Changes In Composition Research Articles

Dispersal shapes compositional and functional diversity in aquatic microbial communities

ABSTRACT Segregation and mixing shape the structure and functioning of aquatic microbial communities, but their respective roles are challenging to disentangle in field studies. We explored the hypothesis that functional differences and beta diversity among stochastically assembled communities would increase in the absence of dispersal. Contrariwise, we expected biotic selection during homogenizing dispersal to reduce beta and gamma diversity as well as functional variability. This was experimentally addressed by examining the compositional and functional changes of 20 freshwater bacterial assemblages maintained at identical conditions over seven growth cycles for 34 days and subjected to two consecutive dispersal regimes. Initial dispersal limitation generated high beta diversity and led to the repeated emergence of community types that were dominated by particular taxa. Compositional stability and evenness of the community types varied over successive growth cycles, reflecting differences in functional properties. Carbon use efficiency increased during cultivation, with some communities of unique composition outperforming the replicate community types. Homogenizing dispersal led to high compositional similarity and reduced gamma diversity. While a neutral and a competition-based (Elo-rating) model together largely explained community assembly, a pseudomonad disproportionally dominated across communities, possibly due to interaction-related genomic traits. In conclusion, microbial assemblages stochastically generated by dispersal limitation can be gradually “refined” into distinct community types by subsequent deterministic processes. Segregation of communities represented an insurance mechanism for highly productive but competitively weak microbial taxa that were excluded during community coalescence. IMPORTANCE We experimentally assessed the compositional and functional responses of freshwater bacterial assemblages exposed to two consecutive dispersal-related events (dispersal limitation and homogenizing dispersal) under identical growth conditions. While segregation led to a decreased local diversity, high beta diversity sustained regional diversity and functional variability. In contrast, homogenizing dispersal reduced the species pool and functional variability of the metacommunity. Our findings highlight the role of dispersal in regulating both diversity and functional variability of aquatic microbial metacommunities, thereby providing crucial insight to predict changes in ecosystem functioning.

Abstract C040: Spatial transcriptomics unveils disparities in tumor microenvironment dynamics between breast cancer responders and non-responders

Abstract Spatial transcriptomics is revolutionizing our understanding of cellular dynamics and interactions in the tumor microenvironment (TME). By mapping distinct cellular populations and their interactions, we can gain valuable insights into tumor behavior. To investigate these dynamics in breast cancer, we conducted Xenium In-situ spatial transcriptomics on twenty formalin-fixed paraffin-embedded (FFPE) samples taken from eight patients undergoing neoadjuvant chemotherapy. These samples have been taken pre-treatment, mid-treatment and post-treatment from four cases with pathological complete response (pCR), and four cases with residual disease (RD) at time of surgery. Our analyses have found distinct cellular composition changes between pCR and RD cases. Patients with RD demonstrated an increase in endothelial, perivascular-like (PVL) and epithelial cells from pre- to post-treatment. This was accompanied by a decrease in myeloid and malignant epithelial cells at mid-treatment. In contrast, patients with pCR demonstrated increases in cancer-associated fibroblasts (CAFs) and myeloid cells, with reductions in plasmablasts and cancer epithelial cells at mid-treatment. This suggests that an increase in CAF and myeloid cells observed between pre-treatment and mid-treatment samples may be predictive of response. We performed ligand-receptor (LR) analyses, which demonstrated diverse myeloid interactions in RD cases and diverse CAF interactions in pCR cases in pre-treatment samples. Mid-treatment samples exhibited a decrease in interactions for CAFs, myeloid and T cells in pCR and RD cases. The most frequently identified CAF LR interactions, as senders, were between TGFB1/TGFB3 and TGFBR1/TGFBR2, while the most frequently identified myeloid LR interactions were between PDCD1LG2 - PDCD1 (encoding PDL2 & PD1), CCL8 - ACKR1 (encoding Atypical Chemokine Receptor 1) and CCL2 - ACKR1. Our findings indicate that the dynamic changes in cellular composition and interactions within the TME differs between responders and non-responders. To further explore these differences, we plan to perform spatially constrained analyses to identify unique cellular niches that may serve as potential biomarkers for informing novel therapeutic strategies. Citation Format: Jeremy Mo, Hanyun Zhang, Kate Harvey, Alexander Swarbrick. Spatial transcriptomics unveils disparities in tumor microenvironment dynamics between breast cancer responders and non-responders [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C040.

