Tag: statistics

J Chem Phys. 2023 Apr 28;158(16):164502. doi: 10.1063/5.0137115.

ABSTRACT

How dense objects, particles, atoms, and molecules can be packed is intimately related to the properties of the corresponding hosts and macrosystems. We present results from extensive Monte Carlo simulations on maximally compressed packings of linear, freely jointed chains of tangent hard spheres of uniform size in films whose thickness is equal to the monomer diameter. We demonstrate that fully flexible chains of hard spheres can be packed as efficiently as monomeric analogs, within a statistical tolerance of less than 1%. The resulting ordered polymer morphology corresponds to an almost perfect hexagonal triangular (TRI) crystal of the p6m wallpaper group, whose sites are occupied by the chain monomers. The Flory scaling exponent, which corresponds to the maximally dense polymer packing in 2D, has a value of ν = 0.62, which lies between the limits of 0.50 (compact and collapsed state) and 0.75 (self-avoiding random walk).

PMID:37092880 | DOI:10.1063/5.0137115

J Chem Phys. 2023 Apr 28;158(16):164501. doi: 10.1063/5.0140951.

ABSTRACT

Clathrate hydrates are crystalline inclusion compounds wherein a water framework encages small guest atoms/molecules within its cavities. Among the others, methane clathrates are the largest fossil fuel resource still available. They can also be used to safely transport gases and can also form spontaneously under suitable conditions plugging pipelines. Understanding the crystallization mechanism is very important, and given the impossibility of experimentally identifying the atomistic path, simulations played an important role in this field. Given the large computational cost of these simulations, in addition to all-atom force fields, scientists considered coarse-grained water models. Here, we have investigated the effect of coarse-graining, as implemented in the water model mW, on the crystallization characteristics of methane clathrate in comparison with the all-atom TIP4P force field. Our analyses revealed that although the characteristics directly depending on the energetics of the water models are well reproduced, dynamical properties are off by the orders of magnitude. Being crystallization a non-equilibrium process, the altered kinetics of the process results in different characteristics of crystalline nuclei. Both TIP4P and mW water models produce methane clathrate nuclei with some amount of the less stable (in the given thermodynamic conditions) structure II phase and an excess of pentagonal dodecahedral cages over the tetrakaidecahedral ones regarding the ideal ratio in structure I. However, the dependence of this excess on the methane concentration in solution is higher with the former water model, whereas with the latter, the methane concentration in solution dependence is reduced and within the statistical error.

PMID:37092879 | DOI:10.1063/5.0140951

Leadersh Health Serv (Bradf Engl). 2023 Apr 25;ahead-of-print(ahead-of-print). doi: 10.1108/LHS-10-2022-0097.

ABSTRACT

PURPOSE: This study aims to investigate the mediating effect of transformational leadership (TL) and work engagement (WE) on health-care clinic nurses’ performance and the crucial role of these variables in the work environment (WEV).

DESIGN/METHODOLOGY/APPROACH: Data were collected from 353 nurses working across various health-care clinics in the United Arab Emirates. This study used descriptive correlational statistics from the Statistical Package for the Social Sciences, the Pearson correlation coefficient, confirmatory factor analysis for model validity, Cronbach’s alpha for reliability and path analysis to determine the results.

FINDINGS: The relationship between TL and job performance among nurses in health-care clinics was strongly influenced by WE. In addition, a moderate WEV increased the positive influence of TL on job accomplishment. Furthermore, there were no statistically significant differences between the participants’ demographics characteristics and the main variables of the study.

PRACTICAL IMPLICATIONS: Health-care management can support and enhance nurses’ job performance through TL, create a more structured WEV and support WE.

ORIGINALITY/VALUE: This study involves a specific investigation into WE as a mediator, WEV as a moderator and the effect of TL on nurses’ job performance.

PMID:37093237 | DOI:10.1108/LHS-10-2022-0097

Plast Reconstr Surg. 2023 Apr 25. doi: 10.1097/PRS.0000000000010592. Online ahead of print.

