A hybrid topological quantum state in an elemental solid.

Topology1-3 and interactions are foundational concepts in the modern understanding of quantum matter. Their nexus yields three important research directions: (1) the competition between distinct interactions, as in several intertwined phases, (2) the interplay between interactions and topology that drives the phenomena in twisted layered materials and topological magnets, and (3) the coalescence of several topological orders to generate distinct novel phases. The first two examples have grown into major areas of research, although the last example remains mostly unexplored, mainly because of the lack of a material platform for experimental studies. Here, using tunnelling microscopy, photoemission spectroscopy and a theoretical analysis, we unveil a 'hybrid' topological phase of matter in the simple elemental-solid arsenic. Through a unique bulk-surface-edge correspondence, we uncover that arsenic features a conjoined strong and higher-order topology that stabilizes a hybrid topological phase. Although momentum-space spectroscopy measurements show signs of topological surface states, real-space microscopy measurements unravel a unique geometry of topologically induced step-edge conduction channels revealed on various natural nanostructures on the surface. Using theoretical models, we show that the existence of gapless step-edge states in arsenic relies on the simultaneous presence of both a non-trivial strong Z2 invariant and a non-trivial higher-order topological invariant, which provide experimental evidence for hybrid topology. Our study highlights pathways for exploring the interplay of different band topologies and harnessing the associated topological conduction channels in engineered quantum or nano-devices.

Topological kagome magnets and superconductors.

A kagome lattice naturally features Dirac fermions, flat bands and van Hove singularities in its electronic structure. The Dirac fermions encode topology, flat bands favour correlated phenomena such as magnetism, and van Hove singularities can lead to instabilities towards long-range many-body orders, altogether allowing for the realization and discovery of a series of topological kagome magnets and superconductors with exotic properties. Recent progress in exploring kagome materials has revealed rich emergent phenomena resulting from the quantum interactions between geometry, topology, spin and correlation. Here we review these key developments in this field, starting from the fundamental concepts of a kagome lattice, to the realizations of Chern and Weyl topological magnetism, to various flat-band many-body correlations, and then to the puzzles of unconventional charge-density waves and superconductivity. We highlight the connection between theoretical ideas and experimental observations, and the bond between quantum interactions within kagome magnets and kagome superconductors, as well as their relation to the concepts in topological insulators, topological superconductors, Weyl semimetals and high-temperature superconductors. These developments broadly bridge topological quantum physics and correlated many-body physics in a wide range of bulk materials and substantially advance the frontier of topological quantum matter.

Observation of a linked-loop quantum state in a topological magnet.

Quantum phases can be classified by topological invariants, which take on discrete values capturing global information about the quantum state1-13. Over the past decades, these invariants have come to play a central role in describing matter, providing the foundation for understanding superfluids5, magnets6,7, the quantum Hall effect3,8, topological insulators9,10, Weyl semimetals11-13 and other phenomena. Here we report an unusual linking-number (knot theory) invariant associated with loops of electronic band crossings in a mirror-symmetric ferromagnet14-20. Using state-of-the-art spectroscopic methods, we directly observe three intertwined degeneracy loops in the material's three-torus, T3, bulk Brillouin zone. We find that each loop links each other loop twice. Through systematic spectroscopic investigation of this linked-loop quantum state, we explicitly draw its link diagram and conclude, in analogy with knot theory, that it exhibits the linking number (2, 2, 2), providing a direct determination of the invariant structure from the experimental data. We further predict and observe, on the surface of our samples, Seifert boundary states protected by the bulk linked loops, suggestive of a remarkable Seifert bulk-boundary correspondence. Our observation of a quantum loop link motivates the application of knot theory to the exploration of magnetic and superconducting quantum matter.

Time-reversal symmetry-breaking charge order in a kagome superconductor.

