Social Relationships and Physical Activity: Perspectives from Home Care Aides and Their Older Clients

Social relationships, such as positive support from behavioral change agents, are known to motivate older adults to engage in healthy activities, such as physical activity (PA). Previous PA intervention studies largely focus on the role of informal social support from family and friends reported by participants and provide limited information about how support from and interactions with formal care providers or behavioral agents may influence participants’ outcomes. To address this knowledge gap in the context of a PA intervention and home care for frail community-dwelling older adults, this dissertation examined exercise-related social support provided by home care aides (HCA) to their clients, as well as HCAs’ and clients’ perceptions and beliefs related to their interactions and PA in the context of HCA-client dyads. Using quantitative and qualitative data from a 4-month home-based PA intervention delivered by HCAs to their clients, this dissertation examined how client function (self-reported daily activity function and performance-based function) is related to: 1) baseline outcome expectations for exercise held by HCAs towards their client, partly through increased exercise-related social support provided by HCAs for their clients after the intervention; and 2) shared perceptions of their relationship or beliefs towards PA within HCA-client dyads at baseline. Two major findings emerged. First, mediation analysis results showed that higher baseline outcome expectations for exercise held by HCAs were related to higher level of exercise-related social support. However, unexpectedly, exercise-related social support was not related to client outcomes. Qualitative data suggested alternative factors, such as clients’ family beliefs in the intervention and clients’ experiences with the intervention participation, may explain the unexpected results. Second, results of linear mixed models showed, as expected, when clients and their HCAs both perceived their interactions positively, or both held positive outcome expectations for exercise at baseline, the clients showed better outcomes. Qualitative data revealed two potential explanations: 1) shared perceptions about HCA-client relationship and shared beliefs in PA may protect HCA-client dyads from stressful situations, such as clients’ health decline, conflicts or issues arisen during the intervention, etc.; 2) clients and HCAs were motivated by each other throughout the intervention and may both benefit from participating in the intervention. This dissertation expands the scope of social relationships and intervention outcomes to a dyadic perspective. It highlights the advantages of using dyadic data and mixed methods in understanding intervention process and outcomes. Finally, this dissertation adds to a growing body of studies that document the role of non-medical home care workers in delivering a health behavior intervention

Table_1_Molecular characterization of chicken astrovirus and pathogenicity of a novel isolate in China.pdf

As an enteric virus, chicken astrovirus has been related to various kinds of diseases in chickens, including white chick syndrome, runting-stunting syndrome, severe kidney disease, urate deposits and visceral gout, generating economic losses in the poultry industry globally. The complete ORF2 gene of 31 CAstV isolates in six provinces of China during 2020–2022 was characterized and analyzed with the purpose of better understanding the molecular epidemiology and genetic diversity of CAstV field isolates. Phylogenetic analysis which was based on the complete ORF2 (capsid) amino acid sequence of 31 CAstV isolates and 57 reference strains indicated that 2 isolates belonged to subgroup Ai, 10 isolates belonged to subgroup Bi, 3 isolates belonged to subgroup Bii, 5 isolates belonged to subgroup Biii, 7 isolates belonged to subgroup Biv, 3 isolates belonged to subgroup Bv, and one isolate (JS202103) belonged to a new B subgroup. In addition, the novel CAstV strain JS202103 was successfully isolated in vitro, and its whole genome shared 76.9–94.3% identity with the 29 CAstV reference strains. JS202103 caused hatchability reduction, dead embryos, kidney disease and visceral gout in chicken embryos. Moreover, this is the also the initial study focusing on diverse CAstV strains including subgroups Biii, Biv, and Bv circulate in China. The current work contributes to improving our understanding of CAstV isolates in China, and it will also provide references for developing efficient measures to control this virus.</p

Effects of C₆₀ on the Photochemical Formation of Reactive Oxygen Species from Natural Organic Matter

