Low Weight Ratio Research Articles

Feasible living donor liver transplantation for patients on chronic hemodialysis: a multicenter study in East Asian countries.

End-stage liver and kidney disease is an indication for simultaneous liver and kidney transplantation. However, in countries where deceased donor transplantation is not well established, living donor liver transplantation (LDLT) is a realistic option for patients on hemodialysis (HD). We investigated the outcomes of LDLT for patients on HD. We conducted a retrospective multicenter survey of patients on chronic HD who underwent LDLT in East Asian countries. The characteristics of donors and recipients and the short and long-term outcomes were analyzed. Between 2001 and 2021, 45 patients on HD underwent LDLT and 11 of these patients also underwent kidney transplantation (KT). The overall survival rate at 5years of the 34 patients who underwent only LDLT was 44.5%. Multivariate analysis identified a low graft recipient weight ratio (< 1%) (p = 0.048) and long HD duration (≥ 10years) (p = 0.046) as independent predictors of poor overall survival. The major complication was posttransplant bleeding, which occurred in12 patients (35%). It is important to establish the indications for LDLT, taking into consideration graft size and HD duration in candidate patients on HD.

Investigation of Solar Air Collectors with Carbon-Nanotube-Based Turbulators and Pin Fin Arrangements

This research attempts to investigate the thermal performance of solar air collectors with pin fins and turbulators. Incorporating carbon-nanotube-based fins and turbulators in solar collectors can enhance their performance due to their high thermal conductivity, low weight, and high aspect ratio. In the present study, numerical analyses of a solar collector with pin fins and turbulators are carried out to investigate its effect on the Nusselt number. The paper begins with the numerical analysis of conventional air collectors and compares them with theoretical results. This is followed by numerical analyses, which are carried out to examine different configurations of the absorber plate with pin fins of varying diameters (10 mm, 20 mm, and 30 mm) and turbulators of varying heights (20 mm, 40 mm, and 60 mm) in the base plate. The analyses include variations in the Reynolds number ranging from 3000 to 15,000. Subsequently, after the performance of the solar collector with pin fins is evaluated, the effect of turbulators of varying heights on the Nusselt number is analyzed, followed by the analysis of the combined effect of pin fins and turbulators. The results are compared with traditional solar collectors and show that the combined effect of pin fins and turbulators can significantly improve the thermal performance of solar air collectors. The findings of this study can contribute to the development of renewable energy-based air conditioning, ventilation, and heating systems.

Investigation of Young's modulus of defective graphene‐reinforced epoxy at different weight ratios by molecular dynamics

AbstractExperimental studies have shown that adding graphene to epoxy at even a low weight ratio increases strength, temperature resistance, and electrical conductivity. This study examines the effects of combining graphene with epoxy and assesses Young's modulus of the resulting nano‐composite materials with various defective graphene types. Molecular dynamics (MD) simulation is are utilized to predict the mechanical properties of nano‐composite materials, and a heuristic protocol is implemented to avoid incorrect bond structures during crosslinking reactions. The study demonstrates that adding graphene to epoxy increases Young's modulus, but the effect declines when the graphene is defective. These results significantly advance the field's knowledge by providing a new understanding of the effects of pristine and defective graphene reinforcement on epoxy Young's modulus. This research stands out for its evaluation of the impact of various graphene defects on epoxy properties using MD simulations. The employed heuristic protocol in this study, which includes thorough updates of both bonded and non‐bonded terms as well as partial charges, serves as a more reliable algorithm than iterative multi‐step protocols by reducing the risk of incorrect molecular linkages resulting from the neglect of angle‐based covalent terms. Additionally, this study evaluates the constant strain minimization method's suitability for determining the mechanical properties of nano‐composite materials. Finally, a thorough comparison between the simulation results and the existing experimental findings reported in scholarly sources was made to guarantee the full disclosure of both qualitative and quantitative results within the scope of the investigation.

