Isopropanol Research Articles

Metabolite identification and disinfection by-product formation in AAO-MBR system with waste liquid isopropyl alcohol as a carbon source

Carbon sources as a substrate can provide organic matter for denitrification and nitrification, facilitating the removal of pollutants. However, low-cost and efficient alternative carbon sources are an urgent problem to be solved for wastewater treatment processes globally. Isopropyl alcohol (IPA), as a waste liquid produced during the cleaning process in the electronics industry, can serve as the carbon source for microbial growth. Herein, the influence of conventional carbon sources (glucose-coupled sodium acetate) and IPA carbon source on denitrification performance, metabolite identification, microbial community composition, and disinfection by-product (DBP) formation was assessed by a denitrification system (AAO-MBR). Results showed that the nitrogen removal efficiency of IPA as a carbon source (69.2 %) was similar to that of conventional carbon sources (72.6 %). Notably, the results of the metabolites of the two carbon source effluents showed that CHO and CHNO compound classes were the most abundant species in terms of quantity, and lignin (59.5–60.1 %) was the main component in two carbon source effluents. Additionally, the diversity of microbial communities at the genus level was significantly different, but organic matter degraded bacteria (i.e., Defluviicoccus and Rhizobacter) and denitrifying functional bacteria (i.e., Dinghuibacter and Amaricoccus) were dominant microorganism when using IPA and conventional carbon sources. Interestingly, the effluent dissolved organic matter (DOM) exhibited a lower susceptibility to transformation into DBP with an IPA carbon source, thus ensuring the safety of reused water. The findings provide valuable insights into utilizing wasted IPA as an effective carbon source in the wastewater treatment process.

Towards a Customizable, SLA 3D-Printed Biliary Stent: Optimizing a Commercially Available Resin and Predicting Stent Behavior with Accurate In Silico Testing.

Inflammation of the bile ducts and surrounding tissues can impede bile flow from the liver into the intestines. If this occurs, a plastic or self-expanding metal (SEM) stent is placed to restore bile drainage. United States (US) Food and Drug Administration (FDA)-approved plastic biliary stents are less expensive than SEMs but have limited patency and can occlude bile flow if placed spanning a duct juncture. Recently, we investigated the effects of variations to post-processing and autoclaving on a commercially available stereolithography (SLA) resin in an effort to produce a suitable material for use in a biliary stent, an FDA Class II medical device. We tested six variations from the manufacturer's recommended post-processing and found that tripling the isopropanol (IPA) wash time to 60 min and reducing the time and temperature of the UV cure to 10 min at 40 °C, followed by a 30 min gravity autoclave cycle, yielded a polymer that was flexible and non-cytotoxic. In turn, we designed and fabricated customizable, SLA 3D-printed polymeric biliary stents that permit bile flow at a duct juncture and can be deployed via catheter. Next, we generated an in silico stent 3-point bend test to predict displacements and peak stresses in the stent designs. We confirmed our simulation accuracy with experimental data from 3-point bend tests on SLA 3D-printed stents. Unfortunately, our 3-point bend test simulation indicates that, when bent to the degree needed for placement via catheter (~30°), the peak stress the stents are predicted to experience would exceed the yield stress of the polymer. Thus, the risk of permanent deformation or damage during placement via catheter to a stent printed and post-processed as we have described would be significant. Moving forward, we will test alternative resins and post-processing parameters that have increased elasticity but would still be compatible with use in a Class II medical device.

The first total syntheses of lorneic acids C and D and improved synthetic routes to lorneic acids A and J

We report the first total syntheses of lorneic acids C and D, each in 4 steps, from commercially-available 2-bromo-5-methyl benzaldehyde in 61 % and 36 % overall yields, respectively. A key feature of the syntheses includes a Suzuki cross-coupling to introduce the carboxylic sidearms in the natural products. Additionally, our group previously reported the construction of lorneic acids A and J, in 7 steps, with 23 % overall yields that included a lengthy 3-step sequence of reactions for the 1-carbon homologation of the allylic alcohols. Herein, we report second-generation synthetic routes towards lorneic acids A and J, each in 5 steps with 50 % and 46 % overall yields. In this case, a palladium-catalyzed carboxylation of allylic alcohol intermediates with formic acid secured the carboxylic acid sidearms. The new and improved routes shorten the total syntheses by 2 steps and double the yields of both natural products.

