ABSTRACT
MOTIVATION: Generalized linear mixed models (GLMMs), such as the negative-binomial or Poisson linear mixed model, are widely applied to single-cell RNA sequencing data to compare transcript expression between different conditions determined at the subject level. However, the model is computationally intensive, and its relative statistical performance to pseudobulk approaches is poorly understood. RESULTS: We propose offset-pseudobulk as a lightweight alternative to GLMMs. We prove that a count-based pseudobulk equipped with a proper offset variable has the same statistical properties as GLMMs in terms of both point estimates and standard errors. We confirm our findings using simulations based on real data. Offset-pseudobulk is substantially faster (>×10) and numerically more stable than GLMMs. AVAILABILITY AND IMPLEMENTATION: Offset pseudobulk can be easily implemented in any generalized linear model software by tweaking a few options. The codes can be found at https://github.com/hanbin973/pseudobulk_is_mm.
Subject(s)
Single-Cell Analysis , Single-Cell Analysis/methods , Linear Models , Software , Case-Control Studies , Sequence Analysis, RNA/methods , Humans , AlgorithmsABSTRACT
Carbon nanotube networks (CNTs)-based devices are well suited for the physically unclonable function (PUF) due to the inherent randomness of the CNT network, but CNT networks can vary significantly during manufacturing due to various controllable process conditions, which have a significant impact on PUF performance. Therefore, optimization of process conditions is essential to have a PUF with excellent performance. However, because it is time-consuming and costly to fabricate directly under various conditions, we implement randomly formed CNT network using simulation and confirm the variable correlation of the CNT network optimized for PUF performance. At the same time, by implementing an analog PUF through simulation, we present a 2D patterned PUF that has excellent security and can compensate for error occurrence problems. To evaluate the performance of analog PUF, a new evaluation method different from the existing digital PUF is proposed, and the PUF performance is compared according to two process variables, CNT density and metallic CNT ratio, and the correlation with PUF performance is confirmed. This study can serve as a basis for research to produce optimized CNT PUF by applying simulation according to the needs of the process of forming a CNT network.
ABSTRACT
Carbon nanotube (CNT) network channels constructed using a high-purity CNT solution for use in CNT thin-film transistors have the advantages of the possibility of requiring a low-temperature process and needing no special equipment. However, there are empty spaces between individual CNTs, resulting in unexpected effects. In this study, double-gate (DG) CNT network transistors were fabricated and measured in four different configurations to observe the capacitive coupling effects between the top gate (TG) and bottom gate (BG) in the DG structure. As a result, the electrical characteristics measured with the BG with a thicker gate oxide while floating the TG were similar to those measured with the TG with a thinner gate oxide. A comparison of the measured transfer curves showed that TG and BG were strongly coupled through the empty spaces in the channels. In addition, we evaluated the capacitance coupling effect due to changes in the CNT density, which is closely related to the empty space of the network channel. Finally, we proposed a method to determine the effective gate capacitance by considering the empty spaces between CNTs, which enabled the accurate evaluation of mobility. The effects of these materials were demonstrated by fabricating transistors using Al2O3, HfO2, and ZrO2 as TG oxide materials. By focusing on considerations based on the properties of CNT materials, our study provides valuable insights into accurate electrical modeling and potential advancements in CNT-based devices.
