Interventions to address parenting stress among caregivers of children with chronic diseases: An umbrella review.

BACKGROUND: Caregivers of children with chronic diseases suffer from great parenting pressure, which directly affects the treatment and rehabilitation of children, reduces the quality of life of caregivers and damages family functioning. Existing reviews have not systematically summarized and evaluated interventions for parenting stress in caregivers of children with chronic diseases. DATA SOURCES: Embase, PubMed, Web of Science, OVID, CNKI, CBM, Wan Fang and Cochrane Library were searched for eligible reviews in November 2021 and October 2022. METHODS: Two reviewers independently screened titles and abstracts, reviewed full texts of articles for eligibility, and appraised the quality of reviews using JBI. The quality of the evidence was assessed using GRADE. Findings are reported in accordance with PRISMA checklist. Narrative summaries grouped findings by intervention types. RESULTS: Out of 2632 records, we included 21 systematic reviews for a synthesis. Interventions for parenting stress in children with chronic diseases were divided into seven categories. Cognitive behavioural interventions, psychosocial interventions, child behavioural and/or developmental parent interventions and synthesized interventions have shown high-level evidence in reducing parenting stress for caregivers of children with chronic diseases. Furthermore, outcome measures and intervention protocols were highly heterogeneous across interventions. CONCLUSIONS: This umbrella review suggest that reducing the parenting stress of caregivers of children with chronic diseases can directly target caregivers' parenting stress through cognitive behavioural interventions/psychosocial interventions and/or provide guidance to parents on the behavioural and developmental problems of children with chronic diseases. A more standardized approach to outcome measures is essential to assess efficacy and compare interventions across studies. RELEVANCE TO CLINICAL PRACTICE: The findings provide information and evidence for reducing parenting stress among caregivers of children with chronic diseases to guide the development of comprehensive intervention strategies. PATIENT OR PUBLIC CONTRIBUTION: Patient or public contribution does not apply to this study.

Automated Optical Inspection for Defect Identification and Classification in Actual Woven Fabric Production Lines.

This paper presents a turnkey integrated system that can be operated in real time for real textile manufacturers. Eight types of defects in woven fabric, including stain, broken end, broken weft, hole, nep, double pick, kinky weft and float can be recognized and classified. First, an image is captured by a CMOS industrial camera with a pixel size of 4600 × 600 above the batcher at 20 m/min. After that, the four-stage image processing procedure is applied to detect defects and for classification. Stage 1 is image pre-processing; the filtration of the image noise is carried out by a Gaussian filter. The light source is corrected to reduce the uneven brightness resulting from halo formation. The improved mask dodging algorithm is used to reduce the standard deviation of the corrected original image. Afterwards, the background texture is filtered by an averaging filter, and the mean value is corrected for histogram shifting, so that this system is robust to the texture and color changes of woven fabric. The binary segmentation threshold is determined using the mean value and standard deviation of an image with a normal sample. Stage 2 uses adaptive binarization for separation of the background and defects and to filter the noise. In Stage 3, the morphological processing is used before the defect contour is circled, i.e., four features of each block, including the defect area, the aspect ratio of the defect, the average gray level of the defect and the defect orientation, which are calculated according to the range of contour. The image defect recognition dataset consists of 2246 images. The results show that the detection success rate is 96.44%, and the false alarm rate is 3.21%. In Stage 4, the defect classification is implemented. The support vector machine (SVM) is used for classification, 230 defect images are used as training samples, and 206 are used as test samples. The experimental results show that the overall defect recognition rate is 96.60%, providing that the software and hardware equipment designed in this study can implement defect detection and classification for woven fabric effectively.

Interventions and strategies to improve social support for caregivers of children with chronic diseases: An umbrella review.

