Nanoparticle aggregation and electro-osmotic propulsion in peristaltic transport of third-grade nanofluids through porous tube.

In the modern era, the utilization of electro-kinetic-driven microfluidic pumping procedures spans various biomedical and physiological domains. The present study introduces a mathematical framework for characterizing the hemodynamics of peristaltic blood flow within a porous tube infused with ZrO2 nanoparticles. This model delves into the interactions between buoyancy, electro-osmotic forces, and aggregated nanoparticles to discern their influence on blood flow. We employ a third-grade fluid model to elucidate the rheological behavior of the pseudoplastic fluid which refers to its response to applied shear stress, specifically the relationship between shear rate and viscosity. The collective influence of accommodating heat convection, joule heating and aggregated nanoparticles contributes to the thermal behavior of fluids. The distribution of electric potential within the electric double layer (EDL) is predicted by solving the Poisson-Boltzmann equation. The rescaled equations are simplified using the lubrication and Debye-Hückel models as the underlying frameworks. The novel homotopy perturbation method is employed to obtain solutions for the finalized non-linear partial differential equation. Theoretical assessment of hemodynamic impacts involves plotting graphical configurations for various emerging parameters. As electro-osmotic parameter increase, the bloodstream encounters greater impedance, thereby enhancing the effectiveness of electro-osmotic assistance. Concurrently, elevated convective heat markedly reduces the rate of heat transfer, potentially resulting in a drop in blood temperature. It is important to note that maximum shear stress occurs when the artery is positioned horizontally, underscoring the significant impact of arterial alignment on wall shear stress. Skin friction intensifies with the increasing wall permeability as aggregated nanofluids pass through the arterial conduit. Therefore, aggregation of nanoparticles into the bloodstream yields a broader spectrum of distinctive physiological features. In summary, these findings enable more effective tool and device designs for addressing medication administration challenges and electro-therapies.

The Role of Microsurgery in Coverage of Defects of the Hand.

Soft tissue defects of the hand may result from trauma, infection, vascular disease, and after resection of tumors. Microsurgery has evolved to a stage where it is relatively commonplace today but procedures such as free flaps still incur significant time, manpower, cost, and material resources. The aim of this article is to articulate the specific situations in hand reconstruction when microsurgery is superior to nonmicrosurgical reconstructive options. The benefits of microsurgical reconstruction include a variety of important metrics, such as improved function, better tissue match, less donor site morbidity, and reduced downtime for the patient.

Revisiting the reconstructive ladder for soft tissue reconstruction in the lower extremity.

Soft tissue reconstruction of the lower limb has seen a paradigm shift over the past two decades. Typically, these defects arise from trauma, infection or tumor. It is no longer enough to simply achieve coverage. Factors like patient-reported outcomes and aesthetic considerations are essential in the decision-making process. This is especially in light of increasing technological advancement, availability of dermal substitutes, microsurgical expertise and development of the field of microsurgical reconstruction as a whole with more novel flaps and techniques. Advancements in reconstructive modalities have also been equally matched by better emergency medical mobilization, transportation and access, early initiation of subspecialty care, accessibility and types of imaging, as well as oncological advances in radiotherapy and chemotherapy regimens. Yet, this has also meant that our patient profile has expanded to include older patients with more co-morbidities and other considerations such as frailty or the irradiated field which could influence what reconstructive modality is suitable and the goals of reconstruction specific to the patient. Previously deemed unsalvageable limbs are now being successfully reconstructed with good function and aesthesis. In the lower limb, this implicates the ability for early mobilization, range of motion and weight bearing which allow the patient to successfully partake in early rehabilitation. Expedient and reliable healing is also important in the oncological population where a proportion of these patients would need to go on to receive post-operative chemotherapy or radiotherapy. The reconstructive ladder has been what many reconstructive surgeons have been taught upon with regard to the basic principles of pre-operative planning and choosing the appropriate reconstructive modality. In this article, we examine the relevance of the reconstructive ladder in modern practice and the additional considerations in the approach to a soft tissue defect in the lower extremity.

Challenges and Solutions in Prosthetic Fitting of Digits after Flap Reconstruction.

Surgical reconstruction can restore length and function, but cannot adequately resolve the problem of disfigurement. Prosthetic fitting can play a complementary role in enhancing the aesthetic outcomes post reconstruction. However, complex reconstruction involving flaps coupled with the surgical imperative for limb length preservation can lead to outcomes where the reconstructed stumps are challenging to fit with prosthesis. This article describes how prosthetic fitting was tackled in a case of a triple-digit amputation after reconstruction that presented with finger stumps that were bulky, long and stiff in extension contracture, compounded by the presence of substantive scar tissues. We discuss major prosthesis modifications that were unconventional but necessary to enable fitting, the techniques involved, as well as the aesthetic and functional considerations behind the modifications. The results showed that enhanced aesthetic appearance, together with a marginal improvement in hand function, was achieved post-prosthetically, meeting the patient's and the clinical team's fitting objective. Level of Evidence: Level V (Therapeutic).