Buckminsterfullerenes (C₆₀) are widely used nanomaterials that are present in surface water. The combination of C₆₀ and humic acid (HA) generates reactive oxygen species (ROS) under solar irradiation, but this process is not well understood. Thus, the present study focused on the photochemical formation of singlet oxygen (¹O₂), hydroxyl radical (HO^•)-like species, superoxide radicals (O₂^•–), hydrogen peroxide (H₂O₂), and triplet excited states (³C₆₀*/³HA*) in solutions containing both C₆₀ and HA. The quantum yield coefficients of excited triplet states (<i>f</i>_TMP) and apparent quantum yields of ROS were measured and compared to the calculated values, which were based on the conservative mixing model. Although C₆₀ proved to have only a slight impact on the ¹O₂ formation from HA, C₆₀ played a key role in the inhibition of O₂^•–. The photochemical formation of H₂O₂ followed the conservative mixing model due to the reaction of C₆₀^•– with HO₂^•/O₂^•–, and the biomolecular reaction rate constant has been measured as (7.4 ± 0.6) × 10⁶ M^–1 s^–1. The apparent <i>f</i>_TMP was significantly lower than the calculated value, indicating that the steric effect of HA was significant in the reaction of ³C₆₀* with the TMP probe. In contrast, C₆₀ did not have an effect on the photochemical formation of HO^• from HA, suggesting that HO^• is elevated from the hydrophilic surface of HA. The aforementioned results may be useful for predicting the photochemical influence of C₆₀ on aqueous environments

Effects of C₆₀ on the Photochemical Formation of Reactive Oxygen Species from Natural Organic Matter

Buckminsterfullerenes (C₆₀) are widely used nanomaterials that are present in surface water. The combination of C₆₀ and humic acid (HA) generates reactive oxygen species (ROS) under solar irradiation, but this process is not well understood. Thus, the present study focused on the photochemical formation of singlet oxygen (¹O₂), hydroxyl radical (HO^•)-like species, superoxide radicals (O₂^•–), hydrogen peroxide (H₂O₂), and triplet excited states (³C₆₀*/³HA*) in solutions containing both C₆₀ and HA. The quantum yield coefficients of excited triplet states (<i>f</i>_TMP) and apparent quantum yields of ROS were measured and compared to the calculated values, which were based on the conservative mixing model. Although C₆₀ proved to have only a slight impact on the ¹O₂ formation from HA, C₆₀ played a key role in the inhibition of O₂^•–. The photochemical formation of H₂O₂ followed the conservative mixing model due to the reaction of C₆₀^•– with HO₂^•/O₂^•–, and the biomolecular reaction rate constant has been measured as (7.4 ± 0.6) × 10⁶ M^–1 s^–1. The apparent <i>f</i>_TMP was significantly lower than the calculated value, indicating that the steric effect of HA was significant in the reaction of ³C₆₀* with the TMP probe. In contrast, C₆₀ did not have an effect on the photochemical formation of HO^• from HA, suggesting that HO^• is elevated from the hydrophilic surface of HA. The aforementioned results may be useful for predicting the photochemical influence of C₆₀ on aqueous environments

Additional file 1: of Defective autophagy leads to the suppression of stem-like features of CD271+ osteosarcoma cells

Cell viaiblities of OS cells after chemotherapeutics treatments. (A, B) The indicated SaoS2 and MNNG/HOS cells were treated with Cisplatin (A) or Epicubicin (B) of different doses for 48 h. Then, the cell viability of the indicated cells was detected by CCK8 assay. The data are showen as the mean ± S.D. (n = 3). (PPTX 232 kb

SAMHD1 overexpression induces stress granules formation.

<p>(A, B) HeLa cells were transfected with pcDNA4, EGFP-SAMHD1 or EGFP-SAMHD1-H233A. Cells were collected at 24h post transfection and immunostained for cellular TIA1 (A) or G3BP1 (B). The secondary antibodies used were Alexa Fluor 594-labeled goat anti-Rabbit antibody (red). The proportion of cells with SGs (%) is shown in the bar graphs. The data are shown as the average of three independent experiments. (C, D, E). ImageStream flow cytometry was utilized to monitor the formation of stress granules in the presence of SAMDH1. HeLa cells were transfected with the wild type EGFP-SAMHD1 DNA or the H233A mutant. 48h post transfection, cells were stained with anti-G3BP1 antibody. (C) Cell populations were first gated for single cells (R1) in focus (R2). EGFP and G3BP1 positive cells were then gated in R3 for further analysis. (D) Representative bright-field and fluorescence emission images for individual cells from each sample shown. The fluorescent granule inside each cell is clearly visible. (E) The frequency of cells with different numbers of G3BP1-positive puncta was calculated in a population of 1x10⁴ cells. The results are shown in the graph. Bars represent 10 μm.</p

Stress granule pathway restricts LINE-1 retrotransposition.

