Gender difference in emotional distress among nursing and health science college students: An online survey.

This cross-sectional study investigates the self-reported emotional distress of medical, nursing, dental, pharmacy, and public health students and identifies gender-related differences through an online survey. The data of 364 students were analyzed using Pearson correlation coefficients and multiple logistic regression. Emotional distress was more prevalent among female respondents (11.7 %) than male (3.8 %) respondents. The stigma, isolation, and depression experienced by female respondents influenced their emotional distress, whereas only the depression of male respondents influenced their emotional distress. Our findings suggest that mental health professionals should consider gender-specific factors when developing interventions for the study population to minimize emotional distress.

Decoding the prognostic significance of integrator complex subunit 9 (INTS9) in glioma: links to TP53 mutations, E2F signaling, and inflammatory microenvironments.

INTRODUCTION: Gliomas, a type of brain neoplasm, are prevalent and often fatal. Molecular diagnostics have improved understanding, but treatment options are limited. This study investigates the role of INTS9 in processing small nuclear RNA (snRNA), which is crucial to generating mature messenger RNA (mRNA). We aim to employ advanced bioinformatics analyses with large-scale databases and conduct functional experiments to elucidate its potential role in glioma therapeutics. MATERIALS AND METHODS: We collected genomic, proteomic, and Whole-Exon-Sequencing data from The Cancer Genome Atlas (TCGA) and Chinese Glioma Genome Atlas (CGGA) for bioinformatic analyses. Then, we validated INTS9 protein expression through immunohistochemistry and assessed its correlation with P53 and KI67 protein expression. Gene Set Enrichment Analysis (GSEA) was performed to identify altered signaling pathways, and functional experiments were conducted on three cell lines treated with siINTS9. Then, we also investigate the impacts of tumor heterogeneity on INTS9 expression by integrating single-cell sequencing, 12-cell state prediction, and CIBERSORT analyses. Finally, we also observed longitudinal changes in INTS9 using the Glioma Longitudinal Analysis (GLASS) dataset. RESULTS: Our findings showed increased INTS9 levels in tumor tissue compared to non-neoplastic components, correlating with high tumor grading and proliferation index. TP53 mutation was the most notable factor associated with upregulated INTS9, along with other potential contributors, such as combined chromosome 7 gain/10 loss, TERT promoter mutation, and increased Tumor Mutational Burden (TMB). In GSEA analyses, we also linked INTS9 with enhanced cell proliferation and inflammation signaling. Downregulating INTS9 impacted cellular proliferation and cell cycle regulation during the function validation. In the context of the 12 cell states, INTS9 correlated with tumor-stem and tumor-proliferative-stem cells. CIBERSORT analyses revealed increased INTS9 associated with increased macrophage M0 and M2 but depletion of monocytes. Longitudinally, we also noticed that the INTS9 expression declined during recurrence in IDH wildtype. CONCLUSION: This study assessed the role of INTS9 protein in glioma development and its potential as a therapeutic target. Results indicated elevated INTS9 levels were linked to increased proliferation capacity, higher tumor grading, and poorer prognosis, potentially resulting from TP53 mutations. This research highlights the potential of INTS9 as a promising target for glioma treatment.

Ancient ubiquitous protein 1 (AUP1) is a prognostic biomarker connected with TP53 mutation and the inflamed microenvironments in glioma.