Background: Social support is an important approach to improve the psychosocial health status and promote positive coping for caregivers of children with chronic diseases. Such an approach can reduce parenting stress, help resolve parenting difficulties through the use of various social support relationships. Methods: We performed an umbrella review methodology using the method of examination, analysis and synthesis of systematic reviews. A PRISMA flow diagram was used to show the search process. The Joanna Briggs Institute was used to appraise the quality of papers and a narrative synthesis was undertaken. Relevant English and Chinese systematic reviews were searched in Embase, PubMed, Web of science, OVID, CNKI, CBM, Wan Fang and Cochrane Library databases, until November 2021, June 2022. Results: Out of 1,905 records, we included fourteen systematic reviews for a synthesis. Evidence to promote social support for caregivers of children with chronic diseases was identified from four key aspects: (i) Intervention content; (ii) Intervention forms; (iii) Intervention time; and (iv) Sources of support. Conclusions: The findings of this review suggest that a combination of differing interventions, especially for early family, including the content of parenting training or education, attitude building and resource provision, which can implement online is recommend. More interventional studies and quantitative evidence syntheses are still needed. Impact: Adequate social support is essential to promote the psychological wellbeing of caregivers of children with chronic diseases. In the early stage of children's diseases, integrating different content and forms of interventions for caregivers' families and actively helping caregivers to identify available support resources can improve social support. The findings from this review can be used to guide caregivers of children with chronic diseases and provide evidence for healthcare professionals and social workers to carry out relevant interventions.

Using machine learning algorithms for predicting cognitive impairment and identifying modifiable factors among Chinese elderly people.

Objectives: This study firstly aimed to explore predicting cognitive impairment at an early stage using a large population-based longitudinal survey of elderly Chinese people. The second aim was to identify reversible factors which may help slow the rate of decline in cognitive function over 3 years in the community. Methods: We included 12,280 elderly people from four waves of the Chinese Longitudinal Healthy Longevity Survey (CLHLS), followed from 2002 to 2014. The Chinese version of the Mini-Mental State Examination (MMSE) was used to examine cognitive function. Six machine learning algorithms (including a neural network model) and an ensemble method were trained on data split 2/3 for training and 1/3 testing. Parameters were explored in training data using 3-fold cross-validation and models were evaluated in test data. The model performance was measured by area-under-curve (AUC), sensitivity, and specificity. In addition, due to its better interpretability, logistic regression (LR) was used to assess the association of life behavior and its change with cognitive impairment after 3 years. Results: Support vector machine and multi-layer perceptron were found to be the best performing algorithms with AUC of 0.8267 and 0.8256, respectively. Fusing the results of all six single models further improves the AUC to 0.8269. Playing more Mahjong or cards (OR = 0.49,95% CI: 0.38-0.64), doing more garden works (OR = 0.54,95% CI: 0.43-0.68), watching TV or listening to the radio more (OR = 0.67,95% CI: 0.59-0.77) were associated with decreased risk of cognitive impairment after 3 years. Conclusions: Machine learning algorithms especially the SVM, and the ensemble model can be leveraged to identify the elderly at risk of cognitive impairment. Doing more leisure activities, doing more gardening work, and engaging in more activities combined were associated with decreased risk of cognitive impairment.

Materials information extraction via automatically generated corpus.

Information Extraction (IE) in Natural Language Processing (NLP) aims to extract structured information from unstructured text to assist a computer in understanding natural language. Machine learning-based IE methods bring more intelligence and possibilities but require an extensive and accurate labeled corpus. In the materials science domain, giving reliable labels is a laborious task that requires the efforts of many professionals. To reduce manual intervention and automatically generate materials corpus during IE, in this work, we propose a semi-supervised IE framework for materials via automatically generated corpus. Taking the superalloy data extraction in our previous work as an example, the proposed framework using Snorkel automatically labels the corpus containing property values. Then Ordered Neurons-Long Short-Term Memory (ON-LSTM) network is adopted to train an information extraction model on the generated corpus. The experimental results show that the F1-score of γ' solvus temperature, density and solidus temperature of superalloys are 83.90%, 94.02%, 89.27%, respectively. Furthermore, we conduct similar experiments on other materials, the experimental results show that the proposed framework is universal in the field of materials.

Reliability and validity of the 15-item Chronic Oral Mucosal Disease Questionnaire in China: A short-form instrument to measure quality of life.