ABSTRACT

BACKGROUND: Autologous breast reconstruction yields improved long-term aesthetic results but requires increased resources of practitioners and hospital systems. Innovations in radiographic imaging have been used increasingly to improve the efficiency and success of free-flap harvest. Augmented reality (AR) affords the opportunity to superimpose relevant imaging on a surgeon’s native field of view, potentially facilitating dissection of anatomically variable structures. To validate the spatial fidelity of AR projections of deep inferior epigastric perforator flap (DIEP) relevant anatomy, comparisons of 3D models and their virtual renderings were performed by four independent observers. Measured discrepancies between the real and holographic models were evaluated.

METHODS: 3D-printed models of DIEP relevant anatomy were fabricated from CTA data from 19 de-identified patients. The corresponding CTA data was similarly formatted for the Microsoft Hololens to generate corresponding projections. Anatomic points were initially measured on 3D models, after which, the corresponding points were measured on the Hololens projections from two separate vantages. Statistical analyses, including Generalized Linear Modeling, were performed to characterize spatial fidelity regarding translation, rotation, and scale of holographic projections.

RESULTS: Amongst all participants, the median translational displacement at corresponding points was 9.0 mm, 12.1 mm, and 13.5 mm between the real 3D model and V1, 3D model and V2, and between V1 and V2, respectively.

CONCLUSION: Corresponding points, including topography of perforating vessels for the purposes of breast reconstruction can be identified within millimeters, but there remain multiple independent contributors of error, most notably the participant and location at which the projection is perceived.

PMID:37092985 | DOI:10.1097/PRS.0000000000010592

J Pediatr Ophthalmol Strabismus. 2023 Apr 25:1-4. doi: 10.3928/01913913-20230323-02. Online ahead of print.

ABSTRACT

PURPOSE: To understand patients’ strabismus surgery experience, including its impact on patients’ appearance and psychosocial factors such as anxiety and depression, via trends on popular social media platforms.

METHODS: TikTok and Instagram were searched for the following post hashtags: “#strabismus,” “#strabismussurgery,” “#crosseyed,” and “#lazyeye.” Data regarding date of post, username, gender, city, state, United States or international location, surgical status (preoperative, perioperative, or postoperative), tone (positive or negative), place of treatment, type of post (photo or video), number of likes/views, and number of followers were recorded for statistical analysis.

RESULTS: A total of 790 posts (400 TikTok, 390 Instagram) were included. The majority (87.8%) had a positive tone, particularly for Instagram (Instagram = 97.7%, TikTok = 78.3%, P < .01). TikTok had significantly more likes/follower (P < .01), as did negative posts (P < .01). #Lazyeye gained significantly more traction than other hashtags (range: P < .001 to .006). There were no differences in likes/follower for treatment phase (preoperative/perioperative/postoperative), gender, or relative age of poster (adult/parent/child).

CONCLUSIONS: These findings demonstrated that TikTok and Instagram users tend to share positive strabismus surgical experiences; however, negative posts were associated with more interactive responses from viewers. Colloquial hashtags (eg, #lazyeye) were more likely to gain traction than medical terms. TikTok posts were associated with more engagement than Instagram, which suggests TikTok may be a better platform going forward for patient outreach. [J Pediatr Ophthalmol Strabismus. 20XX;X(X):XX-XX.].

PMID:37092665 | DOI:10.3928/01913913-20230323-02

J Pediatr Ophthalmol Strabismus. 2023 Apr 25:1-8. doi: 10.3928/01913913-20230118-02. Online ahead of print.

ABSTRACT

PURPOSE: To determine the effects of strabismus on dry eye parameters.

METHODS: In this cross-sectional study, the preliminary assessment of ocular parameters related to dry eye disease was performed in patients with untreated concomitant strabismus. In total, 204 patients with concomitant strabismus and 125 volunteers without strabismus (4 to 30 years old, 170 male and 159 female) were enrolled. The Ocular Surface Disease Index questionnaire (OSDI) was administered, and ocular surface was examined using the Oculus Keratograph 5M (Oculus Optikgeräte GmbH) to collect data on tear film break-up time (TBUT), ocular redness index (based on bulbar conjunctival blood vessel engorgement), and meibomian gland atrophy. Subgroup analysis was performed based on strabismus type (concomitant exotropia, concomitant esotropia, and non-strabismus); age (juvenile versus adults age > 18 years); and 5- to 10-year and 10- to 20-year strabismus course, according to an age of 12 years.