Ultimate tensile behavior of short single‐wall carbon nanotube/epoxy composites and the reinforced mechanism

AbstractShort single‐wall carbon nanotubes (SWCNTs)/epoxy composites were fabricated by a procedure of cutting and functionalizing SWCNTs, dispersion and curing, with a very low weight ratio of SWCNTs from 0.03% to 0.5%. It was found that the tensile fracture strength of composites increases with increasing SWCNT content initially, then reaches a maximum at 0.05 wt% and finally decreases with further increasing the SWCNT content. The fracture strength of the composite with 0.05 wt% SWCNTs (78.46 MPa) is ~160% of that of pure epoxy sample (48.64 MPa). A model analysis based on the competition of local matrix fracture and the debonding of short SWCNT was proposed. It revealed that there is a transition from local matrix fracture to the debonding of SWCNT when the SWCNT content increases, this transition leads to the decrease in the tensile strength. Further analyses indicated that the content of carbon nanotubes (CNTs) at the transition depends on their radius and length. Considering the effect of surface cracks on the fracture strength of pure epoxy sample, the theoretical analyses are qualitatively in agreement with the experimental results. The present study partly explains why the fracture strength of CNT reinforced composites has various results for a similar CNT loading in previous works.

A critical review of advanced techniques to improve machining of titanium alloy (grade 5)

Sea to space applications necessitate advanced materials to fulfill diverse requirements, including Titanium and its alloys, particularly Grade 5 (Ti-6Al-4V alloy). Exhibiting remarkable properties such as high heat resistance, low thermal conductivity, low weight ratio, and minimal corrosiveness, Titanium Grade 5 holds immense potential for applications in aerospace, biomedical, automotive, and military sectors. However, its full utilization is impeded by challenges encountered during machining. This paper provides an overview of the difficulties faced in machining Titanium Grade 5 and emphasizes the ongoing search for the optimal tool-material combination. The paper discusses the properties influencing machinability, such as thermal conductivity, chemical reactivity, elastic modulus, hardness, strength, work hardening, and the effects of temperature on Ti-6Al-4V alloy. The review emphasizes the various techniques employed to enhance machining efficiency, including dry cutting, flood cooling, minimum quantity lubrication, high-pressure coolant environment, cryogenic environment, solid lubricants, and hot machining. While the best pairing remains elusive, significant progress has been made in the machining of titanium alloys, showcasing various evolving techniques and methodologies aimed at enhancing the material's usability in diverse industrial applications.

RECENT PROGRESS IN ALUMINUM HYBRID COMPOSITES REINFORCED WITH NATURAL FIBER ASH: A REVIEW

Modern technology demands have raised the popularity of aluminum metal matrix composites (AMMCs) as it best suits diverse industrial applications. The need to develop an advanced functional material for specific applications attracts global researchers. Commercial needs for cost-effectiveness, quality improvement, superior performance and high strength to low weight ratio are met by composites. Mass production of AMMCs for specific industrial applications prefer stir casting as a simple and cost-effective manufacturing method. In addition, the production of composites turn more economic by reducing the weight percentage of ceramics and adding natural fibers either in the form of fibers, milled powder or ash to achieve the targeted properties. Process parameters being a dominating factor for minimal defect composites, their effect on final cast products are discussed along with strengthening mechanisms. This paper also discusses the applications, challenges and future scope of natural fiber reinforced AMMCs.

Anodization of TiO&lt;sub&gt;2&lt;/sub&gt; Nanotubes on Titanium Alloys and their Analysis of Mechanical Properties

The low weight and high strength ratio of titanium alloy make TiO2 nanotubes ideal for biomedical applications. Increasing the oxidation process has recently been studied as a means of encouraging the formation of nanotubes. This study synthesizes the TiO2 nanotubes with different input voltages. There was an increase in nanotube growth rate as a result of de-ionized water in the electrolyte, as well as an increase in the input potential, which favours oxidation. An analysis of the surface morphology suggests that rib structures were generated in the area where corrosion results were greatly elevated. X-ray diffraction and nanoindentation were used to study phase transformations and nanohardness respectively.

