The prevalence of type 2 diabetes is on the increase worldwide, and it represents about 90% of adults who are diagnosed with diabetes. Overweight and obesity, lifestyle, genetic predisposition and ...gut microbiota dysbiosis have been implicated as possible risk factors in the development of type 2 diabetes. In particular, low intake of dietary fibre and consumption of foods high in fat and sugar, which are common in western lifestyle, have been reported to contribute to the depletion of specific bacterial taxa. Therefore, it is possible that intake of high dietary fibre may alter the environment in the gut and provide the needed substrate for microbial bloom.
The current review is a systematic review and meta-analysis which evaluated the role of dietary fibre in modulating gut microbiota dysbiosis in patients with type 2 diabetes.
This is a systematic review and meta-analysis of randomised controlled trials which relied on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework. Electronic searches were conducted using EBSCOHost with links to Health Sciences Research Databases, EMBASE and Google Scholar. The reference lists of articles were also searched for relevant studies. Searches were conducted from date of commencement of the database to 5 August 2020. The search strategy was based on the Population, Intervention, Comparator, Outcomes, Studies (PICOS) framework and involved the use of synonyms and medical subject headings (MesH). Search terms were combined with Boolean operators (OR/AND).
Nine studies which met the inclusion criteria were selected for the systematic review and meta-analysis, and four distinct areas were identified: the effect of dietary fibre on gut microbiota; the role of dietary fibre on short-chain fatty acids (SCFAs); glycaemic control; and adverse events. There was significant difference (
< 0.01) in the relative abundance of Bifidobacterium with a mean difference of 0.72 (95% CI, 0.56, 0.89) between the dietary fibre group compared with placebo. In relation to the meta-analysis for SCFAs, while there was significant difference (
= 0.02) between the dietary fibre group and placebo with a standardised mean difference of 0.5 (95% CI, 0.08, 0.91) regarding total SCFAs, the differences were not significant (
> 0.05) in relation to acetic acid, propionic acid and butyric acid. There was only significant improvement (
= 0.002) with respect to glycated haemoglobin with a mean difference of -0.18 (95% CI, -0.29, -0.06) between the dietary fibre group and placebo group. Differences between the two groups were not significant (
> 0.05) in relation to fasting blood glucose and homeostatic model assessment of insulin resistance (HOMA-IR). Furthermore, there were no significant differences between the two groups in subjects who reported adverse events. It is possible that the promotion of SCFA producers in greater diversity and abundance by dietary fibre in this review led to improvement in glycated haemoglobin, partly due to increased glucagon-like peptide-1 (GLP-1) production. In addition, Bifidobacterium lactis has been reported to increase glycogen synthesis, decrease expression of hepatic gluconeogenesis genes, improve translocation of glucose transport-4 and promote glucose uptake. It is also possible that the reduction in body weight of participants in the intervention group compared with control may have contributed to the observed improvement in glycated haemoglobin.
This systematic review and meta-analysis have demonstrated that dietary fibre can significantly improve (
< 0.05) the relative abundance of Bifidobacterium, total SCFAs and glycated haemoglobin. However, dietary fibre did not appear to have significant effect (
> 0.05) on fasting blood glucose, HOMA-IR, acetic acid, propionic acid, butyric acid and adverse events.
Understanding how dietary nutrients modulate the gut microbiome is of great interest for the development of food products and eating patterns for combatting the global burden of non-communicable ...diseases. In this narrative review we assess scientific studies published from 2005 to 2019 that evaluated the effect of micro- and macro-nutrients on the composition of the gut microbiome using in vitro and in vivo models, and human clinical trials. The clinical evidence for micronutrients is less clear and generally lacking. However, preclinical evidence suggests that red wine- and tea-derived polyphenols and vitamin D can modulate potentially beneficial bacteria. Current research shows consistent clinical evidence that dietary fibers, including arabinoxylans, galacto-oligosaccharides, inulin, and oligofructose, promote a range of beneficial bacteria and suppress potentially detrimental species. The preclinical evidence suggests that both the quantity and type of fat modulate both beneficial and potentially detrimental microbes, as well as the Firmicutes/Bacteroides ratio in the gut. Clinical and preclinical studies suggest that the type and amount of proteins in the diet has substantial and differential effects on the gut microbiota. Further clinical investigation of the effect of micronutrients and macronutrients on the microbiome and metabolome is warranted, along with understanding how this influences host health.
