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1.
Head Neck ; 2024 Jul 10.
Article in English | MEDLINE | ID: mdl-38984517

ABSTRACT

Major head and neck surgery poses a threat to perioperative airway patency. Adverse airway events are associated with significant morbidity, potentially leading to hypoxic brain injury and even death. Following a review of the literature, recommendations regarding airway management in head and neck surgery were developed with multicenter, multidisciplinary agreement among all Irish head and neck units. Immediate extubation is appropriate in many cases where there is a low risk of adverse airway events. Where a prolonged definitive airway is required, elective tracheostomy provides increased airway security postoperatively while delayed extubation may be appropriate in select cases to reduce postoperative morbidity. Local institutional protocols should be developed to care for a tracheostomy once inserted. We provide guidance on decision making surrounding airway management at time of head and neck surgery. All decisions should be agreed between the operating, anesthetic, and critical care teams.

2.
Spine Deform ; 2024 May 02.
Article in English | MEDLINE | ID: mdl-38698106

ABSTRACT

PURPOSE: New evidence highlights the significance of 3D in-brace correction for Adolescent Idiopathic Scoliosis (AIS) patients. This study explores how axial parameters relate to treatment failure in braced AIS patients. METHODS: AIS patients (Sanders 1-5) undergoing Rigo-Chêneau bracing at a single institution were included. Axial vertebral rotation (AVR) was determined by utilizing pre-brace and in-brace 3D reconstructions from EOS® radiographs. The primary outcome was treatment failure: surgery or coronal curve progression > 5°. Minimum follow-up was two years. RESULTS: 75 patients (81% female) were included. Mean age at bracing initiation was 12.8 ± 1.3 years and patients had a pre-brace major curve of 31.0° ± 6.5°. 25 patients (76% female) experienced curve progression > 5°, and 18/25 required surgical intervention. The treatment failure group had larger in-brace AVR than the success group (5.8° ± 4.1° vs. 9.9° ± 7.6°, p = 0.003), but also larger initial coronal curve measures. In-brace AVR did not appear to be associated with treatment failure after adjusting for the pre-brace major curve (Hazard Ratio (HR):0.99, 95% Confidence Interval (CI):0.94-1.05, p = 0.833). Adjusting for pre-brace major curve, patients with AVR improvement with bracing had an 85% risk reduction in treatment failure versus those without (HR:0.15, 95% CI:0.02-1.13, p = 0.066). At the final follow-up, 42/50 (84%) patients without progression had Sanders ≥ 7. CONCLUSIONS: While in-brace rotation was not an independent predictor of curve progression (due to its correlation with curve magnitude), improved AVR with bracing was a significant predictor of curve progression. This study is the first step toward investigating the interplay between 3D parameters, skeletal maturity, compliance, and brace efficacy, allowing a future prospective multicenter study. LEVEL OF EVIDENCE: Retrospective study; Level III.

3.
JAMA ; 331(20): 1763-1765, 2024 05 28.
Article in English | MEDLINE | ID: mdl-38683587

ABSTRACT

This study evaluates the characteristics of generic active pharmaceutical ingredients (APIs) used to manufacture drugs with shortages in the US and facilities producing APIs worldwide.


Subject(s)
Bulk Drugs , Drug Industry , Drugs, Generic , Bulk Drugs/economics , Bulk Drugs/supply & distribution , Drug Industry/economics , Drug Industry/statistics & numerical data , Drug Industry/trends , Drugs, Generic/economics , Drugs, Generic/supply & distribution , United States , Internationality
4.
Med Teach ; : 1-6, 2024 Apr 08.
Article in English | MEDLINE | ID: mdl-38588719

ABSTRACT

Simulation training in healthcare settings has become a valuable training tool. It provides an ideal formative assessment for interdisciplinary teaching. It provides a high fidelity and highly immersive environment where healthcare staff and students can practice developing their skills in a safe and controlled manner. Simulation training allows staff to practice skills that better prepare them for clinical emergencies, therefore possibly optimising clinical care. While the benefits of simulation education are well understood, establishing a programme for use by critical care staff is complex. Complexities include the highly specialised scenarios that are not typically encountered in non-critical care areas, as well as the need for advanced monitoring equipment, ventilation equipment etc. These 12 tips are intended to assist healthcare educators in navigating the complexities in the establishment of a critical care simulation programme, providing advice on selecting target audiences, learning outcomes, creating a critical care simulation environment and recommendations on evaluation and development of the programme.