Evaluation of hardness and microstructural features in piston aluminum-silicon alloys after different ageing heat treatments

Contemporarily, aluminum alloy is widely used in automobile industries, especially in engine parts, due to the properties of mentioned alloy like low weight ratio and proper thermal conductivity. In the presented research, twelve different heat treatments procedure were conducted on piston aluminum-silicon alloy to examine the influences of time and temperatures of ageing and quenching processes on the hardness values of the aluminum alloy. In addition, the effect of the aforementioned treatments on the microstructures of aluminum alloy was investigated. Therefore, the optical microscopy investigation was conducted to study the microstructural alternation. Moreover, hardness tests were performed to measure the differences in hardness. In addition, the test results were discussed to choose the optimum heat treatment parameters in order to achieve enhancement in hardness values of samples besides the fewer size of Si and intermetallic phases, which could result in better fatigue performance.

Autogenous and Tunable CNTs for Enhanced Polarization and Conduction Loss Enabling Sea Urchin-Like Co3ZnC/Co/C Composites with Excellent Microwave Absorption Performance.

ZIF-67-derived magnetic metal/carbon composites are considered prospective candidates for use as microwave absorption (MA) materials owing to their magnetoelectric synergy. However, the structure of ZIF-67-derived MA materials mainly depends on the morphology and composition of pristine metal-organic frameworks (MOFs), and their microstructures lack a rational design. Herein, a multidimensional sea urchin-like carbon nanotubes (CNTs)-grafted carbon polyhedra-encapsulated Co3ZnC/Co nanoparticle composite was prepared by one-step catalytic pyrolysis of ZIF-67/ZnO using a rational structural design. The autogenous and tunable CNTs obtained with the assistance of zinc evaporation not only overcome the limitation of homogeneous dispersion but also endow the Co3ZnC/Co/C composite with outstanding MA properties owing to the conduction loss provided by CNTs, polarization loss caused by multiple components, and electromagnetic wave trap composed of a special sea urchin-like structure. Consequently, the minimum reflection loss of ZZ0.1-600 reaches -60.3 dB at 1.6 mm, the maximum absorption bandwidth of ZZ0.05-600 is 6.24 GHz (covering nearly the entire Ku band) at 1.9 mm, and the structure has a low weight ratio (30 wt %). Compared with Z-600 and pure ZnO, the MA performance of the sea urchin-like Co3ZnC/Co/C composite obtained by rational structural design has been greatly improved; this strategy offers a new approach for optimizing the MA performance of materials according to their structural design.

Investigation of buckling of laminated composites repaired by resin injection using acoustic emission and cohesive zone simulation method

Due to their low weight ratio, excellent damping behavior, and high strength characteristics, composite materials are widely used in different industries, including aerospace. Despite the excellent mechanical behavior, most of these materials suffer from damages such as delamination when undergoing low-energy impacts. In the present study, repairing the composite structures using the resin injection into the damaged zone is analyzed. In some samples, initial delamination is included during the manufacturing process using the Teflon film, while the other samples are left to be intact. Furthermore, the delamination inside the composite sample has been simulated using the cohesive zone method (CZM) using ABAQUS software. The samples with delamination were repaired with the resin injection method. Finally, all samples underwent the buckling test, and the buckling process of the samples was monitored using the acoustic emission method. The amounts of damage mechanisms of delamination growth, fiber breakage, and matrix cracking were calculated using the wavelet method. The results show a good agreement between the experimental results with both the finite element method (FEM) and the acoustic emission results. Besides, the restoration percentages of compressive strength in samples repaired with stacking sequence [0]8, [90]8, and [0/90]8 were 88%, 87%, and 91.7%, respectively.

Biobased Poly(ethylene succinate)-b-poly(triethylene terephthalate) multiblock copolyesters with high melting temperature and improved crystallization rate and mechanical property

