Toughening of poly(\u3csub\u3eL\u3c/sub\u3e-lactic acid) with Cu\u3csub\u3e3\u3c/sub\u3eBTC\u3csub\u3e2\u3c/sub\u3e metal organic framework crystals

Poly(l-lactic acid) (PLLA) and metal organic framework (MOF) composites were prepared by melt extrusion of PLLA with 5, 10 and 20% w/w of activated Cu3(BTC)2 MOF. The morphology and stability of injection-molded samples were evaluated using thermogravimetric analysis, differential scanning calorimetry (DSC), gel permeation chromatography, X-ray diffraction, and scanning electron microscopy (SEM). The composites showed improved toughness during the tensile tests as compared to the neat PLLA matrix. Toughness mechanism of the composites was studied using SEM and rheological studies. SEM images indicated that cavitation induced by debonding at the interface of PLLA and MOF particles during the uniaxial stress was primarily responsible for the improved toughness of the composites. The SEM images of the composites, the solid like plateau observed in the PLLA composites during the parallel plate rheology at low frequency, and the decrease in the cold crystallization enthalpy during the developed composites indicate potential for various applications, which include gas separation, energy and active packaging

Deterioration of metal–organic framework crystal structure during fabrication of poly(L-lactic acid) mixed-matrix membranes

Poly(l-lactic acid) (PLLA) and metal–organic framework (MOF) mixed-matrix membranes were prepared by melt extrusion of PLLA with 5% (w/w) of either activated or water-saturated Cu3(BTC)2 (Cu3(C9H3O6)2(H2O)3·xH2O, HKUST-1). The morphology and the stability of injection-molded samples were evaluated using thermogravimetric analysis, differential scanning calorimetry, gel permeation chromatography, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The presence of activated and saturated MOF crystals increased the cold crystallization onset temperature as compared to neat PLLA. This can be attributed to the MOF crystals incorporated in the PLLA matrix, which decreased the mobility of PLLA and thus impeded the crystallization process. According to the XRD results, the activated MOF crystals were successfully incorporated into the PLLA matrix without altering the crystal structure of the MOF. Moreover, the findings from permeability and tensile tests as well as SEM imaging indicated good interfacial interactions between PLLA and activated MOF. However, during melt extrusion of PLLA with saturated MOF, water molecules from the saturated MOF altered the MOF crystal structure and contributed to the degradation of the PLLA polymer by reducing its molecular weight by around 21%. © 2013 Society of Chemical Industr

Maleic anhydride compatibilized peach waste as filler in polypropylene and high density polyethylene biocomposites

It is estimated that roughly 103, 515 tons of peach waste is produced annually in the US. The majority of the waste is disposed of in landfills, which contributes to climate change as they release 93 million metric tons of CO2 equivalent. Peach waste principally consists of remaining stone and seed after flesh removal. The agro-waste includes both cellulose and lignin, which can be utilized as a filler in plastic packaging to reduce carbon footprints and material cost. The objectives of this research are (1) to develop peach flour (PF)-filled biocomposites with a polyolefin matrix using maleic anhydride-g-high density polyethylene (MAH-g-HDPE) coupling agent resin and (2) to investigate the composites’ physicomechanical, thermal, and water absorbance changes. First, preliminary experiments examined a range of PF concentrations (5-50%) and MAH concentrations (0-17%) were tested to narrow the variability of PF and MAH loading mixture in an HDPE matrix. Preliminary experiments suggested that a 2:1 ratio of PF:CR provides maximum tensile properties. Response surface methodology (RSM) was utilized to analyze and optimize the tensile strength of the PW composite. The RSM parameters were MAH loading (5-20%), PF loading (2.5-10%), and polyolefin matrix (HDPE or polypropylene). The properties of PF-HDPE biocomposites were analyzed using several instrumental analyses. Mechanical strength (including tensile strength, elongation, and Young’s modulus) and thermal properties (thermal degradation, melting point, and crystallinity), and water resistance with the addition of PF and MAH were investigated. Biocomposite mechanical properties generally resulted in a nonsignificant decrease compared to the controls. Water absorption significantly increased with PF loading (P\u3c0.01, =0.05). PF-PP biocomposites demonstrated a shift in thermal stability with an average 9.6% increase in Td compared to its control, whereas PF-HDPE biocomposites displayed no change in Td compared to its control. PF-PP and PF-HDPE biocomposites experienced a 36.7% and 16.0% decrease, respectively, in crystallinity with PF addition. The results provided evidence that peach byproduct can be diverted from landfills and utilized a filler in a polyolefin matrix. Polyolefin biocomposites with 2.5% PF would possess comparable tensile strength to a commercially available control. PF-polyolefin biocomposites can be used for packaging, automotive, and non-weightbearing construction parts

