Polymer Conjugation to Enhance Cellulase Activity and Preserve Thermal and Functional Stability.

A thermophilic cellulase, FnCel5a, from Fervidobacterium nodosum was conjugated with various functional polymers including cationic, anionic, and strongly and weakly hydrogen bonding polymers. The activity of FnCel5a toward a high-molecular-weight carboxymethyl cellulose substrate was enhanced by polymer conjugation. Activity enhancements of 50% or greater observed for acrylamide and mixed N,N-dimethyl acrylamide-2-(N,N-dimethylamino)ethyl methacrylate polymers, suggesting that the greatest enhancements were caused by polymers capable of noncovalent interactions with the substrate. The conjugates were found to have nearly identical thermodynamic stability to the native enzyme, as assessed by free energy (ΔG), enthalpy (ΔH), and entropy (TΔS) parameters extracted from differential scanning fluorimetry. Polymers tended to confer comparable tolerance to high concentrations of dimethylformamide, with longer polymers typically enabling higher activity relative to shorter polymers. The new FnCel5a conjugates represent an advance in the production of cellulases that maintain activity at high temperatures or in the presence of denaturing organic solvents.

Tobacco Use and Trigeminal Neuralgia: Clinical Features and Outcome After Microvascular Decompression.

BACKGROUND AND OBJECTIVES: Tobacco use is known to affect incidence and postoperative outcome for several neurosurgical disorders, but its relationship to trigeminal neuralgia (TN) is not known. We sought to identify unique population characteristics that correlate with tobacco use in a cohort of patients with TN who underwent microvascular decompression (MVD), including effect on long-term postoperative outcome. METHODS: Data about 171 patients with classic TN treated with MVD were obtained from a prospectively maintained registry. Patients were classified as smokers or nonsmokers based on the use of tobacco within the 6 months before surgery. Analysis of clinical characteristics and postoperative outcome was performed. RESULTS: Compared with nonsmokers with TN, MVD patients using tobacco were significantly younger (53 vs 62 years, P < .01) and less likely to report pain in a single distribution of the trigeminal nerve (36% vs 65%, P < .01). There was no difference between smokers and nonsmokers in the presence of some degree of continuous pain, severity of neurovascular compression, sex, race, obesity, pain duration before presentation, immediate postoperative outcome, length of stay, or postoperative complication profile. Among 128 patients followed for at least 6 months, smokers were significantly less likely to be pain-free off medications at the last follow-up (36% vs 57%, P < .05). CONCLUSION: In patients undergoing MVD for TN, smoking is associated with younger age of TN onset, more widespread facial pain, and worse long-term postoperative outcome after MVD. These features suggest that TN in smokers may represent a more severe disease form compared with TN in nonsmokers with different responses to treatment.

The effects of dacitic (rhyolitic) tuff breccia and corn distillers' dried grains with solubles (DDGS) inclusion on pellet mill electrical efficiency, production rate, and subsequent pellet quality.

Two experiments were conducted to evaluate the effect of Azomite (AZO) and 30% distillers' dried grains with solubles (DDGS) on pellet mill (PM) electrical consumption (kWh/MT), production rate, and pellet quality. Experiment 1 was conducted as a 2 × 2 × 2 factorial with main effects of diet formulation (0% or 30% DDGS), PM (1 or 2), and AZO (0% or 0.25%) with 4 replications per treatment. PMs were equipped with a 4.4 × 39.0-mm (L:D 8.9) or 4.4 × 35.8 mm (L:D 8.2) die with PM production rates held constant at 31.8 metric ton (MT)/h and conditioning temperature was held constant at approximately 82 °C. Experiment 2 was designed as a 2 × 2 factorial of treatments with 4 replicates per treatment to evaluate the impact of AZO and DDGS on PM production rates and pellet quality. PM production rate was adjusted by the feeder screw to maintain 70% motor load, a 4.0 × 35.8-mm (L:D 8.75) PM die was used, and conditioning temperature held constant at approximately 82 °C. For experiment 1, a DDGS × PM interaction (P = 0.040) was observed. Diets containing 30% DDGS had a decreased kWh/MT compared to the control when using PM-1, whereas no differences were observed for kWh/MT between 0% and 30% when using PM-2. A DDGS × PM interaction (P = 0.019) was observed for kWh/MT standard deviation (STD). Diets containing DDGS increased STD compared to the control when pelleted with PM-2; however, there was no evidence of difference between the DDGS and control diets when pelleted with PM-1. There was an AZO × DDGS interaction (P < 0.05) for kWh/ton STD. No differences were observed in kWh/ton STD when pelleting corn-soy diets with or without AZO while AZO reduced kWh/ton STD in 30% DDGS diets. Diets containing AZO had reduced (P < 0.05) kWh/MT and pellet durability index (PDI) compared to diets pelleted without AZO. PDI was improved (P < 0.05) for diets containing DDGS. For experiment 2, diets containing AZO had increased (P < 0.05) PM production rate compared to those without AZO. The inclusion of 30% DDGS reduced (P < 0.05) PM production rate compared to the corn-soy diet. There was a tendency for an AZO × DDGS interaction (P = 0.083) for PDI. Azomite inclusion to corn-soy diets reduced PDI while there was no evidence of difference in diets containing DDGS. In conclusion, the addition of 0.25% AZO to the diet improved PM efficiency; however, this potentially leads to a reduced PDI depending on diet type and PM settings.