6.
Am J Manag Care ; 30(4): 193-196, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38603534

ABSTRACT

The Inflation Reduction Act of 2022 (IRA) allows the Medicare program to negotiate drug prices beginning in 2024. Based on the guidance in the statute, CMS has selected specific data items to use to adjust initial price offers for 10 drugs in the decision-making process. Although much of the data are publicly available, some of these data items will need to be collected directly from drug companies. A 2019 US House of Representatives Committee on Oversight and Accountability investigative report collected a wide range of data from manufacturers of 12 high-revenue drugs that show what is available from the drug companies, including development costs, marketing, pricing, competition, and patent status. This article focuses on the data obtained for ibrutinib, an oral medication for treating hematologic malignancies, which is one of the only drugs reviewed by the committee that also has been selected for Medicare price negotiation. We examine data that can be obtained only from the drug manufacturer that the IRA has explicitly identified as being used to determine the price and suggest potential negotiation strategies for CMS in response.


Subject(s)
Adenine/analogs & derivatives , Drug Costs , Medicare , Piperidines , Aged , Humans , United States , Economic Competition , Drug Industry
7.
Intensive Crit Care Nurs ; 83: 103681, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38518456

ABSTRACT

BACKGROUND: The Braden scale, one of the most widely used risk assessment tools is often criticized when used in the Intensive Care Unit. Most patients in the Intensive Care Unit are at risk of pressure ulcer development meaning that the Braden score will usually indicate high risk for these patients. This study set out to determine the correlation between Sub-Epidermal Moisture measurements and Braden scores among Intensive Care Unit patients. METHODS: This study employed an observational research design. Braden score was assessed on all study days (1-5), in addition to visual skin assessment and Sub-Epidermal Moisture measurements at the sacrum and heels. Sub-Epidermal Moisture measurements were categorised as low (<0.5), borderline abnormal (≥0.5), and high (≥0.8). Correlation was assessed between Sub-Epidermal Moisture levels and Braden scores. RESULTS: A total of 53 participants were recruited. The median (interquartile range) baseline Braden score was 9 (9-10) and 81 % (n = 43) of participants were at very high/high risk of pressure ulcer development. Braden scores remained relatively constant over time with little fluctuation in scores. 19 % (n = 10) of patients had normal (<0.5) Sub-Epidermal Moisture delta measurements on enrolment, and all developed abnormal measurements by day 2. There were no significant correlations between Braden scores and Sub-Epidermal Moisture measurements. CONCLUSION: Although this was not its original intention, a missing link with the Braden scale is that it does not provide information on how patients are responding to the adverse effects of pressure and shear forces. Furthermore, in patients who are critically unwell, most patients are classified as being "at risk" of pressure ulcer development. Therefore, an objective measure of how patients are responding to pressure and shear forces at different anatomical areas is needed. IMPLICATIONS TO CLINICAL PRACTICE: Sub-Epidermal Moisture measurements can offer more information, not only on identifying those who are at risk, but also how those patients are tolerating this risk at different anatomical sites.


Subject(s)
Intensive Care Units , Pressure Ulcer , Humans , Pressure Ulcer/physiopathology , Intensive Care Units/organization & administration , Intensive Care Units/statistics & numerical data , Male , Female , Risk Assessment/methods , Risk Assessment/statistics & numerical data , Risk Assessment/standards , Middle Aged , Aged , Risk Factors , Adult
8.
Am J Respir Crit Care Med ; 209(7): 789-797, 2024 Apr 01.
Article in English | MEDLINE | ID: mdl-38324017

ABSTRACT

There is considerable interest in the potential for cell-based therapies, particularly mesenchymal stromal cells (MSCs) and their products, as a therapy for acute respiratory distress syndrome (ARDS). MSCs exert effects via diverse mechanisms including reducing excessive inflammation by modulating neutrophil, macrophage and T-cell function, decreasing pulmonary permeability and lung edema, and promoting tissue repair. Clinical studies indicate that MSCs are safe and well tolerated, with promising therapeutic benefits in specific clinical settings, leading to regulatory approvals of MSCs for specific indications in some countries.This perspective reassesses the therapeutic potential of MSC-based therapies for ARDS given insights from recent cell therapy trials in both COVID-19 and in 'classic' ARDS, and discusses studies in graft-vs.-host disease, one of the few licensed indications for MSC therapies. We identify important unknowns in the current literature, address challenges to clinical translation, and propose an approach to facilitate assessment of the therapeutic promise of MSC-based therapies for ARDS.