Pd-Catalyzed Aerobic Synthesis of Allylic Sulfones from Allylic Alcohols and Sulfonyl Hydrazines in Water.

A mild and green synthesis of allylic sulfones from allylic alcohols and sulfonyl hydrazines was developed in water media. The simple and commercially available Pd(PPh3)4 is used as the best catalyst, and the reaction can proceed smoothly at 40 °C under air. This new method does not require the common nitrogen protection and organic media, and can be readily scaled up in gram scale, showing the good practicality value.

Gold Nanoclusters Whose Photoluminescent Properties are Dynamically Tunable by Modulating the Assembly Pathway Complexity.

Modulating the assembly pathway is an indispensable strategy for optimizing the performance of optical materials. However, implementing this strategy is nontrivial for metal nanocluster building blocks, due to the limited functional modification of nanoclusters and complexity of their emission mechanism. In this report, we demonstrate that a gold nanocluster modified by 4,6-diamino-2-pyrimidinethiol (DPT-AuNCs) self-assembles into two distinct aggregation structures in methanol (MeOH)/water mixed solvent, thus exhibiting pathway complexity. Kinetic studies show that DPT-AuNCs firstly assembles into non-luminescent nanofibers (kinetically controlled), which further transforms into strongly luminescent microflowers (thermodynamically controlled). In-depth analysis of the assembly mechanism reveals that the transformation of aggregation structures involves the disassembly of nanofibers and a subsequent nucleation-growth process. Temperature-dependent photoluminescence (PL) spectroscopy and infrared (IR) measurements reveal that inter-cluster hydrogen bonding bridged by solvent molecules and C-H⋅⋅⋅π interaction are the key factors for emission enhancement. The photoluminescent property of DPT-AuNCs can be controlled by varying the cosolvent in water, enabling DPT-AuNCs to distinguish different kind of alcohols, particularly the isomerism n-propanol (NPA) and isopropanol (IPA). Additionally, the addition of seeds effectively regulate the assembly kinetics of DPT-AuNCs. This study advances our understanding of assembly pathways and improves the luminescent performance of nanoclusters (NCs).

The catalytic performance of γ-Al2O3/red clay as a highly active, selective, and stable catalyst for methanol dehydration to dimethyl ether at competitive low reaction temperature

This study aims to a more environment eco-friendly approach for producing dimethyl ether (DME), as an alternative fuel, through the dehydration of methanol. The method involves utilizing Egyptian natural red clay (ERC) that has been modified with various percentages of γ-Al2O3 (ranging from 3 to 30 wt%) as catalysts. The most active catalyst (10 % γ-Al2O3/ERC) was then modified with varying HCl percentages (3–7 wt%). The synthesized catalysts properties were examined by various techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), N2-sorption analysis, and transmission electron microscopy (TEM). The surface acidity of the catalysts was assessed using two methods: dehydration of isopropyl alcohol and chemisorption of pyridine and 2,6-dimethyl pyridine. The results of the catalytic activity study reflected that the treatment of ERC by HCl and γ-Al2O3 improved its activity toward DME production. Specifically, the 5 % HCl/10 % γ-Al2O3/ERC catalyst displayed outstanding activity, achieving conversion value of 90 % with 100 % selectivity to DME at 200 °C. Furthermore, this catalyst demonstrated long-term stability, as it maintained its performance over one week without deactivation. Acidity, and the textural characteristics were identified as the key factors contributing to the remarkable improvement in catalytic activity.