Abstract C013: Single cell analysis reveals tumor size-driven immune changes in primary breast tumors and corresponding lymph nodes

Abstract Introduction A sentinel lymph node is the primary node draining the tumor and is likely affected early in the metastatic process. The sentinel node holds a key position in the immune response against tumor in breast and represents a unique connection between the tumor and the host immune response. Detection of lymph node metastasis is important for staging a patient’s disease and is closely associated with prognosis. Although the clinical significance is debated, isolated tumor cells (<0.2 mm) appear to have no impact on survival while macro-metastasis (>2 mm) are linked to a poorer prognosis. Alterations in the immune response in lymph nodes with large versus small metastases have been observed, but little is known about the relationship between the immune response in the primary tumor and the metastatic status of the corresponding lymph nodes. Methods We analyzed single-cell suspensions from primary tumors and lymph nodes of 38 patients with early, operable breast cancer enrolled in the OSLO2 clinical observational trial using mass cytometry with a 47- antibody immune panel (including PanKeratin and EpCAM). In total 3.7 million single cells were analyzed and clustered into 40 metaclusters using FlowSOM. A second set of 22 metastatic lymph nodes from the OSLO2 cohort was used to validate results form the metastatic tumor cells. Additionally, immunofluorescence with E-cadherin and PanKeratin was applied, and intensity measured in 4 metastatic lymph nodes and imaging mass-cytometry was applied on one metastatic lymph node Results We found that the immune microenvironment in primary tumor was dominated by CD4 and CD8 T cells, particularly of exhausted and memory phenotype and with a higher frequency of activated regulatory T cells (Treg). In contrast, the immune composition in lymph nodes was predominantly composed of naturally occurring naive B and T cells. Notably, in line with previous publications we observed a skewing towards memory and exhausted phenotype in T cells, along with increased abundance of activated Treg in lymph nodes with larger metastasis to those with smaller or no metastasis. Furthermore, there were no correlation between the immune profile in the primary tumor and corresponding lymph node. The immune profile in the primary tumor was influenced by tumor size, with larger tumors showing a higher frequency of activated Tregs and exhausted CD8 T cells. Furthermore, In situ analysis revealed that the microenvironment in smaller metastase had an mesenchymal phenotype, while larger tumor deposits exhibited a more epithelial-like phenotype. ConclusionThe immune profile of the primary tumor did not predict the immune profile or metastatic status of the corresponding lymph node. Tumor size in both primary tumors and metastatic lymph nodes is the main drivers of changes in immune cell composition. Tumor cells from smaller metastases exhibited an mesenchymal phenotype, while larger metastasis displayed an epithelial phenotype. Citation Format: Inga Hansine H. Rye, Marit Otterlei Fjørtoft, Inger Riise Bergheim, Karin Teien Lande, Kanutte H. Huse, June Helen H. Myklebust, Ole Christian H. Lingjærde, Øystein. Garred, Jon H. Lømo, Hege H. Russnes. Single cell analysis reveals tumor size-driven immune changes in primary breast tumors and corresponding lymph nodes [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C013.

Acoustic sensing and autoencoder approach for abnormal gas detection in a spent nuclear fuel canister mock-up

