Revision of a CHF correlation for PWR under low pressure conditions with only dimensionless parameters as independent variables

Accurate prediction of the critical heat flux (CHF) is one of the key tasks of PWR core design and safety assessment, for the maximal allowable heat flux in the reactor core is limited by CHF. Since CHF in rod bundle cannot be predicted analytically, up-to-date predictive approach is based on empirical correlations related to the local thermal-hydraulic conditions, geometry and power distribution. However, development of CHF correlation for PWR fuel assemblies under low pressure conditions (2–10 MPa) is constrained by limited amount of experimental data points, which builds up in statistics a typical problem of small sample amounts, but requiring simultaneously high prediction accuracy. In our previous study, stepwise regression method was applied to develop a dimensional, empirical CHF correlation for PWR under low pressure conditions, termed as the advanced low pressure CHF correlation (ALPC), which successfully solves the challenge of small sample problem. However, the ALPC correlation still uses dimensional independent variables with less physical meanings, which limits its physical interpretability. In the current study, stepwise regression method was used to develop a revised, dimensionless version of the ALPC CHF correlation. First, various dimensionless, two-phase thermal-hydraulic parameters that might influence CHF were selected as candidate independent variables. With stepwise regression, the form and coefficients of the revised CHF correlation were optimized in a dynamic manner. Compared to the current ALPC correlation, the revised version developed in this study possesses a similar simple form but a much higher prediction accuracy. Revision of the ALPC correlation demonstrates clearly the advantages of utilizing dimensionless parameters as independent variables in CHF correlation, which points out a new direction of developing rod-bundle CHF correlations for engineering purpose.

The characteristics of internet-based venue sex-seeking and mobility among money boys in Tianjin, China

OBJECTIVES

Internet-based venue sex-seeking is prevalent among money boys (MBs), as is a high degree of mobility, which is crucial for HIV transmission in key populations with high risks of HIV infection. However, correlation studies in MBs are scarce because of the secretive nature of this hard-to-reach subpopulation. We conducted this project to explore the characteristics of MBs.

METHODS

This survey was conducted from December 2014 to June 2015 in Tianjin; a total of 330 MBs were recruited by convenience sampling. Demographic and behavioural data were collected for analysis.

RESULTS

Among the investigated MBs, 38 (11.52%) were HIV positive, 147 (44.55%) reported using internet-based venues to seek sexual partners and 257 (77.88%) had travelled to two or more destinations in the past 6 months. Compared with non-internet-based venue-using MBs, internet-based venue-using MBs were more likely to have part-time employment as MBs, to have a longer duration of working in the sex trade, to engage in finger intercourse and to present a history of substance abuse and sexually transmitted infections. However, internet-based venue-using MBs were less likely to exhibit consistent condom usage and undergo HIV testing. Origin of residence data showed that most MBs were from northern China, with Tianjin, Beijing and Shanghai as the main travel destinations. Mobile MBs were characterized as a group who were fully engaged in the sex trade and frequently took part in sexual activities but had a weak sense of self-protection.

CONCLUSIONS

Internet-based venue sex-seeking and mobility are prevalent in MBs. Renewed efforts in internet-based health promotion and school-based primary health examination programmes may benefit more mobile and/or internet-based venue sex-seeking MBs.

Chemical Composition, Antioxidant and Antihyperglycemic Activities of the Wild Lactarius deliciosus from China

The wild mushroom Lactarius deliciosus from China was studied for the first time to obtain information about its chemical composition, antioxidant, and antihyperglycemic activities. Nutritional value, dietary fiber, fatty acids, metal elements, free sugars, free amino acids, organic acids, flavor 5′-nucleotides, and volatile aroma compounds were determined. Potential antioxidant and antihyperglycemic activities were also tested by investigating 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals scavenging activities, ferric ion reducing activity, as well as α-amylase and α-glucosidase inhibitory activities using ethanol and aqueous extracts. The results showed that L. deliciosus was a good wild mushroom with high protein, carbohydrate, and dietary fiber contents, while low in fat and calorie, extensive unsaturated fatty acids contents, with negligible health risks about harmful metal elements. Twenty kinds of free amino acids were detected with a total content 3389.45 mg per 100 g dw. Flavor 5′-nucleotides including 5′-CMP, 5′-UMP, 5′-IMP, and 5′-AMP were 929.85, 45.21, 311.75, and 14.49 mg per 100 g dw, respectively. Mannitol (7825.00 mg per 100 g dw) was the main free sugar, and quininic acid (729.84 mg per 100 g dw) was the main organic acid. Twenty-five kinds of volatile aroma compounds were identified, acids (84.23%) were the most abundant compounds based on content, while aldehydes (15 of 25) were the most abundant compounds based on variety. In addition, both ethanol and aqueous extracts from L. deliciosus exhibited excellent antioxidant activity. While in antihyperglycemic activity tests, only ethanol extracts showed inhibitory effects on α-amylase and α-glucosidase.