BACKGROUND: Chronic oral mucosal diseases have been a common problem, which affected individuals' health and social functions seriously. Although there has been a rigorous Chinese version of the Chronic Mucosal Diseases Questionnaire (COMDQ-26) to measure the quality of life of patients with chronic oral mucosal diseases, 26 items were so redundant to be a burden for patients. It was necessary to make a brief, practical, and easy-to-use tool in China. This study aimed to test the validity and reliability of the Chinese version of the short-form Chronic Mucosal Diseases Questionnaire (COMDQ-15). METHODS: A total of 165 respondents from a tertiary stomatological hospital were recruited in this study from July to December, 2020. Internal consistency, test-retest reliability, criterion validity, confirmatory factor analysis, and exploratory factor analysis were used to evaluate the reliability and validity of the Chinese version of Chronic Mucosal Diseases Questionnaire-15. RESULTS: The total Cronbach's α of 0.841 and subscale ranging from 0.736 to 0.965 revealed good internal consistency of the reliability. The intraclass correlation coefficients exceeded 0.80 indicated excellent test-retest reliability. Compared with the Oral Health Impact Profile-14, the criterion validity was 0.549. The confirmatory factor analysis results supported acceptable validity of the Chinese version of Chronic Mucosal Diseases Questionnaire-15, and the exploratory factor analysis demonstrated that the 15 items were classified into four domains, with a cumulative proportion of 71.52%. CONCLUSION: The Chinese version of Chronic Mucosal Diseases Questionnaire-15 is a brief and low-burden tool, and has been proved reliable and valid to assess the quality of life of patients with chronic oral mucosal diseases in China (the Chinese Clinical Trial Registry (no. ChiCTR2000031607).

Masticatory performance in patients undergoing free fibula flap for mandible reconstruction.

BACKGROUND: To explore the masticatory performance in patients undergoing an osteo(cutaneous) free fibula (OFF) flap for mandible reconstruction by a prospective design. METHODS: A total of 56 patients who had undergone OFF flap reconstructions for mandibular reconstruction secondary to malignant (squamous cell carcinoma) or benign (ameloblastoma) tumor resection were prospectively enrolled. They were asked to complete the masticatory performance test by the weigh method and the chew domain of the University of Washington quality of life questionnaire (version 4) preoperatively and at 3, 6, and 12 months postoperatively. The pair nonparametric test was used to analyze the dynamic change of masticatory performance and subjective chew function. RESULTS: Fifty-one patients were included for analysis finally. The mean masticatory performance for patients with malignant tumors were 53.4% ± 10.3%, 36.4% ± 10.3%, 42.6% ± 9.6%, 52.8% ± 10.9%, and 53.1% ± 11.8% preoperatively, at 2 weeks, 3 months, 6 months, and 12 months postoperatively, respectively. Compared with the preoperative level, the masticatory performance had a significant reduction immediately after surgery (p < 0.001), followed by a return to the baseline level within three months. A similar trend was noted for those with benign tumors. The mean score of chew domain for patients with malignant tumors were 100 ± 0, 54.3 ± 32.9, 81.4 ± 24.5, and 92.9 ± 17.8 preoperatively, at 3 months, 6 months, and 12 months postoperatively, respectively. Compared with the preoperative level, the subjective chew function was greatly affected within the first three months (p < 0.001), and it gradually recovered to the baseline level in the following nine months. A similar trend was noted in patients with benign tumors. CONCLUSIONS: The masticatory performance and subjective chew function was significantly affected after OFF flap reconstructions in the short term, but both recovered to the preoperative levels within 9-12 months.

Resilience and Related Factors: A Comparison of Fathers and Mothers of Patients With Cleft Lip and/or Palate in China.