Biobased poly(ethylene succinate)- b -poly(triethylene terephthalate) (PES -b- PTEGT) multiblock copolyesters with low weight ratios of PTEGT segment were successfully synthesized from dihydroxyl terminated PES and dihydroxyl terminated PTEGT prepolymers in this work through a chain extension reaction. The thermal, crystallization, and mechanical properties of PES -b- PTEGT were systematically investigated and compared with those of PES also prepared via the chain extension method. Two glass transition temperature ( T g ) values were detected for PES -b- PTEGT, corresponding to the T g of PES segment and that of PTEGT segment, respectively. PES -b- PTEGT showed a high melting temperature of around 100 °C and a thermal decomposition temperature of above 320 °C. The crystallizability of PES segment in PES -b- PTEGT was obviously enhanced under different crystallization conditions, which was attributed to the interface-assisted crystallization. In addition, the mechanical property (including both the elongation at break and the tensile strength) of PES -b- PTEGT was also remarkably improved. The synthesis of PES -b- PTEGT with a high melting temperature, faster crystallization rate, and improved mechanical property provided a new modification method to improve the physical property and extend the practical application of biodegradable polyesters. • Biobased PES -b- PTEGT copolyesters were synthesized via a chain extension reaction. • PES -b- PTEGT showed a high T m of around 100 °C and a T d of above 320 °C. • The crystallizability of PES segment in PES -b- PTEGT was obviously enhanced. • The mechanical property of PES -b- PTEGT was also remarkably improved. • This research proposed a novel method to modify the physical properties of PES.

Influential Parameters and Multi Objective Optimization of Bagasse and Palm Kernel Natural Fibre Plates Using Taguchi Assisted Topsis

Composites that have a good to lower weight ratio can be used to replace conventionally used Engineering Materials. The properties of natural fibers are almost equal to that of artificial fibres. Natural fibers can be used in many applications and is also a cost-effective material. Bagasse fibre reinforced with dry palm kernel fibre powder is used to improve mechanical properties and fabricated in plate form. In this research work, the input constraints that have been used to fabricate the plate are 10, 20, 30 wt% of bagasse fibre, 10, 20, 30 wt% of palm kernel fibre, at 10, 15, 20 MPa compression pressure and 2, 4, 6 mm of speciemn thickness respectively. The optimization has been performed by Taguchi L27 orthogonal array and influence of output parameters viz. Tensile Strength (MPa), Flexural Strength (MPa) and Hardness (Hv) have been measured by using statistical analysis of variance. The multi-criteria decision making of the output parameters has been performed by Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). This research offers new insight into decision-making, particularly in the optimization part, to increase the strength and mechanical property of natural fiber composites.

STUDY THE EFFECT OF ADDING GLENIUM 51 AND POLYMERIC PLASTICS ON THE MECHANICAL AND PHYSICAL PROPERTIES OF ORDINARY PORTLAND CEMENT

Cement is importance as one of the strategic construction of any civilization depends, and its paramount significance in the construction of building, roads, bridges and infrastructure, which requires the use of cement with special specification and thus the use of polymers as additives to increase the compressive, flexural and tensile strength of the cement used in construction. Cement producing can possibility with high specification and for multiple uses, some studies be carried out on the use of some available additives in small quantities so as to give the cement high desirable specification in terms of color, compressive strength, tensile and permeability compared to ordinary cement. This research aims to know the extent to which some of the physical and mechanical properties of cement mortar, such as compressive strength, flexural and tensile strength, are improved upon weight substitution of specific polymeric materials with high efficiency, such as, silica fume .styrene-butadiene, styrene- acrylic in low weight ratio so that it does not add a high economic cost to the production of therequired concrete .for specific uses and sheds light on the effect of different temperatures on the properties where studied in this study . The study showed that the addition of polymeric materials (Glenium 51, silica fume, styrene –butadiene) with different weight ratio of cement weight at 20°C led to obtaining the highest compressive strength, flexural and tensile strength at the optimum level to the development and improvement of properties. Mechanical and physical cement mortar compared to the reference cement free of additives .As for the use of styrene –acrylic, it had a negative effect and led to a decrease in the compressive and tensile strength .especially in the later ages compared to the reference cement. The optimum ratio of Glenium51 was added to the optimum ratio of each material separately and the mixture was added to the cement mortar at different temperatures( 7, 20, 55 )°C .The effect of additives on the properties of the cement mortar was studied. Also, a mixture (Glenium51, silica fume, styrene-butadiene, styrene-acrylic) was added in the optimum proportions for each material to the cement mortar at different temperatures, and this addition led to increase on compressive, flexural and tensile strength at all temperatures compared with reference cement. Silica fume, styrene-butadiene rubber and styrene acrylic were added separately to the cement mortar without Glenium51, then a mixture of silica fume, styrene-butadiene, and styrene-acrylic was added to the cement mortar .The results showed that the compressive, flexural and tensile strength of cement mortar increase while styrene acrylic decrease these properties when compared with the reference mixture.In addition, the study showed the effect of temperature to the properties of added polymers with cement mortar, All experiments were performed at different temperatures (The temperature which Iraq's climate is exposed under natural conditions.All experiments were conducted at different temperatures (7, 20, 55)°C respectively, to show the effect of degrees on cement compressive strength, which the degree7 represents in winter, 20 in spring and autumn, and 55 in summer.