INTRODUCTION: Glioblastoma (GBM) is the most common and lethal brain tumor. The current treatment is surgical removal combined with radiotherapy and chemotherapy, Temozolomide (TMZ). However, tumors tend to develop TMZ resistance which leads to therapeutic failure. Ancient ubiquitous protein 1 (AUP1) is a protein associated with lipid metabolism, which is widely expressed on the surface of ER and Lipid droplets, involved in the degradation of misfolded proteins through autophagy. It has recently been described as a prognostic marker in renal tumors. Here, we aim to use sophisticated bioinformatics and experimental validation to characterize the AUP1's role in glioma. MATERIAL AND METHODS: We collected the mRNA, proteomics, and Whole-Exon-Sequencing from The Cancer Genome Atlas (TCGA) for bioinformatics analyses. The analyses included the expression difference, Kaplan-Meier-survival, COX-survival, and correlation to the clinical factors (tumor mutation burden, microsatellite instability, and driven mutant genes). Next, we validated the AUP1 protein expression using immunohistochemical staining on the 78 clinical cases and correlated them with P53 and KI67. Then, we applied GSEA analyses to identify the altered signalings and set functional experiments (including Western Blot, qPCR, BrdU, migration, cell-cycle, and RNAseq) on cell lines when supplemented with small interfering RNA targeting the AUP1 gene (siAUP1) for further validation. We integrated the single-cell sequencing and CIBERSORT analyses at the Chinese Glioma Genome Atlas (CGGA) and Glioma Longitudinal AnalySiS (GLASS) dataset to rationale the role of AUP1 in glioma. RESULTS: Firstly, the AUP1 is a prognostic marker, increased in the tumor component, and correlated with tumor grade in both transcriptomes and protein levels. Secondly, we found higher AUP1 associated with TP53 status, Tumor mutation burden, and increased proliferation. In the function validation, downregulated AUP1 expression merely impacted the U87MG cells' proliferation instead of altering the lipophagy activity. From the single-cell sequencing and CIBERSORT analyses at CGGA and GLASS data, we understood the AUP1 expression was affected by the tumor proliferation, stromal, and inflammation compositions, particularly the myeloid and T cells. In the longitudinal data, the AUP1 significantly dropped in the recurrent IDH wildtype astrocytoma, which might result from increased AUP1-cold components, including oligodendrocytes, endothelial cells, and pericytes. CONCLUSION: According to the literature, AUP1 regulates lipophagy by stabilizing the ubiquitination of lipid droplets. However, we found no direct link between AUP1 suppression and altered autophagy activity in the functional validation. Instead, we noticed AUP1 expression associated with tumor proliferation and inflammatory status, contributed by myeloid cells and T cells. In addition, the TP53 mutations seem to play an important role here and initiate inflamed microenvironments. At the same time, EGFR amplification and Chromosome 7 gain combined 10 loss are associated with increased tumor growth related to AUP1 levels. This study taught us that AUP1 is a poorer predictive biomarker associated with tumor proliferation and could report inflamed status, potentially impacting the clinical application.

Exploring the Mechanism of Adjuvant Treatment of Glioblastoma Using Temozolomide and Metformin.

Glioblastoma is the most frequent and lethal primary central nervous system tumor in adults, accounting for around 15% of intracranial neoplasms and 40-50% of all primary malignant brain tumors, with an annual incidence of 3-6 cases per 100,000 population. Despite maximum treatment, patients only have a median survival time of 15 months. Metformin is a biguanide drug utilized as the first-line medication in treating type 2 diabetes. Recently, researchers have noticed that metformin can contribute to antineoplastic activity. The objective of this study is to investigate the mechanism of metformin as a potential adjuvant treatment drug in glioblastoma. Glioblastoma cell lines U87MG, LNZ308, and LN229 were treated with metformin, and several cellular functions and metabolic states were evaluated. First, the proliferation capability was investigated using the MTS assay and BrdU assay, while cell apoptosis was evaluated using the annexin V assay. Next, a wound-healing assay and mesenchymal biomarkers (N-cadherin, vimentin, and Twist) were used to detect the cell migration ability and epithelial-mesenchymal transition (EMT) status of tumor cells. Gene set enrichment analysis (GSEA) was applied to the transcriptome of the metformin-treated glioblastoma cell line. Then, DCFH-DA and MitoSOX Red dyes were used to quantify reactive oxygen species (ROS) in the cytosol and mitochondria. JC-1 dye and Western blotting analysis were used to evaluate mitochondrial membrane potential and biogenesis. In addition, the combinatory effect of temozolomide (TMZ) with metformin treatment was assessed by combination index analysis. Metformin could decrease cell viability, proliferation, and migration, increase cell apoptosis, and disrupt EMT in all three glioblastoma cell lines. The GSEA study highlighted increased ROS and hypoxia in the metformin-treated glioblastoma cells. Metformin increased ROS production, impaired mitochondrial membrane potential, and reduced mitochondrial biogenesis. The combined treatment of metformin and TMZ had U87 as synergistic, LNZ308 as antagonistic, and LN229 as additive. Metformin alone or combined with TMZ could suppress mitochondrial transcription factor A, Twist, and O6-methylguanine-DNA methyltransferase (MGMT) proteins in TMZ-resistant LN229 cells. In conclusion, our study showed that metformin decreased metabolic activity, proliferation, migration, mitochondrial biogenesis, and mitochondrial membrane potential and increased apoptosis and ROS in some glioblastoma cells. The sensitivity of the TMZ-resistant glioblastoma cell line to metformin might be mediated via the suppression of mitochondrial biogenesis, EMT, and MGMT expression. Our work provides new insights into the choice of adjuvant agents in TMZ-resistant GBM therapy.