Background: Resilience has become a hot spot in the field of positive psychology to study life-change events. However, there were little information on resilience among the fathers and mothers of patients with cleft lip and/or palate respectively. The present study aimed to explore and compare the level and potential influential factors associated with resilience among fathers/mothers of patients with cleft lip and/or palate in China. Method: A cross-sectional study was carried out between April 2019 and July 2020 among fathers/mothers of patients with cleft lip and/or palate in two cleft lip and/or palate treatment centers in China. Sixty Nine fathers and 179 mothers of patients with cleft lip and/or palate were interviewed with a questionnaire on demographic variables and the Resilience Scale-14 (RS-14), Herth Hope Index (HHI), Multidimensional Scale of Perceived Social Support (MSPSS), Revised Life Orientation Test (LOT-R), Parenting Stress Index-Short Form (PSI-SF) and Coping Health Inventory for Parents (CHIP). T-test/univariate one-way ANOVA, Pearson's r, hierarchical linear regression analysis were conducted to explore the influential factors of resilience. Results: Fathers of patients with cleft lip and/or palate had a higher level of resilience (77.77 ± 14.18) than mothers (74.52 ± 14.33) though without significance. Resilience was positively associated with hope, perceived social support, optimism and coping and negatively correlated with parenting stress both in the fathers and the mothers. Hierarchical linear regression analysis showed that hope (ß = 0.400, P < 0.01), coping (ß = 0.281, P < 0.05), job status, medical payments (ß = -0.240, P < 0.05) were found to be associated with resilience among the fathers of patients with CL/P, and all four variables in the model could explain 42.8% of the variance in resilience; Hope (ß = 0.225, P < 0.05), perceived social support (ß = 0.194, P < 0.05), the age of patients (ß = 0.189, P < 0.05) were found to be associated with resilience among the mothers, and all three variables in the model could explain 27.6% of the variance in resilience. Conclusion: Our study showed that, in China, fathers of patients with cleft lip and/or palate had a higher level of resilience than mothers though without significance. Hope was the only communal variable strongly associated with resilience among both the fathers and the mothers; besides, coping, job status and medical payments were found to be associated with resilience among the fathers; while perceived social support and the age of patients were found to be associated with resilience among the mothers. The results suggest that enhance hope in parents of patients with cleft lip and/or palate might greatly help improve their resilience. Besides, fathers and mothers need specific intervention to prompt their resilience.

Prevalence and predictors of anxiety and depressive symptoms among patients diagnosed with oral cancer in China: a cross-sectional study.

BACKGROUND: Anxiety and depression are common mental health problems among patients with cancer. While many psychological variables have been proven to influence anxiety and depressive symptoms, the variables are not mutually exclusive and their integrated effects on patients with oral cancer are yet unknown. The present study aims to explore the prevalence of anxiety and depressive symptoms among patients with oral cancer, to find out key potentially predictive factors associated with anxiety and depressive symptoms. METHOD: A cross-sectional study was carried out for Chinese patients with oral cancer between May 2016 and October 2017 in two Grade-A Tertiary Hospitals in Shenyang, China. Two hundred thirty patients with oral cancer were interviewed with questionnaires on demographic variables, Zung Self-Rating Anxiety Scale (SAS), Center for Epidemiologic Studies Depression Scale (CES-D), Herth Hope Index (HHI), Social Impact Scale, Multidimensional Scale of Perceived Social Support (MSPSS), Revised Life Orientation Test (LOT-R), Perceived Stress Scale-10 (PSS-10), and General Perceived Self-efficacy Scale(GSE). Chi-square test, nonparametric test, t-test and logistic regression analyses were conducted where appropriate to explore predictive factors of anxiety symptoms and depressive symptoms. RESULTS: The prevalence of anxiety symptoms and depressive symptoms in the sample population was 36.96% (85/230) and 65.21% (150/230), respectively. Social isolation dimension of stigma (ß = 0.436, OR = 1.547, CI:1.211 ~ 1.975), optimism (ß = - 0.276, OR = 0.759, CI:0.624 ~ 0.922), and perceived stress (ß = 0.217, OR = 1.243, CI:1.092 ~ 1.414) were predictors of anxiety symptoms. Marriage (ß = 1.648, OR = 5.198, CI:1.427 ~ 18.924), positive readiness and expectancy dimension of hope (ß = - 0.505, OR = 0.604, CI:0.395 ~ 0.923), social isolation dimension of stigma (ß = 0.314, OR = 1.368, CI:1.054 ~ 1.776) and perceived stress (ß = 0.273, OR = 1.314, CI:1.134 ~ 1.524) were predictors of depressive symptoms among oral cancer patients. CONCLUSION: The prevalence of anxiety symptoms and depressive symptoms was high among oral cancer patients in China. The communal predictors of anxiety and depressive symptoms in patients with oral cancer were levels of perceived stress and social isolation of stigma. In addition, optimism was a predictor of anxiety symptoms and hope was a predictor of depressive symptoms. TRIAL REGISTRATION: 2015-16, registered 20 Dec 2015.