Controlled Release Lercanidipine Tablets: A Study on Formulation and Evaluation by Wet Granulation

Lercanidipine blocks the entry of extracellular calcium into vascular and cardiac muscle cells, preventing myocardial smooth muscle contraction due to decreased intracellular calcium. This results in the dilation of coronary and systemic arteries, reducing blood pressure. This study aimed to develop and evaluate lercanidipine controlled-release tablets for oral administration using polymers like HPMC K 100M, sodium alginate, and guar gum. Lercanidipine, polymers, and diluents were sieved and mixed for 10 minutes. Granules were formed using isopropyl alcohol, dried at 60°C for one hour, and sieved. The granules were lubricated with colloidal silicon dioxide (Aerosil-200) and magnesium stearate, blended for 5 minutes, and compressed using a rotary machine (average weight: 500 mg; hardness: 5-6 kg/cm²). Bulk and tapped densities were nearly identical for all formulations. Compressibility index and Hausner ratio ranged from ?18 to 1.09-1.21, indicating good flow properties. Tablet thickness ranged from 5.82 to 5.91 mm, hardness from 5.9 to 6.3 kg/cm², and friability was less than 1.0 %W/W. Drug content was between 98-102%. The controlled-release order from dissolution data was F9 > F7 > F8, showing optimal release with a combination of HPMC and two natural polymers.

Environmental Influences on the Drying Rate of Spray-Applied Disinfestants from Horticultural Production Surfaces

Drying rates of disinfestants commonly applied to horticultural plant production surfaces were evaluated under cool to hot weather and under laboratory conditions to characterize the range of drying times and how this relates to contact times specified on product labels. Drying rates of six disinfestants (isopropyl alcohol [IPA], two quaternary ammonium compounds [QACs], two peroxygen compounds [PXs], and sodium hypochlorite [bleach]) and water were evaluated when applied to six substrate materials (concrete, galvanized metal, polypropylene ground fabric, polyethylene plastic sheet, pressure-treated pine, and twin-wall clear polycarbonate) based on the weather variables of solar radiation, temperature, and relative humidity. Differences were evident at the point of application. Disinfestants with low (IPA, both QACs, and one PX) and high (bleach, one PX, and water) surface tension provided approximately 100 and 60% coverage, respectively, when applied to horizontal, nonporous solid materials. Disinfestants applied to horizontal porous materials (concrete, fabric, and wood) persisted on the surface for a mean of only 9 to 113 s because solutions were actively drawn into the substrates’ internal structure. Disinfestants applied to vertical twin-wall greenhouse material flowed off, while retaining only a maximum beaded wetness coverage of 14%. A Bayesian analysis procedure was used to model drying effects of disinfestants correlated with substrate and weather variables based on posterior marginal and prediction trends. Generally, the fastest drying rate occurred in the first 2.5 min, and approximately 50% of coverage was retained by 5 min. The evaporative process was variable with distinct interactions occurring among the experimental variables. [Formula: see text] The author(s) have dedicated the work to the public domain under the Creative Commons CC0 “No Rights Reserved” license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2024.

Nickel‐Catalyzed Enantioselective α‐Allylation of Cyclic Ketones with Allylic Alcohols

Nickel‐Catalyzed Enantioselective α‐Allylation of Cyclic Ketones with Allylic Alcohols

MgO Modified by X2, HX, or Alkyl Halide (X = Cl, Br, or I) Catalytic Systems and Their Activity in Chemoselective Transfer Hydrogenation of Acrolein into Allyl Alcohol.

A new type of catalyst containing magnesium oxide modified with various modifiers ranging from bromine and iodine, to interhalogen compounds, hydrohalogenic acids, and alkyl halides have been prepared using chemical vapor deposition (CVD) and wet impregnation methods. The obtained systems were characterized using a number of methods: determination of the concentration of X- ions, surface area determination, powder X-ray diffraction (PXRD), surface acid-base strength measurements, TPD of probe molecules (acetonitrile, pivalonitrile, triethylamine, and n-butylamine), TPD-MS of reaction products of methyl iodide with MgO, and Fourier transform infrared spectroscopy (FTIR). The catalysts' activity and chemoselectivity during transfer hydrogenation from ethanol to acrolein to allyl alcohol was measured. A significant increase in the activity of modified MgO (up to 80% conversion) in the transfer hydrogenation of acrolein was found, while maintaining high chemoselectivity (>90%) to allyl alcohol. As a general conclusion, it was shown that the modification of MgO results in the suppression of strong basic sites of the oxide, with a simultaneous appearance of Brønsted acidic sites on its surface. Independently, extensive research on the reaction progress of thirty alkyl halides with MgO was also performed in order to determine its ability to neutralize chlorinated wastes.

