Post-stroke dysphagia and ambient air pollution are associated with dementia.

Introduction: This cohort study aimed to explore the potential association between ambient air pollution and dementia incidence in adults who have experienced a stroke. Additionally, the study aimed to determine dysphagia as a predictive factor for the subsequent development of dementia in patients with stroke. Materials and methods: This retrospective nested case-control study used data from the Kaohsiung Medical University Hospital Database in Taiwan. Data collected include average ambient air pollution concentrations within 3 months and 1 year after the index dysphagia date. The primary outcome includes incident dementia in patients with or without dysphagia. Logistic regression analysis was performed to examine the association between significant air pollution exposure and the risk of dementia while controlling for baseline demographic characteristics (age and sex), and comorbidities. Results: The univariable regression models revealed a higher likelihood of dementia diagnosis in patients with dysphagia (odds ratio = 1.493, 95% confidence interval = 1.000-2.228). The raw odds ratios indicated a potential link between air pollution exposure and elevated dementia risks in the overall study population and patients with stroke without dysphagia, except for O3. Particulate matter (PM)2.5 and nitrogen oxides (NOx) exhibited significant effects on the risk of dementia in the stepwise logistic regression models. Conclusion: The presence of dysphagia following a stroke may pose a risk of developing dementia. Additionally, PM2.5 and NOx exposure appears to elevate the risk of dementia in patients with stroke.

Effectiveness of gamification and selection of appropriate teaching methods of creativity: Students' perspectives.

Complex creativity and multiple learning objectives often require combining several teaching methods, and gamification may be an effective teaching strategy for enhancing learning. However, few studies have examined the combined effects of implementing gamification and multiple teaching methods in a course from students' perspectives. Therefore, this study implemented gamification and six teaching methods of enhancing college students' creativity in university creativity and innovation course in November and December 2021 and aimed to examine the effects on their creativity, collaboration, and communication skills and used the Analytical Hierarchy Process to identify more effective teaching methods corresponding to the learning objectives from students' perspectives. The results showed that students perceive that gamification could stimulate their motivation, attitudes, and interest in learning and enhance their creativity, collaboration, and communication skills. Furthermore, Mandala thinking was the most effective teaching method for the overall goal. In contrast, the most effective teaching methods for the creativity, collaboration, and communication skills learning objectives were the SCAMPER technique, balloon competition, and Mandala thinking, respectively. The results provide essential references for selecting effective teaching methods that meet the teaching objectives.

Effectiveness of aroma-Tea Tree Oil and Eucalyptus oil in alleviating COVID-19 vaccine discomfort side effects.

CONTEXT: Aromatherapy is considered a mild and non-invasive complementary treatment to relieve post-vaccination discomforts. There have been no studies that examine the use of aroma-Tea Tree oil and Eucalyptus oil to relieve the discomfort side effects related to COVID-19 vaccines. OBJECTIVE: This study examined the use of two aroma-essential oils to relieve discomfort side effects of COVID-19 vaccination. DESIGN: The study used experimental design to match two groups of participants. SETTING: The participants' home. PARTICIPANTS: Adults who had not yet been vaccinated against COVID-19 but were planning to receive it were recruited. The current study included 87 control participants matched to 83 experimental participants. INTERVENTION: The participants in the experimental group used Tea tree and Eucalyptus while the control group did not. MAIN OUTCOME MEASURES: A questionnaire was used to collect data on the topical and systematic symptoms related to COVID-19 vaccines. Both groups were asked to complete the online questionnaire and report their health status 24 h (T1) and 48 h (T2) after vaccination. RESULTS: The results revealed a statistically significant difference between the groups in swelling, injection side pain, lump, fever, and muscle ache (p = .05, 0.04, <0.00, 0.02, 0.02, respectively) for T1; but for T2, a significant difference between the two groups was found only in lump and fever (p = .05, 0.03). Aroma-Tea Tree oil and Eucalyptus oil may be recognized and accepted by more people worldwide to provide a safe and healthy option not only for post-vaccination care but also to relieve pain, fever, and skin lumps associated with other diseases or conditions.

Oxidative stress involves phenotype modulation of morbid soreness symptoms in fibromyalgia.