The effect of Interaction Anxiousness Scale and Brief Social Phobia Scale for screening social anxiety disorder in college students: a study on discriminative validity.

BACKGROUND: Social anxiety disorder (SAD) is one of the most prevalent mental health problems, but there is little research concerning the effective screening instruments in practice. METHODS: This study was designed to examine the discriminative validity of Interaction Anxiousness Scale (IAS) and Brief Social Phobia Scale (BSPS) for the screening of SAD through the compared and combined analysis. Firstly, 421 Chinese undergraduates were screened by the IAS and BSPS. Secondly, in the follow-up stage, 248 students were interviewed by the Structured Clinical Interview for DSM-IV. Receiver operating characteristic (ROC) analysis was used, and the related psychometric characters were checked. RESULTS: The results indicated that the ROC in these two scales demonstrated discrimination is in satisfactory level (range: 0.7-0.8). However, the highest agreement (92.17%) was identified when a cut-off point of 50 measured by the IAS and a cut-off point of 34 by the BSPS were combined, also with higher PPV, SENS, SPEC and OA than that reached when BSPS was used individually, as well as PPV, SPEC and OA in IAS. CONCLUSION: The findings indicate that the combination of these two scales is valid as the general screening instrument for SAD in maximizing the discriminative validity.

Effect of charged amino acid side chain length on lateral cross-strand interactions between carboxylate- and guanidinium-containing residues in a ß-hairpin.

ß-Sheet is one of the major protein secondary structures. Oppositely charged residues are frequently observed across neighboring strands in antiparallel sheets, suggesting the importance of cross-strand ion pairing interactions. The charged amino acids Asp, Glu, Arg, and Lys have different numbers of hydrophobic methylenes linking the charged functionality to the backbone. To investigate the effect of side chain length of guanidinium- and carboxylate-containing residues on lateral cross-strand ion pairing interactions at non-hydrogen-bonded positions, ß-hairpin peptides containing Zbb-Agx (Zbb = Asp, Glu, Aad in increasing length; Agx = Agh, Arg, Agb, Agp in decreasing length) sequence patterns were studied by NMR methods. The fraction folded population and folding energy were derived from the chemical shift deviation data. Peptides with high fraction folded populations involved charged residue side chain lengths that supported high strand propensity. Double mutant cycle analysis was used to determine the interaction energy for the potential lateral ion pairs. Minimal interaction was observed between residues with short side chains, most likely due to the diffused positive charge on the guanidinium group, which weakened cross-strand electrostatic interactions with the carboxylate side chain. Only the Aad-Arg/Agh interactions with long side chains clearly exhibited stabilizing energetics, possibly relying on hydrophobics. A survey of a non-redundant protein structure database revealed that the statistical sheet pair propensity followed the trend Asp-Arg < Glu-Arg, implying the need for matching long side chains. This suggested the need for long side chains on both guanidinium-bearing and carboxylate-bearing residues to stabilize the ß-hairpin motif.

Effect of side chain length on intrahelical interactions between carboxylate- and guanidinium-containing amino acids.