Complexing the Pre-assembled Brush-like siRNA with Poly(β-amino ester) for Efficient Gene Silencing.

Small interfering RNA (siRNA) has been emerging as a highly selective and effective pharmaceutics for treating broad classes of diseases. However, the practical application of siRNA agent is often hampered by its poor crossing of the cellular membrane barrier and ineffective releasing from endosome to cytoplasm, leading to low gene silencing efficacy for clinical purposes. Thus far, cationic lipid and polymer-based vectors have been extensively explored for gene delivery. Yet condensing the rigid and highly negatively charged siRNA duplex to form a stable complex vehicle usually requires a large load of cationic carriers, prone to raising the toxicity issue for delivery. Herein, we develop a simple strategy that can efficiently condense the siRNAs into nanoparticle vehicles for target gene regulation. In this approach, we first employ a DNA-grafted polycaprolactone (DNA-g-PCL) brush as template to organize the small rigid siRNAs into a large brush-like structure (siRNA-brush) through nucleic acid hybridization. Then, the siRNA-brush assembly is condensed by an ionizable and biodegradable polymer (poly(β-amino ester), PBAE) under acidic buffer condition to form a stable nanoparticle for siRNA delivery. Compared to the free siRNAs with poor complexing capability with PBAE, the large brush-like siRNA assemblies with more complicated topological architecture significantly promotes their electrostatic interaction with PBAE, enabling the formation of complexed nanoparticles at low weight ratio of polymer to siRNA. Additionally, PBAE/siRNA-brush complexes exhibit good biocompatibility and stability under physiological condition, as well as enhanced cellular internalization. When equipped with functional siRNAs, the obtained delivery system demonstrates excellent downregulation of target genes both in vitro and in vivo, through which the progression of hypertrophic scars can be retarded with negligible adverse effects in an xenografted mouse model.

In situ synthesis of PEDOT:PSS-Ag nanoparticle composites without acid catalysts

This paper reports in-situ synthesis of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate silver nanoparticle (PEDOT:PSS-AgNP) composites without an acid catalyst via a spontaneous redox reaction between silver nitrate (AgNO3) and 3,4-ethylenedioxythiophene (EDOT). To investigate the effect of solvent on the formation of PEDOT:PSS and AgNP, nitric acid, distilled water, and acetonitrile were prepared as solvent. PEDOT:PSS-AgNPs were produced successfully, regardless of solvent; however, high-quality PEDOT:PSS-AgNPs were formed in an organic solvent; acetonitrile. The effects of polymer additives, polystyrene sulfonate ions, and polyvinylpyrrolidone (PVP) on the synthesis of PEDOT:PSS-AgNP nanocomposites were also investigated. Chemical and morphological analyses revealed that low weight ratio of PVP promoted AgNP nucleation, resulting in a size reduction and enhanced distribution of AgNPs. In addition, PVP reduced the binding energy, thus enhancing S-Ag bonding and PEDOT:PSS at the surface of AgNPs. Our results demonstrate that PEDOT:PSS-AgNP nanocomposites can be fabricated without an acid catalyst. A mechanism for the synthesis process is also proposed.