Subject(s)
Acute Lung Injury , COVID-19 , Mesenchymal Stem Cell Transplantation , Respiratory Distress Syndrome , Humans , Lung , Acute Lung Injury/etiology , Cell- and Tissue-Based Therapy
9.
Surgeon ; 22(2): 125-129, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38071143

ABSTRACT

BACKGROUND: Transfer of all severe TBI patients to a neurosurgical unit (NSU) has been advocated irrespective of levels of complexity and prognostic factors. Previous publications have suggested that only 50% of severe TBI patients in Ireland were managed in NSUs. AIMS: This study aims to audit severe TBI referrals to the National Neurosurgical Centre, to evaluate reasons for nonacceptance, assess for differences in the transferred and not transferred cohorts and to analyse observed and expected mortality rates. METHODS: Data on all patients with TBI referred in 2021 were prospectively collected using an electronic referral system. Patients with severe TBI (GCS ≤ 8 and AIS ≥ 3) were included and dichotomised into transferred and not transferred cohorts. RESULTS: Of 118 patients referred with severe TBI, 45 patients (38.1%) were transferred to the neurosurgical centre. Patients in the transferred cohort were significantly younger (p < 0.001), had a higher GCS score (p < 0.001) and a lower proportion of bilaterally unreactive pupils (p < 0.001) compared to the not transferred cohort. 93% (68/73) of those not transferred were either >65 years old, or had bilaterally unreactive pupils, or both. Based on the IMPACT model, the observed to expected mortality ratios in the transferred and not transferred cohorts were 0.65 (95% CI 0.25-1.05) and 0.88 (95% CI 0.65-1.11) respectively. CONCLUSION: The observed mortality rate for severe TBI in Ireland was similar to or better than expected mortality rates when adjusted for important prognostic factors. 93% of severe TBI patients not transferred to a neurosurgical centre were either elderly or had bilaterally unreactive pupils or both. These patients have an extremely poor prognosis and recommendation for transfer cannot be made based on current available evidence.


Subject(s)
Brain Injuries, Traumatic , Humans , Aged , Ireland/epidemiology , Glasgow Coma Scale , Brain Injuries, Traumatic/diagnosis , Brain Injuries, Traumatic/surgery , Prognosis , Referral and Consultation
10.
JAMA ; 331(1): 72-75, 2024 01 02.
Article in English | MEDLINE | ID: mdl-38095888

ABSTRACT

This study compares Medicare and patient spending for dual over-the-counter and prescription drugs with their over-the-counter cash prices.


Subject(s)
Medicare Part D , Nonprescription Drugs , Prescription Drugs , Aged , Humans , Drug Costs , Health Expenditures , Medicare Part D/economics , Prescription Drugs/economics , Prescriptions/economics , United States , Nonprescription Drugs/economics
11.
J Manag Care Spec Pharm ; 30(3): 269-278, 2024 Mar 01.
Article in English | MEDLINE | ID: mdl-38140901