OBJECTIVES: Muscle soreness occurs after exercise and also in musculoskeletal diseases, such as fibromyalgia (FM). However, the nosography and pathoetiology of morbid soreness in FM remain unknown. This study aimed to investigate the morbid soreness of FM, evaluate its therapeutic responses and probe its pathophysiology with metabolomics profiling. METHODS: Patients with newly diagnosed FM were prospectively recruited and completed self-report questionnaires pertaining to musculoskeletal symptoms. The phenotypes and metabotypes were assessed with variance, classification and correlation analyses. RESULTS: Fifty-one patients and 41 healthy controls were included. Soreness symptoms were prevalent in FM individuals (92.2%). In terms of manifestations and metabolomic features, phenotypes diverged between patients with mixed pain and soreness symptoms (FM-PS) and those with pain dominant symptoms. Conventional treatment for FM did not ameliorate soreness severity despite its efficacy on pain. Moreover, despite the salient therapeutic efficacy on pain relief in FM-PS cases, conventional treatment did not improve their general disease severity. Metabolomics analyses suggested oxidative metabolism dysregulation in FM, and high malondialdehyde level indicated excessive oxidative stress in FM individuals as compared with controls (p=0.009). Contrary to exercise-induced soreness, lactate levels were significantly lower in FM individuals than controls, especially in FM-PS. Moreover, FM-PS cases exclusively featured increased malondialdehyde level (p=0.008) and a correlative trend between malondialdehyde expression and soreness intensity (r=0.337, p=0.086). CONCLUSIONS: Morbid soreness symptoms were prevalent in FM, with the presentation and therapeutic responses different from FM pain conditions. Oxidative stress rather than lactate accumulation involved phenotype modulation of the morbid soreness in FM. TRIAL REGISTRATION NUMBER: NCT04832100.

Shift work is significantly and positively associated with dementia: A meta-analysis study.

Background: Shift work may disrupt the sleep and wake cycles and negatively affect physical and mental health. Dementia is a neurodegenerative disorder with progressively declining cognition that is receiving increasing attention. Studies on the association between shift work and dementia are rare. Herein, we conducted a meta-analysis to investigate the association between shift work and dementia. Materials and methods: This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched the PubMed, Embase, and Web of Science databases using a related set of keywords. The inclusion criteria were as follows: (1) adult employees working in a factory, company, or organization; (2) exposure to shift work/non-shift work; and (3) outcome of dementia based on examination or assessment. A meta-analysis using a fixed-effects model was performed. The hazard ratio of dementia was compared between shift workers and non-shift workers. Results: Five studies were included in the quantitative synthesis, and two were selected for further meta-analysis. A random-effects model showed a modest association between shift work and an increase in dementia cases (pooled hazard ratio = 1.13; 95% confidence interval: 1.04-1.23; p = 0.04). This association also occurred in night workers for more than 1 year. Conclusion: Shift work and long-term night work were modestly associated with a higher risk of developing dementia. Avoiding long-term night shifts may be effective in reducing dementia risk. Further studies are required to confirm this hypothesis.

Videofluoroscopy dysphagia severity scale is predictive of subsequent remote pneumonia in dysphagia patients.

Introduction: Dysphagia-associated pneumonia is a critical health issue especially in the elders and stroke patients which carries a poorer prognosis. Therefore, we aim to identify methods with the potentials to predict subsequent pneumonia in dysphagia patients, which will be of great value in the prevention and early management of pneumonia. Methods: One-hundred dysphagia patients were enrolled and measurements including Dysphagia Severity Scale (DSS), Functional Oral Intake Scale (FOIS), Ohkuma Questionnaire, and Eating Assessment Tool-10 (EAT-10) were assessed by either videofluoroscopy (VF), videoendoscopy (VE), or the study nurse. The patients were categorized into mild or severe groups based on each screening method. All the patients were assessed for pneumonia at 1, 3, 6, and 20 months after the examinations. Results: VF-DSS (p=0.001) is the only measurement being significantly associated with subsequent pneumonia with sensitivity and specificity of 0.857 and 0.486. The Kaplan-Meier curves revealed that significant differences between the mild/severe groups start to emerge 3 months after VF-DSS (p=0.013). Cox regression models used for adjusted hazard ratio of severe VF-DSS in association with subsequent pneumonia of different timepoints after controlling the important covariates showed the following results: 3 months, p=0.026, HR=5.341, 95%CI=1.219-23.405; 6 months, p=0.015, HR=4.557, 95%CI=1.338-15.522; 20 months, p=0.004, HR=4.832, 95%CI=1.670-13.984. Conclusions: Dysphagia severity evaluated by VE-DSS, VE-FOIS, VF-FOIS, Ohkuma Questionnaire, and EAT-10 is not associated with subsequent pneumonia. Only VF-DSS is associated with both short-term and long-term subsequent pneumonia. In patients with dysphagia, VF-DSS is predictive of subsequent pneumonia.