The kagome lattice1, which is the most prominent structural motif in quantum physics, benefits from inherent non-trivial geometry so that it can host diverse quantum phases, ranging from spin-liquid phases, to topological matter, to intertwined orders2-8 and, most rarely, to unconventional superconductivity6,9. Recently, charge sensitive probes have indicated that the kagome superconductors AV3Sb5 (A = K, Rb, Cs)9-11 exhibit unconventional chiral charge order12-19, which is analogous to the long-sought-after quantum order in the Haldane model20 or Varma model21. However, direct evidence for the time-reversal symmetry breaking of the charge order remains elusive. Here we use muon spin relaxation to probe the kagome charge order and superconductivity in KV3Sb5. We observe a noticeable enhancement of the internal field width sensed by the muon ensemble, which takes place just below the charge ordering temperature and persists into the superconducting state. Notably, the muon spin relaxation rate below the charge ordering temperature is substantially enhanced by applying an external magnetic field. We further show the multigap nature of superconductivity in KV3Sb5 and that the [Formula: see text] ratio (where Tc is the superconducting transition temperature and λab is the magnetic penetration depth in the kagome plane) is comparable to those of unconventional high-temperature superconductors. Our results point to time-reversal symmetry-breaking charge order intertwining with unconventional superconductivity in the correlated kagome lattice.

Discovery of charge density wave in a kagome lattice antiferromagnet.

A hallmark of strongly correlated quantum materials is the rich phase diagram resulting from competing and intertwined phases with nearly degenerate ground-state energies1,2. A well-known example is the copper oxides, in which a charge density wave (CDW) is ordered well above and strongly coupled to the magnetic order to form spin-charge-separated stripes that compete with superconductivity1,2. Recently, such rich phase diagrams have also been shown in correlated topological materials. In 2D kagome lattice metals consisting of corner-sharing triangles, the geometry of the lattice can produce flat bands with localized electrons3,4, non-trivial topology5-7, chiral magnetic order8,9, superconductivity and CDW order10-15. Although CDW has been found in weakly electron-correlated non-magnetic AV3Sb5 (A = K, Rb, Cs)10-15, it has not yet been observed in correlated magnetic-ordered kagome lattice metals4,16-21. Here we report the discovery of CDW in the antiferromagnetic (AFM) ordered phase of kagome lattice FeGe (refs. 16-19). The CDW in FeGe occurs at wavevectors identical to that of AV3Sb5 (refs. 10-15), enhances the AFM ordered moment and induces an emergent anomalous Hall effect22,23. Our findings suggest that CDW in FeGe arises from the combination of electron-correlations-driven AFM order and van Hove singularities (vHSs)-driven instability possibly associated with a chiral flux phase24-28, in stark contrast to strongly correlated copper oxides1,2 and nickelates29-31, in which the CDW precedes or accompanies the magnetic order.

Quantum-limit Chern topological magnetism in TbMn6Sn6.

The quantum-level interplay between geometry, topology and correlation is at the forefront of fundamental physics1-15. Kagome magnets are predicted to support intrinsic Chern quantum phases owing to their unusual lattice geometry and breaking of time-reversal symmetry14,15. However, quantum materials hosting ideal spin-orbit-coupled kagome lattices with strong out-of-plane magnetization are lacking16-21. Here, using scanning tunnelling microscopy, we identify a new topological kagome magnet, TbMn6Sn6, that is close to satisfying these criteria. We visualize its effectively defect-free, purely manganese-based ferromagnetic kagome lattice with atomic resolution. Remarkably, its electronic state shows distinct Landau quantization on application of a magnetic field, and the quantized Landau fan structure features spin-polarized Dirac dispersion with a large Chern gap. We further demonstrate the bulk-boundary correspondence between the Chern gap and the topological edge state, as well as the Berry curvature field correspondence of Chern gapped Dirac fermions. Our results point to the realization of a quantum-limit Chern phase in TbMn6Sn6, and may enable the observation of topological quantum phenomena in the RMn6Sn6 (where R is a rare earth element) family with a variety of magnetic structures. Our visualization of the magnetic bulk-boundary-Berry correspondence covering real space and momentum space demonstrates a proof-of-principle method for revealing topological magnets.

Van Hove annihilation and nematic instability on a kagome lattice.