Currently, spent nuclear fuel (SNF) from commercial nuclear power plants is stored in stainless-steel canisters for interim dry storage. To provide an inert environment, these canisters are backfilled with helium after vacuum drying. However, the helium environment may be contaminated during extended storage because of the material degradation. For example, the heavier fission gas xenon may be released from the fuel rods into the canister cavity should the fuel cladding be breached. Other gases such as air and water vapor may also be present as a result of leakage caused by chloride-induced stress corrosion cracking on the canister walls or by insufficient vacuum drying. Therefore, monitoring the gas composition can provide critical information about the health of SNF canisters. In this study, noninvasive testing was conducted on a 2/3-scaled SNF canister mock-up using acoustic sensing. Ultrasonic transducers were placed on the exterior surface of the canister to probe the gas composition. A dataset was collected by sealing the canister mock-up and introducing up to 1.53% argon or 1.29% air into the helium background gas. Three methods were used to detect changes in the gas composition: the time-of-flight (TOF) method, the differential method, and the autoencoder method. Results showed that the TOF method had sufficient resolution to detect abnormal gas concentrations of less than 1.0%. The differential method demonstrated a periodic in-phase and out-of-phase behavior between the benchmark (i.e., pure helium) and abnormal (i.e., with argon or air) state signals. The variational autoencoder (VAE) and the Wasserstein autoencoder (WAE) were trained on the benchmark data and were applied directly to the abnormal state data. It was found that both the unsupervised VAE and the WAE were able to distinguish the benchmark and abnormal states of the canister mock-up based on the reconstruction error.

Host genotype and infection status interact to shape microbiomes in Daphnia magna.

Host–bacterial communities (microbiomes) are influenced by a wide range of factors including host genotype and parasite exposure. However, few studies disentangle temporal and host-genotype-specific variation in microbiome response to infection across several host tissues. We experimentally exposed the freshwater crustacean Daphnia magna to its fungal parasite Metschnikowia bicuspidata and characterized changes in host–bacterial communities associated with the parasite's development within the host. We used 16S rRNA gene sequencing to assess bacterial communities of the host (a) 24 h (‘initial parasite exposure’) and (b) 10 days (‘successful infection’) after exposure to a standard dose of M. bicuspidata spores, in host guts, body tissue (excluding guts) and whole individuals. We also investigated whether bacterial community responses to parasite exposure varied by host genotype.Parasite exposure did not immediately alter host gut bacterial communities, but drove host-genotype-specific changes in the bacterial community composition of whole individuals. We validated that these changes were not driven by shifts in bacterial communities of the culturing medium, due to the addition of the parasite spore solution. Successful infection (i.e. the proliferation of M. bicuspidata spores in the host body) reduced alpha diversity and shifted abundance of dominant bacterial orders in the gut. Moreover, it induced a host-genotype-specific changes in body bacterial community composition. Overall, bacterial community responses to parasite exposure and subsequent infection are complex: they occur in a host-genotype-dependent manner, differentially at distinct timepoints after parasite exposure, and in specific host tissue.

A nearly terrestrial D/H for comet 67P/Churyumov-Gerasimenko.

Cometary comae are a mixture of gas and ice-covered dust. Processing on the surface and in the coma change the composition of ice on dust grains relative to that of the nucleus. As the ice on dust grains sublimates, the local coma composition changes. Rosetta observations of 67P/Churyumov-Gerasimenko previously reported one of the highest D/H values for a comet. However, reanalysis of more than 4000 water isotope measurements over the full mission shows that dust markedly increases local D/H. The isotope ratio measured at a distance from the nucleus where the gas is well mixed is close to terrestrial, like that of other Jupiter family comets. This lower D/H has implications for understanding comet formation and the role of comets in delivering water to Earth.

Lacticaseibacillus rhamnosus LRa05 in the treatment of acute diarrhea in children: a randomized controlled trial

IntroductionThe goal of this study is to assess the efficacy and safety of Lacticaseibacillus rhamnosus LRa05, as an adjunct to the treatment of acute watery diarrhea in children.MethodsEligible diarrheal children were randomized into intervention group (IG, n = 57) and control group (CG, n = 54), and given probiotics or placebo, respectively.ResultsThe total duration of diarrhea in the IG (121.4 ± 13.7 h) was significantly shorter than that in the CG (143.9 ± 19.8 h, p < 0.001). More children in the IG showed improvements in diarrhea than those in the CG for both per protocol analysis (70.2 vs. 46.3%, p = 0.01) and intention-to-treat analysis (66.7 vs. 41.7%, p = 0.003). The LL-37 levels in the IG was markedly higher than that in the CG after the intervention (4349.35 ± 1143.86 pg./g vs. 3682.49 ± 869.21 pg./g, p = 0.039). The intervention led to higher abundance of Bifidobacterium longum and lower abundance of Enterococcus faecium, Lactobacillus rhamnosus, and Bacteroides fragilis (p < 0.05). LRa05 treatment upregulated the functional genes of gut microbiota involving immunity regulation.DiscussionAdministration of the Lacticaseibacillus rhamnosus LRa05 at a dose of 5 × 109 CFU/day to children aged 0-3 years resulted in shorter duration of diarrhea, faster improvement in fecal consistency, and beneficial changes in gut microbiome composition and gene functions.Clinical trial registrationThe present study has been approved and registered in the Chinese Clinical Trial Registration Center with the registration number of ChiCTR2100053700 (https://www.chictr.org.cn/showproj.html?proj=141082).