Auxin plays a role in the adaptation of rice to anaerobic germination and seedling establishment.

Auxin is well known to stimulate coleoptile elongation and rapid seedling growth in the air. However, its role in regulating rice germination and seedling establishment under submergence is largely unknown. Previous studies revealed that excessive levels of indole-3-acetic acid(IAA) frequently cause the inhibition of plant growth and development. In this study, the high-level accumulation of endogenous IAA is observed under dark submergence, stimulating rice coleoptile elongation but limiting the root and primary leaf growth during anaerobic germination (AG). We found that oxygen and light can reduce IAA levels, promote the seedling establishment and enhance rice AG tolerance. miRNA microarray profiling and RNA gel blot analysis results show that the expression of miR167 is negatively regulated by submergence; it subsequently modulates the accumulation of free IAA through the miR167-ARF-GH3 pathway. The OsGH3-8 encodes an IAA-amido synthetase that functions to prevent free IAA accumulation. Reduced miR167 levels or overexpressing OsGH3-8 increase auxin metabolism, reduce endogenous levels of free IAA and enhance rice AG tolerance. Our studies reveal that poor seed germination and seedling growth inhibition resulting from excessive IAA accumulation would cause intolerance to submergence in rice, suggesting that a certain threshold level of auxin is essential for rice AG tolerance.

Single Nucleotide Polymorphism of TWIST2 May Be a Modifier for the Association between High-Density Lipoprotein Cholesterol and Blood Lead (Pb) Level.

The association between lead (Pb) exposure and lower high-density lipoprotein cholesterol (HDL-C) was reported; however, the mechanism was unclear. Our purpose was to investigate the association of Pb, lipid profile, and to study the associated SNPs using a genome-wide association study (GWAS). A total of 511 participants were recruited to check blood Pb levels, lipid profile, and genotypes with Taiwan Biobank version 2.0 (TWB2). Our main result shows that HDL-C was significantly negatively associated with blood Pb levels, adjusted for gender, body mass index (BMI), and potential confounders. In addition, via the TWB2 GWAS, only two SNPs were found, including rs150813626 (single-nucleotide variation in the TWIST2 gene on chromosome 2), and rs1983079 (unclear SNP on chromosome 3). Compared to the rs150813626 GG carriers, the AA and AG carriers were significantly and negatively associated with HDL-C. We analyzed the interaction of rs150813626 SNP and blood Pb, and the HDL-C was consistently and negatively associated with blood Pb, male, BMI, and the rs150813626 AA and AG carriers. Moreover, the rs150813626 AA and blood Pb interaction was significantly and positively associated with HDL-C. In conclusion, the SNPs rs150813626 and rs1983079 were significantly associated with HDL-C in Pb-exposed workers. Furthermore, the interaction of rs150813626 AA and blood Pb had a positive influence on HDL-C. TWIST may inhibit osteoblast maturation, which might relate to bone Pb deposition and calcium metabolism. The mechanism needs more investigation in the future.

The impact of antiseizure medications on polysomnographic parameters: a systematic review and meta-analysis.