Survey on compression property of sandwich 3D printed PLA components

Additive Manufacturing (AM) is a trending technology to manufacture functional parts from 3D design to real-time products. Lightweight structure with expected mechanical property is a difficult task in conventional manufacturing. In aircraft, interior design parts should have high-strength parts with a low weight ratio. The high strength to low weight ratio can be developed using different materials, but the influenced factor is cost. Making a sandwich component is one of the best methods to fabricate the parts with high strength to low weight ratio. Sandwich structure is one type of design that can be fabricated using additive manufacturing with different materials. Sandwich structures comprise three components: a lightweight core and two face sheets at the top and bottom. Many materials can be used in this technique to produce sandwich parts, but this article focused on existing PLA and its composites. PLA is widely renowned for its characteristics and environmental awareness. This review is focused on the compression property investigation of the 3D printed Sandwich Structure and methods to improve the mechanical property of 3D printed parts.

Lithiated Tin di-sulfide micro-flowers with expanded interlayer spaces coupled with bakelite-carbon for an enhanced performance supercapacitor

Lithiated SnS2 (LiSnS2) is a highly promising supercapacitor electrode owing to the wide interlayer spaces in its crystal structure and the large effective surface area, afforded by its nanostructure. Here, LiSnS2 micro-flowers with a nominal conductivity of ∼0.4 μS cm−1 are directly prepared for the first time, by solid-sate diffusion, with a 2D layered rhombohedral pre-lithiated structure, affording facile intercalation of electrolyte cations in an asymmetric supercapacitor, with Bakelite sourced porous carbon (BSPC) as the anode. Significant enhancement in the storage performance by mixing LiSnS2 with BSPC in 3:1 (High) and 1.66:1 (Low) weight ratios, with the High LiSnS2 cell encompassing an aqueous electrolyte delivering a specific capacitance (SC) of 249 F g−1 at current density of 1 A g−1, Emax and Pmax of 34 Wh kg−1 and 3.5 kW kg−1, and enduring 10,000 cycles, with 88% SC retention, over a potential window of 1.4 V. Both diffusive and capacitive contributions account for this performance with the ability of short diffusion path lengths of the sulfide, and the large electrical conductivity of BSPC imparting a fast kinetic response to the cell. A non-aqueous High LiSnS2 supercapacitor, could be charged to a high voltage of 2.7 V, with a SC of 32 F g−1, thus ratifying the suitability of this cell for practical applications. This work opens up the possibility of developing a variety of previously difficult to synthesize pre-lithiated metal chalcogenides or oxides, for such materials are more conducive for undergoing reversible ion-intercalation/de-intercalation contrasting with their non-lithiated analogues and have the potential to give a tremendous boost to their energy storage performances.

Exploring phosphonium and ammonium chitosan polymers and their PEGylated analogs for high performance gene delivery

• New chitosan derivatives containing triethylammonium chloride or triethylphosphonium chloride and their PEGylated analogs have been synthesized and characterized. • The derivatives efficiently bind pDNA at low weight ratio of derivative:pDNA of 2.8:1. • Apoptosis measurements by flow cytometry indicated that the derivatives containing triethylammonium chloride or triethylphosphonium chloride and PEG induce no perceptible and mild apoptosis with their concentration at 100 µg/mL. • The present study provides evidence that these PEGylated derivatives are safe and effective vectors for efficient nucleic acid delivery. Among cationic polymers, chitosan (CS) is a promising non-viral vector due to its biocompatibility, biodegradability and safety profile. However, its application for gene delivery is hindered by its poor solubility at physiological pH. In this study, novel water-soluble chitosan derivatives containing triethylphosphonium chloride ((N-(1-carboxybutyl-4-triethylphosphonium chloride) chitosan = TEPB-CS)) or triethylammonium chloride ((N-(1-carboxybutyl-4-triethylammonium chloride) chitosan = TEAB-CS)) with 4-carbon spacers separating the cationic units from the chitosan backbone were synthesized by carbodiimide mediated coupling reactions. Two different degrees of substitution of quaternary phosphonium (43% and 21%) and ammonium (40.6% and 26%) were synthesized. The polymers with higher degrees of substitutions displayed higher solubility in aqueous media and were further grafted with mPEG (TEAB-CS-g-mPEG and TEPB-CS-g-mPEG) and used for DNA complexation, cytotoxicity, apoptosis, and gene transfection studies. Chemical characterization of the above polymers was performed by FTIR, 1 H NMR, and 31 P NMR, and the degree of substitution of the grafted phosphonium and ammonium and mPEG was calculated by 1 H NMR. The polymers efficiently bound pDNA at weight ratio of polymer:pDNA of 2.8:1. From dynamic light scattering experiments, the mean diameters of the calf thymus DNA complexes with the polymers, in water and phosphate buffer (pH 7.4), were in the range of 140 – 330 nm. Zeta potential of these complexes in water became positive as the weight ratios of the polymers/DNA exceeded 2:1. Most of these polymers mildly affect the viability of HeLa cells with a final concentration of 10 µg/mL or higher. Cell viability was only modestly compromised in the presence of 100 µg/mL of TEPB-CS-g-mPEG, and this derivative was also found to display the highest transfection efficiencies among all four polymers. Apoptosis measurements by flow cytometry indicated that both TEAB-CS-g-mPEG and TEPB-CS-g-mPEG induce no perceptible and mild apoptosis with their concentration at 100 µg/mL, respectively. Together, the present study provides evidence that these PEGylated TEPB-CS and TEAB-CS are safe and effective vectors for efficient nucleic acid delivery.