ABSTRACT

BACKGROUND: The 2022 Inflation Reduction Act authorizes Medicare to negotiate the prices of 10 drugs in 2026 and additional drugs thereafter. Understanding the sociodemographic and spending characteristics of beneficiaries taking these specific drugs could be important describing the impact of the legislation. OBJECTIVE: To describe sociodemographic and spending characteristics of Medicare beneficiaries who use the 10 prescription drugs ("negotiated drugs") that will face Medicare drug price negotiations in 2026. METHODS: A 20% sample of Medicare Part D beneficiaries from 2020 (n = 10,224,642) was used. Sociodemographic and spending characteristics were descriptively reported for beneficiaries taking the negotiated drugs, including subgroups by low-income subsidy (LIS) status and by drug, and for Part D beneficiaries not taking negotiated drugs. RESULTS: Part D beneficiaries taking a negotiated drug compared with Part D beneficiaries not taking a negotiated drug overall had similar sociodemographic characteristics, more comorbidities (3.9 vs 2.2) and higher mean [median] Medicare ($33,882 [$18,251] vs $12,366 [$3,429]) and out-of-pocket (OOP) spending ($813 [$307] vs $441 [$160]). There was variation in characteristics by LIS status. The mean age was highest among non-LIS beneficiaries taking a negotiated drug compared with LIS beneficiaries taking a negotiated drug and beneficiaries not taking a negotiated drug (76.2 vs 69.9 vs 71.4). Among beneficiaries using negotiated drugs, a higher percentage of LIS beneficiaries compared with non-LIS was female (59.7% vs 48.0%), was Black (20.9% vs 6.6%), and resided in lower-income areas (39.1% vs 20.3%). Mean [median] annual Part D OOP spending for negotiated drugs was $115 [$59] for beneficiaries with LIS and $1,475 [$1,204] for beneficiaries without LIS. There were also differences depending on which negotiated drug was used. Drugs for cancer and blood clots had the highest proportions of White users, whereas type 2 diabetes and heart failure drugs had the highest proportions of Black users and beneficiaries residing in lower-income areas. Annual Part D OOP costs were lowest for sitagliptin (LIS: $104 [$60], non-LIS: $1,391 [$1,153]) and highest for ibrutinib (LIS: $649 [$649], non-LIS: $6,449 [$6,867]). Among non-LIS beneficiaries, 24% (22% to 76%) had more than $2,000 in OOP costs. CONCLUSIONS: Inflation Reduction Act OOP spending caps and LIS expansion will lower prescription drug costs for beneficiaries with OOP costs exceeding $2,000 who are mostly White and live in higher-income areas, insulin users who are disproportionately Black with multiple chronic conditions, and beneficiaries with low incomes. However, these provisions will not impact the 76% of non-LIS beneficiaries using negotiated drugs who have OOP costs that are still substantial but below $2,000. Negotiations could reduce OOP costs through reduced coinsurance payments for this group, which is older and has more chronic conditions compared with beneficiaries not taking negotiated drugs. Part D plan design, spending, and utilization changes should be monitored after negotiation to determine if further solutions are needed to lower OOP costs for this group.


Subject(s)
Diabetes Mellitus, Type 2 , Medicare Part D , Prescription Drugs , United States , Aged , Female , Humans , Negotiating , Prescriptions
12.
Pediatr Crit Care Med ; 24(12): e627-e634, 2023 Dec 01.
Article in English | MEDLINE | ID: mdl-38055290

ABSTRACT

OBJECTIVES: Amplitude integrated electroencephalography (aEEG) is a mainstay of care in neonatal ICUs; however, knowledge gaps exist in relation to its accuracy for identifying seizures in older children. We aimed to review the diagnostic accuracy of existing neonatal seizure detection criteria for seizure detection in older children in hospital. DESIGN: Retrospective study. SETTING: PICU/Neurophysiology Department in Dublin. PATIENTS: One hundred twenty patients (2 mo to 16 yr old) were chosen from a database of formal 10-20 system, 21-lead electroencephalography recordings (2012-2020), comprising 30 studies with seizures, 90 without. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Electroencephalography studies containing electrographic seizures (ESzs) were annotated to describe number, duration, distribution, and spread. Two-channel aEEG (using leads C3-P3, C4-P4) recordings were generated and independently reviewed by a professional specialist in clinical neurophysiology blinded to outcome and without reference to the raw electroencephalography trace. Logistic regression was used to identify factors associated with correct seizure identification on aEEG. Median patient age was 6.1 years. Abnormal recordings featured 123 seizures. Status epilepticus (SE) was evident by electroencephalography in 10 cases. Using neonatal criteria, aEEG had a sensitivity of 70% and negative predictive value of 90% for identifying any ESz. Accurate detection of individual seizures was diminished when seizures were very short or occurred during waking. Sensitivity for individual seizures was 81% when seizures less than 1 minute were excluded. aEEG correctly identified SE in 70% of the 10 cases, although ESz were confirmed to be present in 80% of this subpopulation. CONCLUSIONS: aEEG criteria for neonatal seizure identification can be applied with caution to older children and should be supplemented by formal electroencephalography. Seizure identification is better for longer seizures and those arising from sleep. SE is not always recognized by aEEG among older children.


Subject(s)
Epilepsy , Infant, Newborn, Diseases , Status Epilepticus , Child , Infant, Newborn , Humans , Adolescent , Retrospective Studies , Seizures/diagnosis , Electroencephalography , Intensive Care Units, Neonatal
13.
Pharmacol Ther ; 252: 108562, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37952904