Association Between Type 1 Diabetes Mellitus and Dental Caries in Children: A Systematic Review

Background: Diabetes mellitus is one of the diseases with chronic prevalence. Keep going increased, not only in adults but also in children. Diabetes mellitus type 1, the most common, occurs in children. Dental caries is an infection caused by metabolizing bacteria Streptococcus mutans, and Lactobacilli that convert carbohydrates into acid that damages tooth enamel. Diabetes can cause changes in saliva composition and flow. Saliva is vital in guarding a healthy tooth by neutralizing acid and providing minerals for remineralizing tooth enamel. Method: A systematic review was done by reviewing research through English data sources Pub Med, Proquest, Cochran, and Wiley. Four studies were included according to the inclusion criteria. Result: The results of a review of these four journals showed that children aged 6-18 who have type 1 or type 2 diabetes mellitus have a higher risk of developing dental caries or dental diseases. Children with diabetes are predisposed to have more glucose in their saliva. High glucose can become a source of nutrition for bacteria cariogenic, which contributes to the formation of plaque and acids that damage teeth. Conclusion: Diabetes mellitus is a risk factor for oral health. Diabetes Mellitus had a significant correlation with dental caries in children. Keywords: Diabetes Mellitus, Children.

Concrete Infrastructure: Recent Advancements and Needs with a Focus on North America

This letter provides an overview of the continent’s diversity in geography and climatic exposure and the impact of chlorides on reinforced concrete structures in North America. Several research needs are identified, including those that arise as specifications begin to change from prescriptive to performance-based approaches. Further, the widespread changes in material compositions or chloride exposures, require important changes to specifications, design practices, or maintenance procedures. Related to reducing carbon emissions, there is a need to reduce clinker content in concrete mixtures, increase the use of novel cementitious and supplementary cementitious materials (SCM), and to understand the durability of such concretes. The following research efforts from a North American context are warranted: (i) investigating the long-term durability of novel cement and SCM systems, including non-Portland cement-based materials and those made with CO2 mineralization used to meet carbon emission targets; (ii) understanding climate change impacts of temperature and sea levels, including flood impact, on chloride exposure and chloride-induced corrosion; (iii) developing rapid and reliable tests to estimate durability in practice, particularly for scaling, freeze-thaw, salt damage, and chloride-induced corrosion; and (v) developing better understanding of the short and long-term implications of changes in constituent materials and exposure.

A study of chemical composition and physical-mechanical properties of rigid polyurethane-polyisocyanurate foams changes under conditions of extreme heating

Polyurethane-polyisocyanurate rigid (PIR) foams are used as thermal insulation materials in a wide range of applications such as construction and pipe insulation. Some of the utilizations require the maximum operating temperature of these materials to reach extremely high temperatures. This work is devoted to the study of changes in the chemical composition and the main physical-mechanical and thermophysical characteristics of PIR foams subjected to prolonged extreme heating in the presence of the material direct contact with air and in its absence. Based on the results obtained, prolonged extreme heating of such materials leads to a significant change in their chemical composition, mainly due to the thermal decomposition of allophanate, urethane and urea linkages, as well as the gradual formation of uretidione, linear carbodiimide polymer and the oxidation of ethers to esters. The relative compressive strength of these materials changes only to a small extent, while the thermal conductivity of these materials increases significantly during heating.

