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1.
Ultrasonics ; 141: 107343, 2024 May 11.
Article in English | MEDLINE | ID: mdl-38754149

ABSTRACT

Nomex honeycomb composite (NHC) has been increasingly used in the automotive, aerospace and defence applications due to its excellent thermal and mechanical properties. Its complex cellular hexagonal thin-walled configuration along with heterogeneous, soft and brittle nature pose substantial processing defects such as burr formation, tearing of walls, surface roughness, dimensional inaccuracy and low machining quality during conventional machining (CM). These surface defects have a substantial influence on the operating life and functional performance of its sandwiched structural members. Hybrid ultrasonic vibration assisted machining (HUSVAM) technology has been introduced to overcome such limitations. For an in depth research on HUSVAM of NHC using ultrasonic toothed disc cutter (UTDC), three dimensional finite element model was developed and experimental validation was carried out. The numerical simulation and experimental results were found to be in good agreement with one another. The influence of various machining parameters including the ultrasonic tool vibration amplitude (UTVA), feed rate (FR), depth of cut (DoC) and spindle angular speed (SAS) on NHC cutting forces, chip formation and surface quality was investigated using both HUSVAM and CM techniques. Furthermore, stresses, deformation and forces near tool-workpiece interaction along with the surface topography and morphologies were also analysed and compared for various operating conditions. A reduction in the cutting forces was found with the increase of SAS and UTVA (up to 65.47 % and 65.74 %, respectively). Although, the cutting forces were observed to increase by increasing the DoC and FR (up to 159.45 % and 126.33 %, respectively). DoC has a greater impact on the cutting forces among all machining parameters according to 4 levels, 4 factors (L16) orthogonal experiments based on Taguchi method. The results show that the chip formation and machining quality of NHC core can be improved with HUSVAM technique using UTDC. HUSVAM also reduced the cutting forces (up to 73 %) compared to CM. The ultrasonic toothed disc cutter generated large number of burr with very short length, no tearing defects and no uncut fibers as observed from scanning electron microscopy of NHC hexagonal cell structure, walls and triple points. A burr formation of less than 10 % was realized during HUSVAM of NHC cores for Fx≤3N, while it was found up to 20 % if Fx>3N, compared to at least 40 % during CM. The finite element model developed can be used to investigate the influence of HUSVAM on modern difficult to machine materials for enhanced surface quality.

2.
J Pak Med Assoc ; 74(4): 719-723, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38751268

ABSTRACT

Objective: To compare the procrastination and self-efficacy scores among students with respect to the academic year of dental undergraduate programme, and to assess the relationship between self-efficacy and academic procrastination among the students. METHODS: The descriptive study was conducted at Sindh Institute of Oral Health Sciences, Jinnah Sindh Medical University, Karachi, from January to March 2023, and comprised medical students of either gender from all the 4 academic years. Data was collected using a structured questionnaire whose validity was assessed using a pilot study. Data was analysed using SPSS 18. RESULTS: Of the 136 students, 84(61.8%) were females and 52(38.2%) were males. There were 34(25%) students from the 1st year, 32(23.5%) from 2nd year, 38(28%) from the 3rd year, and 32(23.5%) from the final year. The highest mean score for procrastination was from 3rd year students 67.7±12.8, while the highest mean score for self-efficacy was from 1st year students 30.2±4. There was no significant difference in terms of gender (p>0.05). Procrastination scores had a significant association with the academic year (p=0.016). Conclusion: Procrastination scores were high among the dental students with the highest score from 3rd year students. The academic environment should provide support help the students devise strategies to optimally utilise the available time.