A nematic phase breaks the point-group symmetry of the crystal lattice and is known to emerge in correlated materials. Here we report the observation of an intra-unit-cell nematic order and associated Fermi surface deformation in the kagome metal ScV6Sn6. Using scanning tunnelling microscopy and scanning tunnelling spectroscopy, we reveal a stripe-like nematic order breaking the crystal rotational symmetry within the kagome lattice itself. Moreover, we identify a set of Van Hove singularities adhering to the kagome-layer electrons, which appear along one direction of the Brillouin zone and are annihilated along other high-symmetry directions, revealing rotational symmetry breaking. Via detailed spectroscopic maps, we further observe an elliptical deformation of the Fermi surface, which provides direct evidence for an electronically mediated nematic order. Our work not only bridges the gap between electronic nematicity and kagome physics but also sheds light on the potential mechanism for realizing symmetry-broken phases in correlated electron systems.

Topological chiral crystals with helicoid-arc quantum states.

The quantum behaviour of electrons in materials is the foundation of modern electronics and information technology1-11, and quantum materials with topological electronic and optical properties are essential for realizing quantized electronic responses that can be used for next generation technology. Here we report the first observation of topological quantum properties of chiral crystals6,7 in the RhSi family. We find that this material class hosts a quantum phase of matter that exhibits nearly ideal topological surface properties originating from the crystals' structural chirality. Electrons on the surface of these crystals show a highly unusual helicoid fermionic structure that spirals around two high-symmetry momenta, indicating electronic topological chirality. The existence of bulk multiply degenerate band fermions is guaranteed by the crystal symmetries; however, to determine the topological invariant or charge in these chiral crystals, it is essential to identify and study the helicoid topology of the arc states. The helicoid arcs that we observe on the surface characterize the topological charges of ±2, which arise from bulk higher-spin chiral fermions. These topological conductors exhibit giant Fermi arcs of maximum length (π), which are orders of magnitude larger than those found in known chiral Weyl fermion semimetals5,8-11. Our results demonstrate an electronic topological state of matter on structurally chiral crystals featuring helicoid-arc quantum states. Such exotic multifold chiral fermion semimetal states could be used to detect a quantized photogalvanic optical response, the chiral magnetic effect and other optoelectronic phenomena predicted for this class of materials6.

Benefits and Risks of Iron Interventions in Infants in Rural Bangladesh.

BACKGROUND: Universal provision of iron supplements (drops or syrup) or multiple micronutrient powders to young children in low-to-middle-income countries where anemia is prevalent is recommended by the World Health Organization and widely implemented. The functional benefits and safety of these interventions are unclear. METHODS: We conducted a three-group, double-blind, double-dummy, individually randomized, placebo-controlled trial to assess the immediate and medium-term benefits and risks of 3 months of daily supplementation with iron syrup or iron-containing multiple micronutrient powders, as compared with placebo, in 8-month-old children in rural Bangladesh. The primary outcome was cognitive development, as assessed by the cognitive composite score on the Bayley Scales of Infant and Toddler Development, third edition, immediately after completion of the assigned 3-month regimen; scores range from 55 to 145, with higher scores indicating better cognitive performance. Secondary outcomes included the cognitive composite score at 9 months after completion of the assigned regimen; behavioral, language, and motor development, as well as growth and hematologic markers, immediately after completion and at 9 months after completion; and safety. RESULTS: We randomly assigned 3300 infants to receive iron syrup (1101 infants), multiple micronutrient powders (1099), or placebo (1100) daily. After completion of the assigned 3-month regimen, no apparent effect on the cognitive composite score was observed with iron syrup as compared with placebo (mean between-group difference in change in score from baseline, -0.30 points; 95% confidence interval [CI], -1.08 to 0.48) or with multiple micronutrient powders as compared with placebo (mean between-group difference in change in score from baseline, 0.23 points; 95% CI, -0.55 to 1.00). No apparent effect on any other developmental or growth outcome was observed immediately after completion of the assigned regimen or at 9 months after completion. At 9 months after completion of the assigned regimen, the prevalences of anemia, iron deficiency, and iron deficiency anemia increased in all three trial groups but remained lower among the children who received iron syrup or multiple micronutrient powders than among those who received placebo. The risk of serious adverse events and incidence of symptoms of infection were similar in the three trial groups. CONCLUSIONS: In this trial involving infants in Bangladesh, 3 months of daily supplementation with iron syrup or multiple micronutrient powders did not appear to have an effect on child development or other functional outcomes as compared with placebo. (Funded by the National Health and Medical Research Council of Australia; BRISC Australian New Zealand Clinical Trials Registry number, ACTRN12617000660381.).

