 = worst image quality). Results: Longest fibers were observed for b values between 675 and 1,025s/mm2. Maximum FDi was found at b values of 1,025s/mm2. FA was between 0.5 and 0.6 for all b values. ADC gradually decreased from 1.44 × 10−3 to 0.92 × 10−3mm2/s with increasing b values. Maximum SNR ± standard deviation (175.4 ± 72.6) was observed at the lowest b value and decreased with increasing b values. SNR at b values of 1,025s/mm2 was 48.5% of the maximum SNR. Optimal fiber tract image quality was found for b values of 1,025s/mm2. Conclusions: The optimal b value for diffusion tensor imaging and fiber tractography of the median nerve at 1.5T was 1,025s/mm

Validasi Metode dan Penetapan Kadar Nitrit (NO2) pada Hasil Rebusan Sayuran Hijau (Kangkung, Brokoli, Seledri) Menggunakan Spektrofotometer UV-Vis

Telah dilakukan penelitian tentang penetapan kadar nitrit (NO2) pada beberapa sayuran yaitu kangkung, brokoli, dan seledri. Sayur kangkung diperoleh dari kebun warga daerah Kenten, Palembang, sedangkan sayur brokoli dan seledri diperoleh dari salah satu swalayan di kota Palembang. Kandungan nitrit ditentukan dari hasil air rebusan sampel sayuran dengan metode spektrofotometer UV-Vis. Dari hasil penelitian ini diperoleh nilai kandungan nitrit untuk hasil air rebusan sayuran dengan variasi waktu 5, 15, 20, 25, dan 30 menit. Untuk hasil air rebusan sayur kangkung diperoleh 0,664 mg/kg; 0,665 mg/kg; 0,685 mg/kg; 0,702 mg/kg; 0,710mg/kg. Untuk hasil air rebusan sayur brokoli diperoleh 0,646 mg/kg; 0,647 mg/kg; 0,650 mg/kg; 0,680 mg/kg; 0,704 mg/kg. Untuk hasil air rebusan sayur seledri diperoleh 0,718 mg/kg; 0,730 mg/kg; 0,818 mg/kg; 0,821 mg/kg; 0,849 mg/kg. Dari hasil perebusan pada sayuran kangkung, brokoli, seledri masih aman sesuai dengan ketentuan ADI (Acceptable Daily Intake)/ jumlah asupan harian menurut WHO (World Health Organization)

MRI-based cerebrovascular reactivity using transfer function analysis reveals temporal group differences between patients with sickle cell disease and healthy controls

AbstractObjectivesCerebrovascular reactivity (CVR) measures the ability of cerebral blood vessels to change their diameter and, hence, their capacity to regulate regional blood flow in the brain. High resolution quantitative maps of CVR can be produced using blood-oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) in combination with a carbon dioxide stimulus, and these maps have become a useful tool in the clinical evaluation of cerebrovascular disorders. However, conventional CVR analysis does not fully characterize the BOLD response to a stimulus as certain regions of the brain are slower to react to the stimulus than others, especially in disease. Transfer function analysis (TFA) is an alternative technique that can account for dynamic temporal relations between signals and has recently been adapted for CVR computation. We investigated the application of TFA in data on children with sickle cell disease (SCD) and healthy controls, and compared them to results derived from conventional CVR analysis.Materials and methodsData from 62 pediatric patients with SCD and 34 age-matched healthy controls were processed using conventional CVR analysis and TFA. BOLD data were acquired on a 3Tesla MRI scanner while a carbon dioxide stimulus was quantified by sampling the end-tidal partial pressures of each exhaled breath. In addition, T1 weighted structural imaging was performed to identify grey and white matter regions for analysis. The TFA method generated maps representing both the relative magnitude change of the BOLD signal in response to the stimulus (Gain), as well as the BOLD signal speed of response (Phase) for each subject. These were compared to CVR maps calculated from conventional analysis. The effect of applying TFA on data from SCD patients versus controls was also examined.ResultsThe Gain measures derived from TFA were significantly higher than CVR values based on conventional analysis in both SCD patients and healthy controls, but the difference was greater in the SCD data. Moreover, while these differences were uniform across the grey and white matter regions of controls, they were greater in white matter than grey matter in the SCD group. Phase was also shown to be significantly correlated with the amount that TFA increases CVR estimates in both the grey and white matter.ConclusionsWe demonstrated that conventional CVR analysis underestimates vessel reactivity and this effect is more prominent in patients with SCD. By using TFA, the resulting Gain and Phase measures more accurately characterize the BOLD response as it accounts for the temporal dynamics responsible for the CVR underestimation. We suggest that the additional information offered through TFA can provide insight into the mechanisms underlying CVR compromise in cerebrovascular diseases

Feasibility and precision of cerebral blood flow and cerebrovascular reactivity MRI measurements using a computer-controlled gas delivery system in an anesthetised juvenile animal model