BACKGROUND: Oral antiseizure medications (ASMs) are first-line treatments for patients with epilepsy. However, ASMs may alter sleep architecture, adversely affecting patient outcomes. The meta-analysis aimed to elucidate the effect of ASMs on sleep architecture. METHODS: PubMed, Embase, and Cochrane Central database (up to Febrary 2021) were searched for randomized control trials (RCT) with effects of ASMs on polysomnography parameters. A meta-analysis using a random-effects model was performed. We did not set limitation to the participants with underlying diagnosis of epilepsy. RESULTS: Eighteen randomized-controlled trials fulfilled the eligibility criteria. The effects of five main groups of ASMs (sodium channel blockers, calcium channel blockers, GABA enhancers, synaptic vesicle glycoprotein 2A [SV2A] ligand, and broad-spetrum ASMs) on slow-wave sleep (SWS), rapid eye movement (REM) sleep, and sleep efficiency (SE) were analyzed. Compared with placebo, calcium channel blockers and GABA enhancers significantly increased SWS. GABA enhancers also decreased REM sleep percentage, whereas calcium channel blockers significantly increased SE. Sodium channel blockers, SV2A ligand and broad-spectrum ASMs did not affect SWS, REM sleep, or SE. The subgroup analysis revealed that gabapentin, pregabalin, and tiagabine increased the percentage of SWS. Tiagabine also decreased REM sleep, whereas pregabalin increased SE. Finally, levetiracetam did not affect SWS, REM sleep, and SE. CONCLUSIONS: This meta-analysis indicated that ASMs can have a statistically significant effect on sleep parameters; the effect differs between ASMs.

The association between shift work and possible obstructive sleep apnea: a systematic review and meta-analysis.

BACKGROUND: Shift work is a workschedule, since industrial era and some employees work in shift. It causes a desynchronization of the biological clock with consequences on sleep amount and quality, such as insomnia and easy fatigue. Obstructive sleep apnea (OSA) is one of the sleep problems that are getting more and more attention, but studies on the association between shift work and OSA were rare. Herein, we aimed to conduct a systematic review and meta-analysis to investigate the association between shift work and possible OSA. METHODS: This study was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We queried PubMed, Embase, and Web of Science databases using a related set of keywords. The inclusion criteria were as follows: (1) participants were adult employees hired by a company or organization; (2) exposure was shift work; and (3) outcome was possible OSA according to examination or assessment. RESULTS: We included six studies in the systematic review and five studies were selected for further meta-analysis. A random-effects model showed an association of shift work with a small, non-significant increase in possible OSA cases (pooled prevalence relative risk = 1.05; 95% CI 0.85-1.30; p = 0.65). This association occurred in both healthcare and non-healthcare workers group. CONCLUSION: The association between shift work and possible OSA remains inconclusive and could be small if not negligible. Future studies should assess the association between specific work schedules and specific OSA definitions. TRIAL REGISTRATION NUMBER: PROSPERO ID: CRD42020156837.

Rapid eye movement sleep disturbance in patients with refractory epilepsy: A polysomnographic study.

OBJECTIVE/BACKGROUND: Patients with epilepsy have disrupted sleep architecture and a higher prevalence of sleep disturbance. Moreover, obstructive sleep apnea (OSA) is more common among patients with refractory epilepsy. Few studies have compared subjective sleep quality, sleep architecture, and prevalence of OSA between patients with refractory epilepsy and those with medically controlled epilepsy. Therefore, this study aimed to evaluate the differences in sleep quality, sleep architecture, and prevalence of OSA between patients with refractory epilepsy and patients with medically controlled epilepsy. PATIENTS: This retrospective case-control study included 38 patients with refractory epilepsy and 96 patients with medically controlled epilepsy. Sleep parameters and indices of sleep-related breathing disorders were recorded by standard in-laboratory polysomnography. The scores from sleep questionnaires on sleep quality and daytime sleepiness were compared between the two groups. RESULTS: Patients with refractory epilepsy versus medically controlled epilepsy had statistically significantly decreased rapid eye movement (REM) sleep (13.5 ± 6.1% vs. 16.2 ± 6.1%) and longer REM latency (152.2 ± 84.1 min vs. 117.2 ± 61.9 min). Further, no differences were found in the prevalence of sleep-related breathing disorders, subjective sleep quality, prevalence of daytime sleepiness, and quality of life. Although not statistically significant, patients with refractory epilepsy have a lower rate of OSA compared with those with medically controlled epilepsy (21.1% vs. 30.2%). CONCLUSIONS: Patients with refractory epilepsy had more disrupted REM sleep regulation than those with medically controlled epilepsy. Although patients with epilepsy have a higher risk of OSA, in this study patients with refractory epilepsy were not susceptible to OSA.