Neighborhood Deprivation is Associated With Hospital Length of Stay, Discharge Disposition, and Readmission Rates for Patients Who Survive Hospitalization With Traumatic Brain Injury.

BACKGROUND AND OBJECTIVES: Traumatic brain injury (TBI) is a leading cause of disability in the United States. Limited research exists on the influence of area-level socioeconomic status and outcomes after TBI. This study investigated the correlation between the Area Deprivation Index (ADI) and (1) 90-day hospital readmission rates, (2) facility discharge, and (3) prolonged (≥5 days) hospital length of stay (LOS). METHODS: Single-center retrospective review of adult (18 years or older) patients who were admitted for TBI during 2018 was performed. Patients were excluded if they were admitted for management of a chronic or subacute hematoma. We extracted relevant clinical and demographic data including sex, comorbidities, age, body mass index, smoking status, TBI mechanism, and national ADI. We categorized national ADI rankings into quartiles for analysis. Univariate, multivariate, and area under the receiver operating characteristic curve (AUROC) analyses were performed to assess the relationship between ADI and 90-day readmission, hospital LOS, and discharge disposition. RESULTS: A total of 523 patients were included in final analysis. Patients from neighborhoods in the fourth ADI quartile were more likely to be Black (P = .007), have a body mass index ≥30 kg/m2 (P = .03), have a Charlson Comorbidity Index ≥5 (P = .004), and have sustained a penetrating TBI (P = .01). After controlling for confounders in multivariate analyses, being from a neighborhood in the fourth ADI quartile was independently predictive of 90-day hospital readmission (odds ratio [OR]: 1.35 [1.12-1.91], P = .011) (model AUROC: 0.82), discharge to a facility (OR: 1.46 [1.09-1.78], P = .03) (model AUROC: 0.79), and prolonged hospital LOS (OR: 1.95 [1.29-2.43], P = .015) (model AUROC: 0.85). CONCLUSION: After adjusting for confounders, including comorbidities, TBI mechanism/severity, and age, higher ADI was independently predictive of longer hospital LOS, increased risk of 90-day readmission, and nonhome discharge. These results may help establish targeted interventions to identify at-risk patients after TBI.

Approaches for Conjugating Tailor-Made Polymers to Proteins.

A series of methods are outlined for attaching functional polymers to proteins. Polymers with good control over structure, functionality, and composition can be created using reversible addition-fragmentation chain transfer (RAFT) polymerization. These polymers can be covalently linked to enzymes and proteins using either the "grafting-to" approach, where a preformed polymer is attached to the protein surface, or the "grafting-from" approach, where the polymer is grown from the protein surface. Methods for grafting-to, or attaching the RAFT chain transfer agent to the protein surface outlined include the commonly used carbodiimide/activated ester (EDC/NHS) coupling. Methods are also outlined to graft-from the surface of the protein using RAFT polymerization. Additionally, it is possible to site specifically introduce a reactive azide group to the protein surface using enzymatic ligation as a posttranslational modification. This reactive azide group can be conjugated to an alkyne-containing polymer using highly efficient click chemistry. These robust protocols can produce protein-polymer conjugates with various architectures and functionalities. Methods are also outlined for characterization of the resulting bioconjugates.

Miniature Mercury Contact Switches For Instrument Temperature Control.

In this short note, we describe the design and construction of several modifications of miniature mercury contact switches for use in laboratory temperature control applications. Commercial contact switches, or contact thermometers as they are commonly called, are limited in their application because of their large size. The units which we present here are much more compact and are thus suitable for a wider range of applications. The limitations of the miniature contact switches in their present configurations are also discussed.