Subject(s)
Procrastination , Self Efficacy , Students, Dental , Humans , Female , Male , Pakistan , Students, Dental/psychology , Students, Dental/statistics & numerical data , Young Adult , Surveys and Questionnaires , Education, Dental/methods , Adult
3.
Front Cardiovasc Med ; 11: 1345449, 2024.
Article in English | MEDLINE | ID: mdl-38774659

ABSTRACT

Viral myocarditis is an important cause of non-ischemic cardiomyopathy. Multiple clinical manifestations have been reported, including acute heart failure, cardiogenic shock, and ventricular arrhythmias. We present three patients with clinically suspected viral myocarditis causing acute heart failure. Serum coxsackievirus B antibodies were positive in all three patients. Each case resulted in significant clinical improvement with hemodynamic support and acute recovery of left ventricular ejection fraction. Despite an initial critical presentation concerning for cardiogenic shock, we highlight three cases of clinically suspected coxsackie myocarditis with an excellent short-term prognosis.

4.
J Prim Care Community Health ; 15: 21501319241241470, 2024.
Article in English | MEDLINE | ID: mdl-38654523

ABSTRACT

BACKGROUND: Tobacco smoking exacerbates diabetes-related complications; its prevalence is notwithstanding substantial. Persons with diabetes face a number of barriers and challenges to quitting such as multiple lifestyle restrictions; tailored interventions are required for smoking cessation. OBJECTIVE: To identify research on behavioral interventions for smoking cessation in diabetes. METHODS: Studies had to be randomized controlled trials, quasiexperimental or systematic reviews. The behavioral interventions included were: the 5As, Cognitive-Behavioral Therapy, Motivational Interviewing, Contingency Management, Health Coaching and Counselling, as compared to standard care. The outcomes were self-reported and/or biochemically verified smoking cessation. CINAHL Complete, MEDLINE Complete, the Cochrane databases of systematic reviews and randomized controlled trials, PsychInfo and PubMed Central were searched until July, 2023. Keywords used included diabetes, smoking cessation and each of the behavioral interventions included. RESULTS: 1615 papers were identified. Three studies on the 5As/brief advice, 4 on Motivational Intervention and 1 on counseling were retained. The results on the 5As and Motivational Interviewing were conflicting. More intensive interventions appear to be more successful in achieving smoking cessation in smokers with diabetes. CONCLUSIONS: Future research should focus on the continued development and evaluation of structured smoking cessation interventions based on the 5As, Motivational interviewing and Cognitive Behavioral Therapy.


Subject(s)
Behavior Therapy , Diabetes Mellitus , Smoking Cessation , Humans , Smoking Cessation/methods , Diabetes Mellitus/therapy , Behavior Therapy/methods , Motivational Interviewing/methods , Cognitive Behavioral Therapy/methods
5.
Orphanet J Rare Dis ; 19(1): 154, 2024 Apr 11.
Article in English | MEDLINE | ID: mdl-38605392

ABSTRACT

BACKGROUND: The minimal clinically important difference (MCID) is the smallest change in outcome that physicians or patients would consider meaningful and is relevant when evaluating disease progression or the efficacy of interventions. Studies of patients with late-onset Pompe disease (LOPD) have used the 6-min walk distance (6MWD) as an endpoint to assess motor function. However, an MCID for 6MWD (% predicted and meters) has yet to be established in LOPD. The objective of the study was to derive 6MWD MCID (% predicted and meters) with different analysis methods and for subgroups of different disease severity for LOPD. METHODS: Data from the PROPEL trial were used to calculate 6MWD MCID in the overall PROPEL population and subgroups of baseline severity as assessed by walking distance and body mass index (BMI), using anchor- and distribution-based approaches. RESULTS: The 6MWD MCIDs varied widely, depending on the method and subgroup, ranging from 2.27%-8.11% predicted for the overall LOPD population (23.7 m-57.2 m). For patients with baseline 6MWD < 150 m, MCIDs ranged from -0.74%-3.37% (-2.1 m-11.3 m). MCIDs increased with distance walked at baseline until a plateau was reached. For BMI subgroups, the MCIDs were generally lowest in obese patients. CONCLUSION: Our analysis shows that MCID depends on the chosen method and disease severity. The findings suggest that applying a single MCID to all patients can be misleading; consequently, a range of possible MCIDs should be considered. This may also be highly relevant for other neuromuscular diseases. This study provides a range of 6MWD MCIDs for LOPD, with lower MCIDs for more severe patients.