The charge-containing hydrophilic functionalities of encoded charged amino acids are linked to the backbone via different numbers of hydrophobic methylenes, despite the apparent electrostatic nature of protein ion pairing interactions. To investigate the effect of side chain length of guanidinium- and carboxylate-containing residues on ion pairing interactions, α-helical peptides containing Zbb-Xaa (i, i + 3), (i, i + 4) and (i, i + 5) (Zbb = carboxylate-containing residues Aad, Glu, Asp in decreasing length; Xaa = guanidinium residues Agh, Arg, Agb, Agp in decreasing length) sequence patterns were studied by circular dichroism spectroscopy (CD). The helicity of Aad- and Glu-containing peptides was similar and mostly pH independent, whereas the helicity of Asp-containing peptides was mostly pH dependent. Furthermore, the Arg-containing peptides consistently exhibited higher helicity compared to the corresponding Agp-, Agb-, and Agh-containing peptides. Side chain conformational analysis by molecular mechanics calculations showed that the Zbb-Xaa (i, i + 3) and (i, i + 4) interactions mainly involved the χ 1 dihedral combinations (g+, g+) and (g-, g+), respectively. These low energy conformations were also observed in intrahelical Asp-Arg and Glu-Arg salt bridges of natural proteins. Accordingly, Asp and Glu provides variation in helix characteristics associated with Arg, but Aad does not provide features beyond those already delivered by Glu. Importantly, nature may have chosen the side chain length of Arg to support helical conformations through inherent high helix propensity coupled with stabilizing intrahelical ion pairing interactions with the carboxylate-containing residues.

Effect of charged amino acid side chain length on lateral cross-strand interactions between carboxylate-containing residues and lysine analogues in a ß-hairpin.

ß-Sheets are one of the fundamental three-dimensional building blocks for protein structures. Oppositely charged amino acids are frequently observed directly across one another in antiparallel sheet structures, suggesting the importance of cross-strand ion pairing interactions. Despite the apparent electrostatic nature of ion pairing interactions, the charged amino acids Asp, Glu, Arg, Lys have different numbers of hydrophobic methylenes linking the charged functionality to the backbone. Accordingly, the effect of charged amino acid side chain length on cross-strand ion pairing interactions at lateral non-hydrogen bonded positions was investigated in a ß-hairpin motif. The negatively charged residues with a carboxylate (Asp, Glu, Aad in increasing length) were incorporated at position 4, and the positively charged residues with an ammonium (Dap, Dab, Orn, Lys in increasing length) were incorporated at position 9. The fraction folded population and folding free energy were derived from the chemical shift deviation data. Double mutant cycle analysis was used to determine the interaction energy for the potential lateral ion pairs. Only the Asp/Glu-Dap interactions with shorter side chains and the Aad-Orn/Lys interactions with longer side chains exhibited stabilizing energetics, mostly relying on electrostatics and hydrophobics, respectively. This suggested the need for length matching of the interacting residues to stabilize the ß-hairpin motif. A survey of a nonredundant protein structure database revealed that the statistical sheet pair propensity followed the trend Asp-Lys < Glu-Lys, also implying the need for length matching of the oppositely charged residues.

Effect of charged amino acid side chain length at non-hydrogen bonded strand positions on ß-hairpin stability.

ß-Sheets have been implicated in various neurological disorders, and ∼20% of protein residues adopt a sheet conformation. Therefore, studies on the structural origin of sheet stability can provide fundamental knowledge with potential biomedical applications. Oppositely charged amino acids are frequently observed across one another in antiparallel ß-sheets. Interestingly, the side chains of natural charged amino acids Asp, Glu, Arg, Lys have different numbers of hydrophobic methylenes linking the backbone to the hydrophilic charged functionalities. To explore the inherent effect of charged amino acid side chain length on antiparallel sheets, the stability of a designed hairpin motif containing charged amino acids with varying side chain lengths at non-hydrogen bonded positions was studied. Peptides with the guest position on the N-terminal strand and the C-terminal strand were investigated by NMR methods. The charged amino acids (Xaa) included negatively charged residues with a carboxylate group (Asp, Glu, Aad in increasing length), positively charged residues with an ammonium group (Dap, Dab, Orn, Lys in increasing length), and positively charged residues with a guanidinium group (Agp, Agb, Arg, Agh in increasing length). The fraction folded and folding free energy for each peptide were derived from the chemical shift deviation data. The stability of the peptides with the charged residues at the N-terminal guest position followed the trends: Asp > Glu > Aad, Dap < Dab < Orn ∼ Lys, and Agb < Arg < Agh < Agp. The stability of the peptides with the charged residues at the C-terminal guest position followed the trends: Asp < Glu < Aad, Dap ∼ Dab < Orn ∼ Lys, and Agb < Arg ∼ Agp < Agh. These trends were rationalized by thermodynamic sheet propensity and cross-strand interactions.

