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Fulltext On the Computational Power of Spiking Neural P Systems with Self-Organization

Wang X, Song T, Gong F, Zheng P

Sci Rep, 2016 06 10;6:27624.
PMID: 27283843 DOI: 10.1038/srep27624

Neural-like computing models are versatile computing mechanisms in the field of artificial intelligence. Spiking neural P systems (SN P systems for short) are one of the recently developed spiking neural network models inspired by the way neurons communicate. The communications among neurons are essentially achieved by spikes, i. e. short electrical pulses. In terms of motivation, SN P systems fall into the third generation of neural network models. In this study, a novel variant of SN P systems, namely SN P systems with self-organization, is introduced, and the computational power of the system is investigated and evaluated. It is proved that SN P systems with self-organization are capable of computing and accept the family of sets of Turing computable natural numbers. Moreover, with 87 neurons the system can compute any Turing computable recursive function, thus achieves Turing universality. These results demonstrate promising initiatives to solve an open problem arisen by Gh Păun.
Construction of DNA nanotubes with controllable diameters and patterns using hierarchical DNA sub-tiles

Shi X, Wu X, Song T, Li X

Nanoscale, 2016 Jul 22.
PMID: 27444699

The design of DNA nanotubes is a promising and hot research branch in structural DNA nanotechnology, which is rapidly developing as a versatile method for achieving subtle nanometer scale materials and molecular diagnostic/curative devices. Multifarious methods have been proposed to achieve varied DNA nanotubes, such as using square tiles and single-stranded tiles, but it is still a challenge to develop a bottom-up assembly way to build DNA nanotubes with different diameters and patterns using certain universal DNA nanostructures. This work addresses the challenge by assembling three types of spatial DNA nanotubes with different diameters and patterns from the so-called "basic bricks", i.e., hierarchical DNA sub-tiles. A high processing rate and throughput synthesis of DNA nanotubes are observed and analyzed by atomic force microscopy. Experimental observations and data analysis suggests the stability and controllability of DNA nanotubes assembled by hierarchical DNA sub-tiles.
Fulltext 5α-Reduced neurosteroids sex-dependently reverse central prenatal programming of neuroendocrine stress responses in rats

Brunton PJ, Donadio MV, Yao ST, Greenwood M, Seckl JR, Murphy D, et al.

J Neurosci, 2015 Jan 14;35(2):666-77.
PMID: 25589761 DOI: 10.1523/JNEUROSCI.5104-13.2015

Maternal social stress during late pregnancy programs hypothalamo-pituitary-adrenal (HPA) axis hyper-responsiveness to stressors, such that adult prenatally stressed (PNS) offspring display exaggerated HPA axis responses to a physical stressor (systemic interleukin-1β; IL-1β) in adulthood, compared with controls. IL-1β acts via a noradrenergic relay from the nucleus tractus solitarii (NTS) to corticotropin releasing hormone neurons in the paraventricular nucleus (PVN). Neurosteroids can reduce HPA axis responses, so allopregnanolone and 3β-androstanediol (3β-diol; 5α-reduced metabolites of progesterone and testosterone, respectively) were given subacutely (over 24 h) to PNS rats to seek reversal of the "programmed" hyper-responsive HPA phenotype. Allopregnanolone attenuated ACTH responses to IL-1β (500 ng/kg, i.v.) in PNS females, but not in PNS males. However, 3β-diol normalized HPA axis responses to IL-1β in PNS males. Impaired testosterone and progesterone metabolism or increased secretion in PNS rats was indicated by greater plasma testosterone and progesterone concentrations in male and female PNS rats, respectively. Deficits in central neurosteroid production were indicated by reduced 5α-reductase mRNA levels in both male and female PNS offspring in the NTS, and in the PVN in males. In PNS females, adenovirus-mediated gene transfer was used to upregulate expression of 5α-reductase and 3α-hydroxysteroid dehydrogenase mRNAs in the NTS, and this normalized hyperactive HPA axis responses to IL-1β. Thus, downregulation of neurosteroid production in the brain may underlie HPA axis hyper-responsiveness in prenatally programmed offspring, and administration of 5α-reduced steroids acutely to PNS rats overrides programming of hyperactive HPA axis responses to immune challenge in a sex-dependent manner.
Fulltext A Novel Computational Method to Reduce Leaky Reaction in DNA Strand Displacement