[Improving the Rate of Eating Safety Guidance Implementation Among the Elderly].

BACKGROUND & PROBLEM: The provision by nurses of effective swallowing assessments and eating safety guidance improves eating safety in the elderly. The authors of this study found that elderly clients experienced a high proportion of aspiration pneumonia after choking episodes and that the rate of implementation of eating safety guidance among these clients by nursing staff was only 64.6%. The problems identified included a lack of education and training related to eating safety for the elderly, inconsistent health education methods, oral health education only, lack of unified health education content, and lack of proper health education guidance aids. PURPOSE: To raise the rate of implementing eating safety guidance among the elderly from 64.6% to 90.0%. RESOLUTION: The project included promoting an eating safety guidance workflow for the elderly using cross-team collaboration, using human body models and food models, promoting oral healthcare and oral exercises, using multilingual instructional leaflets and videos on eating safety and hygiene education, promoting a treasure hunting activity to the elderly related to eating safely using a food texture selection chart, and implementing a workshop on simulated eating safety scenarios. RESULTS: After project implementation, the eating safety guidance implementation rate increased from 64.6% to 92.1%, demonstrating that the intervention measures achieved remarkable results. CONCLUSIONS: Formulating care procedures and cooperating across teams to draft concrete and feasible improvement measures effectively increased the rate of eating safety guidance implementation for elderly clients by nursing staff.

Factors associated with intensiveness of use of child preventive health services in Taiwan: a comparative study between cross-cultural immigrant families and native-born families.

OBJECTIVES: To compare intensiveness of use of child preventive health services (CPHS) between cross-cultural immigrant families and native-born families in Taiwan and to explore factors associated with differences in intensiveness of CPHS use. DESIGN: Cross-cultural immigrant families were defined as families where the mother was an immigrant from another southeast Asian country. In native-born families, both parents were Taiwanese-born. Data were collected from 318 immigrant mothers and 340 native-born mothers of children aged 7 years or younger in a cross-sectional survey in central Taiwan. A social determinants framework of health inequities was constructed, and ordinal logistic regression models were used to examine the effect of four domains of intermediary determinants on the relationship between family type and underuse of CPHS: CPHS-related factors, medical-related factors, maternal acculturation factors, and sociodemographic/socioeconomic characteristics. RESULTS: Cross-cultural immigrant families were less likely to intensively use CPHS than native-born families. This difference appeared to be mediated by the greater likelihood of having an older child or a lower educated father in cross-cultural families. CONCLUSION: Findings of this study highlight the importance of promoting health behaviors and combating health inequities and social inequalities for cross-cultural immigrant families in Taiwan from a sociodemographic/socioeconomic and political context.