Pediatric urgent heart transplantation with age or weight mismatched donors: Reducing waiting time by enlarging donor criteria.

Despite considerable progress in heart transplantation, pediatric waiting list mortality is still high, and often patients do not have enough time to wait. We hypothesized that extending the donor criteria regarding age and weight mismatch does not significantly affect the early follow-up. We retrospectively analyzed our pediatric heart transplantation patients operated on from 2014 to 2020 for high (>3.0) or low (<0.6) donor-recipient weight ratio (DRWR) or chronological age mismatches (donor organ >5 years older than recipient age). This patient cohort constituted "mismatched heart transplantations" (mHTX). We compared mHTX preoperative status, postoperative course, 1-year survival, and early clinical follow-up to standard pediatric heart transplantations (sHTX). We performed 20 pediatric heart transplantations-10 mHTX and 10 sHTX. The minimum DRWR was 0.44, the maximum was 5.60, and the maximum age mismatch was 42.6 years. Median days in the intensive care unit (p = .436) and time-to-first-rejection episode (p = .925) were comparable. Nine patients in each group were alive after 1 year, two patients were operated within 1 year of follow-up. One mHTX patient developed cardiac allograft vasculopathy after 15 months and died 648 days after transplantation (p = .237). All other patients were alive at the end of follow-up and in good clinical conditions (median follow-up for mHTX was 732.5 days, 1149.5 days for sHTX). Postoperative course and early follow-up after mHTX were comparable to sHTX. In urgent clinical situations, extended donor criteria may be considered an additional option for pediatric heart transplantation.

The water soluble zinc based metal-organic frameworks (Zn-MOFs) as potential inhibitors for collagen fibrillogenesis

Small molecules ranging from organic to inorganic systems have been reported as stabilizing agents for collagen. Various transition metal complexes have been utilized as tanning agent. However, as per the environmental norms issued by various regulatory agencies, the presence of certain metals such as Cr, Fe, Al, Zr and Ti in leather has been restricted to minimal amount (50 ppm), an unsurmountable task. To overcome the above issue and find an alternative tanning system, here in this study, we have reported the interaction of two water-soluble zinc-based metal-organic frameworks (MOFs), i.e., ZnPV (1) and ZnPA (2), with collagen using various spectroscopic techniques. Fibrillation kinetics studies showed that a significant delay in fibril formation with Zn-MOFs treated collagen was observed compared to the collagen untreated/ treated with individual ligands and metal salt. Circular dichroism studies show that at a low weight ratio (1:0.2 and 1:1::Collagen: MOF), no perturbation in the triple helical structure was observed, while at higher weight ratio (1:4), denaturation of collagen occurs. FT-IR studies showed that no perturbation was observed in the amide backbone in MOF-treated collagen. Differential scanning calorimetric data revealed that both Zn-MOFs increased the thermal denaturation temperature by 22 ± 2 °C compared to the collagen treated with individual entities. The viscosity of collagen rises with the increase in the concentration of Zn-MOFs. To the best of our knowledge, this is the first report on the use of the metal-organic framework as a stabilizing agent for collagen structure and might help in exploring the MOFs as potential tanning agents.