Phyllospheric bacterial communities in spinach are influenced by soil nitrogen availability

Nitrogen is an essential macronutrient for the growth and development of plants. As with most crops, nitrogen-based fertilizers are used to improve productivity and quality of spinach. Although the significance of the soil microbiome in the inorganic nitrogen cycle is recognized, soil nitrogen's impact on phyllosphere bacterial communities remains unclear. This study investigates changes in the bacterial community composition and diversity residing on spinach leaves cultivated in soils with varying nitrogen levels. Sixty-eight spinach samples were processed using culture-dependent and independent methods to evaluate phyllosphere-associated bacterial communities. In culture-dependent methods, populations of Mesophiles (MS), Psychrotrophs (PY), coliforms (CL), and lactic acid bacteria (LAB) were quantified by plate counts using appropriate culture media. In culture-independent methods, bacteria were determined by amplicon sequencing based on the V3-V4 region of the bacterial 16S rRNA gene. Counts of MS, PY, CL, and LAB on low-nitrogen soil-grown spinach were 7.4, 7.1, 6.9, and 5.5 log CFU/g, respectively, while high-nitrogen soil-grown spinach showed counts of 7.5, 7.0, 7.0, and 5.7 log CFU/g. These counts did not differ significantly between the nitrogen levels used for spinach cultivation (p > 0.05). Amplicon sequencing, however, revealed differences in relative abundance between different taxa levels and soil nitrogen levels. The relative abundance of Erwinaceae and Planococcaceae was higher in high-nitrogen soil-grown spinach. The relative abundance of Pseudomonadaceae, Enterobacteriaceae, and Rhizobiaceae was higher in low-nitrogen soil-grown spinach. Soil nitrogen content significantly affected spinach phyllosphere microbiome beta-diversity. Our results suggest that bacterial communities of spinach phyllosphere are influenced by soil nitrogen content.

Substrate induced composition change during Ge2Sb2Te5 atomic layer deposition and study of initial reactions on SiO2 surface

Ge2Sb2Te5 (GST) is a well-known phase change material used in nonvolatile memory devices, photonics, and nonvolatile displays. This study investigates the impact of precursor sequence during atomic layer deposition (ALD) of GST from GeCl2.C4H8O2, SbCl3, and Te[(CH3)3Si]2 on Si/SiO2 substrates, focusing on growth per cycle, morphology, and composition along with initial precursor reactions on the substrate. We found that while thick layers approach stoichiometric Ge2Sb2Te5, a Ge-rich interfacial layer is initially formed, regardless of the binary ALD sequence used to start the deposition (GeTe vs Sb2Te3). Starting the ALD process with the GeTe-Sb2Te3 sequence results in a higher Ge content near the GST/SiO2 interface compared to the Sb2Te3-GeTe sequence. To understand these phenomena, we examine the initial precursor reactions on the SiO2 substrate by total reflection x-ray fluorescence spectrometry. The analysis reveals that SbCl3 exhibits lower reactivity with the SiO2 substrate than GeCl2.C4H8O2, and not all Ge adspecies react with the Te[(CH3)3Si]2 precursors. Additionally, the impact of the initial SiO2 surface on deposition extends over several ALD cycles, as the SiO2 surface only gradually gets covered by GST due to island growth. These processes contribute to the formation of a Ge-rich GST layer at the interface, irrespective of the precursor pulse sequence. These insights from the study may contribute to optimizing the initial deposition stages of GST and other ternary ALD processes to enable better composition control and enhanced device performance.

Utility of fat-free adipose tissue correction formula for tracking body composition changes with dual-energy X-ray absorptiometry.