Comparing the effects of water temperature and additives in glucose solution on pregnant women's taste, side effects, and glycemic levels during an oral glucose tolerance test: a randomized controlled trial.

BACKGROUND: The oral glucose tolerance test is a common method of diagnosing gestational diabetes mellitus. This test causes several unpleasant side effects such as nausea, vomiting, abdominal bloating, and headache. OBJECTIVE: This study aimed to assess the effect of liquid temperature and additives on pregnant women's taste perception, side effects, and glycemic levels in an oral glucose tolerance test. STUDY DESIGN: This study was a single-center, randomized, and multi- and open-arm clinical trial. A total of 399 participants receiving the 75-g oral glucose tolerance test for gestational diabetes mellitus diagnosis were included. Solutions for use in the 75-g oral glucose tolerance test were prepared in 8 formulas, with the participants randomly assigned to 1 of the 8 groups: room-temperature water, hot water, cold water, hot water with tea bag, room-temperature water with tea bag, cold water with tea bag, room-temperature soda water, and cold soda water. The main study outcomes were glycemic levels, satisfaction, perceived taste, side effects, and gestational diabetes mellitus. Glycemic levels were measured when fasted and at 1 hour and 2 hours after glucose administration. Satisfaction, taste perception, and side effects were evaluated immediately after the oral glucose tolerance test, and gestational diabetes mellitus was determined on the basis of glycemic levels. RESULTS: The cold soda water solution led to a significantly higher glycemic level at 1 hour after glucose intake compared with room-temperature soda water solution (P=.009). Glucose formula was found to not significantly affect gestational diabetes mellitus incidence (P>.05) or the participants' satisfaction, vomiting, headache, or abdominal bloating (P>.05). However, the formula did significantly affect perceived taste (P=.027) and the degree of nausea (P=.014). CONCLUSION: Several glucose solutions, such as cold glucose solution and any-temperature glucose solution containing a tea bag, led to slightly higher taste scores and a lower degree of nausea compared with the room-temperature water-based glucose solution. However, soda water was found to affect the glycemic level at 1 hour after glucose intake, and is not suggested for use for gestational diabetes mellitus diagnosis.

The Significant Predictors for Breast, Cervical, Colorectal, or Oral Cancer Screening Intention and Behavior in Taiwan.

BACKGROUND: Cancer screening can improve outcomes in patients with cancer. Accordingly, under the direction of the National Health Insurance program, the Taiwan government conducts screenings for breast cancer, cervical cancer, oral cancer, and colorectal cancer. OBJECTIVE: The aim of this study was to identify the primary predictors of cancer screening intention and behavior at 1 and 6 months after patients are provided information and an invitation by telephone to attend cancer screenings. METHODS: In this prospective longitudinal study, 339 participants meeting the screening criteria were recruited. At baseline, telephone interviews were used to collect information on demographic characteristics, exercise and smoking habits, family cancer history, screening beliefs, and screening intention. Screening behavior was followed up at 1 and 6 months after the telephone interviews. RESULTS: At baseline, 87.02% of the participants intended to undergo screening, and 31.86% and 63.42% had undergone screening after 1 and 6 months, respectively. The predictors of screening intention were awareness of the screening policy, willingness to learn about screening, and believing in the health benefits of screening. The predictor of screening behavior after 1 month was screening intention at baseline, and the predictors of behavior after 6 months were screening intention, marital status, and belief that cancer is a hereditary disease. CONCLUSION: Adults with screening intention tended to undergo cancer screenings. IMPLICATIONS FOR PRACTICE: The use of strategies based on screening intention, beliefs, and information can be used to improve participation in cancer screening in Taiwan.

Self-Confidence, Not Self-Awareness, Is Negatively Associated With Areca Nut Dependence.