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INTRODUCTION: We describe a case of acute exudative polymorphous vitelliform maculopathy (AEPVM) that recurred 9 years after the initial event. To the best of our knowledge, this is the first report of recurrent AEPVM showing recovery of retinal and retinal pigment epithelium (RPE) function and good visual outcome following treatment with intravitreal corticosteroid. CASE DESCRIPTION: A 45-year-old Caucasian woman first presented with AEVPM in 2009. Her condition spontaneously resolved and she remained stable over several years. 9 years later, her condition recurred with bilateral reduction in visual acuity. Fundus examination revealed multiple small yellowish subretinal lesions across the posterior pole in both eyes. Optical coherence tomography (OCT) showed bilateral cystoid macular oedema (CMO). She was referred for electrophysiology and her electrooculogram findings were in keeping with severe generalised RPE dysfunction bilaterally, with a light peak to dark trough ratio (Arden index) of 110%, comparable to her initial presentation 9 years earlier. She was initially treated with oral steroids with some improvement. However, the maculopathy in the left eye recurred on cessation of oral treatment. A sustained-release 700ug dexamethasone intravitreal implant (Ozurdex®) was inserted in the left eye to which she responded remarkably, with improvement in visual acuity and complete resolution of the CMO. A year later, at her most recent clinic visit in March 2021, there was no evidence of any further recurrence. CONCLUSION: Our case demonstrates clinical and imaging findings consistent with recurrence of AEPVM with CMO that has been successfully treated with Ozurdex®.
Subject(s)
Macular Edema , Retinal Diseases , Vitelliform Macular Dystrophy , Humans , Female , Middle Aged , Vitelliform Macular Dystrophy/diagnosis , Vitelliform Macular Dystrophy/drug therapy , Dexamethasone , Retinal Diseases/diagnosis , Retinal Pigment Epithelium , Tomography, Optical Coherence , Macular Edema/diagnosis , Macular Edema/drug therapy , Macular Edema/etiology , Intravitreal Injections , Drug Implants/therapeutic useABSTRACT
BACKGROUND: People with hearing impairment have many problems with healthcare use, which is associated with health literacy. Research on health literacy is less focused on people with hearing impairments. This research aimed to explore the levels of health literacy in people with hearing impairment, find the barriers to health literacy, and summarize methods for improving health literacy. METHODS: A systematic review was conducted using three databases (PubMed, Cochrane, and Embase) to search the relevant articles and analyze them. The studies were selected using pre-defined inclusion/exclusion criteria in two steps: first, selection by examining the title and abstract; and second, after reading the study in full. The Risk of Bias Assessment Tool for Nonrandomized Studies (RoBANS) was used to assess the quality of the articles. RESULTS: Twenty-nine studies were synthesized qualitatively. Individuals with hearing impairment were found to have lower health literacy, when compared to those without impairment, which can lead to a higher medical cost. Most of the people with hearing impairment faced barriers to obtaining health-related information and found it difficult to communicate with healthcare providers. To improve their health literacy, it is essential to explore new ways of accessing health information and improving the relationship between patients and healthcare providers. CONCLUSIONS: Our findings show that people with hearing impairment have lower health literacy than those without. This suggests that developing new technology and policies for people with hearing impairment is necessary not to mention promoting provision of information via sign language. TRIAL REGISTRATION: OSF: https://doi.org/10.17605/OSF.IO/V6UGW . PROSPERO ID: CRD42023395556.
ABSTRACT
This review aimed to compare the outcomes of Descemet's membrane endothelial keratoplasty (DMEK) in combination with (category 1), before (category 2), or after cataract surgery (category 3) in patients with Fuchs' endothelial dystrophy (FED). Primary outcome was gain in best-corrected log of minimum angle of resolution (logMAR) visual acuity (BCVA). Secondary outcomes were graft detachment, rebubbling rates, rejection, failure, and endothelial cell loss (ECL). In category 1, 2, and 3, 12 studies (N = 1932) were included (five in category 1 [n = 696], one in category 2 [n = 286], and two in category 3 [n = 950], and the remaining four compared between two of the three categories). At 6 months, the gain in BCVA was 0.34 ± 0.04, 0.25 ± 0.03, and 0.38 ± 0.03 logMAR in category 1, 2, and 3, respectively. The difference was significant between categories 1 and 2 (Chi2 = 11.47, P < 0.01) and categories 2 and 3 (Chi2 = 35.53, P < 0.01). At 12 months, the gain in BCVA was 0.52 ± 0.05 and 0.38 ± 0.06 logMAR in categories 1 & 3 (Chi2 = 14.04, P < 0.01). The rebubbling rates were 15%, 4%, and 10% (P < 0.01) and the graft detachment rates were 31%, 8%, and 13% (P < 0.01) in categories 1, 2, and 3, respectively. However, graft rejection, survival rates, and ECL at 12 months were not different between categories 1 and 3. There is low certainty evidence that gain in BCVA in category 1 was comparable to category 3 at 6 months; however, it was significantly better with category 3 at 12 months. Although rebubbling and graft detachment rates were highest in category 1, there was no significant difference in graft rejection, survival rates, and ECL. Further high-quality studies are likely to change the effect estimate and have an impact on the confidence of the estimate.