Aesthetic Considerations in Pollicisation Using the Buck-Gramcko Technique.

The Buck-Gramcko (BG) technique of pollicisation has stood the test of time and provides good to excellent prehensile function in thumb hypoplasia. Proponents of the technique favour it because it provides good exposure to the palmar neurovascular structures. However, the skin flap design may occasionally lead to a 'finger-like' appearance with a sharp interdigital cleft and a triphalangeal form. In this report, we describe some of the important aspects of the operative technique so that the outcome is aesthetically pleasing in addition to providing good function. Level of Evidence: Level V (Therapeutic).

Interplay between anti-anti and syn-anti conformations of thiourea modulating ON-OFF catalysis.

The design, synthesis and operation of a readily accessible two-state switch are demonstrated. The switch initially exists in an intramolecularly hydrogen-bonded self-locked state, as evidenced by the solution-state NMR and solid-state structure. The switch can be reversibly altered between anti-anti and syn-anti conformations by adding and removing Cu+ ions, as evidenced by the NMR and crystallographic study. The anti-anti form was found to be catalytically active in the Michael addition reaction, whereas the syn-anti form was catalytically inactive.

Functional use of esthetic hand prosthesis: A patient's perspective.

Published reports on the functional benefits of esthetic prosthesis are based on either anecdotal evidence or simplified, nonstandard forms of hand function evaluation performed by the researcher. It is not clear whether and how patients actually make functional use of their prosthesis on a daily basis. We report a case of a patient with a partial hand amputation who was initially ambivalent about fitting an esthetic prosthesis, but went on to make functional use of her prosthesis for activities of daily living, work, and social life at 3 years after injury. We present the patient's own assessment and video recordings, made without influence from rehabilitation personnel that demonstrates this functional use. From this case, we discuss the important factors of a favorable residual limb type, together with targeted modifications made to the prosthesis to optimize function.

Outcomes Associated with Moberg and Modified Moberg Flaps in Thumb Reconstruction: A Systematic Review.

Background: Appropriate thumb function is critical as it is makes up approximately 40% of the hand's function leading to the greatest influence in activities of daily living (ADLs). Local flaps are the primary option for thumb reconstruction, of which the Moberg flap has been reported to have the added advantage of its advancement capacity relative to other flaps. This systematic review aims to describe the outcomes of the Moberg advancement flap and its associated modifications for coverage of palmar thumb defects. Methods: Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed for the conduct of this systematic review. Medline, Embase, CINAHL and Cochrane Library were systematically searched to retrieve relevant citations. Title and abstract as well as full-text assessment were performed in duplicate. Full texts were extracted by one reviewer and data extracted was confirmed by a second. Complication rates and overall means were calculated for the appropriate outcomes. Results: A total of 1,794 citations were retrieved; 15 papers were retained, including 169 patients. The overall mean follow-up was 28.6 months (n = 5 studies). In 136 patients, there was 100% flap viability (n = 12 studies). With regard to thumb aesthetics, 92% (59/64 patients) had favourable outcomes (n = 6 studies). No evidence of postoperative flexion contractures (n = 0/56 patients, 5 studies) was found. Cold intolerance occurred at a rate of 29.8% (n = 17/57, 4 studies) and the infection rate was 10.3% (6/58 patients, 3 studies). Conclusions: Moberg/modified Moberg flaps are a safe option for thumb reconstruction given their associated postoperative outcome and complication profile. Level of Evidence: Level III (Therapeutic).

Light-Triggered Reversible Open-Close Motion of a Chiral Molecular Plier to Modulate Guest Binding.

A chiral molecular plier's design, synthesis, characterisation and operations are presented. The molecular plier encompasses three units: a BINOL unit which acts as a pivot as well as a chiral inducer, an azobenzene unit, which acts as a photo-switchable component and two zinc porphyrin, acting as a reporter. E to Z isomerisation persuaded by irradiating with 370 nm light alters the dihedral angle of the pivot BINOL unit, which adjusts the distance between two porphyrin units. The plier can be switched to its initial state by exposure to 456 nm light or heating at 50 °C. NMR, CD and molecular modelling supported the reversible switching and change in dihedral angle and distance between reporter moiety, which was further exploited for binding with several ditopic guests. The longest guest was found to form the strongest complex, R,R-isomer formed a stronger complex than S,S-isomer, Z-isomer of the plier formed stronger complex than the E-isomer with the guest. Moreover, complexation also increased the E-to-Z switching efficiency and decreased the thermal back isomerisation of the azobenzene unit.

Surgical Technique: Lateral Plate Osteosynthesis of Proximal Phalanx Fractures.

Dorsal plate fixation of proximal phalanx (PP) fractures is a conventional approach but interferes with the extensor mechanism and results in stiffness. Biomechanical studies have shown that laterally placed plates on the proximal phalanges are equally stable and rigid. This technique obviates the issue of tendon adhesion and may result in better postoperative range of motion and lower secondary procedures such as removal of implant and tenolysis. The low adoption of this technique may be related to lack of familiarity with the surgical approach. We describe our surgical technique with lateral plating of PP fractures and present our case that lateral plate osteosynthesis is an acceptable surgical fixation option for PP fractures, which extends the hand surgeon's armamentarium for more challenging and comminuted fractures.