<p>(A) The ORF1-tRFP DNA and Myc-G3BP1 DNA were transfected into HeLa cells. Cells were stained with mouse anti-Myc antibody and rabbit anti-TIA1 antibody. (B) The ORF1-tRFP DNA and Myc-TIA1 DNA were transfected into HeLa cells. Cells were stained with mouse anti-Myc antibody and rabbit anti-G3BP1 antibody. The number of SG-containing cells was calculated in more than 6 randomly chosen fields for each slide, and 200 cells were examined in at least three independent transfections. The results are summarized in the bar graphs. (C) HeLa cells were transfected with CMV-L1-neo^RT DNA together with SAMHD1, TIA1 or G3BP1 DNA. Neomycin-resistant cell colonies were scored and results of three independent experiments are presented in the bar graph. Number of neomycin-resistant colonies with control vector is arbitrarily set as 1. Results of three independent experiments are shown in the bar graph. Images of a representative colony assay are presented. Ectopic expression of Myc-SAMHD1, Myc-TIA1 or Myc-G3BP1 was examined by western blotting. (D) Knockdown TIA1 or G3BP1 increases LINE-1 activity. HeLa cells were treated with siRNA targeting either TIA1 or G3BP1 prior to transfection with LINE-1 reporter DNA CMV-L1-neo^RT. Neomycin-resistant cell colonies were scored and results of three independent experiments are presented in the bar graph. Number of neo-resistant colonies with control siRNA is arbitrarily set as 1. The knockdown of TIA1 or G3BP1 was examined by western blotting. Intensities of TIA1 or G3BP1 bands were determined using the ImageJ program. The results were used to calculate the knockdown efficiency as indicated under the western blots. (E) The CMV-L1-neo^RT DNA was transfected into HeLa cells. 6 hours post transfection, cells were cultured in the presence of 1 μM arsenite (AS) for 48h, then fixed and processed for visualization of G3BP1 and ORF1p using fluorescence microscopy. The number of SG-containing cells was calculated in more than 6 randomly chosen fields for each slide, and 200 cells were examined in at least three independent transfections. The results are summarized in the bar graphs in the right panel. Bars represents 10 μm. (F) The LINE-1 EGFP reporter DNA was transfected into 293T cells. Six hours post transfection, cells were treated with 1 μM arsenite for 48 h. GFP-positive cells were scored by flow cytometry at day 5. As a control, cells were also transfected with the pEGFP-C1 vector DNA that constitutively expresses EGFP. Results are normalized to control (without arsenite) and summarized in the bar graphs (n = 3). * indicates <i>p</i>< 0.05, ** represents <i>p</i>< 0.01.</p

TIA1 and G3BP1 are required for SAMHD1 to inhibit LINE-1 retrotransposition.

<p>(A) Knockdown of TIA1 or G3BP1 prevents the SAMHD1 from inhibiting LINE-1. HeLa cells were transfected with siRNA targeting TIA1 or G3BP1 prior to co-transfection with Myc-SAMHD1 and CMV-L1-neo^RT. Neomycin-resistant colonies were scored and results of three independent experiments are shown in the bar graph. Levels of TIA1, G3BP1 and Myc-SAMHD1 were determined by western blotting. The knockdown efficiency of TIA1 and G3BP1 was calculated on the basis of the intensities of TIA1 or G3BP1 bands in the western blots. (B) Endogenous SAMHD1 loses inhibition of LINE-1 upon depletion of TIA1 or G3BP1. HeLa cells were treated with siRNAs targeting TIA1, G3BP1 or SAMHD1, followed by transfection with CMV-L1-neo^RT DNA. Number of neomycin-resistant colonies was determined and shown in the bar graph. The number of neomycin-resistant colonies with control siRNA is arbitrarily set as 1. Levels of endogenous TIA1, G3BP1 and SAMHD1 were examined by western blotting. The knockdown efficiency was calculated on the basis of the protein band intensities as determined using the ImageJ program. * indicates <i>p</i>< 0.05, ns denotes “not significant”.</p