Li X, Wang X, Song T, Lu W, Chen Z, Shi X

J Anal Methods Chem, 2015;2015:675827.
PMID: 26491602 DOI: 10.1155/2015/675827

DNA strand displacement technique is widely used in DNA programming, DNA biosensors, and gene analysis. In DNA strand displacement, leaky reactions can cause DNA signals decay and detecting DNA signals fails. The mostly used method to avoid leakage is cleaning up after upstream leaky reactions, and it remains a challenge to develop reliable DNA strand displacement technique with low leakage. In this work, we address the challenge by experimentally evaluating the basic factors, including reaction time, ratio of reactants, and ion concentration to the leakage in DNA strand displacement. Specifically, fluorescent probes and a hairpin structure reporting DNA strand are designed to detect the output of DNA strand displacement, and thus can evaluate the leakage of DNA strand displacement reactions with different reaction time, ratios of reactants, and ion concentrations. From the obtained data, mathematical models for evaluating leakage are achieved by curve derivation. As a result, it is obtained that long time incubation, high concentration of fuel strand, and inappropriate amount of ion concentration can weaken leaky reactions. This contributes to a method to set proper reaction conditions to reduce leakage in DNA strand displacement.
Fulltext Meaning in life and smartphone addiction among Chinese female college students: The mediating role of school adjustment and the moderating role of grade

Zhao H, Rafik-Galea S, Fitriana M, Song T

Front Psychol, 2023;14:1092893.
PMID: 36818081 DOI: 10.3389/fpsyg.2023.1092893

BACKGROUND: The fact that female college students are more addicted to smartphones than male college students has raised public concerns. However, previous studies have rarely explored the mechanism of female college students' smartphone addiction. Previous studies have shown that identity may affect the formation process of female college students' smartphone addiction, and the identity of female college students in different grades may be different. Nonetheless, few studies have explored the grade differences in the formation process of female college students' smartphone addiction.
METHODS: The present study examined the relationship between meaning in life, school adjustment, and smartphone addiction among Chinese female college students using a moderated mediation model in which school adjustment played a mediating role and grade played a moderating role. A total of 1,076 Chinese female college students (Age: 19.83 ± 1.11; 369 freshmen, 379 sophomores, and 328 juniors) completed an online questionnaire regarding meaning in life, school adjustment, and smartphone addiction.
RESULTS: (1) School adjustment mediated the relationship between meaning in life and smartphone addiction. (2) School adjustment had a partial mediating effect between meaning in life and smartphone addiction for female freshmen and sophomores, but it did not exist among female juniors. (3) The influence of school adjustment on female sophomores' smartphone addiction was significantly stronger than that of female freshmen.
CONCLUSION: The findings of this study advance our understanding of the potential impacts of meaning in life on smartphone addiction and provide a grade perspective for targeted prevention or intervention with female college students' smartphone addiction.
NES-REBS: A novel nuclear export signal prediction method using regular expressions and biochemical properties

Wu T, Wang X, Zhang Z, Gong F, Song T, Chen Z, et al.

J Bioinform Comput Biol, 2016 06;14(3):1650013.
PMID: 27225342 DOI: 10.1142/S021972001650013X

A nuclear export signal (NES) is a protein localization signal, which is involved in binding of cargo proteins to nuclear export receptor, thus contributes to regulate localization of cellular proteins. Consensus sequences of NES have been used to detect NES from protein sequences, but suffer from poor predictive power. Some recent peering works were proposed to use biochemical properties of experimental verified NES to refine NES candidates. Those methods can achieve high prediction rates, but their execution time will become unacceptable for large-scale NES searching if too much properties are involved. In this work, we developed a novel computational approach, named NES-REBS, to search NES from protein sequences, where biochemical properties of experimental verified NES, including secondary structure and surface accessibility, are utilized to refine NES candidates obtained by matching popular consensus sequences. We test our method by searching 262 experimental verified NES from 221 NES-containing protein sequences. It is obtained that NES-REBS runs in 2-3[Formula: see text]mins and performs well by achieving precision rate 47.2% and sensitivity 54.6%.
Fulltext The reciprocal relationships between meaning in life and smartphone addiction among Chinese college students: evidence from a three-wave cross-lagged panel model

Zhao H, Song T, Rafik-Galea S, Dong J, Fitriana M, Ji Y, et al.