Subject(s)
Cataract Extraction , Cataract , Corneal Transplantation , Fuchs' Endothelial Dystrophy , Humans , Descemet MembraneABSTRACT
Herein, we describe an iron-catalyzed benzylic C-H borylation reaction. The reaction targets primary and secondary C(sp3)-H bonds to deliver high-value boronic esters under mild conditions with short (7-8 min) reaction times. Functional groups are well tolerated, and complete site selectivity is observed in the presence of multiple benzylic C-H bonds.
Subject(s)
Esters , Iron , Iron/chemistry , Catalysis , Esters/chemistry , Boron/chemistryABSTRACT
Almost always, the analysis of single-cell RNA-sequencing (scRNA-seq) data begins with the generation of the low dimensional embedding of the data by principal-component analysis (PCA). Because scRNA-seq data are count data, log transformation is routinely applied to correct skewness prior to PCA, which is often argued to have added bias to data. Alternatively, studies have proposed methods that directly assume a count model and use approximately normally distributed count residuals for PCA. Despite their theoretical advantage of directly modeling count data, these methods are extremely slow for large datasets. In fact, when the data size grows, even the standard log normalization becomes inefficient. Here, we present FastRNA, a highly efficient solution for PCA of scRNA-seq data based on a count model accounting for both batches and cell size factors. Although we assume the same general count model as previous methods, our method uses two orders of magnitude less time and memory than the other count-based methods and an order of magnitude less time and memory than the standard log normalization. This achievement results from our unique algebraic optimization that completely avoids the formation of the large dense residual matrix in memory. In addition, our method enjoys a benefit that the batch effects are eliminated from data prior to PCA. Generating a batch-accounted PC of an atlas-scale dataset with 2 million cells takes less than a minute and 1 GB memory with our method.
Subject(s)
RNA , Single-Cell Analysis , Humans , Sequence Analysis, RNA/methods , Single-Cell Analysis/methods , Principal Component Analysis , Exome Sequencing , Gene Expression ProfilingABSTRACT
Most genomic cohorts are retrospective where the exposures and outcomes are predetermined prior to sample collection. Therefore, a spurious association between an exposure and an outcome can arise if both variables affect study participation. Such concerns were raised in previous studies questioning the representativeness of the UK Biobank. Recently, a genome-wide association study (GWAS) on biological sex found many autosomal hits and non-negligible autosomal heritability which the authors attribute to selection bias. In this study, we propose a simple and a practical method that can overcome sex-driven selection bias based on theoretical analysis and simulations.
Subject(s)
Genome-Wide Association Study , Polymorphism, Single Nucleotide , Bias , Genome-Wide Association Study/methods , Genomics , Retrospective StudiesABSTRACT
The standard analysis pipeline for single-cell RNA-seq data consists of sequential steps initiated by clustering the cells. An innate limitation of this pipeline is that an imperfect clustering result can irreversibly affect the succeeding steps. For example, there can be cell types not well distinguished by clustering because they largely share the global structure, such as the anterior primitive streak and mid primitive streak cells. If one searches differentially expressed genes (DEGs) solely based on clustering, marker genes for distinguishing these types will be missed. Moreover, clustering depends on many parameters and can often be subjective to manual decisions. To overcome these limitations, we propose MarcoPolo, a method that identifies informative DEGs independently of prior clustering. MarcoPolo sorts out genes by evaluating if the distributions are bimodal, if similar expression patterns are observed in other genes, and if the expressing cells are proximal in a low-dimensional space. Using real datasets with FACS-purified cell labels, we demonstrate that MarcoPolo recovers marker genes better than competing methods. Notably, MarcoPolo finds key genes that can distinguish cell types that are not distinguishable by the standard clustering. MarcoPolo is built in a convenient software package that provides analysis results in an HTML file.