Parkinsonism with newly diagnosed flare-up rheumatoid arthritis mimicking progressive supranuclear palsy.

In order to make a correct diagnosis of idiopathic Parkinson's disease (PD), it is essential to exclude atypical parkinsonian features, such as early dementia, fall, and autonomic dysfunction. Rheumatoid arthritis (RA), which is a systemic inflammatory disorder, although most patients present in a polyarticular manner. Still some may also present with extra-articular involvement including skin, lung, heart, and the central or peripheral nervous systems. A possible pathogenetic link between RA and PD are proposed. However, the coexistence of RA and progressive supranuclear palsy (PSP) is rarely reported. Here, we report a parkinsonian patient with a newly diagnosed flare-up RA presenting with early falls, postural instability and supra-nuclear gaze palsy, which suggestive of clinically probable PSP. Furthermore, the parkinsonian features respond to anti-rheumatic agents, but not levodopa. Finally, the patient looks like a clinical possible PD. In summary, Parkinsonian patient with newly diagnosed flare-up RA can present with clinically probable PSP. Unbearably painful limb contracture is a clue of the coexistence of RA. Both typical and atypical parkinsonian features respond dramatically to anti-rheumatic medication, but not levodopa.

Rice Big Grain 1 promotes cell division to enhance organ development, stress tolerance and grain yield.

Grain/seed yield and plant stress tolerance are two major traits that determine the yield potential of many crops. In cereals, grain size is one of the key factors affecting grain yield. Here, we identify and characterize a newly discovered gene Rice Big Grain 1 (RBG1) that regulates grain and organ development, as well as abiotic stress tolerance. Ectopic expression of RBG1 leads to significant increases in the size of not only grains but also other major organs such as roots, shoots and panicles. Increased grain size is primarily due to elevated cell numbers rather than cell enlargement. RBG1 is preferentially expressed in meristematic and proliferating tissues. Ectopic expression of RBG1 promotes cell division, and RBG1 co-localizes with microtubules known to be involved in cell division, which may account for the increase in organ size. Ectopic expression of RBG1 also increases auxin accumulation and sensitivity, which facilitates root development, particularly crown roots. Moreover, overexpression of RBG1 up-regulated a large number of heat-shock proteins, leading to enhanced tolerance to heat, osmotic and salt stresses, as well as rapid recovery from water-deficit stress. Ectopic expression of RBG1 regulated by a specific constitutive promoter, GOS2, enhanced harvest index and grain yield in rice. Taken together, we have discovered that RBG1 regulates two distinct and important traits in rice, namely grain yield and stress tolerance, via its effects on cell division, auxin and stress protein induction.

A Unique Case Report on Methadone Used for Treatment of Opioid-induced Hyperalgesia in a Cancer Patient at the End of Life.

Opioids are the cornerstone of palliative pain management. Opioids work on the mu-opioid receptor as an agonist for the treatment of pain. Repeated exposure to opioids over time can lead to undesired desensitization of the antinociceptive receptor while sensitizing the N-methyl-D-aspartate (NMDA) pathway, causing a paradoxical effect where the treatment of pain creates more sensitivity to certain stimuli. This phenomenon is known as opioid-induced hyperalgesia (OIH). Methadone, a synthetic opioid, may be more effective for pain and offers advantages over other opioids in specific clinical situations due to its partial antagonistic effect on the NMDA pathway. We describe a unique case where as needed (prn) and continuous intravenous (IV) methadone was effective in relieving OIH caused by high doses of IV Dilaudid for intractable cancer pain at the end of life. Given its unique pharmacokinetics, effective pain control, and the prevention of suffering from OIH, methadone should be considered earlier on in palliative pain management, especially in those patients predicted to require high levels of opioid dosing.

Identification of sugar response complex in the metallothionein OsMT2b gene promoter for enhancement of foreign protein production in transgenic rice.