Multicolor fluorescent imaging by space-constrained computational spectral imaging

Spectral imaging is a powerful technique used to simultaneously study multiple fluorophore labels with overlapping emissions. Here, we present a computational spectral imaging method, which uses sample spatial fluorescence information as a reconstruction constraint. Our method addresses both the under-sampling issue of compressive spectral imaging and the low throughput issue of scanning spectral imaging. With simulated and experimental data, we have demonstrated the reconstruction precision of our method in two and three-color imaging. We have experimentally validated this method for differentiating cellular structures labeled with two red-colored fluorescent proteins, tdTomato and mCherry, which have highly overlapping emission spectra. Our method has the advantage of totally free wavelength choice and can also be combined with conventional filter-based sequential multi-color imaging to further improve multiplexing capability.

A steady-state analytical profile method for determining methane oxidation in landfill cover

Gas concentration profiles of carbon dioxide (CO₂), oxygen (O₂), methane (CH₄) and nitrogen (N₂) are usually measured during tests investigating microbial aerobic methane oxidation in landfill cover. However, only qualitative/limited information can be obtained from gas concentration profiles by existing methods. A new method is proposed to determine methane oxidation in soil quantitatively and comprehensively, including methane oxidation efficiency, stoichiometry, gas transfer mechanism, methane generation rate and gas reaction rate distributions. Governing equations are established based on mass balance for O₂, CO₂, CH₄ and N₂ at one-dimensional and steady-state condition. Gas transfer mechanisms considered include gas diffusion, advection and gas reaction. The method utilizes gas concentration profiles to determine gas diffusion for each gas component according to Fick's law. Then gas advections and reactions can be determined by mass balance. The method is validated by (i) published soil column tests investigating methane oxidation and (ii) a calibrated numerical model based on a selected soil column test. The new method is capable of determining methane oxidation efficiency, stoichiometry, gas transfer mechanism, methane generation rate and gas reaction rate distributions for CH₄, CO₂ and O₂.

[Study of de novo point mutations in known genes among patients with unexplained intellectual disability or developmental delay]

Objective: To analyze the de novo point mutations in known genes among patients with unexplained intellectual disability (ID) or developmental retardation (DD). Methods: A total of 120 outpatients with ID or DD were recruited in the Department of Neurology, Affiliated Children's Hospital of Capital Institute of Pediatrics between September 2015 and April 2017. Target gene sequencing was used to screen the candidate gene. The sequencing data were analyzed by a variety of bioinformatics software. Combining with the phenotypes of the patients, the candidate genetic/genomic variants were identified from next-generation sequencing data. The final pathogenicity of the genetic/genomic variants were interpreted according to the guideline of the American College of Medical Genetics and Genomics (ACMG) for variants after segregation analysis in the parents and necessary family members by Sanger sequencing. The comprehensive physiological function and signaling pathways of 20 disease genes with de novo point mutation discovery was also studied. Results: Among the 120 patients, 23 patients were found to carry clear pathological changes, and the incidence of de novo point variation was 19.2%. The patients included 12 males and 11 females, with an age of 2 months to 6-year-6-month. Five patients were diagnosed with early onset of epileptic encephalopathy. Seven had mental retardation type 5, 6, 8, 19, 20, 22, 39, respectively. Weill-Marchesani syndrome type 2 was found in one case, Wiedemann-Steiner syndrome in one case, Coffin-Siris syndrome in two cases, Rubinstein-Taybi syndrome in one case, GLUT1 deficiency syndrome in one case, Rett syndrome in one case, cardio-facio-cutaneous syndrome 3 in one case, neurodegeneration with brain iron accumulation in one case, corpus callosum local dysplasia in one case, and congenital fibrosis of the extra-ocular muscles in one case. A total of 20 novel mutations were reported in this study. No somatic mutation was found in the samples of 6 patients with mutation and their parents' peripheral blood DNA samples by amplicon-based deep sequencing. This study found that the main disease genes were involved in chromatin remodeling, transcriptional regulation, autophagy body assembly, MAPK signal pathway, DNA methylation, potassium, sodium ion transport, cell skeleton assembly and skeletal muscle development. These genes were significantly enriched in the following biological processes: Ras signaling pathways, transcription factor binding and cancer related signaling pathway. Conclusions: The etiology of children affected with intellectual disability or developmental delay is complex. Harmful de novo point mutation plays an important role in these diseases. Targeted exome/genome sequencing based on the core family is helpful for the molecular diagnosis of patients and the discovery of more genes.