Subject(s)
Glycogen Storage Disease Type II , Humans , Disease Progression , Minimal Clinically Important Difference , Walking , Clinical Trials as Topic
6.
Nanoscale ; 16(16): 7965-7975, 2024 Apr 25.
Article in English | MEDLINE | ID: mdl-38567436

ABSTRACT

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease that mostly affects joints. Although RA therapy has made significant progress, difficulties including extensive medication metabolism and its quick clearance result in its inadequate bioavailability. The anti-inflammatory effect of zein was reported with other medications, but it has certain limitations. There are reports on the anti-oxidant and anti-inflammatory effect of aescin, which exhibits low bioavailability for the treatment of rheumatoid arthritis. Also, the combinatorial effect of zein with other effective drug delivery systems is still under investigation for the treatment of experimental collagen-induced rheumatoid arthritis. The focus of this study was to formulate and define the characteristics of zein-coated gelatin nanoparticles encapsulated with aescin (Ze@Aes-GNPs) and to assess and contrast the therapeutic effectiveness of Ze@Aes-GNPs towards collagen-induced RA in Wistar rats. Nanoprecipitation and the layer-by-layer coating process were used to fabricate Ze@Aes-GNPs and their hydrodynamic diameter was determined to be 182 nm. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to further validate the size, shape, and surface morphology of Ze@Aes-GNPs. When tested against foreskin fibroblasts (BJ), these nanoparticles demonstrated significantly high cytocompatibility. Both Aes and Ze@Aes-GNPs were effective in treating arthritis, as shown by the decreased edoema, erythema, and swelling of the joints, between which Ze@Aes-GNPs were more effective. Further, it was demonstrated that Aes and Ze@Aes-GNPs reduced the levels of oxidative stress (articular elastase, lipid peroxidation, catalase, superoxide dismutase and nitric oxide) and inflammatory indicators (TNF-α, IL-1ß and myeloperoxidase). The histopathology findings further demonstrated that Ze@Aes-GNPs considerably reduced the infiltration of inflammatory cells at the ankle joint cartilage compared to Aes. Additionally, immunohistochemistry examination showed that treatment with Ze@Aes-GNPs suppressed the expression of pro-inflammatory markers (COX-2 and IL-6) while increasing the expression of SOD1. In summary, the experiments indicated that Aes and Ze@Aes-GNPs lowered the severity of arthritis, and critically, Ze@Aes-GNPs showed better effectiveness in comparison to Aes. This suppression of oxidative stress and inflammation was likely driven by Aes and Ze@Aes-GNPs.


Subject(s)
Arthritis, Experimental , Escin , Gelatin , Nanoparticles , Rats, Wistar , Zein , Animals , Gelatin/chemistry , Zein/chemistry , Rats , Nanoparticles/chemistry , Arthritis, Experimental/drug therapy , Arthritis, Experimental/pathology , Arthritis, Experimental/metabolism , Escin/chemistry , Escin/pharmacology , Male , Anti-Inflammatory Agents/chemistry , Anti-Inflammatory Agents/pharmacology , Anti-Inflammatory Agents/therapeutic use , Arthritis, Rheumatoid/drug therapy , Arthritis, Rheumatoid/pathology , Arthritis, Rheumatoid/metabolism , Humans , Fibroblasts/metabolism , Fibroblasts/drug effects , Inflammation/drug therapy , Inflammation/pathology , Collagen/chemistry
7.
Langmuir ; 40(16): 8463-8473, 2024 Apr 23.
Article in English | MEDLINE | ID: mdl-38591916