Redox signalling in plant-nematode interactions: Insights into molecular crosstalk and defense mechanisms.

Plant-parasitic nematodes, specifically cyst nematodes (CNs) and root-knot nematodes (RKNs), pose significant threats to global agriculture, leading to substantial crop losses. Both CNs and RKNs induce permanent feeding sites in the root of their host plants, which then serve as their only source of nutrients throughout their lifecycle. Plants deploy reactive oxygen species (ROS) as a primary defense mechanism against nematode invasion. Notably, both CNs and RKNs have evolved sophisticated strategies to manipulate the host's redox environment to their advantage, with each employing distinct tactics to combat ROS. In this review, we have focused on the role of ROS and its scavenging network in interactions between host plants and CNs and RKNs. Overall, this review emphasizes the complex interplay between plant defense mechanism, redox signalling and nematode survival tactics, suggesting potential avenues for developing innovative nematode management strategies in agriculture.

The effects of higher versus lower protein delivery in critically ill patients: an updated systematic review and meta-analysis of randomized controlled trials with trial sequential analysis.

BACKGROUND: A recent large multicentre trial found no difference in clinical outcomes but identified a possibility of increased mortality rates in patients with acute kidney injury (AKI) receiving higher protein. These alarming findings highlighted the urgent need to conduct an updated systematic review and meta-analysis to inform clinical practice. METHODS: From personal files, citation searching, and three databases searched up to 29-5-2023, we included randomized controlled trials (RCTs) of adult critically ill patients that compared higher vs lower protein delivery with similar energy delivery between groups and reported clinical and/or patient-centred outcomes. We conducted random-effect meta-analyses and subsequently trial sequential analyses (TSA) to control for type-1 and type-2 errors. The main subgroup analysis investigated studies with and without combined early physical rehabilitation intervention. A subgroup analysis of AKI vs no/not known AKI was also conducted. RESULTS: Twenty-three RCTs (n = 3303) with protein delivery of 1.49 ± 0.48 vs 0.92 ± 0.30 g/kg/d were included. Higher protein delivery was not associated with overall mortality (risk ratio [RR]: 0.99, 95% confidence interval [CI] 0.88-1.11; I2 = 0%; 21 studies; low certainty) and other clinical outcomes. In 2 small studies, higher protein combined with early physical rehabilitation showed a trend towards improved self-reported quality-of-life physical function measurements at day-90 (standardized mean difference 0.40, 95% CI - 0.04 to 0.84; I2 = 30%). In the AKI subgroup, higher protein delivery significantly increased mortality (RR 1.42, 95% CI 1.11-1.82; I2 = 0%; 3 studies; confirmed by TSA with high certainty, and the number needed to harm is 7). Higher protein delivery also significantly increased serum urea (mean difference 2.31 mmol/L, 95% CI 1.64-2.97; I2 = 0%; 7 studies). CONCLUSION: Higher, compared with lower protein delivery, does not appear to affect clinical outcomes in general critically ill patients but may increase mortality rates in patients with AKI. Further investigation of the combined early physical rehabilitation intervention in non-AKI patients is warranted. PROSPERO ID: CRD42023441059.

Giant and anisotropic many-body spin-orbit tunability in a strongly correlated kagome magnet.