Categorization of Marketed Artificial Tear Formulations Based on Their Ingredients: A Rational Approach for Their Use

Dry eye disease is a common ocular condition affecting millions of people worldwide. Artificial tears are the first line therapy for the management of dry eye disease. Artificial tear formulations contain a variety of active ingredients, biologically active excipients, and preservatives. Many of these formulations are also available as preservative-free. This study was conducted to inspect artificial tear formulations currently marketed in the United States for their active ingredients, biologically relevant excipients, and preservatives. The marketed artificial tears were examined at various US retail pharmacy chains and using the manufacturers’ website to compile information about active ingredients, inactive ingredients, and preservatives. The currently marketed artificial tears can be grouped into four categories based on their active ingredients. The artificial tears also contain biologically active chemicals listed as inactive ingredients, which have osmoprotectant, humectant, and tear film lipid layer or mucous layer mimicking properties. Most artificial tears contain vanishing type preservatives such as purite or sodium perborate and safer quaternary compound polyquaternium-1. The majority of these artificial tear formulations are also available as preservative-free single dose unit. The study provides a formulary of artificial tears based on active ingredients, biologically active excipients, and the preservative-free option. The formulary should assist healthcare providers in making a stepwise and rational selection of appropriate artificial tears for patients suffering from dry eye disease

Synthesis of nanoporous carbohydrate metal-organic framework and encapsulation of acetaldehyde

Gamma cyclodextrin (γ-CD) metal organic frameworks (CDMOFs) were synthesized by coordinating γ-CDs with potassium hydroxide (KOH), referred hereafter as CDMOF-a, and potassium benzoate (C7H5KO2), denoted as CDMOF-b. The obtained CDMOF structures were characterized using nitrogen sorption isotherm, thermo-gravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). High surface areas were achieved by the γ-CD based MOF structures where the Langmuir specific surface areas (SSA) of CDMOF-a and CDMOF-b were determined as 1376 m2 g−1 and 607 m2 g−1; respectively. The dehydrated CDMOF structures demonstrated good thermal stability up to 250 °C as observed by the TGA studies. XRD results for CDMOF-a and CDMOF-b reveal a body centered-cubic (BCC) and trigonal crystal system; respectively. Due to its accessible porous structure and high surface area, acetaldehyde was successfully encapsulated in CDMOF-b. During the release kinetic studies, we observed peak release of 53 μg of acetaldehyde per g of CDMOF-b, which was 100 times greater than previously reported encapsulation in β-CD. However, aldol condensation reaction occurred during encapsulation of acetaldehyde into CDMOF-a. This research work demonstrates the potential to encapsulate volatile organic compounds in CDMOF-b, and their associated release for applications including food, pharmaceuticals and packaging

CYP2C9 Polymorphism and Use of Oral Nonsteroidal Anti-Inflammatory Drugs

Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used for management of inflammation and pain, but they can cause gastrointestinal, cardiovascular, and renal adverse effects. Genetic variations in CYP450 enzymes affect their metabolic activity, thus impacting the hepatic clearance, elimination half-life, and risk of adverse effects of drugs metabolized by that CYP. Celecoxib, ibuprofen, flurbiprofen, meloxicam, and piroxicam are significantly metabolized by CYP2C9. The Clinical Pharmacogenetic Implementation Consortium has published evidence-based recommendations on CYP2C9 polymorphism–based safe usage of NSAIDs. As pharmacogenetics becomes more common, pharmacists will play a critical role in optimizing drug regimens based on pharmacogenetic test results

Optimal Polyethyleneimine Molecular Weight and Arrangement for Modification of γ-Cyclodextrin Metal Organic Frameworks (γ-CD-MOFs) for Post-Combustion CO2 Capture

Modified γ-cyclodextrin metal organic frameworks (γ-CD-MOFs) are a promising eco-friendly sorbents for post-combustion CO2 capture. Polyethyleneimine (PEI) has been widely used for modifying MOFs to enhance their CO2 sorption capacity and selectivity through the introduction of CO2 selective amine groups. The main objective of this study was to determine the optimal PEI molecular weight and arrangement (linear or branched) to enhance γ-CD-MOF’s CO2 sorption capacity. γ-CD-MOFs were impregnated with linear as well as branched PEI with molecular weights of 600, 1200 or 10,000. The CO2 sorption capacity of the PEI-impregnated γ-CD-MOFs was determined using a quartz crystal microbalance assembly at CO2 partial pressures from 0.35–1.0 atm. Impregnation with 600 g/mole branched PEI achieved the highest CO2 sorption capacity of 0.9 mmole/g CO2 at 1 atm, followed by the linear PEI (0.12 mmol/g). Modification with the other branched PEI molecular weights did not achieve detectable CO2 sorption, likely because of pore blockage with the relatively larger PEI molecular weights, as demonstrated by molecular docking simulations. Furthermore, the control γ-CD-MOFs did not sorb CO2, likely because of the lower attraction forces between CO2 and the large pore volume of the unmodified MOFs