Effect of Different Surface Treatments as Methods of Improving the Mechanical Properties after Repairs of PMMA for Dentures.

Denture fractures are a common problem in dental practice, and their repair is considered a first option to restore their functional properties. However, the inter-material resistance may become compromised. Typically, the bond between these materials weakens. Therefore, various surface treatment methods may be considered to enhance their mechanical properties. Poly(methyl methacrylate) (PMMA) heat-polymerized resin (HPR) was used as the repaired material, cold-polymerized material (CPR) for the repairs, and different variants of alumina abrasive blasting (AB), methyl methacrylate (M), ethyl acetate (EA), methylene chloride (CH), and isopropyl alcohol (IA) treatments were applied. Finally, combined surface treatments were chosen and analyzed. Surface morphologies after treatments were observed by scanning electron microscopy and the flexural, shear, and impact strengths were tested. AB and chemical treatment with CH, M, and EA was used to improve all mechanical properties, and further improvement of the properties could be achieved by combining both types of treatments. Varied changes in surface morphologies were observed. Treatment with IA yielded less favorable results due to the low impact strength. The best results were achieved for the combination of AB and CH, but during the application of CH it was necessary to strictly control the exposure time.

Evaluation of the effects of temperature and centrifugation time on elimination of uncured resin from 3D-printed dental aligners

The study investigated the effects of temperature and centrifugation time on the efficacy of removing uncured resin from 3D-printed clear aligners. Using a photo-polymerizable polyurethane resin (Tera Harz TC-85, Graphy Inc., Seoul, Korea), aligners were printed and subjected to cleaning processes using isopropyl alcohol (IPA) or centrifugation (g-force 27.95g) at room temperature (RT, 23 °C) and high temperature (HT, 55 °C) for 2, 4, and 6 min. The control group received no treatment (NT). Cleaning efficiency was assessed through rheological analysis, weight measurement, transparency evaluation, SEM imaging, 3D geometry evaluation, stress relaxation, and cell viability tests. Results showed increased temperature and longer centrifugation times significantly reduced aligner viscosity, weight (P < 0.05), and transmittance. IPA-cleaned aligners exhibited significantly lower transparency and rougher surfaces in SEM images. All groups met ISO biocompatibility standards in cytotoxicity tests. The NT group had higher root mean square (RMS) values, indicating greater deviation from the original design. Stress relaxation tests revealed over 95% recovery in all groups after 60 min. The findings suggest that a 2-min HT centrifugation process effectively removes uncured resin without significantly impacting the aligners’ physical and optical properties, making it a clinically viable option.

Rhodium-Catalyzed Asymmetric N2-C5 Allylation of Indazoles with Dienyl Allylic Alcohols.

The development of site-selective and regio- and enantioselective reactions of substrates with multiple active sites is an important topic and remains a substantial challenge in synthetic chemistry. Here, we describe a rhodium-catalyzed asymmetric N2-C5 allylation of indazoles with dienyl allylic alcohols under mild conditions. In the presence of a Rh/(P/olefin) catalyst and formic acid, chiral N2-C5 allylic indazoles were formed in good yields with excellent enantioselectivities (up to 97% ee). The mechanism proceeds through an elusive intermediate Int B, which represents a challenging task on asymmetric allylic substitution (AAS) of dienyl substrates.

Stereoselective Synthesis of meso- and l,l-Diaminopimelic Acids from Enone-Derived α-Amino Acids.