Owing to the unusual geometry of kagome lattices-lattices made of corner-sharing triangles-their electrons are useful for studying the physics of frustrated, correlated and topological quantum electronic states1-9. In the presence of strong spin-orbit coupling, the magnetic and electronic structures of kagome lattices are further entangled, which can lead to hitherto unknown spin-orbit phenomena. Here we use a combination of vector-magnetic-field capability and scanning tunnelling microscopy to elucidate the spin-orbit nature of the kagome ferromagnet Fe3Sn2 and explore the associated exotic correlated phenomena. We discover that a many-body electronic state from the kagome lattice couples strongly to the vector field with three-dimensional anisotropy, exhibiting a magnetization-driven giant nematic (two-fold-symmetric) energy shift. Probing the fermionic quasi-particle interference reveals consistent spontaneous nematicity-a clear indication of electron correlation-and vector magnetization is capable of altering this state, thus controlling the many-body electronic symmetry. These spin-driven giant electronic responses go well beyond Zeeman physics and point to the realization of an underlying correlated magnetic topological phase. The tunability of this kagome magnet reveals a strong interplay between an externally applied field, electronic excitations and nematicity, providing new ways of controlling spin-orbit properties and exploring emergent phenomena in topological or quantum materials10-12.

Early experience of using regional citrate anticoagulation for continuous renal replacement therapy in critically ill patients in a resource-limited setting.

AIM: Despite the superiority of regional citrate anticoagulation (RCA) in continuous renal replacement therapy (CRRT), its application is limited in resource-limited settings. We aim to explore the cost and safety of RCA for CRRT in critically ill patients, compared to usual care. METHODS: This prospective observational study included patients requiring CRRT in a tertiary intensive care unit (ICU) from February 2022 to January 2023. They were classified to either the RCA or usual care groups based on the anticoagulation technique chosen by the treating physician, considering contraindications. The CRRT prescription follows the institutional protocol. All relevant data were obtained from the ICU CRRT-RCA charts and electronic medical records. A cost analysis was performed. RESULTS: A total of 54 patients (27 per group) were included, with no demographic differences. Sequential Organ Failure Assessment score and lactate levels were significantly higher in the usual care group. The number of filters used were comparable (p = .108). The median filter duration in the RCA group was numerically longer (35.00 [15.50-56.00] vs. 23.00 [17.00-29.00] h), but not statistically significant (p = .253). The duration of mechanical ventilation, vasopressor requirement, and mortality were similar, but the RCA group had a significantly longer ICU stay. The rate of adverse events was similar, with four severe metabolic alkalosis cases in the RCA group. The RCA group had higher total cost per patient per day (USD 611 vs. 408; p = .013). CONCLUSION: In this resource-limited setting, RCA for CRRT appeared safe and had clinically longer filter lifespan compared with usual care, albeit the increased cost.

Analysis and prediction of nutritional outcome of patients with pediatric inflammatory bowel disease from Bahrain.

BACKGROUND: Inflammatory bowel disease (IBD) is a chronic gastrointestinal disease that causes anorexia, malabsorption, and increased energy requirements. Childhood IBD can significantly impact nutritional status and future health. OBJECTIVE: This study aimed to analyze the nutritional status of patients with pediatric IBD at presentation and during follow-up and to identify predictors of nutritional outcome. METHODS: This retrospective cohort study reviewed the medical records of children diagnosed with IBD in the Pediatric Department, Salmaniya Medical Complex, Bahrain, 1984 - 2023. Demographic data, clinical characteristics, and anthropometric data were collected. World Health Organization growth standards were used to interpret nutritional status. RESULTS: Of the 165 patients, 99 (60%) had anthropometric data at presentation, and 130 (78.8%) had follow-up data. Most patients were males (64.6%) and had Crohn's disease (CD) (56.2%), while 43.8% had ulcerative colitis (UC). The median age at presentation was 10.9 years and the mean follow-up duration was 12.6 years. At presentation, 53.5% of the patients were malnourished, that decreased to 46.9% on follow-up. Thinness was reduced from 27.3% at presentation to 12.1% at follow-up (p = 0.003). There was an increased tendency to normal weight on follow-up (59.6%) compared to time of presentation (46.5%), p = 0.035. Overweightness showed a non-significant increase from 26.3% at presentation to 28.3% at follow-up (p = 0.791). Children with IBD were more likely to become obese when they grow up to adulthood (2.3% versus 20.5%, respectively, p < 0.001). Weight-for-age, and height-for-age at presentation were higher among CD compared to UC, but body mass index (BMI) at follow-up was higher among UC patients (p < 0.05). Thinness at follow up was associated with very early-onset disease (p = 0.02), lower weight and BMI at presentation (p < 0.001 each), younger age at follow-up (p = 0.002), pediatric age group (p = 0.023), lower hematocrit (p = 0.017), and higher C-reactive protein (p = 0.007). Overweight at follow up was associated with increased weight and BMI at presentation (p < 0.001 each), longer disease duration (p = 0.005), older age (p = 0.002), and azathioprine intake (p = 0.026). Considering follow-up duration, univariate analysis exhibited that Bahraini nationality, post-diagnosis disease duration, age at follow-up, occurrence of diarrhea, height, and BMI at presentation were factors that decreased liability to abnormal nutritional status, while CD, history of weight loss, perianal disease, and skin rash, and intake of prednisolone expressed increased liability of abnormal nutritional status (p < 0.05). CONCLUSION: Pediatric IBD is associated with a high incidence of malnutrition. Thinness is more prominent at presentation, while overweight is higher on follow-up. Multiple risk factors aggravating abnormal nutritional status were highlighted. Accordingly, nutritional counseling should be prioritized in a multidisciplinary approach.