ABSTRACT

The two-dimensional (2D) semiconducting family of XSi2N4 (X = Mo and W), an emergent class of air-stable monolayers, has recently gained attention due to its distinctive structural, mechanical, transport, and optical properties. However, the electrical contact between XSi2N4 and metals remains a mystery. In this study, we inspect the electronic and transport properties, specifically the Schottky barrier height (SBH) and tunneling probability, of XSi2N4-based van der Waals contacts by means of first-principles calculations. Our findings reveal that the electrical contacts of XSi2N4 with metals can serve as the foundation for nanoelectronic devices with ultralow SBHs. We further analyzed the tunneling probability of different metal contacts with XSi2N4. We found that the H-phase XSi2N4/metal contact shows superior tunneling probability compared to that of H́-based metal contacts. Our results suggest that heterostructures at interfaces can potentially enable efficient tunneling barrier modulation in metal contacts, particularly in the case of MoSi2N4/borophene compared to MoSi2N4/graphene and WSi2N4/graphene in transport-efficient electronic devices. Among the studied heterostructures, tunneling efficiency is highest at the H and H́-MoSi2N4/borophene interfaces, with barrier heights of 2.1 and 1.52 eV, respectively, and barrier widths of 1.04 and 0.8 Å. Furthermore, the tunneling probability for these interfaces was identified to be 21.3 and 36.4%, indicating a good efficiency of carrier injection. Thus, our study highlights the potential of MoSi2N4/borophene contact in designing power-efficient Ohmic devices.

9.
Front Chem ; 12: 1291230, 2024.
Article in English | MEDLINE | ID: mdl-38476652

ABSTRACT

Background: Ulcerative colitis is a chronic immune-mediated inflammatory bowel disease that involves inflammation and ulcers of the colon and rectum. To date, no definite cure for this disease is available. Objective: The objective of the current study was to assess the effect of Calliandra haematocephala on inflammatory mediators and oxidative stress markers for the exploration of its anti-ulcerative colitis activity in rat models of acetic acid-induced ulcerative colitis. Methods: Methanolic and n-hexane extracts of areal parts of the plant were prepared by cold extraction method. Phytochemical analysis of both extracts was performed by qualitative analysis, quantitative methods, and high-performance liquid chromatography (HPLC). Prednisone at 2 mg/kg dose and plant extracts at 250, 500, and 750 mg/kg doses were given to Wistar rats for 11 days, which were given acetic acid on 8th day through the trans-rectal route for the induction of ulcerative colitis. A comparison of treatment groups was done with a normal control group and a colitis control group. To evaluate the anti-ulcerative colitis activity of Calliandra haematocephala, different parameters such as colon macroscopic damage, ulcer index, oxidative stress markers, histopathological examination, and mRNA expression of pro and anti-inflammatory mediators were evaluated. mRNA expression analysis was carried out by reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR). Results: The phytochemical evaluation revealed polyphenols, flavonoids, tannins, alkaloids, and sterols in both extracts of the plant. Results of the present study exhibited that both extracts attenuated the large bowel inflammation and prevented colon ulceration at all tested doses. Macroscopic damage and ulcer scoreswere significantly decreased by both extracts. Malondialdehyde (MDA) levels and nitrite/nitrate concentrations in colon tissues were returned to normal levels while superoxide dismutase (SOD) activity was significantly improved by all doses. Histopathological examination exhibited that both extracts prevented the inflammatory changes, cellular infiltration, and colon thickening. Gene expression analysis by RT-qPCR revealed the downregulation of pro-inflammatory markers such as tumor necrosis factor-alpha (TNF-α) and cyclooxygenase-2 (COX-2) whereas the anti-inflammatory cytokines including Interleukin-4 (IL-4) and Interleukin-10 (IL-10) were found to be upregulated in treated rats. Conclusion: It was concluded based on study outcomes that methanolic and n-hexane extracts of Calliandra haematocephala exhibited anti-ulcerative colitis activity through modulation of antioxidant defense mechanisms and the immune system. In this context, C. haematocephala can be considered as a potential therapeutic approach for cure of ulcerative colitis after bioassay-directed isolation of bioactive phytochemicals and clinical evaluation.