Purpose: To demonstrate the feasibility and repeatability of cerebrovascular reactivity (CVR) imaging using a controlled CO2 challenge in mechanically ventilated juvenile pigs. Materials and Methods: Precise end-tidal partial pressure CO2 (PETCO2) control was achieved via a computer-controlled model-driven prospective end-tidal targeting (MPET) system integrated with mechanical ventilation using a custom-built secondary breathing circuit. Test-retest blood-oxygen level dependent (BOLD) CVR images were collected in nine juvenile pigs by quantifying the BOLD response to iso-oxic square-wave PETCO2 changes. For comparison, test-retest baseline arterial spin labeling (ASL) cerebral blood flow (CBF) images were collected. Repeatability was quantified using the intra-class correlation coefficient (ICC) and coefficient of variation (CV). Results: The repeatability of the PETCO2 (CV \u3c 2%) step changes resulted in BOLD CVR ICC \u3e 0.94 and CV \u3c 6% for cortical brain regions, which was similar to ASL CBF repeatability (ICC \u3e 0.96 and CV \u3c 4%). Conclusion: This study demonstrates the feasibility and precision of CVR imaging with an MPET CO2 challenge in mechanically ventilated subjects using an animal model. Translation of this method into clinical imaging protocols may enable CVR imaging in young children with cerebrovascular disease who require general anesthesia. © 2010 Wiley-Liss, Inc

Noninvasive MRI measures of microstructural and cerebrovascular changes during normal swine brain development

The swine brain is emerging as a potentially valuable translational animal model of neurodevelopment and offers the ability to assess the impact of experimentally induced neurological disorders. The goal for this study was to characterize swine brain development using noninvasive MRI measures of microstructural and cerebrovascular changes. Thirteen pigs at various postnatal ages (2.3-43.5 kg) were imaged on a 1.5-Tesla MRI system. Microstructural changes were assessed using diffusion tensor imaging measures of mean diffusivity and fractional anisotropy. Cerebrovascular changes were assessed using arterial spin labeling measures of baseline cerebral blood flow (CBF) and the cerebrovascular reactivity (CVR) of the blood-oxygen level dependent (BOLD) MRI signal to CO2. We found a positive logarithmic relationship for regional tissue volumes and fractional anisotropy with body weight, which is similar to the pattern reported in the developing human brain. Unlike in the maturing human brain, no consistent changes in mean diffusivity or baseline CBF with development were observed. Changes in BOLD CVR exhibited a positive logarithmic relationship with body weight, which may impact the interpretation of functional MRI results at different stages of development. This animal model can be validated by applying the same noninvasive measures in humans. Copyright © 2011 International Pediatric Research Foundation, Inc

Long-Term ERK Inhibition in

Induction of compensatory mechanisms and ERK reactivation has limited the effectiveness of Raf and MEK inhibitors in -mutant cancers. We determined that direct pharmacologic inhibition of ERK suppressed the growth of a subset of -mutant pancreatic cancer cell lines and that concurrent phosphatidylinositol 3-kinase (PI3K) inhibition caused synergistic cell death. Additional combinations that enhanced ERK inhibitor action were also identified. Unexpectedly, long-term treatment of sensitive cell lines caused senescence, mediated in part by MYC degradation and p16 reactivation. Enhanced basal PI3K-AKT-mTOR signaling was associated with de novo resistance to ERK inhibitor, as were other protein kinases identified by kinome-wide siRNA screening and a genetic gain-of-function screen. Our findings reveal distinct consequences of inhibiting this kinase cascade at the level of ERK

Bronchogenic cyst associated with pericardial defect: Case report and review of the literature

Partial defect of the pericardium combined with bronchogenic cyst is a very rare congenital anomaly. We describe the case of a 32-year-old man with a partial defect of the left pericardium and a bronchogenic cyst arising from the border of the pericardial defect. The cyst was successfully resected with the harmonic scalpel by three-port videothoracoscopic approach

Non-Standard Errors

In statistics, samples are drawn from a population in a data-generating process (DGP). Standard errors measure the uncertainty in estimates of population parameters. In science, evidence is generated to test hypotheses in an evidence-generating process (EGP). We claim that EGP variation across researchers adds uncertainty: Non-standard errors (NSEs). We study NSEs by letting 164 teams test the same hypotheses on the same data. NSEs turn out to be sizable, but smaller for better reproducible or higher rated research. Adding peer-review stages reduces NSEs. We further find that this type of uncertainty is underestimated by participants

BLOOM: A 176B-Parameter Open-Access Multilingual Language Model

Large language models (LLMs) have been shown to be able to perform new tasks based on a few demonstrations or natural language instructions. While these capabilities have led to widespread adoption, most LLMs are developed by resource-rich organizations and are frequently kept from the public. As a step towards democratizing this powerful technology, we present BLOOM, a 176B-parameter open-access language model designed and built thanks to a collaboration of hundreds of researchers. BLOOM is a decoder-only Transformer language model that was trained on the ROOTS corpus, a dataset comprising hundreds of sources in 46 natural and 13 programming languages (59 in total). We find that BLOOM achieves competitive performance on a wide variety of benchmarks, with stronger results after undergoing multitask prompted finetuning. To facilitate future research and applications using LLMs, we publicly release our models and code under the Responsible AI License