Effects of mass casualty incidents on anxiety, depression, and post-traumatic stress disorder among doctors and nurses: a systematic review.

OBJECTIVES: Doctors and nurses suffer different mental health conditions following traumatic incidents. We systematically synthesized existing evidence on the prevalence of anxiety, depression, and post-traumatic stress disorder (PTSD) and their associated risk factors among doctors and nurses following mass casualty incidents (MCIs). STUDY DESIGN: Systematic review. METHODS: Seven databases were searched (2010-2022) with peer-reviewed articles in English using the predefined keywords. Two reviewers screened the titles, abstracts, and full texts using the eligibility criteria and extracted data independently. We used the National Institutes of Health Quality Assessment Tools (NIH-QAT) and the Critical Appraisal Skills Programme checklist (CASP) to measure the quality appraisal of the included studies. RESULTS: A total of 5170 articles were retrieved, and 2512 articles were assessed by title and abstract (53 were eligible for full-text review). Finally, we included 19 studies. Most were assessed as of fair quality with a considerable risk of bias. PTSD was the highest-reported mental health condition. Nurses reported higher mental conditions, particularly PTSD. Two sets of risk factors (personal and workplace) are associated with anxiety, depression, and PTSD were found. CONCLUSIONS: MCIs have a significant impact on the mental health outcomes of emergency health workers. Preventive measures should be designed considering the high-risk group, personal, and organizational risk factors of mental health outcomes.

Medical students' career preferences in Bangladesh.

AIM: This study aimed to investigate the career preferences among Bangladeshi medical students, identify the factors that influence their present choices, and additionally report the role of gender and academic year behind their decisions. METHODS: This cross-sectional study conducted in Bangladesh from August 2022 to April 2023 included 801 medical students conveniently selected from medical colleges in eight divisions. Data were collected using a web-based survey and analysed using STATA version 16.0. Statistical tests included the Kolmogorov-Smirnov test, arithmetic mean, standard deviation, frequency, and Kruskal-Wallis H test. The response rate was 94.6%, and the CHERRIES guideline was followed for reporting the results. RESULT: The majority of the participants were female (64.42%) and under the age of 23 years (58.8%). The study revealed that medicine was the preferred career choice for the majority of students (65%), with surgery being the most popular first choice (30.21%) among them. Female medical students showed a significantly higher preference for gynaecology & obstetrics (p < 0.001), while male students had a significantly higher tendency to choose general practice (p = 0.002). There is a significant gender difference (p < 0.05) in the career preference factors, including professional prestige, role model influence, easy money, family time, promotion opportunities, income for lifestyle, and research opportunities. Academic year differences were also observed, with increasing interest in medicine and public health (p < 0.001), a decrease in interest in surgery (p < 0.001), and a decline in preference for non-medical careers as students progressed through their MBBS life (p < 0.05). CONCLUSION: Overall, medicine was the most popular speciality choice, however, male students preferred general practice and female students preferred gynaecology and obstetrics more. Personal passion, opportunities for contribution to society, professional prestige, having a direct dealing with patients, and income will allow an enjoyable lifestyle were the most important factors in the choice of their career.