Neutron measurements at the ELISE neutral beam test facility and implications for neutron based diagnostics at SPIDER

Along the route to the development of a neutral beam injector for ITER, the Padua based Source for Production of Ion of Deuterium Extracted from Rf plasma (SPIDER) and megavolt ITER injector and concept advancement facilities will make use of neutron diagnostics to quantify the homogeneity of the neutral beam profile by measuring the map of the neutron emission from the beam dump with the close-contact neutron emission surface mapping (CNESM) system. Neutrons are here produced from beam-target reactions between the deuterium beam and the deuterons previously adsorbed in the calorimeter. In order to aid the interpretation of the diagnostic data, a dedicated experiment on neutron emission from beam-target reactions with beam parameters approaching those expected at SPIDER has been performed at the Extraction from a Large Ion Source Experiment (ELISE) neutral beam test facility. The time trace of neutron emission has been measured using a calibrated liquid scintillator detector at increasing power densities on the target. Compared to calculations based on the local mixing model, a systematic discrepancy was observed exceeding the statistical accuracy of the measurements and increasing as a linear function of the power density. The data are used to derive an empirical temperature dependent correction for applications to neutron measurements at SPIDER.

Abstract P3-14-06: The prevention and management of chemotherapy-induced peripheral neuropathy in breast cancer patients: A systematic review

Background: Chemotherapy induced peripheral neuropathy (CIPN) remains a common treatment related adverse event for breast cancer (BC) patients. CIPN interferes with the ability to complete chemotherapy & therefore potentially compromises survival outcomes. CIPN can worsen health-related quality of life and also add to the ongoing morbidity experienced by BC survivors. Previously, systematic reviews & ASCO guidelines have examined CIPN across many cancer types & different chemotherapies, which may lead to the introduction of confounding factors not relevant to BC patients. A recent prospective cohort also identified other specific lifestyle factors associated with CIPN in BC patients (1). From our search, a systematic review specifically looking at CIPN in BC patients has not previously been undertaken.

Methods: We conducted a systematic search in PubMed, EMBASE, CINAHL and CENTRAL. Clinical trials and observational studies for all potential pharmacological and non-pharmacological interventions were included. Risk of bias for full-text papers was assessed using the Cochrane Risk of Bias Assessment or the modified Newcastle Ottawa score.

Results: Of 706 records being identified, 601 unique citations were screened with 21 full text papers retrieved for assessment, and 16 studies included in the qualitative assessment. We identified 10 randomised controlled trials (RCTs), one observational cohort study, and five controlled before-and-after studies (CBA). Pharmacological interventions which were investigated included calcium/magnesium infusion, glutamine, amifostine, goshajinkigan, omega 3 fatty acids, acetyl-L-carnitine, pregabalin, alpha-lipoic acid and minocycline. Non-pharmacological interventions included body mass index & lifestyle factors, electroacupuncture, exercise, limb hypothermia, carbon dioxide limb bathing and limb compression therapy. All trials identified were investigating primary prevention of CIPN in the setting of taxane chemotherapy. Improvements in the incidence of CIPN were reported with omega 3 fatty acids, glutamine and alpha-lipoic acid, but only one of these studies is a published RCT. In two of the studies, the benefit was identified only on physical examination, but no significant benefit with nerve conduction (NCS) testing. On subgroup analysis of trials investigating exercise, there was a benefit in the use of high intensity exercise versus low intensity exercise, particularly in patients <50 years old within a healthy weight range. Mixed results were seen with goshajinkigan. An increase in CIPN was seen with antioxidant use, electroacupuncture and acetyl L carnitine. Majority of the RCTs were associated with a high overall risk of bias.

Conclusions: There has been a paucity of research on CIPN in BC patients. There were no interventions identified in this systematic review which show a clear clinical benefit in the prevention of CIPN in BC patients. BC patients may have specific lifestyle and hormonal factors which influence CIPN and this should prompt ongoing specific patient focussed research within this subgroup with large, blinded, randomised controlled trials.

Greenlee, et al. Natl Cancer Inst 2017; 109(2).

Citation Format: Roberts KE, Feng S, Adsett I, Rickett K, Woodward N. The prevention and management of chemotherapy-induced peripheral neuropathy in breast cancer patients: A systematic review [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-14-06.