High-sensitivity cardiac SPECT system design with collimator-less interspaced mosaic-patterned scintillators.

Purpose: Single-photon emission computed tomography (SPECT) is an important tool for myocardial perfusion imaging (MPI). Mechanical collimators cause the resolution-sensitivity trade-off in the existing cardiac SPECT systems, which hinders fast cardiac scan capability. In this work, we propose a novel collimator-less cardiac SPECT system with interspaced mosaic-patterned scintillators, aiming to significantly improve sensitivity and reduce scan time without trading-off image resolution. Methods: We propose to assemble a collimator-less cardiac SPECT with 7 mosaic-patterned detector modules forming a half-ring geometry. The detector module consists of 10 blocks, each of which is assembled with 768 sparsely distributed scintillators with a size of 1.68 mm × 1.68 mm × 20 mm, forming a mosaic pattern in the trans-axial direction. Each scintillator bar contains 5 GAGG(Ce) scintillators and 5 optical-guide elements, forming a mosaic pattern in the axial direction. In the Monte Carlo simulations, the in-plane resolution and axial resolution are evaluated using a hot-rod phantom and 5 disk phantoms, respectively. We simulate a cardiac phantom that is placed in a water-filled cylinder and evaluate the image performance with different data acquisition time. We perform image reconstruction with the expectation-maximization algorithm using system matrices derived from the simulation of a uniform cylindrical source filling the field-of-view (FOV). Besides, a 2-D prototype system is designed to demonstrate the feasibility of the collimator-less imaging concept. Results: In the simulation system, the sensitivity is 16.31% ± 8.85% in a 180 mm (Φ) × 100 mm (L) FOV. The 6-mm rods in the hot rod phantom and the 5-mm disks in the disk phantom are clearly separable. Satisfactory MPI image quality is achieved in the cardiac phantom study with an acquisition time of 30 s. In prototype experiments, the point sources with an 8 mm center-to-center distance are clearly separable at different positions across the FOV. Conclusion: The study reveals a promising approach to high-sensitivity SPECT imaging without a heavy-metal collimator. In cardiac imaging, this approach opens the way to a very fast cardiac scan with good resolution. Further works are ongoing to build a practical 3-D imaging system based on the existing design.

Effects of Exogenous Lanthanum Nitrate on the Active Substance Content and Antioxidant Activity of Caterpillar Medicinal Mushroom Cordyceps militaris (Ascomycetes).

Cordyceps militaris is a medicinal and edible mushroom. Researchers often add exogenous substances to the culture medium to increase the active substance content in C. militaris. However, the effect of earth elements on the active substance content in C. militaris and its antioxidant effects have not been reported. In this study, the active substance content in C. militaris treated with lanthanum nitrate was determined using high-performance liquid chromatography and ultraviolet spectrophotometry, and the effect on the antioxidant capacity of C. militaris after lanthanum nitrate spraying was further explored. The results showed that, in the experimental concentration range, the two concentrations of 10 mg/L and 50 mg/L had a significant influence on the active substance content of C. militaris. When the concentration of lanthanum nitrate was 10 mg/L, the synthesis of pentostatin and cordycepin was promoted. When the concentration of lanthanum nitrate was 50 mg/L, it significantly promoted the synthesis of cordycepin, and the ferric-reducing power and DPPH· scavenging rate of C. militaris treated at this concentration were significantly higher than those of the control group. However, lanthanum nitrate had no significant effect on ergosterol synthesis (P > 0.05). Finally, considering that the residual amount of lanthanum in C. militaris and the residual amount of lanthanum in 50 mg/L lanthanum nitrate-treated C. militaris is within the allowable daily intake of 4.2 mg for humans, the optimal concentration of lanthanum nitrate-treated C. militaris is 50 mg/L.

Characterization and Assessment of Projection Probability Density Function and Enhanced Sampling in Self-Collimation SPECT.