Chitosan-grafted salicylaldehyde/algae composite for methyl violet dye removal: adsorption modeling and optimization.

In this study, a hydrothermal approach was employed to graft chitosan (Chit)/algae (ALG) with salicylaldehyde (SA), resulting in the synthesis of a biocomposite named salicylaldehyde-based chitosan Schiff base/algae (Chit-SA/ALG). The main objective of this biocomposite was to effectively remove methyl violet (MV), an organic dye, from aqueous solutions. The adsorption performance of Chit-SA/ALG toward MV was investigated in detail, considering the effects of three factors: (A) Chit-SA/ALG dose (ranging from 0.02 to 0.1 g/100 mL), (B) pH (ranging from 4 to 10), and (C) time (ranging from 10 to 120 min). The Box-Behnken design (BBD) was utilized for experimental design and analysis. The experimental results exhibited a good fit with both the pseudo-second-order kinetic model and the Freundlich isotherm, suggesting their suitability for describing the MV adsorption process on Chit-SA/ALG. The maximum adsorption capacity of Chit-SA/ALG, as calculated by the Langmuir model, was found to be 115.6 mg/g. The remarkable adsorption of MV onto Chit-SA/ALG can be primarily attributed to the electrostatic forces between Chit-SA/ALG and MV as well as the involvement of various interactions such as n-π, π-π, and H-bond interactions. This research demonstrates that Chit-SA/ALG exhibits promising potential as a highly efficient adsorbent for the removal of organic dyes from water systems.

The novelty of this work comes from introducing a new bio-organic based composite adsorbent of chitosan (Chit) biopolymer and algae (ALG) biomass. Moreover, the functionality and chemical stability of Chit­ALG composite was further developed by grafting process with salicylaldehyde (SA) using hydrothermal process. The incorporation of ALG biomass into polymeric matrix of Chit and grafting process with SA makes Chit a unique hybrid adsorbent toward cationic dye (methyl violet dye).

Food-grade algae modified Schiff base-chitosan benzaldehyde composite for cationic methyl violet 2B dye removal: RSM statistical parametric optimization.

This work aims to apply the use of food-grade algae (FGA) composited with chitosan-benzaldehyde Schiff base biopolymer (CHA-BD) as a new adsorbent (CHA-BA/FGA) for methyl violet 2B (MV 2B) dye removal from aqueous solutions. The effect of three processing variables, including CHA-BA/FGA dosage (0.02-0.1 g/100 mL), pH solution (4-10), and contact duration (10-120 min) on the removal of MV 2B was investigated using the Box-Behnken design (BBD) model. Kinetic and equilibrium dye adsorption profiles reveal that the uptake of MV 2B dye by CHA-BA/FGA is described by the pseudo-second kinetics and the Langmuir models. The thermodynamics of the adsorption process (ΔG°, ΔH°, and ΔS°) reveal spontaneous and favorable adsorption parameters of MV 2B dye onto the CHA-BA/FGA biocomposite at ambient conditions. The CHA-BA/FGA exhibited the maximum ability to absorb MV 2B of 126.51 mg/g (operating conditions: CHA-BA/FGA dose = 0.09 g/100 mL, solution pH = 8.68, and temperature = 25 °C). Various interactions, including H-bonding, electrostatic forces, π-π stacking, and n-π stacking provide an account of the hypothesized mechanism of MV 2B adsorption onto the surface of CHA-BA/FGA. This research reveals that CHA-BA/FGA with its unique biocomposite structure and favorable adsorption properties can be used to remove harmful cationic dyes from wastewater.

The first novel aspect of this research work comes from the utilization of food-grade algae which contains various types of negative functional groups hydroxyl, carboxyl, and phosphate to modify a cationic biopolymer (Chitosan) to improve its adsorptive property toward removal of a cationic dye such as methyl violet 2B. The second novel aspect of this research work is to use the hydrothermal process to assist the grafting of an aromatic ring of benzaldehyde into the polymer matrix of the chitosan-food grade algae composite via a Schiff base linkage to improve its chemical stability and functionality.