10.
Methods Mol Biol ; 2761: 559-567, 2024.
Article in English | MEDLINE | ID: mdl-38427261

ABSTRACT

Spinal cord injury (SCI) is a devastating clinical condition that affects millions of people worldwide. SCI primarily affects males in younger age groups. It is characterized by a complex of neurological dysfunctions that can lead to permanent disability. We describe an adapted technique for SCI, i.e., a contusion model of SCI, in this chapter. This model is widely used to study the pathology of SCI and test potential therapies. The experimental contusion is performed by using a compression device, which allows the creation of a reproducible injury animal model through the definition of specific injury parameters. A detailed methodology has been developed and described here that utilizes a stereotactic frame and impactor to produce reproducible injuries.


Subject(s)
Contusions , Spinal Cord Injuries , Humans , Male , Rats , Animals , Spinal Cord Injuries/pathology , Disease Models, Animal , Imaging, Three-Dimensional , Spinal Cord/pathology
11.
Methods Mol Biol ; 2761: 623-633, 2024.
Article in English | MEDLINE | ID: mdl-38427265

ABSTRACT

Stroke is the third-leading cause of death and the leading cause of acquired adult disability worldwide. Several ischemic stroke models are currently available. However, mimicking focal cerebral ischemia (FCI) is the most common. The formation of an embolic or thrombotic occlusion at or near the middle cerebral artery causes most events in FCI. The current protocol closely mimics the etiology of human stroke and ensures that the results obtained are highly relevant. The method described in this protocol yields reproducible results. The success of this model in ischemic research can be examined through the utilization of Doppler blood flow imaging equipment.


Subject(s)
Brain Ischemia , Ischemic Stroke , Stroke , Rats , Humans , Animals , Infarction, Middle Cerebral Artery/complications , Disease Models, Animal , Brain Ischemia/etiology , Middle Cerebral Artery/diagnostic imaging
13.
Sci Rep ; 14(1): 5604, 2024 03 07.
Article in English | MEDLINE | ID: mdl-38453950

ABSTRACT

Control charts are a statistical approach for monitoring cancer data that can assist discover patterns, trends, and unusual deviations in cancer-related data across time. To detect deviations from predicted patterns, control charts are extensively used in quality control and process management. Control charts may be used to track numerous parameters in cancer data, such as incidence rates, death rates, survival time, recovery time, and other related indicators. In this study, CDEC chart is proposed to monitor the cancer patients recovery time censored data. This paper presents a composite dual exponentially weighted moving average Cumulative sum (CDEC) control chart for monitoring cancer patients recovery time censored data. This approach seeks to detect changes in the mean recovery time of cancer patients which usually follows Weibull lifetimes. The results are calculated using type I censored data under known and estimated parameter conditions. We combine the conditional expected value (CEV) and conditional median (CM) approaches, which are extensively used in statistical analysis to determine the central tendency of a dataset, to create an efficient control chart. The suggested chart's performance is assessed using the average run length (ARL), which evaluates how efficiently the chart can detect a change in the process mean. The CDEC chart is compared to existing control charts. A simulation study and a real-world data set related to cancer patients recovery time censored data is used for results illustration. The proposed CDEC control chart is developed for the data monitoring when complete information about the patients are not available. So, instead of doping the patients information we can used the proposed chart to monitor the patients information even if it is censored. The authors conclude that the suggested CDEC chart is more efficient than competitor control charts for monitoring cancer patients recovery time censored data. Overall, this study introduces an efficient new approach for cancer patients recovery time censored data, which might have significant effect on quality control and process improvement across a wide range of healthcare and medical studies.


Subject(s)
Ditiocarb/analogs & derivatives , Health Facilities , Neoplasms , Humans , Computer Simulation , Time , Quality Control , Neoplasms/diagnosis
14.
HPB (Oxford) ; 26(5): 630-638, 2024 May.
Article in English | MEDLINE | ID: mdl-38383207