Effect of glutamate side chain length on intrahelical glutamate-lysine ion pairing interactions.

Ion pairing interactions between oppositely charged amino acids are important for protein structure stability. Despite the apparent electrostatic nature of these interactions, the charged amino acids Lys, Arg, Glu, and Asp have a different number of hydrophobic methylenes linking the charged functionality to the backbone. To investigate the effect of Glu (and Asp) side chain length on ion pairing interactions, a series of 36 monomeric α-helical peptides containing Zbb-Xaa (i, i+3), (i, i+4), and (i, i+5) (Zbb = Aad, Glu, Asp; Xaa = Lys, Orn, Dab, Dap) sequence patterns were studied by circular dichroism (CD) spectroscopy at pH 7 and 2. Peptides with Glu and Aad exhibited similar helicity and pH dependence, whereas peptides with Asp behaved distinctly different. The side chain interaction energetics were derived from the CD data using the nesting block method coupled with modified Lifson-Roig theory. At pH 7, no Zbb-Xaa (i, i+5) interaction was observed, regardless of side chain length (consistent with the helix geometry). Interestingly, only Lys was capable of supporting Zbb-Xaa (i, i+3) interactions, whereas any Xaa side chain length supported Zbb-Xaa (i, i+4) interactions. In particular, the magnitude of both Zbb(-)-Lys (i, i+4) and Zbb(-)-Orn (i, i+4) interaction energies followed the trend Asp > Glu > Aad. Side chain conformational analysis by molecular mechanics calculations showed that the Zbb-Xaa (i, i+3) interactions involved the χ(1) dihedral combination (g+, g+) for the i and i+3 residues, whereas the Zbb-Xaa (i, i+4) interactions were supported by the χ(1) dihedral combination (t, g+) for the i and i+4 residues. These calculated low energy conformers were consistent with conformations of intrahelical Asp-Lys and Glu-Lys salt bridges in a nonredundant protein structure database. These results suggest that Asp and Glu provide natural variation, and lengthening the Glu side chain further to Aad does not furnish additional characteristics that Glu cannot supply.

Helix formation and capping energetics of arginine analogs with varying side chain length.

Arginine (Arg) has been used for recognizing negatively charged biological molecules, cell penetration, and oligosaccharide mass signal enhancement. The versatility of Arg has inspired the need to develop Arg analogs and to research the structural effects of incorporating Arg analogs. Accordingly, we investigated the effect of Arg side chain length on helix formation by studying 12 Ala-based peptides containing the Arg analogs (S)-2-amino-6-guanidino-hexanoic acid (Agh), (S)-2-amino-4-guanidinobutyric acid (Agb), and (S)-2-amino-3-guanidinopropionic acid (Agp). Solid phase guanidinylation with orthogonal protection strategies was necessary to synthesize Agb- and Agp-containing peptides using Fmoc-based chemistry. The fraction helix for the peptides was determined by circular dichroism spectroscopy, and used to derive the statistical mechanical parameters and energetics for N-capping, C-capping, and helix propagation (propensity). All four Arg analogs were unfavorable for N-capping. The C-cap parameter followed the trend AgpAgh, highlighting the uniqueness of the Arg side chain length in helix formation. Molecular mechanics calculations and a survey on protein structures were consistent with the experimental results. Furthermore, calculations and survey both showed that the g- conformation for the χ1 dihedral was present for the first two residues at the N-terminus of helices, but not favored in the center or C-terminus of helices due to sterics. These results should serve as the foundation for developing Arg-related bioactive compounds and technologies.

Positional effects on helical Ala-based peptides.