Subject(s)
Single-Cell Analysis , Software , Algorithms , Biomarkers , Cluster Analysis , Gene Expression Profiling/methods , RNA-Seq , Sequence Analysis, RNA/methods , Single-Cell Analysis/methods , Exome SequencingABSTRACT
BACKGROUND: Patients who develop hospital-onset unresponsiveness should be promptly managed in order to avoid clinical deterioration. Pupillary examination through pupillary light reflex is the gold standard method in the initial evaluation of unresponsive patients. However, the current method of shining light and subjective description often shows poor reliability. The objective of this study is to explore whether a quantitative measurement of pupillary light reflexes is useful in detecting brain herniation syndrome and predicting neurological outcomes in patients who developed hospital-onset unresponsiveness after admission for non-neurological reasons. METHODS: This was a registry-based observational study on patients who activated the neurological rapid response team at Asan Medical Center (Seoul, Korea). Hospital-onset unresponsiveness was defined as a newly developed unresponsive state as assessed by the ACDU (Alert, Confused, Drowsy, and Unresponsive) scale during the hospital stay. Demographics, comorbidities, pupillometry parameters including Neurological Pupil index, brain herniation syndrome, in-hospital mortality, and modified Rankin Scale at 3-months were analyzed. RESULTS: In 214 consecutive patients with hospital-onset unresponsiveness, 37 (17%) had brain herniation syndrome. The optimal cut-off value of Neurological Pupil index for detecting brain herniation syndrome was < 1.6 (specificity, 91% [95% confidence interval (CI) = 86-95]; sensitivity, 49% [95% CI = 32-66]). The in-hospital mortality rate was 28% (59/214); the Neurological Pupil index was negatively associated with in-hospital mortality after adjustments for the presence of brain herniation syndrome (adjusted odds ratio = 0.77, 95% CI = 0.62-0.96). Poor neurological outcomes (modified Rankin Scale ≥4) at 3 months was observed in 76% (152/201) of the patients; the Neurological Pupil index was negatively associated with poor neurological outcomes after adjustments for clinical variables (adjusted odds ratio = 0.67, 95% CI = 0.49-0.90). CONCLUSIONS: Quantitative measurements of pupillary light reflexes may be useful for early detection of potentially life-threatening neurological conditions in patients with hospital-onset unresponsiveness.
Subject(s)
Consciousness Disorders/diagnosis , Hospitalization , Reflex, Pupillary/physiology , Brain Diseases/diagnosis , Hospital Mortality , Humans , Pupil/physiology , Republic of Korea , Sensitivity and SpecificityABSTRACT
Unlike echocardiography, cardiac magnetic resonance imaging (cardiac MRI) results in a near-exact assessment of cardiac structures and function. However, most veterinary studies have focused on dogs with normal cardiac function. We hypothesized that there would be significant differences in cardiac measurements between cardiac MRI and echocardiography when left ventricular (LV) function was abnormal. This study was undertaken to compare measurements of LV function produced by cardiac MRI and echocardiography in dogs whose LV function was altered by pharmacological agents. This study was conducted with six healthy beagle dogs. We increased left ventricular contractility by administration of dobutamine; we decreased cardiac contractility with esmolol. Stroke volume measurements were made by using both cardiac MRI and echocardiography under seven different conditions with general anesthesia: control, three doses of esmolol (100, 200, and 500 µg/kg/min), and three doses of dobutamine (10, 20, and 50 µg/kg/min). Experiments involving each condition were conducted at least 1 week apart. When LV contractility was normal, ejection fraction (EF) and stroke volume (SV), as measured by echocardiography and cardiac MRI, were not significantly different. However, when contractility was changed by pharmacological agents, EF and SV were overestimated by echocardiography, compared to MRI. Evaluation of cardiac function in patients treated with pharmacological agents should be conducted carefully because EF and SV measured by echocardiography can be overestimated, compared with EF and SV obtained by cardiac MRI.