RESULTS: Concomitant exotropia and esotropia were reported in 134 and 70 patients, respectively. A total of 125 healthy volunteers were recruited. The three groups showed significant differences in the ocular redness index (right eye: P = .012, left eye: P = .018). In contrast, other parameters were not significantly different. Similarly, no statistical differences in ocular surface indicators were observed when patients were divided by age (P > .05 for all) and the 5- to 10-year and 10-to 20-year strabismus course. The meibomian gland showed varying degrees atrophy in both strabismus and non-strabismus groups.

CONCLUSIONS: Strabismus does not affect tear film stability with age in this cohort with constant strabismus up to 30 years, indicating that strabismus may not increase the risk of dry eye disease. [J Pediatr Ophthalmol Strabismus. 20XX;X(X):XX-XX.].

PMID:37092662 | DOI:10.3928/01913913-20230118-02

J Pediatr Ophthalmol Strabismus. 2023 Apr 25:1-6. doi: 10.3928/01913913-20230331-02. Online ahead of print.

ABSTRACT

PURPOSE: To determine the normal values of optic nerve sheath diameter (ONSD) by computed tomography (CT) in the pediatric population.

METHODS: The CT scans of pediatric patients aged 1 to 16 years who underwent brain CT for different reasons, who did not have intracranial pathology or increased intracranial pressure, and who had no pathology on CT were included in the study. Four age groups were defined with the following ranges: 1 to 2, 3 to 6, 7 to 10, and 11 to 16 years. ONSD was measured from axial CT images, 3 and 10 mm behind the optic globe.

RESULTS: The normative values of ONSD measured on CT imaging in children aged 1 to 16 years were reported. The change in ONSD according to age was investigated. ONSD was found to increase with age at both levels measured. The difference was statistically significant.

CONCLUSIONS: Normal values should be known to detect pathologies that may cause an increase in optic nerve diameter. The values reported in this study can serve as a reference for normal optic nerve sheath diameter in the pediatric age group. [J Pediatr Ophthalmol Strabismus. 20XX;X(X):XX-XX.].

PMID:37092660 | DOI:10.3928/01913913-20230331-02

J Adhes Dent. 2023 Apr 24;25(1):87-97. doi: 10.3290/j.jad.b4043039.

ABSTRACT

PURPOSE: To retrospectively evaluate the clinical behavior of direct anterior composite restorations performed with a universal adhesive or with a three-step etch-and-rinse (E&R) adhesive.

MATERIAL AND METHODS: Patients were randomly treated with a three-step E&R adhesive (Optibond FL, Kerr) or a universal adhesive (Clearfil Universal Bond Quick, Kuraray Noritake) applied in E&R mode. All restorations were performed with a nanohybrid composite (ClearFil Majesty ES-2, Kuraray Noritake) by the same experienced operator. Two calibrated examiners evaluated the restorations using a dental mirror and explorer, in accordance with modified United States Public Health Service (USPHS) procedures. Clinical events were registered and classified as either failure (F), survival (SR), or success (S).

RESULTS: 168 restorations were evaluated in 90 patients with an average follow-up period of 37.9 (± 22.9) months. A total of 132 restorations were performed on vital teeth, and 36 were performed on endodontically treated teeth (ETT). A total of 128 Class-IV and 40 Class-III restorations were performed. In 89 restorations, a three-step E&R adhesive was applied (14 Class-III and 75 Class-IV), while in 79, a universal adhesive was used (26 Class-III and 53 Class-IV, p = 0.0091). A Cox regression analysis was performed (p < 0.05) to analyze which factors were involved in the failure of the restorations, considering failure (F) as restorations that needed re-intervention at the follow-up period of 37.9 (± 22.9) months. No statistically significant differences were observed when considering parameters directly involved with the adhesives tested. Endodontically treated teeth were more prone to fractures (p = 0.0006) compared to vital teeth. Restorations made with universal adhesives failed by fracturing significantly more frequently (p = 0.0234), while restorations made on endodontically treated teeth had a significantly worse outcome (p = 0.0001). Restorations made on canines also failed significantly more frequently (HR = 3.8, 95% CI = 1.4-10.1, p = 0.0062).