We have recently reported a self-collimation SPECT (SC-SPECT) design concept that constructs sensitive detectors in a multi-ring interspaced mosaic architecture to simultaneously improve system spatial resolution and sensitivity. In this work, through numerical and Monte-Carlo simulation studies, we investigate this new design concept by analyzing its projection probability density functions (PPDF) and the effects of enhanced sampling, i.e. having rotational and translational object movements during imaging. We first quantitatively characterize PPDFs by their widths and edge slopes. Then we compare the PPDFs of an SC-SPECT and a series of multiple-pinhole SPECT (MPH-SPECT) systems and assess the impact of PPDFs - combined with enhanced sampling - on image contrast recovery coefficient and variance through phantom studies. We show the PPDFs of SC- SPECT have steeper edges and a wider range of width, and these attributes enable SC-SPECT to achieve better performance.

Factors Determining Consumer Acceptance of Biofortified Food: Case of Zinc-Fortified Wheat in Pakistan's Punjab Province.

Zinc (Zn) is a fundamental micronutrient required by all living organisms. Zn deficiency among children under 5 years, pregnant, and child-bearing women has been identified in developing countries such as Pakistan. Biofortified crops can increase micronutrient levels and decrease deficiencies. Meanwhile, consumer acceptance is essential, given that genetic alterations can occur during biofortification, resulting in changes in sensory traits and the quality of grains. Therefore, the present study focuses on the determining factors for consumer acceptance of Zn-biofortified wheat., an experimental survey was conducted to achieve the study's objectives. Qualitative and quantitative data were collected and analyzed from 203 respondents in the Punjab province. The results regarding sensory perceptions revealed that people attached great importance to the appearance of the chapati prepared with Zn-biofortified wheat. Therefore, they were willing to purchase Zn-biofortified wheat when asked to choose between the conventional wheat and the Zn-biofortified wheat. Moreover, the probit model illustrates that the level of education in the family and having young children aged under 5 years in the household positively impacted the acceptance of Zn-biofortified wheat among the participants. The findings suggest that there is significant scope for promoting Zn-biofortified wheat in the country. It is also imperative to ensure its availability across various regions so that households with weak purchasing power can buy and address their Zn deficiency. Furthermore, policymakers could introduce reforms targeting business communities for food management, keeping Zn-biofortified wheat in the priority stream.

Self-Collimating SPECT With Multi-Layer Interspaced Mosaic Detectors.

Conventional single photon emission computed tomography (SPECT) relies on mechanical collimation whose resolution and sensitivity are interdependent, the best performance a SPECT system can attain is only a compromise of these two equally desired properties. To simultaneously achieve high resolution and sensitivity, we propose to use sensitive detectors constructed in a multi-layer in ter spaced mosaicdetectors (MATRICES) architecture to accomplish part of the collimation needed. We name this new approach self-collimation. We evaluate three self-collimating SPECT systems and report their imaging performance: 1) A simulated human brain SPECT achieves 3.88% sensitivity, it clearly resolves 0.5-mm and 1.0-mm hot-rod patterns at noise-free and realistic count-levels, respectively; 2) a simulated mouse SPECT achieves 1.25% sensitivity, it clearly resolves 50- [Formula: see text] and 100- [Formula: see text] hot-rod patterns at noise-free and realistic count-levels, respectively; 3) a SPECT prototype achieves 0.14% sensitivity and clearly separates 0.3-mm-diameter point sources of which the center-to-center neighbor distance is also 0.3 mm. Simulated contrast phantom studies show excellent resolution and signal-to-noise performance. The unprecedented system performance demonstrated by these 3 SPECT scanners is a clear manifestation of the superiority of the self-collimating approach over conventional mechanical collimation. It represents a potential paradigm shift in SPECT technology development.

[Current development of gene editing].