Areca nut is the fourth most commonly used addictive substance globally. Therefore, this study aimed to examine correlations among areca nut self-awareness, areca nut cessation self-confidence, and areca nut dependence in the Taiwanese population. This was a descriptive study in which 120 areca nut chewers who sought medical attention at a regional hospital and were residents of the Yunlin-Chiayi area, were recruited as study subjects. A structured questionnaire was used for data collection, which included demographic data, an areca nut self-awareness scale, an areca nut cessation self-confidence scale, and an areca nut dependence scale. A Pearson correlation analysis revealed that areca nut self-awareness and areca nut cessation self-confidence were not significantly correlated (r = 0.16, p = 0.069). Areca nut self-awareness and areca nut dependence also did not have a significant correlation (r = -0.06, p = 0.511). However, we found that areca nut cessation self-confidence and areca nut dependence were significantly negatively correlated (r = -0.37, p < 0.001), that is, the higher the areca nut cessation self-confidence, the lower the areca nut dependence. In addition, areca nut self-awareness showed significant correlations by age (r = 4.54, p = 0.005), occupation (r = 2.91, p = 0.02), and family support (r = 3.83, p = 0.03). Scheffe's post-hoc test revealed significant differences that subjects whose family members were extremely supportive of areca nut cessation had higher areca nut self-awareness. In conclusion, areca nut cessation self-confidence and areca nut dependence showed a significant negative correlation. Areca nut self-awareness revealed significant correlations by age, occupation, and family support. The results of this study can be used to provide a reference for implementing areca nut cessation policies in the future.

Geriatric Functional Impairment Using the Integrated Care for Older People (ICOPE) Approach in Community-Dwelling Elderly and Its Association with Dyslipidemia.

BACKGROUND: The World Health Organization (WHO) proposed the integrated care for older people (ICOPE) screening tool to identify functional impairment. We explore the association of geriatric functional impairment and hypertension, diabetes, dyslipidemia in the community-dwelling elderly. METHODS: We enrolled individuals aged at least 65 with hypertension, diabetes, or dyslipidemia; or those aged at least 75 from May to July 2019. We applied ICOPE tools to evaluate six function assessments: cognitive decline, limited mobility, malnutrition, visual impairment, hearing loss, and depressive symptoms. Factors were analyzed using stepwise multivariable linear regression for ICOPE scores and logistic regression for geriatric functional impairment. All analyses were adjusted for age and glomerular filtration rate. RESULTS: We enrolled 457 participants including 303 (66.3%) participants with hypertension, 296 (64.8%) diabetes, and 221 (48.4%) dyslipidemia. Seventy-eight (17.1%) participants have at least one geriatric functional impairment, including 41 (25.9%) participants aged ≥ 75 and 37 (12.4%) aged 65-74. The ICOPE score (0.4 ± 0.6) of participants aged at least 75 was higher than that (0.1 ± 0.4) of the participants aged 65-74 (p < 0.001). Dyslipidemia (p = 0.002) was positively associated with ICOPE score. Dyslipidemia (odds ratio: 2.15, 95% confidence interval: 1.27-3.70, p = 0.005), not hypertension (p = 0.3) and diabetes (p = 0.9), was associated with geriatric functional impairment. Visual impairment was the most common function impairment. Female was linked to limited mobility, renal function was associated with mobility (p < 0.001) and nutrition (p = 0.02). CONCLUSION: Dyslipidemia but not hypertension, diabetes is linked to geriatric functional impairment in community-dwelling elderly. Lower renal function is associated with decreased mobility and nutrition. More studies are needed to determine if treatment of dyslipidemia reduces geriatric functional impairment.

Factors associated with cessation of exclusive breastfeeding at 1 and 2 months postpartum in Taiwan.