Helix-coil equilibrium studies are important for understanding helix formation in protein folding, and for helical foldamer design. The quantitative description of a helix using statistical mechanical models is based on experimentally derived helix propensities and the assumption that helix propensity is position-independent. To investigate this assumption, we studied a series of 19-residue Ala-based peptides, to measure the helix propensity for Leu, Phe, and Pff at positions 6, 11, and 16. Circular dichroism spectroscopy revealed that substituting Ala with a given amino acid (Leu, Phe, or Pff) resulted in the following fraction helix trend: KXaa16 > KXaa6 > KXaa11. Helix propensities for Leu, Phe, and Pff at the different positions were derived from the CD data. For the same amino acid, helix propensities were similar at positions 6 and 11, but much higher at position 16 (close to the C-terminus). A survey of protein helices revealed that Leu/Phe-Lys (i, i + 3) sequence patterns frequently occur in two structural patterns involving the helix C-terminus; however, these cases include a left-handed conformation residue. Furthermore, no Leu/Phe-Lys interaction was found except for the Lys-Phe cation-π interaction in two cases of Phe-Ala-Ala-Lys. The apparent high helix propensity at position 16 may be due to helix capping, adoption of a 310-helix near the C-terminus perhaps with Xaa-Lys (i, i + 3) interactions, or proximity to the peptide chain terminus. Accordingly, helix propensity is generally position-independent except in the presence of alternative structures or in the proximity of either chain terminus. These results should facilitate the design of helical peptides, proteins, and foldamers.

The development of magnetic degradable DP-Bioglass for hyperthermia cancer therapy.

In this study, a novel magnetic degradable material was developed by adding Fe ions into DP-Bioglass (Na(2)O-CaO-P(2)O(5)-SiO(2)) as thermoseed for hyperthermia cancer therapy under an alternating magnetic field. We have investigated the properties of developed magnetic DP-Bioglass including morphology, chemical composition, and magnetism. The degradability was conducted by measuring the released concentrations of Na, Ca, Si, P, and Fe ions. The biocompatibility was analyzed by biological assays, and the functional hyperthermia effect to cancer cells was evaluated by in vitro cell culture test. In the results, the morphology of synthesized magnetic DP-Bioglass was revealed in sphere and rod shape with particle size around 50-100 nm. From the hysteresis loop analysis, it showed that the group of Fe/Bioglass = 0.2 possessed the maximum magnetization property. When cultured with fibroblasts, the magnetic DP-Bioglass had no significant influence on cell viability and mediated low cytotoxicity. The thermal-induced property demonstrated that after exposure to an alternating magnetic field, the cell number of human Caucasian lung carcinoma cells (A549) was significantly decreased when temperature was increasing to 45 degrees C. In brief, successfully incorporated with Fe ions by sol-gel method, this magnetic degradable DP-Bioglass possessed the potential and properties of hyperthermia effect to lung carcinoma cells.

[Preventive effects of heat-shock response against circulatory collapse induced by hyperthermia].

OBJECTIVE: To investigate the preventive effects of heat-shock response (HSR) against circulatory collapse induced by hyperthermia and understand its mechanism. METHODS: Twenty-four SD rats were randomized equally into heat-shock group (HS group), high temperature control group (HC group) and normal temperature control group (NC group). The rats in HS group, but not HC group, were subjected to heat shock pretreatment. After a recovery period for 20 h at room temperature, the rats in HS and HC groups were exposed to high temperature environment, and their blood pressures and electrocardiograms were measured continuously. Heat exposure was terminated at 73 min and the contents of myocardial malondialdehyde (MDA) and NO were measured. Using Chart software, the data of the mean arterial pressure (MAP), systolic pressure (SP), diastolic pressure (DP), heart rate (HR) were acquired. The rats in NC group did not receive any treatment to obtain the measurements in normal condition. RESULTS: Compared with NC group, the MAP, SP and DP were significantly lowered (P P<0.01) in HS and HC group and HR accelerated (P P<0.01) after a 73-min heat exposure, and HS group had significantly higher measurements of the above indices than HC group did. In comparison with NC group, the contents of MDA and NO in the myocardium in HC group were significantly elevated after the exposure (P P<0.01). The MDA content in HS group, which was comparable with that of NC group, was significantly lower than that of HC group (P P<0.05), and compared with HC group, HS also had lower NO content (P<0.01). CONCLUSION: HSR may relieve circulatory collapse induced by hyperthermia, which involves the inhibitory effect of HSR on the production of MDA and NO in the myocardium.