Subject(s)
Dobutamine , Ventricular Function, Left , Animals , Dobutamine/pharmacology , Dogs , Echocardiography/veterinary , Magnetic Resonance Imaging/veterinary , Propanolamines , Stroke VolumeABSTRACT
OBJECTIVES: Performing magnetic resonance imaging (MRI) in neurocritically ill patients is challenging because it often requires sedation and withholding care in the neurological intensive care unit. This study investigated the incidence of and reasons for failed or complicated MRI (MRI-FC) in such patients. METHODS: A consecutive series of 218 neurocritically ill patients who underwent brain MRI were retrospectively evaluated. Failed or complicated MRI included failure to obtain all ordered sequences, unscheduled sedative administration, decrease in oxygen saturation to less than 90%, hypotension (≥40-mm Hg decrease and/or use of inotropic agents), and cardiac or respiratory arrest. RESULTS: Failed or complicated MRI occurred in 66 patients (30.3%) and included failure to obtain MRI sequences (n = 13), unscheduled use of sedatives (n = 62), oxygen desaturation (n = 9), and hypotension (n = 6). Cardiac or respiratory arrest did not occur. Use of sedative agents while in intensive care (P < 0.01), high Acute Physiology and Chronic Health Evaluation II score (P = 0.031), and low Glasgow Coma Scale score on admission (P = 0.047) were associated with MRI-FC. Scan times were longer (P = 0.004) and Glasgow Coma Scale (P < 0.001) and Richmond Agitation Sedation Scale (P = 0.003) scores were lower (P = 0.004) after imaging in patients with MRI-FC. Previous use of sedative agents was independently associated with MRI-FC (adjusted odds ratio = 3.57, 95% confidence interval = 1.78 to 7.24, P < 0.001). CONCLUSIONS: Failed or complicated MRI was common and was associated with the use of sedative agents, severity of illness, and lower level of consciousness. Studies to ensure effective and safe performance of MRI in neurocritically ill patients are needed.
Subject(s)
Hypnotics and Sedatives , Intensive Care Units , Critical Care , Critical Illness , Humans , Hypnotics and Sedatives/adverse effects , Magnetic Resonance Imaging , Retrospective StudiesABSTRACT
PURPOSE: To assess whether pars plana vitrectomy (PPV) is an aerosol-generating procedure (AGP) in an ex vivo experimental model. METHODS: In this ex vivo study on 10 porcine eyes, optical particle counter was used to measure particles ≤10 µm using cumulative mode in the six in-built channels: 0.3 µm, 0.5 µm, 1 µm, 2.5 µm, 5 µm and 10 µm aerosols during PPV. Two parts of the study were as follows: (1) to assess the pre-experimental baseline aerosol count in the theatre environment where there are dynamic changes in temperature and humidity and (2) to measure aerosol generation with 23-gauge and 25-gauge set-up. For each porcine eye, five measurements were taken for each consecutive step in the experiment including pre-PPV, during PPV, fluid-air exchange (FAX) and venting using a flute with 23-gauge set-up and a chimney with 25-gauge set-up. Therefore, a total of 200 measurements were recorded. RESULTS: With 23-gauge and 25-gauge PPV, there was no significant difference in aerosol generation in all six channels comparing pre-PPV versus PPV or pre-PPV versus FAX. Venting using flute with 23-gauge PPV showed significant reduction of aerosol ≤1 µm. Air venting using chimney with 25-gauge set-up showed no significant difference in aerosol of ≤1 µm. For cumulative aerosol counts of all particles measuring ≤5 µm, compared with pre-PPV, PPV or FAX, flute venting in 23-gauge set-up showed significant reduction unlike the same comparison for chimney venting in 25-gauge set-up. CONCLUSION: PPV and its associate steps do not generate aerosols ≤10 µm with 23-gauge and 25-gauge set-ups.