The stereoselective synthesis of meso-diaminopimelic acid (meso-DAP), the key cross-linking amino acid of the peptidoglycan cell wall layer in Gram-negative bacteria, and its biological precursor, l,l-DAP, is described. The key step involved stereoselective reduction of a common enone-derived amino acid by substrate- or reagent-based control. Overman rearrangement of the resulting allylic alcohols, concurrent alkene hydrogenation and trichloroacetamide reduction, and subsequent ruthenium-catalyzed arene oxidation completed the synthesis of each stereoisomer. The synthetic utility of this approach was demonstrated with the efficient preparation of an l,l-DAP-derived dipeptide.

Reducing Blood Culture Contamination Rates: Introduction of a Combined Education and Skin Antisepsis Intervention.

Background. Blood culture contamination (BCC) is an important quality concern in clinical microbiology as it can lead to unnecessary antimicrobial therapy in patients and increased workload for laboratory scientists. The Clinical Laboratory and Standards Institute recommend BCC rates to be <3 % and recently updated guidelines have set a new goal of 1 %. The aim of this project was to design and implement interventions to reduce BCC rates at our institution. Methods. We introduced a combined education and skin antisepsis intervention in a large Model 4 academic teaching hospital in the South of Ireland. BD ChloraPrep skin antisepsis applicators (2 % chlorhexidine gluconate/70 % isopropyl alcohol), licensed for use for blood culture specimen collection, were introduced, replacing Clinell (2 % chlorhexidine gluconate/70 % isopropyl alcohol) wipes. In addition, a multimodal education programme was designed and delivered. This consisted of a video demonstrating the recommended blood culture specimen collection technique using the new applicators as well as simulation training for all interns. The video was uploaded to the intranet as an educational resource available to all staff. Results. The interventions were implemented in July 2022 and BCC rates pre- and post-intervention were calculated. The average BCC rate for the 12 months preceding the intervention (July 2021 to July 2022) was 2.56 % with highest rates in the Emergency Department. This compared to an average rate of 2.2 % in the 12 months post-intervention (July 2022 to July 2023). In comparing the two rates the reduction in BCC rates between the two periods was not statistically significant (P=0.30). Conclusion. Overall BCC rates reduced but the difference between the two periods did not reach statistical significance. The resource-intensive nature of providing regular and timely feedback of contamination rates and the larger impact of in-person education and training over virtual modalities may explain the modest reduction. Further investments in these areas, particularly in the Emergency Department, will be necessary to further reduce rates in line with new recommendations.

Solvent-assisted salt-free reactive dyeing of cotton fabric

The objective of this study was to establish a solvent-assisted salt-free dyeing method for cotton fabric utilizing commercially available reactive dyes. In this study, the feasibility of substituting water as the dyeing medium with environmentally friendly solvents, specifically ethanol (EtOH), isopropyl alcohol (IPA), and propanol (PrOH), was investigated. Eight commercial reactive dyes, each possessing distinct chemical structures, were examined with various dyeing characteristics including exhaustion, fixation, and fastness properties, in the presence of various alcohols. However, solvent-assisted dyeing exhibited comparable or enhanced color strength (K/S) values, exhaustion, and fixation rates compared to conventional aqueous dyeing. For instance, the RR35 dye demonstrated a substantial increase in K/S values with PrOH, EtOH, and IPA, ranging from 115 to 369% improvement. The substitution of alcohol for water did not affect the wash, rub, and light-color fastness properties, as these properties remained consistently excellent. Solvent-assisted salt-free dyeing of cotton fabrics offers a promising solution to address the environmental impacts of traditional water-based dyeing methods by eliminating the requirement for water and salt. Overall, this study presents a solvent-assisted salt-free dyeing technique and contributes to the field by offering detailed insights into its mechanisms and performance. Our research has the potential to reduce water consumption, eliminate salt usage, and mitigate environmental pollution.

Structural Diversification of Pyrazinone Metabolites via Spontaneous Oxa-Michael Addition in Staphylococcus xylosus.

A family of pyrazinone metabolites (1-11) were characterized from Staphylococcus xylosus ATCC 29971. Six of them were hydroxylated or methoxylated, which were proposed to be produced by the rare noncatalytic oxa-Michael addition reaction with a water or methanol molecule. It was confirmed that isopropyl alcohol can also be the Michael donor of the reaction. 1-7 and the synthetic precursor 2a showed significant inhibition of breast cancer cell migration.