ABSTRACT

BACKGROUND: To investigate the relationship between preoperative Carbohydrate Antigen19-9(CA19-9)and pancreatic cancer occult metastasis. METHODS: Systematic search of MEDLINE, CENTRAL, Web of Science and bibliographic reference lists were conducted. All comparative observational studies investigating the predictive ability of preoperative CA 19-9 in patients with pancreatic cancer were considered. Mean CA-19-9 value in the pancreatic cancer patients with and without metastasis were evaluated. Best cut-off value of CA 19-9 for metastasis was determined using ROC analysis. RESULTS: Ten comparative observational studies reporting a total of 1431 pancreatic cancer patients with (n = 496) and without (n = 935) metastasis were included. Subsequent meta-analysis demonstrated that mean preoperative CA 19-9 level was significantly higher in patients with metastases compared to those without (MD: 904.4; 95 % CI, 642.08-1166.74, P < 0.0001). The between-study heterogeneity was significant (I2: 99 %, P < 0.00001). ROC analysis yielded a cut-off CA 19-9 level of 336 with a sensitivity and specificity for predicting metastasis of 90 % and 80 %, respectively (AUC = 0.90). CONCLUSIONS: CA 19-9 level is significantly higher in patients with metastatic pancreatic cancer. A preoperative CA 19-9 value of 336 should be considered as an acceptable cut-off value to design prospective studies.


Subject(s)
CA-19-9 Antigen , Pancreatic Neoplasms , Predictive Value of Tests , Humans , Pancreatic Neoplasms/blood , Pancreatic Neoplasms/surgery , Pancreatic Neoplasms/pathology , CA-19-9 Antigen/blood , Biomarkers, Tumor/blood , Risk Factors , Male , Female , Middle Aged , Area Under Curve , Up-Regulation , Neoplasm Metastasis , Aged
15.
Environ Sci Pollut Res Int ; 31(14): 20881-20897, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38381295

ABSTRACT

The presence of high chromium (Cr) levels induces the buildup of reactive oxygen species (ROS), resulting in hindered plant development. Riboflavin (vitamin B2) is produced by plants, fungi, and microbes. It serves as a precursor to the coenzymes flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN), which play a crucial role in cellular metabolism. The objective of this work was to clarify the underlying mechanisms by which riboflavin alleviates Cr stress in Praecitrullus fistulosus L. Further, the role of riboflavin in growth, ions homeostasis, methylglyoxal detoxification, and antioxidant defense mechanism are not well documented in plants under Cr toxicity. We found greater biomass and minimal production of ROS in plants pretreated with riboflavin under Cr stress. Results manifested a clear abridge in growth, chlorophyll content, and nutrient uptake in Indian squash plants exposed to Cr stress. Findings displayed that Cr stress visibly enhanced oxidative injury reflected as higher malondialdehyde (MDA), hydrogen peroxide (H2O2), superoxide radical (O2•‒), methylglyoxal (MG) levels alongside vivid lipoxygenase activity. Riboflavin strengthened antioxidant system, enhanced osmolyte production and improved membrane integrity. Riboflavin diminished Cr accumulation in aerial parts that led to improved nutrient acquisition. Taken together, riboflavin abridged Cr phytotoxic effects by improving redox balance because plants treated with riboflavin had strong antioxidant system that carried out effective ROS detoxification. Riboflavin protected membrane integrity that, in turn, improved nutrient uptake in plants.


Subject(s)
Antioxidants , Cucurbita , Antioxidants/metabolism , Chromium/toxicity , Chromium/metabolism , Pyruvaldehyde , Reactive Oxygen Species/metabolism , Hydrogen Peroxide/metabolism , Oxidation-Reduction , Plants/metabolism , Riboflavin/metabolism
16.
Surgery ; 175(5): 1329-1336, 2024 May.
Article in English | MEDLINE | ID: mdl-38383242