Subject(s)
Aerosols/adverse effects , Endophthalmitis/etiology , Eye Infections/etiology , Microsurgery/adverse effects , Surgical Wound Infection/etiology , Vitrectomy/adverse effects , Animals , Disease Models, Animal , Eye Infections/transmission , Retrospective Studies , Surgical Wound Infection/transmission , Swine , Vitrectomy/methodsABSTRACT
OBJECTIVE: We aimed to present neurological profiles and clinical outcomes of patients with acute neurological symptoms, which developed during hospitalization with nonneurological illness. METHODS: We organized the neurological alert team (NAT), a neurological rapid response team, to manage in-hospital neurological emergencies. In this registry-based study, we analyzed the clinical profiles and outcomes of patients who were consulted to the NAT. We also compared the 3-month mortality of patients with acute neurological symptoms with that of patients without acute neurological symptoms. RESULTS: Among the 85,507 adult patients, 591 (0.7%) activated the NAT. The most common reason for NAT activation was stroke symptoms (37.6%), followed by seizures (28.6%), and sudden unresponsiveness (24.0%). The most common diagnosis by the NAT neurologists was metabolic encephalopathy (45.5%), followed by ischemic stroke (21.2%) and seizures or status epilepticus (21.0%). Patients with NAT activation had high rates in mortality before hospital discharge (22.5%) and at 3 months (34.7%), transfer to intensive care units (39.6%), and length of hospital stay (43.1 ± 57.1 days). They also had high prevalence of poor functional status (78.1%) and recurrence of neurological symptoms at 3 months (27.2%). In a Cox proportional hazards model, patients with in-hospital neurological emergencies had a hazard ratio of 13.2 in terms of mortality at 3 months (95% confidence interval, 11.5-15.3; P < 0.001). CONCLUSIONS: Occurrence of acute neurological symptoms during hospital admission was associated with high rate of mortality and poor functional status. These results call for enhanced awareness and hospital-wide strategies for managing in-hospital neurological emergencies.
Subject(s)
Emergencies , Stroke , Adult , Hospitalization , Humans , Intensive Care Units , Length of Stay , Stroke/epidemiology , Stroke/therapySubject(s)
Corneal Diseases , Corneal Transplantation , Corneal Diseases/surgery , Graft Rejection , Humans , United KingdomSubject(s)
Coronavirus Infections , Pandemics , Pneumonia, Viral , Betacoronavirus , COVID-19 , Humans , SARS-CoV-2ABSTRACT
Even though casein has an intrinsic potential ability to act as a flame retardant (FR) additive, the research regarding the FR performance of casein filled polymeric composites has not been thoroughly conducted. In the present work, two commercial casein products, such as lactic casein 720 (LAC) and sodium casein 180 (SC), were chosen to investigate their effects on the performances of the polypropylene (PP) composites. The melt compounding and compression moulding processes were employed to fabricate these casein-based composites. Ammonium polyphosphate (APP) was also selected to explore its combined effects in conjunction with casein on the composite's flammability. The cone calorimeter results showed that the addition of casein significantly reduced (66%) the peak heat release rate (PHRR) of the composite compared to that of neat PP. In particular, the combination of LAC and APP led to the formation of more compact and rigid char compared to that for SC based sample; hence, a further reduction (80%) in PHRR and self-extinguishment under a vertical burn test were accomplished. Moreover, the tensile modulus of the composite improved (23%) by the combined effects of LAC and APP. The overall research outcome has established the potential of casein as a natural protein FR reducing a polymer's flammability.