Front Public Health, 2023;11:1202741.
PMID: 37521981 DOI: 10.3389/fpubh.2023.1202741

BACKGROUND: Previous cross-sectional studies have shown that meaning in life (MIL) is closely associated with college students' smartphone addiction (SA), but the causal relationship between MIL and college students' SA is uncertain. Therefore, conducting a longitudinal study to explore their relationship is very necessary. Furthermore, some studies have implied possible gender differences in the relationship between MIL and SA and the relationship between SA and MIL. Therefore, it is necessary to further examine whether there are gender differences in the above relationships.
METHODS: The present study constructed a three-wave cross-lag panel model to explore the relationships between MIL and college students' SA. Three waves of data were collected from 705 college students (male: 338; female: 367) in China for three consecutive years, and the interval of data collection was 1 year. These college students completed the same online questionnaire regarding MIL and SA.
RESULTS: (1) The MIL of male college students was significantly stronger than that of female college students at time 1, time 2, and time 3, (2) Female college students' SA at time 1, time 2, and time 3 was more serious than that of male college students, (3) There were reciprocal relationships between MIL and college students' SA, (4) The influence of MIL on female college students' SA was significantly stronger than that of male college students, and (5) The influence of SA on female college students' MIL was significantly stronger than that of male college students.
CONCLUSION: This study showed reciprocal relationships between MIL and SA among male college students and female college students. The findings further deepen our understanding of the relationship between MIL and SA and provide a gender perspective for preventing or intervening with college students' SA.
Fulltext Osmoregulation requires brain expression of the renal Na-K-2Cl cotransporter NKCC2

Konopacka A, Qiu J, Yao ST, Greenwood MP, Greenwood M, Lancaster T, et al.

J Neurosci, 2015 Apr 01;35(13):5144-55.
PMID: 25834041 DOI: 10.1523/JNEUROSCI.4121-14.2015

The Na-K-2Cl cotransporter 2 (NKCC2) was thought to be kidney specific. Here we show expression in the brain hypothalamo-neurohypophyseal system (HNS), wherein upregulation follows osmotic stress. The HNS controls osmotic stability through the synthesis and release of the neuropeptide hormone, arginine vasopressin (AVP). AVP travels through the bloodstream to the kidney, where it promotes water conservation. Knockdown of HNS NKCC2 elicited profound effects on fluid balance following ingestion of a high-salt solution-rats produced significantly more urine, concomitant with increases in fluid intake and plasma osmolality. Since NKCC2 is the molecular target of the loop diuretics bumetanide and furosemide, we asked about their effects on HNS function following disturbed water balance. Dehydration-evoked GABA-mediated excitation of AVP neurons was reversed by bumetanide, and furosemide blocked AVP release, both in vivo and in hypothalamic explants. Thus, NKCC2-dependent brain mechanisms that regulate osmotic stability are disrupted by loop diuretics in rats.
Ethnic Differences in the Role of Adipocytokines Linking Abdominal Adiposity and Insulin Sensitivity Among Asians

Parvaresh Rizi E, Teo Y, Leow MK, Venkataraman K, Khoo EY, Yeo CR, et al.

J Clin Endocrinol Metab, 2015 11;100(11):4249-56.
PMID: 26308293 DOI: 10.1210/jc.2015-2639

CONTEXT: Among Asian ethnic groups, Chinese or Malays are more insulin sensitive than South Asians, in particular in lean individuals. We have further reported that body fat partitioning did not explain this ethnic difference in insulin sensitivity.
OBJECTIVE: We examined whether adipocytokines might explain the ethnic differences in the relationship between obesity and insulin resistance among the three major ethnic groups in Singapore.
DESIGN AND PARTICIPANTS: This was a cross-sectional study of 101 Chinese, 82 Malays, and 81 South Asian men. Insulin sensitivity index (ISI) was measured using hyperinsulinemic euglycemic clamp. Visceral (VAT) and subcutaneous adipose tissue (SAT) volumes were quantified using magnetic resonance imaging.
MAIN OUTCOME MEASURES: Plasma total and high-molecular-weight adiponectin, leptin, visfatin, apelin, IL-6, fibroblast growth factor 21 (FGF21), retinol binding protein-4 (RBP 4), and resistin were measured using enzyme-linked immunoassays.
RESULTS: Principle component (PC) analysis on the adipocytokines identified three PCs, which explained 49.5% of the total variance. Adiponectin loaded negatively, and leptin and FGF21 loaded positively onto PC1. Visfatin, resistin, and apelin all loaded positively onto PC2. IL-6 loaded positively and RBP-4 negatively onto PC3. Only PC1 was negatively associated with ISI in all ethnic groups. In the path analysis, SAT and VAT were negatively associated with ISI in Chinese and Malays without significant mediatory role of PC1. In South Asians, the relationship between VAT and ISI was mediated partly through PC1, whereas the relationship between SAT and ISI was mediated mainly through PC1.
CONCLUSIONS: The relationships between abdominal obesity, adipocytokines and insulin sensitivity differ between ethnic groups. Adiponectin, leptin, and FGF21 play a mediating role in the relationship between abdominal adiposity and insulin resistance in South Asians, but not in Malays or Chinese.