ABSTRACT

BACKGROUND: Mortality after severe complications after hepatectomy (failure to rescue) is strongly linked to center volume. The aim of this study was to evaluate the risk factors for failure to rescue after hepatectomy in a high-volume center. METHODS: Retrospective study of 1,826 consecutive patients who underwent hepatectomy from 2011 to 2018. The primary outcome was a 90-day failure to rescue, defined as death within 90 days posthepatectomy after a severe (Clavien-Dindo grade 3+) complication. Risk factors for 90-day failure to rescue were evaluated using a multivariable binary logistic regression model. RESULTS: The cohort had a median age of 65.3 years, and 56.6% of patients were male. The commonest indication for hepatectomy was colorectal metastasis (58.9%), and 46.9% of patients underwent major or extra-major hepatectomy. Severe complications developed in 209 patients (11.4%), for whom the 30- and 90-day failure to rescue rates were 17.0% and 35.4%, respectively. On multivariable analysis, increasing age (P = .006) and modified Frailty Index (P = .044), complication type (medical or combined medical/surgical versus surgical; P < .001), and body mass index (P = .018) were found to be significant independent predictors of 90-day failure to rescue. CONCLUSION: Older and frail patients who experience medical complications are particularly at risk of failure to rescue after hepatectomy. These results may inform preoperative counseling and may help to identify candidates for prehabilitation. Further study is needed to assess whether failure to rescue rates could be reduced by perioperative interventions.


Subject(s)
Hepatectomy , Postoperative Complications , Humans , Male , Aged , Female , Hepatectomy/adverse effects , Retrospective Studies , Tertiary Care Centers , Risk Factors , United Kingdom/epidemiology , Postoperative Complications/epidemiology , Postoperative Complications/etiology
17.
Heliyon ; 10(3): e25506, 2024 Feb 15.
Article in English | MEDLINE | ID: mdl-38352740

ABSTRACT

IN939 is a modern class of nickel-based superalloys designed for continuous operational sustenance at elevated temperatures owing to their excellent combination of fatigue, creep, and corrosion resistance. This unique performance of IN939 is associated with the composition of this alloy, along with specific post-processing treatments such as solution treatment and aging, giving rise to features such as the presence of γ' residues, as well as the presence of MC and M23C6 carbides. This also includes the absence of the eutectic and incipient melting phases. For this alloy, the primary part development is by the powder bed fusion process using a laser powder bed fusion machine. At the same time, a solo study highlights the use of an EB-PBF machine for the synthesis. The AM development process of these alloys is hindered by machine parameters, which have been found ineffective in isolation to obtain a fully dense structure with desired properties. The purpose of these parameters is to improve their core properties while minimizing defects associated with powder metallurgy routes, such as porosity, detrimental precipitates, grain anisotropy, etc. This study aims to provide an overview of the advancements in research related to IN939, explicitly focusing on the benchmarks achieved through additive manufacturing techniques. We have discussed the work performed in this area, compared the results of different studies, and identified the gaps in current research. By doing so, we aim to provide a comprehensive understanding of the potential of IN939 and its applications in extreme environments.

18.
ACS Omega ; 9(5): 5846-5853, 2024 Feb 06.
Article in English | MEDLINE | ID: mdl-38343952

ABSTRACT

Wide-range NIR lifetimes of lanthanide ion-doped nanocrystals are highly desired for numerous bioapplications. As one of the most promising NIR emission bands, the lifetime of Er3+ at 1.5 µm can be as long as ∼10 ms and be greatly shortened by increasing the doping level of either activator Er3+ or sensitizer Yb3+. However, the shortened lifetime is mostly accompanied by the quenching effects, highly restraining the light signal intensity. Alternatively, prolonging the lifetime of Er3+ NIR lifetime without luminescence quenching is of vital significance as it raises the upper limit of the lifetime range and maintains the effective signal intensity. In this work, we revealed that Yb3+ can bidirectionally tune the NIR lifetime of Er3+. By introducing Yb3+, in addition to the substantially improved luminescence intensities, the prolonged NIR lifetime can be generated in low-Er3+-doped NaYF4 nanocrystals, while monotonously decreased lifetime appears in Er3+ heavily doped nanocrystals. To investigate the mechanisms of this bidirectional lifetime tuning and meanwhile avoid additional structural influences, the size and morphology of nanocrystals with different doping compositions were controlled to be similar. The decay dynamics of Er3+ NIR emissions of different nanocrystals were simulated to explain the effects of Yb3+. This work provides insights into the manipulation of the NIR lifetime in Er3+/Yb3+-codoped nanocrystals.