Optically transparent and refractive thiol‐ene polymers containing cyclotriphosphazenes

AbstractA colorless, transparent thiol‐ene polymer network was developed that contains cyclic phosphazene units in the polymer chain. Hexakis (allyloxy) cyclotriphosphazene (HAP) was synthesized from the nucleophilic substitution reaction of phosphonitrilic chloride trimer and allyl alcohol. Thiol‐ene polymers (HAP‐SH) were successfully prepared without by‐products or the use of solvents through photopolymerization of the HAP and multithiol monomers with various functional group and flexible structures (e.g., 1,4‐butanedithiol (BDTH), 1,3,5‐benzenetrithiol (BTTH), trimethylolpropane tris (3‐mercaptopropionate) (TTMP) and pentaerythritol tetrakis (3‐mercaptopropionate) (PTTH)). The prepared HAP‐SH polymers showed sufficient thermal stability due to the high degree of cross‐linking. In addition, the HAP‐SH polymer films exhibited high optical transparency of over 90% in the visible region. The refractive indices of the HAP‐SH polymers measured at 637 nm were in the range of 1.5530–1.6344, and the Abbe number was calculated to be in the range of 34.5–47.1. These results are attributed to the structure of the cyclophosphazine and the polymer main chain containing aliphatic linkers with sulfur atoms. Another significant result was the transparency of the HAP‐SH polymer films in the mid‐infrared (MWIR) region. The thermal stability and excellent optical properties of the HAP‐SH polymers make them good candidates for application as a protective film for IR lenses, which are easily damaged by external factors.

PhI(OAc)2-Promoted 1,2-Transfer Reaction between 1,1-Disubstituted Allylic Alcohols and Thiophenols.

The PhI(OAc)2-promoted 1,2-transfer reaction between allylic alcohols and thiophenols, conducted in an argon atmosphere, has proven to be effective in producing β-carbonyl sulfides from 1,1-disubstituted allylic alcohols in high yields. This method offers a fast and efficient way to synthesize β-carbonyl sulfides, which are valuable intermediates in organic synthesis. This discussion focuses on the effects of the oxidizer, temperature, and solvent on the reaction. A proposed tentative mechanism for this reaction is also discussed.

Impact of intermittent versus continuous infusions on central line-associated bloodstream infection risk in haemato-oncology patients: a quasi-experimental study

Continuous fluid infusions delivered between therapies by piggy-back systems avoid disconnection and reconnection of central venous catheters (CVCs), thereby reducing opportunities for line contamination. However, the impact of continuous versus intermittent infusions on central line-associated bloodstream infections (CLABSIs) is unknown. To investigate the effect of temporary infusion interruption and line disconnection, with or without use of a 70% isopropyl alcohol cap (IPA-C) on CLABSI rates in haematology patients. Quasi-experimental study in two haemato-oncology units. At baseline (P1, September 2020 to August 2021), continuous intravenous piggy-back infusions were mandatory. In a first intervention phase (P2, September 2021 to August 2022), infusion disconnections were implemented with use of a 70% isopropyl alcohol cap (IPA-C) for passive decontamination. In a second intervention phase (P3, September 2022 to August 2023), infusion disconnections continued without the use of IPA-C. Rates of CLABSI were compared across the three intervention periods using segmented Poisson regression. A total of 11,039 catheter-days across 764 CVCs and 16,226 patient-days were included. Twenty-one CLABSIs were recorded across all intervention periods. Compared with P1, incidence rate ratios (IRRs) for CLABSI did not significantly change in P2 (IRR 0.76 (95% CI 0.27-2.15)) and P3 (IRR 0.79 (95% CI 0.28-2.22)). No CVCs were removed due to occlusion during the study period. Five of 21 CLABSIs were polymicrobial, and coagulase-negative staphylococci were isolated in 19/21 cases (90%). Interruption of continuous infusions in haemato-oncology patients with a CVC was not associated with a substantial change in CLABSI rates, whether or not an IPA-C was used.