Prolonged vs Intermittent Infusions of ß-Lactam Antibiotics in Adults With Sepsis or Septic Shock: A Systematic Review and Meta-Analysis.

Importance: There is uncertainty about whether prolonged infusions of ß-lactam antibiotics improve clinically important outcomes in critically ill adults with sepsis or septic shock. Objective: To determine whether prolonged ß-lactam antibiotic infusions are associated with a reduced risk of death in critically ill adults with sepsis or septic shock compared with intermittent infusions. Data Sources: The primary search was conducted with MEDLINE (via PubMed), CINAHL, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and ClinicalTrials.gov from inception to May 2, 2024. Study Selection: Randomized clinical trials comparing prolonged (continuous or extended) and intermittent infusions of ß-lactam antibiotics in critically ill adults with sepsis or septic shock. Data Extraction and Synthesis: Data extraction and risk of bias were assessed independently by 2 reviewers. Certainty of evidence was evaluated with the Grading of Recommendations Assessment, Development and Evaluation approach. A bayesian framework was used as the primary analysis approach and a frequentist framework as the secondary approach. Main Outcomes and Measures: The primary outcome was all-cause 90-day mortality. Secondary outcomes included intensive care unit (ICU) mortality and clinical cure. Results: From 18 eligible randomized clinical trials that included 9108 critically ill adults with sepsis or septic shock (median age, 54 years; IQR, 48-57; 5961 men [65%]), 17 trials (9014 participants) contributed data to the primary outcome. The pooled estimated risk ratio for all-cause 90-day mortality for prolonged infusions of ß-lactam antibiotics compared with intermittent infusions was 0.86 (95% credible interval, 0.72-0.98; I2 = 21.5%; high certainty), with a 99.1% posterior probability that prolonged infusions were associated with lower 90-day mortality. Prolonged infusion of ß-lactam antibiotics was associated with a reduced risk of intensive care unit mortality (risk ratio, 0.84; 95% credible interval, 0.70-0.97; high certainty) and an increase in clinical cure (risk ratio, 1.16; 95% credible interval, 1.07-1.31; moderate certainty). Conclusions and Relevance: Among adults in the intensive care unit who had sepsis or septic shock, the use of prolonged ß-lactam antibiotic infusions was associated with a reduced risk of 90-day mortality compared with intermittent infusions. The current evidence presents a high degree of certainty for clinicians to consider prolonged infusions as a standard of care in the management of sepsis and septic shock. Trial Registration: PROSPERO Identifier: CRD42023399434.

An Aspen plus process simulation model for exploring the feasibility and profitability of pyrolysis process for plastic waste management.

Plastics, integral to various human activities, have led to a surge in production, posing substantial challenges in waste management. The persistent non-biodegradability of plastics, taking over a century to decompose, necessitates exploration into technologies for their conversion into sustainable fuels. Pyrolysis, an oxygen-free thermal decomposition process, emerges as a promising avenue for producing liquid fuels from plastic waste. This study's primary objective is to create and validate an Aspen Plus simulation model, enabling techno-economic evaluation and sensitivity analysis of pyrolysis for converting waste plastics into liquid fuels. Critical parameters-temperature, retention time, and particle size-are examined for their impact on product yield and quality. The methodology involves model development, validation, and subsequent simulations with various waste plastic types under different pyrolysis conditions. Experimental investigation using waste high-density polyethylene (HDPE) in an auger reactor yielded an oil yield of 61.29%, char yield of 10.98%, and syngas yield of 27.73% at 525 °C. Post-validation against this data, the model explored four plastic types, revealing significant influences of plastic type and reactor temperature on product yields. Polystyrene (PS) at 500 °C produced the highest oil content at 83.69%, with temperature affecting yield before secondary cracking. Techno-economic evaluation for a pyrolysis plant processing 10,000 tons of waste HDPE annually indicated a minimum selling price (MSP) of $302.50/ton, a net present value (NPV) of $12,594,659.7, and a 1.03-year payback period. This study provides crucial insights for designing an economically viable and sustainable pyrolysis process, guiding further research and industrial implementation.