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BACKGROUND: Genetic variants may play a role in determining the location of cerebral atherosclerosis. We aimed to investigate the association between RNF213, MMP2, and genetic polymorphisms linked to vascular tortuosity with the location of cerebral arterial atherosclerosis. METHODS: A prospective case-control study was conducted on patients with ischemic stroke and age- and sex-matched stroke-free controls. The stroke patients were categorized into those with intracranial artery atherosclerosis (ICAS), extracranial artery atherosclerosis (ECAS), and small vessel occlusion (SVO). Six single nucleotide polymorphisms (SNPs) including rs2118181 (FBN1), rs2179357 (SLC2A10), rs1036095 (TGFBR2), rs243865 (MMP2), rs1800470 (TGFB1), and rs112735431 (RNF213) were analyzed with the TaqMan Genotyping Assay, and the distribution of genotypes across groups was compared. RESULTS: None of the 6 SNPs were associated with stroke on comparing the 449 stroke patients (71 with ECAS, 169 with ICAS, and 209 with SVO) to the 447 controls. In the subgroup analysis, the adjusted odds ratios (aORs) for age and sex indicated a significant association between rs112735431 and ICAS in the allele comparison analysis and in the additive and dominant model analyses. rs112735431 was associated with anterior circulation involvement and increased burden of cerebral atherosclerosis. rs2179357 was significantly associated with ICAS in the recessive model analysis, and rs1800470 was significantly associated with ECAS in the recessive model analysis when compared to controls. CONCLUSION: rs112735431 was associated with ICAS and increased atherosclerosis burden in Korean stroke patients. Further studies are needed to elucidate the role of rs112735431 and to confirm the association of rs2179357 and rs1800470 with cerebral atherosclerosis.
Subject(s)
Adenosine Triphosphatases/genetics , Cerebral Small Vessel Diseases/genetics , Intracranial Arteriosclerosis/genetics , Polymorphism, Single Nucleotide , Stroke/genetics , Ubiquitin-Protein Ligases/genetics , Aged , Case-Control Studies , Cerebral Small Vessel Diseases/diagnostic imaging , Female , Fibrillin-1/genetics , Genetic Predisposition to Disease , Glucose Transport Proteins, Facilitative/genetics , Humans , Intracranial Arteriosclerosis/diagnostic imaging , Male , Matrix Metalloproteinase 2/genetics , Middle Aged , Phenotype , Receptor, Transforming Growth Factor-beta Type II/genetics , Risk Assessment , Risk Factors , Seoul , Stroke/diagnostic imaging , Transforming Growth Factor beta1/geneticsABSTRACT
PURPOSE: To evaluate whether phacoemulsification is an aerosol-generating procedure in an ex vivo experimental model. SETTING: Sussex Eye Hospital, Brighton, United Kingdom. DESIGN: Experimental study. METHODS: In this ex vivo study on 15 porcine eyes, an optical particle counter was used to measure particles of 10 µm and less using the cumulative mode based on the 6 in-built channel sizes. The 2 parts of the study were to: (1) assess the efficacy of the particle counter in the theater environment where there are dynamic changes in temperature and humidity; and (2) to measure aerosol generation with 3 phacoemulsification settings: (i) continuous power with 80% longitudinal (5 eyes); (ii) continuous power with 100% torsional (5 eyes); and (iii) continuous power with 80% longitudinal with application of hydroxypropyl methylcellulose (HPMC) on the ocular surface (5 eyes). Five measurements were taken prephacoemulsification and 5 during phacoemulsification per eye therefore totaling 75 measurements. RESULTS: Maximum aerosols were captured when the counter faced the aerosol source. There was no significant difference in aerosol generation of all sizes during each phacoemulsification setting with torsional, longitudinal, and longitudinal with HPMC (P > .01). Combining data of all 3 phacoemulsification settings (150 measurements from 15 eyes), there was no significant difference comparing prephacoemulsification and during phacoemulsification for aerosols of 5 µm or less (1455 vs 1363.85, P = .60), more than 5 to 10 µm (1.5 vs 1.03, P = .43), and of 10 µm or less (1209 vs 1131.55, P = .60). CONCLUSIONS: Phacoemulsification did not generate aerosols of 10 µm or less with continuous power using 80% longitudinal, 100% torsional, and 80% longitudinal setting with HPMC on the surface.