Optimal Polyethyleneimine Molecular Weight and Arrangement for Modification of γ-Cyclodextrin Metal Organic Frameworks (γ-CD-MOFs) for Post-Combustion CO₂ Capture

Modified γ-cyclodextrin metal organic frameworks (γ-CD-MOFs) are a promising eco-friendly sorbents for post-combustion CO2 capture. Polyethyleneimine (PEI) has been widely used for modifying MOFs to enhance their CO2 sorption capacity and selectivity through the introduction of CO2 selective amine groups. The main objective of this study was to determine the optimal PEI molecular weight and arrangement (linear or branched) to enhance γ-CD-MOF’s CO2 sorption capacity. γ-CD-MOFs were impregnated with linear as well as branched PEI with molecular weights of 600, 1200 or 10,000. The CO2 sorption capacity of the PEI-impregnated γ-CD-MOFs was determined using a quartz crystal microbalance assembly at CO2 partial pressures from 0.35–1.0 atm. Impregnation with 600 g/mole branched PEI achieved the highest CO2 sorption capacity of 0.9 mmole/g CO2 at 1 atm, followed by the linear PEI (0.12 mmol/g). Modification with the other branched PEI molecular weights did not achieve detectable CO2 sorption, likely because of pore blockage with the relatively larger PEI molecular weights, as demonstrated by molecular docking simulations. Furthermore, the control γ-CD-MOFs did not sorb CO2, likely because of the lower attraction forces between CO2 and the large pore volume of the unmodified MOFs

Robotic assisted laparoscopic adrenalectomy: Initial experience from a tertiary care centre in India

Introduction: Laparoscopic adrenalectomy (LA) is now considered the standard for treatment of surgically correctable adrenal disorders. Robotic adrenalectomy has been performed worldwide and has established itself as safe, feasible and effective approach. We hereby present the first study in robotic transperitoneal LA from Indian subcontinent. Materials and Methods: We conducted a retrospective evaluation of 25 patients who had undergone robotic assisted LA at a tertiary health centre by a single surgeon. Demographic, clinical, histopathological and perioperative outcome data were collected and analysed. Results: Mean age of the patients was 45 years (range: 27-65 years). Eleven male and 14 female patients were operated. Mean operative time was 139 min ± 30 min (range: 110-232 min) and mean blood loss was 85 ml ± 12 ml (range: 34-313 ml). Mean hospital stay was 2.5 ± 1.05 days (range: 2-6 days). Mean visual analogue scale score was 3.2 (range: 1-6) mean analgesic requirement was 50 mg diclofenac daily (range: 0-150 mg). Histopathological evaluation revealed 11 adenomas, eight phaeochromocytomas, two adrenocortical carcinomas, and four myelolipomas. According to Clavien-Dindo classification, three patients developed Grade I post-operative complications namely hypotension and pleural effusion. Conclusion: Robotic adrenalectomy is safe, technically feasible and comfortable to the surgeon. It is easier to perform with a short learning curve

Defining the Pros and Cons of Open, Conventional Laparoscopy, and Robot-Assisted Pyeloplasty in a Developing Nation

Introduction. Congenital pelviureteric junction obstruction (PUJO) is one of the most common causes of hydronephrosis. Historically, open dismembered pyeloplasty has been considered the gold standard intervention for correcting PUJO. The aim of this study was to compare the surgical and functional outcomes of three different approaches, namely, open, conventional laparoscopy, and robotic pyeloplasty. Material and Methods. 60 patients underwent minimally invasive pyeloplasty (30 conventional laparoscopies and 30 robotics) for congenital PUJO at a tertiary health center in India. Demographic, perioperative, and postoperative data were prospectively collected and analyzed. The data of these patients were retrospectively compared with another cohort of 30 patients who had undergone open pyeloplasty. Results. There was significant difference in operative time, time to drain removal, hospital stay, pain score, and complications rate between open and minimally invasive pyeloplasty (P<0.05). SFI was considerably lesser in robotic as compared to conventional laparoscopy. The success rate in OP, CLP, and RP was 93.33, 96.67, and 96.67%. Conclusion. Robotic pyeloplasty is safe, effective, and feasible. It is associated with significantly lesser operative time, lesser blood loss, less pain, shorter hospital stay, and fewer complications. It is also associated with considerably lesser surgeon fatigue as compared to conventional laparoscopy pyeloplasty