As the breakthrough in gene editing, represented by CRISPR/Cas9, gene manipulations now are more maneuverable, economically feasible and time saving. It is possible for China to catch an overtaking in researching and industrializing of downside sections (especially the application of plant gene editing), also the incubation of professional companies in gene editing fields. For this consideration, it is necessary and urgent to find the key demands and potential application for gene editing in China. Questionnaire and statistic analysis were carried out to find the key demands and the most potential application fields of the development for gene editing. Firstly, an ordered multi-classification Logistic regression model was established following with dependent variable analysis. Eight out of 24 questionnaires questions in 4 categories were regarded as independent variables with significance test. Then, regression model based on ordered multi-classification logistic method was established to analyze the specific impact of different options on the development of gene editing. The results showed that most researchers in the field of gene editing take the view that development of potential competitive advantages lies in the field of plant science. The results also showed that major gene editing experts believe more attention should be paid on how to carry out technology industrialization while focusing on basic technology development, as well as the development of potential competitive advantages of gene editing technology in plant field. To promote the development of gene editing in China, not only the participation of scientific research institution was needed, but also the synergy of various forces both universities and governments. It is urgent both properly guiding public opinion on gene editing and establishing a national safety standard system. At the same time, the key point of technology risk avoidance should be put on biological weapons and bioterrorism, gene editing related infectious disease, and the potential risk of species genetic change on the ecological environment, etc.

Genome editing with the CRISPR-Cas system: an art, ethics and global regulatory perspective.

Over the last three decades, the development of new genome editing techniques, such as ODM, TALENs, ZFNs and the CRISPR-Cas system, has led to significant progress in the field of plant and animal breeding. The CRISPR-Cas system is the most versatile genome editing tool discovered in the history of molecular biology because it can be used to alter diverse genomes (e.g. genomes from both plants and animals) including human genomes with unprecedented ease, accuracy and high efficiency. The recent development and scope of CRISPR-Cas system have raised new regulatory challenges around the world due to moral, ethical, safety and technical concerns associated with its applications in pre-clinical and clinical research, biomedicine and agriculture. Here, we review the art, applications and potential risks of CRISPR-Cas system in genome editing. We also highlight the patent and ethical issues of this technology along with regulatory frameworks established by various nations to regulate CRISPR-Cas-modified organisms/products.

Urinary kidney injury molecule-1 as an early indicator to predict contrast-induced acute kidney injury in patients with diabetes mellitus undergoing percutaneous coronary intervention.

With the improvement of the skill level of coronary intervention, contrast agents are used more widely. As a result, contrast-induced acute kidney injury (CI-AKI) is currently the third leading cause of hospital-acquired AKI. Traditionally, AKI is defined by measuring an increase of the serum creatinine concentration (Scr). CI-AKI indicates impairment in renal function, which is diagnosed as an elevation in the SCr levels following intravascular injection of the contrast media. However, Scr is an insensitive indicator for detecting CI-AKI. The present study was designed to investigate whether human urinary kidney injury molecule-1 (KIM-1) is an early marker to predict CI-AKI in patients with diabetes mellitus undergoing percutaneous coronary intervention (PCI). The present study includes the general clinical data of 145 patients with diabetes mellitus who underwent PCI between March 1, 2013 and December 31, 2013. A non-ionic, low osmolarity contrast agent was used during the present study. The Scr levels and estimated glomerular filtration rate were measured prior to and within 24 and 48 h after the injection of contrast agents. Urinary samples were collected prior to and within 2, 6, 12, 24 and 48 h after the coronary interventional procedure. Simultaneously, the urinary KIM-1 values were measured using an ELISA kit. CI-AKI was diagnosed as an increase of ≥0.5 mg/dl or ≥25% in Scr concentration over baseline, 24-48 h after the procedure. In total, 19 of 145 (13.1%) patients exhibited CI-AKI. There was a significant difference (P<0.05) between the urinary KIM-1 levels measured 2, 6, 12, 24 and 48 h after the procedure and those prior to the procedure in the CI-AKI group. There was no significant difference between the Scr values measured 24 h after the procedure and those prior to the procedure. Evidently, using KIM-1 values to predict CI-AKI was <24 h earlier compared to using Scr values. The area under the receiver operating characteristic curve of KIM-1 24 h after the procedure was 0.856 and the 95% confidence interval of the corresponding area was 0.782-0.929. When the pivotal point of CI-AKI diagnosis was 6,327.755 pg/ml, the specificity was 85.7% and the sensitivity was 73.7%. Univariate analysis showed that the Scr concentration was positively correlated with the urinary KIM-1 level during the time prior to the procedure and 24 and 48 h after the procedure. In conclusion, the urinary KIM-1 may be a potential indicator for the early diagnosis of CI-AKI.