ABSTRACT

The pathogenesis of pulmonary fibrosis, including idiopathic pulmonary fibrosis (IPF) and other forms of interstitial lung disease, involves a complex interplay of various factors including host genetics, environmental pollutants, infection, aberrant repair and dysregulated immune responses. Highly variable clinical outcomes of some ILDs, in particular IPF, have made it difficult to identify the precise mechanisms involved in disease pathogenesis and thus the development of a specific cure or treatment to halt and reverse the decline in patient health. With the advent of in-depth molecular diagnostics, it is becoming evident that the pathogenesis of IPF is unlikely to be the same for all patients and therefore will likely require different treatment approaches. Chronic inflammation is a cardinal feature of IPF and is driven by both innate and adaptive immune responses. Inflammatory cells and activated fibroblasts secrete various pro-inflammatory cytokines and chemokines that perpetuate the inflammatory response and contribute to the recruitment and activation of more immune cells and fibroblasts. The balance between pro-inflammatory and regulatory immune cell subsets, as well as the interactions between immune cell types and resident cells within the lung microenvironment, ultimately determines the extent of fibrosis and the potential for resolution. This review examines the role of the innate and adaptive immune responses in pulmonary fibrosis, with an emphasis on IPF. The role of different immune cell types is discussed as well as novel anti-inflammatory and immunotherapy approaches currently in clinical trial or in preclinical development.


Subject(s)
Idiopathic Pulmonary Fibrosis , Lung Diseases, Interstitial , Humans , Idiopathic Pulmonary Fibrosis/drug therapy , Lung/metabolism , Fibrosis , Inflammation/pathology
14.
JAMA Health Forum ; 4(10): e233660, 2023 Oct 06.
Article in English | MEDLINE | ID: mdl-37862035

ABSTRACT

This cross-sectional study uses Medicare Part D claims for high-utilization generic drugs to analyze gross profits accumulated by pharmacy benefit managers, pharmacies, wholesalers, and manufacturers in the pharmaceutical supply chain.


Subject(s)
Pharmacies , Pharmacy , Drugs, Generic , Costs and Cost Analysis
15.
Biomedicines ; 11(10)2023 Oct 20.
Article in English | MEDLINE | ID: mdl-37893220

ABSTRACT

Cyclin-dependent kinases (CDKs) play a crucial role in regulation of the mammalian cell cycle. CDK4 and CDK6 control the G1/S restriction checkpoint through their ability to associate with cyclin D proteins in response to growth factor signals. CDK4 deficiency in mice gives rise to a range of endocrine-specific phenotypes including diabetes, infertility, dwarfism, and atrophy of the anterior pituitary. Although CDK6 deficiency can cause thymic atrophy due to a block in the double-negative (DN) to double-positive (DP) stage of T cell development, there are no overt defects in immune cell development reported for CDK4-deficient mice. Here, we examined the impact of a novel N-ethyl-N-nitrosourea-induced point mutation in the gene encoding CDK4 on immune cell development. Mutant mice (Cdk4wnch/wnch) showed normal development and differentiation of major immune cell subsets in the thymus and spleen. Moreover, T cells from Cdk4wnch/wnch mice exhibited normal cytokine production in response to in vitro stimulation. However, analysis of the mixed bone marrow chimeras revealed that Cdk4wnch/wnch-derived T cell subsets and NK cells are at a competitive disadvantage compared to Cdk4+/+-derived cells in the thymus and periphery of recipients. These results suggest a possible role for the CDK4wnch mutation in the development of some immune cells, which only becomes apparent when the Cdk4wnch/wnch mutant cells are in direct competition with wild-type immune cells in the mixed bone marrow chimera.

16.
Value Health ; 26(11): 1618-1624, 2023 11.
Article in English | MEDLINE | ID: mdl-37689264

ABSTRACT

OBJECTIVES: US Medicare will begin negotiating prices for top-selling drugs in 2023. This study describes and estimates potential savings from a therapeutic reference pricing approach, linking comparative effectiveness with the costs of existing therapeutic alternatives, that Medicare could use to adjust the starting point for price negotiations. METHODS: First, we identified target drugs likely to be selected for Medicare negotiation. Second, we identified comparative effectiveness ratings for target drugs based on French Haute Autorité de Santé reports. For target drugs with minor or no added benefit, we identified therapeutic alternatives based on the French reports and US clinical guidelines. For each target drug with minor or no added benefit, we computed the difference between spending based on the drug's estimated statutory ceiling price and spending based on the weighted average cost of therapeutic alternatives or the lowest cost therapeutic alternative. Finally, we calculated potential annual savings from using a starting point in negotiations based on costs of therapeutic alternatives. RESULTS: Potential drug-level savings to Medicare from using a starting point in negotiations based on average spending across therapeutic alternatives, compared with using the statutory ceiling price alone, ranged from $186 541 340 to $2 173 441 197. Potential savings from using a starting point based on the lowest cost alternative ranged from $199 872 163 to $3 605 904 765. CONCLUSIONS: Although we do not expect Medicare to rely on French comparative effectiveness assessments, this study demonstrates the potential for additional savings when using comparative effectiveness and costs of therapeutic alternatives to inform the starting price for negotiations.