19.
Life Sci ; 340: 122480, 2024 Mar 01.
Article in English | MEDLINE | ID: mdl-38301876

ABSTRACT

AIM: The liver plays a crucial role in biotransformation but it is susceptible to chemical-induced damage, known as hepatotoxicity. Traditional therapies for protecting the liver face significant challenges, including poor bioavailability, off-target effects, adverse reactions, drug breakdown, and inadequate uptake. These issues emphasize the need for precise, targeted therapeutic approaches against hepatotoxicity. MATERIALS AND METHODS: The objective of our research was to develop a customized, biocompatible, and biodegradable nanodrug delivery system for hepatoprotection. We chose collagen hydrolyzed protein, or gelatin, as the base material and utilized solvent evaporation and nanoprecipitation methods to create nanoparticles with size ranging from 130 to 155 nm. The resulting nanoparticles exhibited a spherical and smooth surface, as confirmed by scanning and transmission electron microscopy. KEY FINDINGS: Bioactive aescin (AES), into these gelatin nanoparticles (AES-loaded gel NPs), we tested these nanoparticles using a hepatotoxicity model. The results were indicating a significant reduction in the levels of key biomolecules, including NF-κB, iNOS, BAX, and COX-2 and decreased serum levels of enzymes ALT and AST. This reduction correlated with a notable alleviation in the severity of hepatotoxicity. Furthermore, the treatment with AES-loaded gel NPs resulted in the downregulation of several inflammatory and liver-specific biomarkers, including nitrite, MPO, TNF-α, and IL-6. SIGNIFICANCE: In summary, our study demonstrates that the AES-loaded gel NPs were markedly more effective in mitigating experimental hepatotoxicity when compared to the free aescin. The nanoparticles exhibited a propensity for suppressing liver damage, showcasing the potential of this targeted therapeutic approach for safeguarding the liver from harmful chemical insults.


Subject(s)
Chemical and Drug Induced Liver Injury , Nanoparticles , Rats , Animals , Rats, Wistar , Escin/metabolism , Gelatin/pharmacology , Carbon Tetrachloride/toxicity , Liver/metabolism , Chemical and Drug Induced Liver Injury/drug therapy , Chemical and Drug Induced Liver Injury/prevention & control , Chemical and Drug Induced Liver Injury/metabolism , Nanoparticles/chemistry
20.
Cureus ; 16(1): e52662, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38380220

ABSTRACT

BACKGROUND: There is a lack of regional and local evidence that describes the nature of cystinosis, a multiorgan accumulation of cystine, and its extent of organ damage. Therefore, this study aimed to determine the outcomes of cystinosis in patients who were followed up at a large tertiary care hospital. METHODS: Medical records of patients with cystinosis were retrospectively reviewed. Patients' baseline demographics, lab values, medications, comorbidities, and complications were collected and described. Univariable and multivariable logistics regression models were constructed to control for confounders and build prediction models. RESULTS: In our cohort of 39 patients, the mean age was 13.8±9.9 years. Approximately 56.4% of the patients had stunted growth, and the mortality rate was 25.6%. Regarding complications, the majority of patients developed myopathy (79.5%), end-stage renal disease (ESRD) (74.4%), and hypothyroidism (71.8%). Age (odds ratio=1.14, 95% confidence interval (95% CI): 1.012, 1.285) and stunted growth (odds ratio=6.62, 95% CI: 1.024, 42.835) were found to be predictors of renal replacement therapy and renal transplantation, respectively (p<0.047). CONCLUSION: This study on cystinosis patients reveals a high incidence of renal complications, with a significant mortality rate and common complications such as myopathy and ESRD. Age was found to be an independent risk factor for renal replacement therapy, while stunted growth predicted the need for transplantation. These findings underscore the urgency for early diagnosis, comprehensive treatment, and careful monitoring in managing cystinosis effectively.

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