Identification of grain shape determining genes can facilitate breeding of rice cultivars with optimal grain shape and appearance quality. Here, we identify GS9 (Grain Shape Gene on Chromosome 9) ...gene by map-based cloning. The gs9 null mutant has slender grains, while overexpression GS9 results in round grains. GS9 encodes a protein without known conserved functional domain. It regulates grain shape by altering cell division. The interaction of GS9 and ovate family proteins OsOFP14 and OsOFP8 is modulated by OsGSK2 kinase, a key regulator of the brassinosteroids signaling pathway. Genetic interaction analysis reveals that GS9 functions independently from other previously identified grain size genes. Introducing the gs9 allele into elite rice cultivars significantly improves grain shape and appearance quality. It suggests potential application of gs9, alone or in combination with other grain size determining genes, in breeding of rice varieties with optimized grain shape.
The impact of the COVID-19 lockdown on glycaemic control and other metabolic parameters in patients with type 2 diabetes is still evolving.
This systematic review and meta-analysis aims to examine ...the effects of COVID-19 lockdown on glycaemic control and lipid profile in patients with type 2 diabetes.
The PRISMA framework was the method used to conduct the systematic review and meta-analysis, and the search strategy was based on the population, intervention, control and outcome (PICO) model. The Health Sciences Research databases was accessed via EBSCO-host, and EMBASE were searched for relevant articles. Searches were conducted from inception of the databases until 17 September 2021.
The results identified three distinct areas: glycaemic control, lipid parameters and body mass index. It was found that COVID-19 lockdown led to a significant (
< 0.01) increase in the levels of glycated haemoglobin (%) compared with pre-COVID group (gp) with a mean difference of 0.34 (95% CI: 0.30, 0.38). Eleven studies contributed to the data for glycated haemoglobin analysis with a total of 16,895 participants (post-COVID-19 lockdown gp,
= 8417; pre-COVID gp,
= 8478). The meta-analysis of fasting plasma glucose (mg/dL) also showed a significant (
< 0.05) increase in levels of post-COVID-19 lockdown gp compared with pre-COVID gp, with a mean difference of 7.19 (95% CI: 5.28, 9.10). Six studies contributed to fasting plasma glucose analysis involving a total of 2327 participants (post-COVID-19 lockdown,
= 1159; pre-COVID gp,
= 1168). The body mass index (BMI) (kg/m
) analysis also demonstrated that post-COVID-19 lockdown gp had a significantly (
< 0.05) higher BMI than the pre-COVID gp with a mean difference of 1.13 (95% CI: 0.99; 1.28), involving six studies and a total of 2363 participants (post-COVID-19 lockdown gp,
= 1186; pre-COVID gp,
= 1177). There were significantly (
< 0.05) lower levels of total cholesterol (mmol/L), triglyceride (mmol/L) and LDL cholesterol (mmol/L), and higher levels of HDL cholesterol (mg/dL) in the post-COVID-19 lockdown gp compared with pre-COVID gp, although these results were not consistent following sensitivity analysis.
The findings of the systematic review and meta-analysis have demonstrated that COVID-19 lockdown resulted in a significant increase (
< 0.05) in the levels of glycated haemoglobin, fasting glucose and body mass index in patients with type 2 diabetes. In contrast, the effect of the lockdown on lipid parameters, including total cholesterol, triglycerides, LDL and HDL cholesterol was not consistent.
Hepatocellular carcinoma is one of the most common malignancies worldwide, representing a big health-care challenge globally. M2-like macrophages are significantly correlated with tumor progression, ...metastasis and treatment resistance. Integrative 10 machine learning algorithms were performed to developed a M2-like macrophage related prognostic signature (MRPS). Single-cell RNA-sequencing analysis was performed to dissect the ecosystem of HCC. Several approaches, including TIDE score, immunophenoscore, TMB score and tumor escape score were used to evaluate the predictive role of MRPS in immunology response. The optimal MRPS constructed by the combination of stepCox + superPC algorithm served as an independent risk factor and showed stable and powerful performances in predicting the overall survival rate of HCC patients with 2-, 3-, and 4-year AUCs of 0. 763, 0.751, and 0.699 in TCGA cohort. HCC patients with low risk score possessed a more interaction of immunoactivated cells, including NK, CD8.sup.+ cytotoxic T, and activated B, and a less interaction of immunosuppressive cells, including Treg, CD4.sup.+ exhauster T, and M2-like macrophage. Low risk score indicated a higher PD1&CTLA4 immunophenoscore, higher TMB score, lower TIDE score and lower tumor escape score in HCC, suggesting a better immunotherapy response. The IC50 value of docetaxel, gemcitabine, crizotinib and Osimertinib in HCC with high risk score were lower versus that with low risk score. HCC patients with high risk score had a higher score of cancer-related hallmarks, including angiogenesis, DNA repair, EMT, glycolysis, and NOTCH signaling. Our study proposed a novel MRPS for predicting the prognosis, ecosystem and immunotherapy response in HCC.