Subject(s)
Medicare , Negotiating , Aged , United States , Humans , Drug Costs , Costs and Cost Analysis
17.
Neurosurg Clin N Am ; 34(4): 585-597, 2023 Oct.
Article in English | MEDLINE | ID: mdl-37718105

ABSTRACT

Distal junctional pathology remains an unsolved issue in spine surgery. Distal junctional pathology can occur on a spectrum from asymptomatic radiographic finding to catastrophic distal construct failure. It is significant to address as postoperative sagittal balance has been shown to be correlated with patient-reported outcomes. Current literature and clinical experience suggest there are techniques that can be implemented regardless of setting to avoid distal junctional pathology. Much of the avoidant strategy relies on understanding the deformity pathology, selection of the lowest instrumented vertebra (LIV), health of the segments caudal to the LIV, and methods of fixation.


Subject(s)
Spine , Humans , Postoperative Period , Spine/diagnostic imaging , Spine/surgery
18.
JAMA ; 330(14): 1331-1332, 2023 Oct 10.
Article in English | MEDLINE | ID: mdl-37755921

ABSTRACT

This Viewpoint discusses how the design of the Centers for Medicare & Medicaid Services (CMS) registry could impact Medicare's ability to evaluate whether monoclonal antibodies are reasonable and necessary for patients with Alzheimer disease and help physicians understand when the drug is most beneficial.

19.
Health Aff (Millwood) ; 42(8): 1110-1118, 2023 08.
Article in English | MEDLINE | ID: mdl-37549324

ABSTRACT

Most major insurers operate in both the commercial health insurance and Medicare Advantage (MA) markets. We investigated the ratio of commercial-to-MA prices negotiated by the same insurer, in the same hospital and for the same services, using 2022 price information disclosed by hospitals in compliance with the hospital price transparency rule. Insurers negotiated median hospital prices for commercial plans that were two to three times higher than their MA prices in the same hospital for the same service. The median commercial-to-MA price ratio in the same hospital varied, from 1.8 for surgery and medicine services to 2.2 for laboratory tests and emergency department visits and 2.4 for imaging services. In multivariable Poisson regression analysis, higher ratios were associated with system-affiliated, nonprofit, and teaching hospitals, as well as with large national insurers. These findings reflect the differences in financial incentives and regulatory policies in the commercial and MA markets. Because insurers respond to differing incentives by obtaining different negotiated prices across markets, policy and practice efforts that alter incentives for insurers may have the potential to lower commercial prices.


Subject(s)
Medicare Part C , Aged , Humans , United States , Insurance Carriers , Insurance, Health , Negotiating/methods , Hospitals, Teaching
20.
ACS Appl Bio Mater ; 6(8): 3153-3165, 2023 08 21.
Article in English | MEDLINE | ID: mdl-37523247

ABSTRACT

This paper reports on the production of electro-spun nanofibers from softwood Kraft lignin without the need for polymer blending and/or chemical modification. Commercially available softwood Kraft lignin was fractionated using acetone. The acetone-soluble lignin (AcSL) had an ash content of 0.06 wt %, a weight average molecular weight of 4250 g·mol-1 along with the polydispersity index of 1.73. The corresponding values for as-received lignin (ARL) were 1.20 wt %, 6000 g·mol-1, and 2.22, respectively. The AcS was dissolved in a binary solvent consisting of acetone, and dimethyl sulfoxide (2:1, v/v) was selected for dissolving the AcSL. Conventional and custom-designed grounded electrode configurations were used to produce electro-spun neat lignin fibers that were randomly oriented or highly aligned, respectively. The diameter of the electro-spun fibers ranged from 1.12 to 1.46 µm. After vacuum drying at 140 °C for 6 h to remove the solvents and oxidation at 250 °C, the fibers were carbonized at 1000, 1200, and 1500 °C for 1 h. The carbonized fibers were unfused and void-free with an average diameter of 500 nm. Raman spectroscopy, scanning electron microscopy, and image analysis were used to characterize the carbonized fibers.


Subject(s)
Acetone , Lignin , Solvents/chemistry , Lignin/chemistry , Chemical Fractionation
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