Fat loss is often the target of weight loss interventions; however, preservation of lean soft tissue (LST) may be more important for health and weight maintenance. Though some LST loss may be inevitable when tracking body composition changes using dual-energy X-ray absorptiometry (DXA), correcting for the fat-free component of adipose tissue (FFAT) in DXA-derived LST (DXALST) has been proposed. This analysis sought to evaluate differences between DXALST and FFAT-corrected LST (FFATLST) amongst varied populations and interventions to understand application of the correction formula on LST outcomes. 226 subjects were analyzed across five prior studies. Three studies evaluated combined nutrition and exercise (high-intensity interval training [HIIT] or high-intensity resistance training [HIRT]) interventions, including HIIT + HIRT with pre- and post-nutrient timing (HIITRT), HIIT + essential amino acids (HIITAA), and HIRT + protein (HIRTPRO). Remaining studies evaluated HIIT (HIITOW) and protein following bariatric surgery (BARPRO). Pre and post total body DXA scans were used to measure DXALST, body mass, and fat mass (FM). The correction formula was applied to calculate FFATLST. Paired sample t-tests were used to evaluate differences between DXALST and FFATLST change scores (Δ) across all subjects, within each study and intervention. Significant differences between ΔDXALST and ΔFFATLST were observed for BARPRO (mean difference [MD; ΔDXALST-ΔFFATLST] ± standard error [SE]: -3.5 ± 1.2 kg, p < 0.001), as well as HIRTPRO (-0.1 ± 0.2 kg, p = 0.004). When evaluating LST, the FFAT correction may be specifically applicable to cases of significant weight loss (>10% of original weight) or body recomposition (≥2% FM loss and ≥2% LST gain).

The unrevealed links: periodontal health, human milk composition, and infant gut microbiome dynamics.

This review aims to identify the mechanistic relationships related to periodontal diseases and its possible association with changes in human milk composition and the composition and function of infants' gut microbiome. Maternal health conditions, especially inflammatory, are associated with altered human milk composition. It is not known whether maternal oral inflammatory diseases, including periodontal diseases, deleteriously affect human milk composition. A narrative review was conducted according to SANRA, the Scale for the Assessment of Narrative Review Articles, guidelines. PubMed, Google Scholar, and Cochrane database of systematic reviews were searched from September 2019 up to December 2023 using keywords such as breast/human milk, maternal health/infections, and periodontal diseases. Reference lists of relevant articles were also screened. Our primary outcome of interest was human milk composition (i.e., any changes in macronutrients, immunological components, etc.). Secondary outcomes included changes in human milk microbiome and subsequent changes in the infant gut microbiome. Outcomes were synthesized using a narrative approach where the existing evidence and current literature were summarized. No risk of bias assessment of the studies was performed in this review. The search yielded no studies investigating the relationship between periodontal diseases in nursing mothers and changes in human milk composition. However, a dose-response relationship exists between the severity of periodontal diseases and the risk of adverse pregnancy outcomes such as preterm birth. Mastitis and diabetes affected milk lipids. Immunoglobulin A (sIgA) was increased in mastitis, whereas reduced concentrations were reported in diabetes. Potential biological pathways through which periodontal diseases can negatively affect human milk composition include the systemic dissemination of inflammatory cytokines like IL-6, PGE2, and tumor necrosis factor (TNF)-β that can be up-regulated by bacterial by-products. This biological plausibility needs to be investigated, given the potentially negative impact on the quality of human milk that could be caused by periodontal inflammation.

Al-Mg electrodeposition using chloride-based molten salts

Al-Mg alloys were potentiostatically electrodeposited from electrolyte with AlCl3, NaCl, KCl and MgCl2 at 180 °C for aircraft applications. The electrode setup includes a Cu cathode, Pt-mesh anode, and Al-rod pseudo-reference electrode. Cyclic voltammetry (CV) reveals the Al deposition sources as Al2Cl7-and AlCl4-. The Mg deposition source can be a reaction between Al2Cl7- and MgCl2 and MgCl2 dissociation (both releasing Mg2+). Depositions at over­poten­tials: -1.03, -1.05, -1.06, and -1.10 V show current density-time curves with almost steady-state j, indicating planar diffusional growth. This is confirmed by layer-like morphologies with near-globular growth features. The average feature size decreases to -1.06 V and increases slightly at -1.10 V due to further deposition over the existing features. The deposit composition (Mg content) increases from 0.36 to 5.68 at.% from -1.03 to -1.10 V. Such a wide range of Mg content is obtained through minimal compositional changes in spent electrolytes, indicating the ease of less-noble Mg deposition. Al-Mg deposition scheme is devised with Al and Mg deposition perceived as Al3+ + 3e- Al and Mg2+ + 2e- Mg; and 2Cl- Cl2(↑)+ 2e- supplying electrons for deposition.