Phononic metamaterials are capable of manipulating mechanical wave propagation in applications ranging from nanoscale heat transfer to noise and vibration mitigation. The design of phononic ...metamaterials to control low-frequency vibrations, such as those induced by ground transportation and low-amplitude seismic waves, however, remains a challenge. Here we propose a new design methodology to generate seismic metamaterials that can attenuate surface waves below 10 Hz. Our design concept evolves around the engineering of the multi-layered soil, the use of conventional construction materials, and operational construction constraints. The proposed seismic metamaterials are constructed by periodically varying concrete piles in the host multi-layered soil. We first validate the design concept and the numerical models by performing a lab-scale experiment on the low-amplitude surface wave propagation in a finite-size seismic metamaterial. To the best of the Authors' knowledge, this is one of the few attempts made to date to experimentally understand the vibration mitigation capability of seismic metamaterials. We then numerically demonstrate that the multi-layered seismic metamaterials can attenuate surface waves over a wide frequency range, with the incident wave energy being confined within the softest layer of the shallow layered seismic metamaterials. In addition to the localized wave energy distribution, deep layered seismic metamaterials exhibit broadband cut-off band gaps up to 7.2 Hz due to the strongly imposed constraint between piles and surrounding soil. Furthermore, these cut-off band gaps strongly depend on the constraint between the piles and the bottom layer of the soil and hence can be tuned by tailoring the foundation stiffness. We also evidence the possibility to create constant wave band gaps by introducing hollow concrete piles with pile volume fraction <10% in the deep layered seismic metamaterials. The findings reported here open new avenues to protect engineering structures from low-frequency seismic vibrations.
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•Lab scale experiments were conducted to understand elastic wave propagation in seismic metamaterials.•Finite element models for wave propagation analysis were validated against the experiments.•Multi-layered seismic metamaterials can attenuate surface waves by confining wave energy.•Broadband cut-off band gaps up to 7.2 Hz were predicted in the multilayered seismic metamaterials.
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•A bio-inspired bi-stable piezoelectric energy harvester is designed, prototyped, and tested.•Dynamics and energy harvesting performance of the harvester are investigated.•Harvester ...experiences local multiple high-frequency vibrations under low-frequency excitation.•Average power output and frequency bandwidth increase significantly as the excitation level increases.
Inspired by the rapid shape transition of the Venus flytrap, a novel low-cost, bi-stable piezoelectric energy harvester is proposed, analyzed, and experimentally tested for the purpose of broadband energy harvesting. The harvester consists of a piezoelectric macro fiber composite (MFC) transducer, a tip mass, and two sub-beams with bending and twisting deformations created by pre-displacement constraints at the free ends using rigid tip-mass blocks. Different from bi-stable harvesters realized by nonlinear magnetic forces or residual stresses in laminate composites, the bio-inspired bi-stable piezoelectric energy harvester stores the potential energy induced by the mutual self-constraint of the sub-beams and harvests the large energy released during the rapid shape transition. Detailed design steps and principles are introduced and a prototype is fabricated to demonstrate and validate the concept. The experimentally measured nonlinear force–displacement curve of the harvester exhibits a discontinuous feature as the harvester jumps between the stable states. The dynamics of the proposed bio-inspired bi-stable piezoelectric energy harvester is investigated under sweeping frequency and harmonic excitations. The results show that the sub-beams of the harvester experience local vibrations including broadband high-frequency oscillations during the snap-through. The energy harvesting performance of the harvester is evaluated at different excitation levels over the frequency range of 9.0–14.0 Hz. Broadband energy harvesting is attained at relatively high excitation levels. An average power output of 0.193 mW for a load resistance of 8.2 kΩ is harvested at the excitation frequency of 10 Hz and amplitude of 4.0 g.
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