CONCLUSIONS: Based on the obtained results, both the universal adhesive and the three-step E&R adhesive proved to be good treatment choices for direct anterior restorations after 37.9 (± 22.9) months of follow-up. Tooth vitality seems fundamental for the prognosis of a direct anterior composite restoration over time.

PMID:37093568 | DOI:10.3290/j.jad.b4043039

Probiotics Antimicrob Proteins. 2023 Apr 24. doi: 10.1007/s12602-023-10075-5. Online ahead of print.

ABSTRACT

Prebiotics are substrates selectively utilized by host microorganisms conferring a health benefit. The effects of prebiotics on the gut microbiome of individuals with inflammatory processes need further investigations. The purpose of this study was to evaluate the effects of prebiotics on the gastrointestinal microbiome of individuals with some types of inflammatory conditions. Randomized controlled clinical trials (RCTs) evaluating the effects of different prebiotics on the gut microbiome were included. A systematic review of the literature including searches in PubMed/MEDLINE, EMBASE, Cochrane Library, Web of Science, and Scopus databases was performed until 23 March 2023. The risk of bias was assessed using the Cochrane Collaboration’s criteria. Qualitative data was tabulated to facilitate comparisons and represented in the form of descriptive statistics and summary tables. Thirty trials, ranging from 12 to 135 patients, were included. The most commonly used prebiotic type was inulin-type fructans, and the treatment duration ranged from 1 to 36 weeks. The majority of the trials investigated the gut microbiome using 16 s rRNA gene sequencing on the Illumina Miseq platform. In general, prebiotic therapy exerted positive effects on inflammatory conditions. An increase in Bifidobacterium genus was the most common shift in bacterial composition observed. Within the limits of this systematic review, it can be suggested that prebiotic therapy presents the potential to favorably modulate the gastrointestinal microbiome of individuals with different types of inflammatory conditions.

PMID:37093515 | DOI:10.1007/s12602-023-10075-5

J Robot Surg. 2023 Apr 24. doi: 10.1007/s11701-023-01597-9. Online ahead of print.

ABSTRACT

The objective of this study was to compare the surgical outcomes of robotic multi-site myomectomy (RMSM) with those of robotic single-site myomectomy (RSSM). We conducted a systematic search of the PubMed, CINAHL, Scopus, and Google Scholar databases for articles comparing RMSM and RSSM until March 2023. Data analysis was performed using Review Manager V5.3 (Cochrane), and the main outcomes examined were perioperative outcomes and complications. A total of five studies, covering 823 patients, were included in the analysis. The statistical analysis revealed no significant differences between RMSM and RSSM with regard to docking time (p = 0.9), console time (p = 0.37), estimated blood loss (p = 0.38), postoperative hemoglobin (Hb) loss (p = 0.61), transfusion rate (p = 0.25), length of stay (p = 0.08), conversion (p = 0.36), postoperative fever (p = 0.46), intraoperative complication (p = 0.23), or postoperative complication (p = 0.12). However, compared to RMSM, RSSM was found to have a shorter morcellation time (weighted mean difference [WMD] – 4.52 min; 95% confidence interval [CI] – 6.89 to 2.15; p = 0.0002), less total operative time (WMD – 9.83 min; 95% CI – 18.27 to – 1.38; p = 0.02), lower Hb change (WMD – 0.28 g/dL; 95% CI – 0.49 to – 0.07; p = 0.008), and fewer overall complications (odds ratio [OR] 0.55; 95% CI 0.32-0.92; p = 0.02). Our findings suggest that RSSM is a safe and effective alternative to RMSM for the most studied outcomes. Further randomized studies are necessary to validate these results.

PMID:37093509 | DOI:10.1007/s11701-023-01597-9