Shifts in bacterial community composition during symbiotic seed germination of a terrestrial orchid and effects on protocorm development.

It is well known that orchid seeds depend on mycorrhizal fungi to supply the necessary nutrients that support germination in natural environments. Apart from fungi, bacteria may also be involved in the germination process of orchid seeds, but so far, their role has not been intensively studied. This research provides evidence that bacterial community composition changes during seed germination of the terrestrial orchid Gymnadenia conopsea. Interestingly, in vitro experiments showed that Pseudomonas spp., which were the most dominant bacteria in the later germination stages, improved protocorm growth. These results suggest that bacteria contribute to the germination of orchid seeds, which may open new perspectives to apply bacteria as a biofertilizer in the introduction and restoration of G. conopsea populations.

Moisture-induced mechanical property changes in natural hybrid composites with mwcnt fillers

ABSTRACT This study investigates the moisture absorption behaviour and its effects on the mechanical properties of polyester composites reinforced with jute and hemp fibres. The differences in moisture absorption between distilled water and saltwater are examined. Tensile and flexural tests are conducted on pure jute fibre-reinforced polyester composite, pure hemp fibre-reinforced polyester composite, and jute (J-P) and hemp (H-P) fibre-reinforced polyester composite. Changes in mechanical properties due to varying moisture conditions are analysed. Furthermore, the impact of a synthetic nano filler, multiwall carbon nanotubes (MWCNTs), on these composites is assessed. The study reveals that MWCNTs enhance mechanical properties, particularly in moist conditions. Fracture behaviour analysis aids in understanding the interaction between natural fibres, the matrix, and nano-reinforcement. At maximum natural fibre weight fractions (40%), moisture absorption reaches 8.17% for the J-P composite in distilled water and 9.61% in saltwater, while the H-P composite shows maximum absorptions of 6.61% and 8.27%, respectively. The hybrid composite records 4.18% and 7.17% under similar conditions. Compared to the plain jute fibre-reinforced composite, the addition of multiwall carbon tubes into the polymer matrix significantly reduces the moisture absorption capacity of the jute composite to 34.89% and 31.30% for distilled water and saltwater, respectively.

OGC SO42 - A comparison of body composition changes between neoadjuvant FLOT and MAGIC regimes in patients with locally advanced oesophageal cancer

Abstract Background Several studies have documented the changes in body composition that can occur between pre and post neoadjuvant chemotherapy for locally advanced OGA. However, none have compared the changes between different neoadjuvant regimes following the shift in practice from MAGIC to FLOT neoadjuvant chemotherapy. Specifically, given that the FLOT regimen has been thought to be more toxic than MAGIC regimen, it is unclear whether this toxicity is measurable and clinically significant with regards to body composition. This study aims to compare the changes in body composition between these two regimens in patients with locally advanced oesophageal cancer. Method We conducted a retrospective cohort study comparing changes in body composition between patients receiving either MAGIC or FLOT neoadjuvant chemotherapy. 115 patients treated with FLOT (n = 61) or MAGIC (n = 54) who underwent an oesophagectomy for OGA between 2008 and 2020 at Queen Elizabeth Hospital, Birmingham, UK were ultimately enrolled in the study. Changes in body composition between pre- and post-neo-adjuvant chemotherapy were determined by analysis of computed tomography (CT) imaging. Slice-O-Matic is a software tool allowing segmentation of body tissues into different classes Including skeletal muscle and fat based on the Hounsfield units. Results Our findings showed a statistically significant difference in the weight loss of participants enrolled the MAGIC group compared to FLOT (FLOT -0.6 ±6.9 vs MAGIC -3.4 ±1.2, p=0.034) which was therefore also reflected in BMI differential before and after neoadjuvant chemotherapy (FLOT -0.2 ± 2.2 vs MAGIC -1.2 ± 2.7, p=0.024). However, there was no statistically significant difference in the L3 skeletal muscle index in both regimes (FLOT -2.8 ± 4.1 vs MAGIC -2.9 ± 4.1; p=0.93). Finally, changes in L3 fat index between the two cohorts did not demonstrate statistically significant difference in our study (FLOT -0.9 ± 22.6 vs MAGIC -5.6 ± 24.8; p=0.29). Conclusion Our study suggests that a large proportion of patients with locally-advanced OGA were sarcopenic prior to starting chemotherapy and this proportion increased post treatment. There was no statistically significant loss of muscle mass or fat during treatment with either MAGIC or FLOT. Despite this, weight loss and decreases in BMI were greater in the MAGIC group compared to FLOT, suggesting FLOT may have a more favourable toxicity profile with regard to body composition. Overall, our findings support the safety profile of FLOT chemotherapy with regard to body composition changes and illustrates a superior pathological response to FLOT therapy for OGA.