Ectopic expression of SAMHD1 leads to sequestration of LINE-1 ORF1p in stress granules.

<p>(A, B) The CMV-L1-neo^RT DNA and wild type EGFP-SAMHD1 or its H233A mutant DNA were transfected into HeLa cells. Endogenous TIA1 (shown in (A)) and G3BP1 (shown in (B)) were detected by indirect immunofluorescence staining. (C, D) The ORF1-tRFP DNA and wild type EGFP-SAMHD1 or its H233A mutant DNA were transfected into HeLa cells. Endogenous TIA1 (shown in (C)) and G3BP1 (shown in (D)) were detected by indirect immunofluorescence staining. A number of 200 cells were examined for each transfection to score the TIA1- or G3BP1-strained stress granule (SG) cells. The results are summarized in the bar graphs. Colocalization of TIA1 or G3BP1 with ORF1-tRFP was further analyzed with fluorescence intensity analysis software from LAS AF (Leica). (E, F) EGFP-SAMHD1 was expressed in HEK-293 cells. Cellular localizations of SAMHD1 and endogenous LINE-1 ORF1p were determined by immunostaining and confocal microscopy. Endogenous TIA1 (E), G3BP1 (F) and LINE-1 ORF1p were detected by indirect immunofluorescence staining. The number of SG-containing cells was calculated in more than 6 randomly chosen fields for each slide, 200 cells were examined in at least three independent transfections. The results are summarized in the bar graphs. Bars represents 10 μm. Statistical significance (Student's t test) was calculated, * indicates <i>p</i>< 0.05.</p

SAMHD1 increases LINE-1 RNP sequestration in stress granules.

<p>(A) HeLa cells were co-transfected with CMV-L1-neo^RT DNA and wild type Myc-SAMHD1 or SAMHD1-H233A mutant DNA. Endogenous G3BP1 was precipitated with anti-G3BP1 antibody. The anti-rabbit IgG was utilized as a control for non-specific binding. Co-immunoprecipitation of ORF1 and LINE-1 RNA was determined by western blotting and nest RT-PCR, respectively. Intensities of ORF1 bands (western blotting) and LINE-1 RNA bands (nest RT-PCR) were quantified using the ImageJ automated digitizing program (NIH). The results from three independent experiments are summarized in the bar graph. Levels of ORF1 and LINE-1 RNA in the control (SAMHD1 (-), G3BP1 antibody (+)) are arbitrarily set as 1. (B) Co-immunoprecipitation of LINE-1 RNA was determined by real-time quantitative PCR as described in Materials and Methods. The results from three independent experiments are summarized in the bar graph. Levels of ORF1 and LINE-1 RNA in the control (SAMHD1 (-), G3BP1 antibody (+)) are arbitrarily set as 1. (C) HeLa cells were co-transfected with Myc-KPNA2, Flag-ORF1 with or without HA-SAMDH1. Immunoprecipitation was performed with anti-Flag M2 gel. Presence of Myc-KPNA2 in the precipitated materials was determined by western blotting. Intensities of the KPNA2 bands were quantified using the ImageJ automated digitizing program (NIH), the results from three independent experiments are summarized in the bar graph. Level of KPNA2 in the control cells is arbitrarily set as 1. (D) SAMHD1 is not associated with ORF1. HeLa cells were co-transfected with Myc-SAMHD1 DNA and ORF1-Flag DNA. Myc-SAMHD1 was immunoprecipitated with anti-Myc antibody. The presence of ORF1 in the precipitated materials was examined by western blotting. * indicates p<0.05, ns denotes “not significant”.</p