KEY MESSAGE: A 146-bp sugar response complex MTSRC is identified in the promoter of rice metallothionein OsMT2b gene conferring high-level expression of luciferase reporter gene and bioactive recombinant haFGF in transgenic rice. A rice subfamily type 2 plant metallothionein (pMT) gene, OsMT2b, encoding a reactive oxygen species (ROS) scavenger protein, has been previously shown to exhibit the most abundant gene expression in young rice seedling. Expression of OsMT2b was found to be regulated negatively by ethylene and hydrogen peroxide in rice stem node under flooding stress, but little is known about its response to sugar depletion. In this study, transient expression assay and transgenic approach were employed to characterize the regulation of the OsMT2b gene expression in rice. We found that the expression of OsMT2b gene is induced by sugar starvation in both rice suspension cells and germinated embryos. Deletion analysis and functional assay of the OsMT2b promoter revealed that the 5'-flanking region of the OsMT2b between nucleotides - 351 and - 121, which contains the sugar response complex (- 266 to - 121, designated MTSRC) is responsible for high-level promoter activity under sugar starvation. It was also found that MTSRC significantly enhances the Act1 promoter activity in transgenic rice cells and seedlings. The modified Act1 promoter, Act1-MTSRC, was used to produce the recombinant human acidic fibroblast growth factor (haFGF) in rice cells. Our result shows that the bioactive recombinant haFGF is stably produced in transformed rice cell culture and yields are up to 2% of total medium proteins. Our studies reveal that MTSRC serves as a strong transcriptional activator and the Act1-MTSRC promoter can be applicable in establishing an efficient expression system for the high-level production of foreign proteins in transgenic rice cells and seedlings.

Multicenter integrated positron emission tomography/computer tomography imaging quality assurance accreditation interobserver reliability study with the American College of Radiology phantom.

BACKGROUND: Integrated positron emission tomography/computer tomography (PET/CT) image quality assurance ensures accurate, reproducible, and quantitative assessment of comparable scanner performance. We performed a preliminary multicenter PET/CT imaging quality assurance test with a fillable tomographic phantom in six medical centers in Taiwan. METHODS: The phantom was filled with fixed proportions of fluorine-18 radionuclide solution in the background and with different spheres to simulate cold and hot lesions, and body background radioactivity. Imaging acquisitions were performed by using recommended parameters in different sites according to different brand names of the instrument. All imaging was subjectively scored by eight experienced nuclear medicine physicians as the spatial resolution of four hot vials (score 0-4), six cold spheres (score 0-6), and six cold rod areas (score 0-6), and overall satisfaction (score 0-5). Interobserver correlation and receiver operating characteristic (ROC) curve were analyzed. RESULTS: The detection ability of hot vials, cold spheres, and cold rods was 4.0 ± 0.1, 5.2 ± 0.8, and 3.8 ± 0.9, respectively. Overall satisfaction was 4.0 ± 0.8. The ROC analysis revealed that the area under the curve for hot vials, cold spheres, and cold rods was 0.984, 0.887, and 0.928 respectively. The interobserver correlation for detectability of cold spheres and cold rods was 0.88 and 0.96, respectively. CONCLUSION: The results of the study indicated that (1) PET/CT imaging quality assurance for comparable scanner performance could be established on the basis of a standard phantom and (2) good interobserver correlation can be observed for those with accurate and interpretable results.

Fulminant course in a patient with anti-N-methyl-D-aspartate receptor encephalitis with bilateral ovarian teratomas: A case report and literature review.

RATIONALE: Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis is an autoimmune disorder that can be controlled and reversed by immunotherapy. The presentation of NMDA receptor encephalitis varies, but NMDA receptor encephalitis is seldom reported in patients with both bilateral teratomas and preexisting brain injury. PATIENT CONCERNS: A 28-year-old female with a history of traumatic intracranial hemorrhage presented acute psychosis, seizure, involuntary movement, and conscious disturbance with a fulminant course. Anti-NMDA receptor antibody was identified in both serum and cerebrospinal fluid, confirming the diagnosis of anti-NMDA receptor encephalitis. Bilateral teratomas were also identified during tumor survey. DIAGNOSES:: anti-N-methyl-D-aspartate receptor encephalitis. INTERVENTIONS: Tumor resection and immunotherapy were performed early during the course. OUTCOMES: The patient responded well to tumor resection and immunotherapy. Compared with other reports in the literature, her symptoms rapidly improved without further relapse. LESSONS: This case report demonstrates that bilateral teratomas may be related to high anybody titers and that the preexisting head injury may be responsible for lowering the threshold of neurological deficits. Early diagnosis and therapy are crucial for a good prognosis in such patients.