The Anti-Elixir Triad: Non-Synced Circadian Rhythm, Gut Dysbiosis and Telomeric Damage.

Aging is an inevitable life process which is accelerated by lifestyle and environmental factors. It is an irreversible accretion of molecular and cellular damage associated with changes in the body composition and deterioration in physiological functions. Each cell (other than stem cells), reaches the limit of its ability to replicate, known as cellular or replicative senescence and consequently, the organs lose their physiological functions resulting in overall impairment. Other factors that promote aging include smoking, alcohol, UV rays, sleep habits, food, stress, sedentary life style and genetic abnormalities. These stress factors, can alter our endogenous clock (the circadian rhythm) and the microbial commensals. As a result of effect of these stressors, the microorganisms that generally support human physiological processes become baleful. The disturbance of natural physiology instigates many age-related pathologies, such as cardiovascular diseases, chronic obstructive pulmonary disorder, cerebrovascular diseases, opportunistic infections, high blood pressure, cancer, diabetes, kidney diseases, dementia, and Alzheimer's disease. The present review covers the three most essential processes of the circadian clock; the circadian gene mechanism and regulation, the mitotic clock (which plays a vital role in the telomere's attrition) and gut microbiota and their metabolome that drive aging and lead to age-related pathologies. In conclusion, maintaining a synchronized circadian rhythm, a healthy gut microbiome and telomere integrity is essential for mitigating the effects of aging and promoting longevity. The interplay among these factors underscores the importance of lifestyle choices in enhancing overall health and lifespan.

The effect of filler distribution on electromagnetic properties of nanocarbon/magnetic particles/polymer composites

The type of multi-component fillers and their spatial distribution in conductive polymer-based composites greatly influenced their electrical properties, electromagnetic shielding efficiency (SE), and absorption capability, which require a deep understanding of how these properties improve with changes in the phase composition, content, and distribution of these fillers in the composite. In this study, three-phase polymer composite materials (CMs) with random (epoxy-based) and segregated (polyethylene-based) distribution of nanocarbon (graphite nanoplatelets GNP and carbon nanotubes CNTs) and magnetic (Fe and Co3O4) fillers have been developed. It was found that permittivity εr′ in the frequency range (40–60 GHz) increases sufficiently with the nanocarbon content and their values are slightly higher for random GNP-filled CMs (εr′=10–15 for 3–5 wt. % GNP) compared to CNT-filled CMs and much higher compared to segregated CMs (εr′=4–7 for 3–5 wt. % of nanocarbon). Dielectric loss tangent tanδ is increased with the nanocarbon content (especially for Fe-filled CMs) and sufficiently higher in segregated CMs compared to similar random composites. These enhanced tanδ values correlate with higher electromagnetic shielding efficiency due to absorption of segregated nanocarbon/magnetic/polyethylene CMs, for example, SEAd ≈ 18–23 dB/mm for 5 wt. %GNP. The most preferable for microwave absorption are random and segregated CMs with 2–3 wt. % GNP/30 wt. % magnetic filler: RLmin = −(27–35) dB, effective absorption bandwidth (EAB) Δf10dB=11.5–12.5GHz at a sample thickness of 0.5–0.7 mm. In CNT-based segregated CMs, |RLmin| and EAB values are lower compared with GNP-based CMs. The ability to manipulate these characteristics is important for obtaining good shielding and absorptive properties in the microwave range of electromagnetic radiation.