Background: Breastfeeding benefits both mothers and infants. Even though Taiwan national policy promotes exclusive breastfeeding (EBF), the rates in Taiwan are below those in other developed countries. This study aimed to investigate factors associated with EBF cessation at 1 and 2 months postpartum. Methods: This study was conducted in a community hospital in southern Taiwan between December 2016 and June 2017. Birth mothers (n = 1077) were interviewed by telephone at 1 and 2 months postpartum to collect information on infant feeding patterns (EBF since birth or not) and reasons for EBF cessation. Multivariate logistic regression models were used to determine risk factors associated with EBF cessation at 1 and 2 months. Results: At 1 month, 432 participants (40.1%) maintained EBF. Factors associated with cessation were lack of tertiary education, primiparity, perceived low milk quantity, mother/infant separation, medical condition in mother, inconvenience/fatigue due to breastfeeding, and baby-centered factors. At 2 months, 316 participants (29.3%) maintained EBF. Factors associated with cessation were lack of tertiary education, primiparity, perceived low milk quantity, and return to work. Conclusions: Education level, primiparity, perceived low milk quantity, and return to work are associated with premature cessation of EBF in Taiwan. Strategies about health education, family support, and baby-mother friendly environment can be used to achieve higher EBF rate.

Protective and therapeutic activity of honokiol in reversing motor deficits and neuronal degeneration in the mouse model of Parkinson's disease.

BACKGROUND: Parkinson's disease (PD) is a progressive and profound movement disorder resulting from neurodegeneration in the nigrostriatal dopaminergic system, but current treatment neither cures nor stops PD from advancing. Based on the ability to suppress oxidative stress, excitotoxicity, and neuroinflammation, the potential of honokiol as a novel neuroprotective agent for PD treatment was determined. METHODS: The hemi-parkinsonian model was used to investigate the protective and therapeutic effects of honokiol on motor dysfunctions and dopaminergic neurodegeneration in mice, with a single unilateral striatal injection of 6-hydroxydopamine (6-OHDA). RESULTS: One day after 6-OHDA-induced lesion, the mice exhibited spontaneous ipsilateral turning, motor imbalance, and incoordination which were mild with a single administration of honokiol prior to 6-OHDA injection. Thereafter, honokiol was continually applied daily for 14 days, which ameliorated apomorphine-induced contralateral rotation and reduced the loss of tyrosine hydroxylase-immunoreactive (TH-ir) fibers in the lesioned striatum. In addition, honokiol posttreatment, beginning on day 8 after 6-OHDA lesion, for 14 days efficiently rescued motor deficits and recovered the TH-ir neuronal loss in both the lesioned striatum and the ipsilateral substantia nigra. The 6-OHDA-induced increases in nigrostriatal expression of inducible nitric oxide synthase (iNOS) and decreases in that of nNOS were also reversed by honokiol posttreatment. CONCLUSIONS: These findings revealed that honokiol has both protective and therapeutic effects on motor impairments and dopaminergic progressive damage, at least in part through modulation of NOS signaling, in 6-OHDA-lesioned mice. Honokiol may represent a potential therapeutic candidate for the management of motor symptoms and neurodegeneration in PD.

Therapeutic effects of honokiol on motor impairment in hemiparkinsonian mice are associated with reversing neurodegeneration and targeting PPARγ regulation.

Parkinson's disease (PD) is a profound neurodegenerative disorder with gradual loss of dopamine nigrostriatal neurons linked to serious behavioral symptoms. While the current treatment strategies present limitations on halting the progression of PD, this study aimed to investigate the therapeutic potential of honokiol, as a partial peroxisome proliferator-activated receptor-gamma (PPARγ) mimic, on the proceeding behavioral and biochemical alterations in hemiparkinsonian mice. Results showed that unilateral striatal 6-hydroxydopamine (6-OHDA)-lesioned mice exhibited motor impairment, reflecting the contralateral rotation induced by apomorphine at 1-3 weeks post-lesion. Subchronic honokiol administration for 1-2 weeks, beginning 7 days after 6-OHDA-lesion, dose-dependently ameliorated motor dysfunction in hemiparkinsonian mice. Recovery of motor function was correlated with reversal of nigrostriatal dopaminergic neuronal loss, accompanied by higher tyrosine hydroxylase (TH) density, dopamine transporter (DAT) expression and vesicular monoamine transporter-2 (VMAT2) levels. Furthermore, honokiol attenuated oxidative stress and reactive astrocyte induction via decreasing NADPH-oxidase and glial fibrillary acidic protein (GFAP) expressions in 6-OHDA-lesioned striatum. The reversal effects of honokiol on behavioral impairment and striatal PPARγ expression were impeded by PPARγ antagonist GW9662. Notably, subchronic honokiol treatment extended the lifespan of these hemiparkinsonian mice. The present findings demonstrate the therapeutic activities of honokiol in ameliorating motor impairment and progressive dopaminergic damage that could be associated with regulating PPARγ signaling. Therefore, honokiol may potentially exert as a novel therapeutic candidate through PPARγ activation for management of motor symptoms and progressive neurodegeneration in PD.