COMPARING TWO MEASUREMENTS OF THE SAME COSMIC-RAY NEUTRON SPECTRUM USING STANDARD BONNER SPHERES AND HIGH-SENSITIVITY BONNER CYLINDERS.

Ground-level cosmic-ray neutron spectra in Taiwan were measured using two neutron spectrometers, standard Bonner spheres and homemade high-sensitivity Bonner cylinders. The Bonner sphere system consisted of 12 polyethylene spheres of various diameters and four extended-range spheres that contained embedded metal shells. A set of 16 similarly designed Bonner cylinders was assembled based on a large cylindrical 3He proportional counter, showing an efficiency ~18 times higher than that of the central probe of the Bonner spheres. However, these Bonner cylinders were not fully symmetrical and exhibited angular dependence in their responses to incoming neutrons. Focusing on the low-intensity neutron background, this study presents a systematic comparison between Bonner spheres and cylinders in terms of their response characteristics, counting statistics, and unfolded neutron spectra. The comparison indicated that the neutron probe of the Bonner spheres had a small but non-negligible counting noise that required subtraction from the recorded data. According to the response functions calculated for isotropic neutron incidence, the neutron spectrum determined using the high-sensitivity Bonner cylinders agreed well with that measured using the Bonner spheres. The annual effective doses from cosmic-ray neutrons at the location were determined to be 30.5 and 30.8 µSv by using the Bonner sphere and cylinder spectrometers, respectively, which corresponded to respective total neutron fluxes of 5.39 × 10-3 and 5.43 × 10-3 cm-2s-1.

Comparing dose rates near a radioactive patient evaluated using various source models: point, line, cylinder, and anthropomorphic phantoms.

This study investigated radiation exposures from nuclear medicine patients by systematically comparing the dose rates calculated using various source models, ranging from simplified point, line, and cylinder sources to high-quality anthropomorphic phantoms. Three widely used radionuclides, (99m)Tc, (18)F, and I(131), were considered in these source models with uniform or organ-dependent distributions. Conducting Monte Carlo simulations with anthropomorphic phantoms is a realistic but time-consuming approach. The point source model is simple but too conservative, overestimating dose rates by approximately a factor of 2 at a distance of 30 cm and by 30-40% at 1 m. Both the line and cylinder source models provided improved estimates, reducing the overestimation of dose rates to 10-20% at distances of interest. The line source model was comparable to the cylinder source model because of the offset of two competing effects (i.e., attenuation and buildup) caused by the source volume. The influence of various photon energies and cylinder sizes on the result of compensating errors was examined to evaluate the effective range of the line source model. The line source model, which is relatively easy to implement and predicts slightly conservative dose rates, is considered the most practical method for calculating dose rates near radioactive patients. An application of the line source model to 51 post-thyroidectomy patients in Taiwan was demonstrated. The consistency between calculations and measurements was satisfactory after considering the room-scattering effect.

Metabolic adaptation to sugar/O2 deficiency for anaerobic germination and seedling growth in rice.

Rice is characterized by a broad range of metabolic and morphological adaptations to flooding, such as germination and mobilization of stored nutrients under submergence until seedlings reach the water surface to carry out photosynthesis, and sustainable growth of mature plants for long durations under partial submergence. The underlying mechanisms of the molecular basis of adaptation to anaerobic germination and seedling growth in rice are being uncovered. Induction of an ensemble of hydrolases to mobilize endosperm nutrient reserves is one of the key factors for successful germination and coleoptile elongation in rice under submergence. To compensate for reduced efficiency of Tricarboxylic Acid cycle and oxidative respiration in mitochondria under O2 deficient conditions, α-amylases play a central role in the hydrolysis of starch to provide sugar substrates for glycolysis and alcohol fermentation for generating ATP. We review the progress on the molecular mechanism regulating α-amylase expression that involves the integration of signals generated by the hormone gibberellin (GA), sugar starvation and O2 deprivation that results in germination and sustainable seedling growth in rice under anaerobic conditions. Comparisons are also made between dicots and monocots for the molecular mechanism of induction of genes involved in alcohol fermentation and sugar/O2 deficiency sensing system.