The in vivo anti-leukemia activity of N-(1-Pyrenlyl) maleimide in a bioluminescent mouse model.

In a search for anticancer drugs by screening for inhibitors of telomerase, we have identified several small-molecule inhibitors that selectively inhibit telomerase in a cell-free system. Among these inhibitors, N-(1-pyrenyl) maleimide (NPM) induced apoptosis and displayed the greatest differential cytotoxicity against acute T cell leukemia-derived Jurkat cells cultured in vitro. In this work, the in vivo anti-leukemia activity of NPM was investigated using a bioluminescent mouse model. The luciferase-expressing Jurkat cells (Jurkat-Luc) were mixed with matrigel and injected subcutaneously into the nude mice. Drug treatment was commenced on day 7 after tumor implantation. The growth of xenografted tumors was significantly inhibited in the mice treated with NPM, which is comparable to the inhibitory effect of a classical anti-leukemia drug, cyclophosphamide. Combined treatment with NPM and cyclophosphamide further enhanced the growth inhibition of xenografted Jurkat-Luc cells. Immunohistochemistry staining with cleaved caspase 3 (cl-caspase 3) indicated a very heavy staining of cl-caspase 3 only in the tumor implants excised from the NPM-treated mice. We conclude that NPM induced apoptosis and inhibited the growth of xenografted Jurkat-Luc cells in nude mice, demonstrating that NPM displays anti-leukemia activity in vivo.

Characteristics of martensitic and strain-glass transitions of the Fe-substituted TiNi shape memory alloys probed by transport and thermal measurements.

The electrical resistivity, Seebeck coefficient, thermal conductivity, and specific heat of Ti50Ni50-x Fe x (x = 2.0-10.0 at.%) shape memory alloys (SMAs) were measured to investigate the influence of point defects (Fe) on the martensitic transformation characteristics. Our results show that the Ti50Ni48Fe2 and Ti50Ni47Fe3 SMAs have a two-step martensitic transformation (B2 → R and R → B19'), while the Ti50Ni46Fe4, Ti50Ni44.5Fe5.5, and Ti50Ni44Fe6 SMAs display a one-step martensitic transition (B2 → R). However, the compounds Ti50Ni42Fe8 and Ti50Ni40Fe10 show strain glass features (frozen strain-ordered state). Importantly, the induced point defects significantly alter the martensitic transformation characteristics, namely transition temperature and width of thermal hysteresis during the transition. This can be explained by the stabilization of austenite B2 phase upon Fe substitution, which ultimately leads to the decrease in enthalpy that associated to the martensitic transition. To determine the boundary composition that separates the R-phase and strain glass systems in this series of SMAs, a Ni-rich specimen Ti49Ni45Fe6 was fabricated. Remarkably, a slight change in Ti/Ni ratio converts Ti49Ni45Fe6 SMA into a strain glass system. Overall, the evolution of phase transformation in the Fe-substituted TiNi SMAs is presumably caused by the changes in local lattice structure via the induced local strain fields by Fe point defects.