Randomised controlled trials in hand surgery: a scoping review.

OBJECTIVES: To identify the evidence gaps that exist regarding the efficacy or effectiveness of hand surgery. SETTING: A scoping review. We systematically searched MEDLINE, Embase and CENTRAL databases to identify all hand surgical randomised controlled trials from inception to 7 November 2020. RESULTS: Of the 220 identified randomised controlled trials, none were fundamental efficacy trials, that is, compared surgery with placebo surgery. 172 (78%) trials compared the outcomes of different surgical techniques, and 143 (65%) trials were trauma related. We identified only 47 (21%) trials comparing surgery with non-operative care or injection. CONCLUSION: The evidence supporting use of surgery especially for chronic hand conditions is scarce. To determine optimal care for people with hand conditions, more resources should be aimed at placebo-controlled trials and pragmatic effectiveness trials comparing hand surgery with non-operative care. PROSPERO REGISTRATION NUMBER: CRD42019122710.

Pigmented Nail Lesions: When to Observe, When to Biopsy, When to Widely Excise, and When to Amputate?

Pigmented nail lesions are challenging problems. The differential diagnosis is broad and ranges from common self-limiting conditions, such as subungual hematoma and infection, to potentially fatal conditions, such as subungual melanoma. Clinical assessment and adjuncts, such as dermoscopy and imaging, are usually insufficient to establish a diagnosis, and a nail bed biopsy is often required. However, this is not an innocuous procedure and may result in permanent nail deformity. In addition, subjecting every patient with nail pigmentation to a biopsy will result in an unacceptably high rate of negative test results. Furthermore, histopathologic diagnosis of subungual melanoma remains challenging for several reasons. Once the diagnosis of subungual melanoma is established, the definitive treatment is controversial because the existing guidelines have largely been adapted from those for cutaneous melanoma. This review presents an approach to the diagnosis and management of pigmented subungual lesions and subungual melanoma, in particular, on the basis of the latest available evidence.

Recent Advances in Fuel-Driven Molecular Switches and Machines.

The molecular switches and machines arena has entered a new phase in which molecular machines operate under out-of-equilibrium conditions using appropriate fuel. Unlike the equilibrium version, the dissipative off-equilibrium machines necessitate only one stimulus input to complete each cycle and decrease chemical waste. Such a modus operandi would set significant steps towards mimicking the natural machines and may offer a platform for advancing new applications by providing temporal control. This review summarises the recent progress and blueprint of autonomous fuel-driven off-equilibrium molecular switches and machines.

Mirror hand-ulnar dimelia: a single centre experience with 13 patients.

Mirror hand-ulnar dimelia (MHUD) is rare congenital disorder with a wide range of clinical and radiographic features. The current nomenclature is confusing and the existing classification systems focus mainly on morphology without providing much guidance for treatment. The goal of this study was to review the clinical and radiological features in 13 children with MHUD that were treated at a single institution. Our findings support the hypothesis that MHUD typically involves the entire upper limb, and the treatment plan should consider the predictors of function at each limb segment. A logical and comprehensive management algorithm is proposed.Level of evidence: IV.

Bias in Hand Surgical Randomized Controlled Trials: Systematic Review and Meta-Epidemiological Study.

PURPOSE: Inappropriately reported or conducted studies may decrease the quality of care due to under- or overestimation of the benefits or harms of interventions. Our aim was to evaluate how often hand surgical randomized controlled trials (RCTs) use and report adequate methods to ensure internal validity, and whether inadequate reporting or methods are associated with the magnitude of treatment effect estimates. METHODS: Data Sources were the Cochrane Central Register of Controlled Trials, MEDLINE, and Embase databases until November 2020. We included published RCTs investigating the effects of any surgical intervention in the hand and wrist region. We assessed internal validity using the Cochrane Risk of Bias (RoB) tool for 6 domains: selection, performance, detection, attrition, selective reporting, and "other" bias. We extracted the primary outcome and calculated the effect size for each study. We used mixed-effect meta-regression to assess whether the RoB modified the magnitude of the effects. RESULTS: For 207 assessed trials, the RoB was unclear or high for 72% in selection, 93% in performance, 88% in detection, 25% in attrition, 22% in selective reporting, and 34% in the "other" bias domain. Trials with a high or unclear risk of selection bias yielded 0.28 standardized mean difference (95% confidence interval, 0.02-0.55) larger effect sizes compared to studies with a low risk. Risks of bias for other domains did not modify the intervention effects. The risk for selection bias declined over time: the odds ratio for a high or unclear RoB was 0.90 (95% confidence interval, 0.85-0.95) per additional year of publication CONCLUSIONS: The internal validity and credibility of hand surgical RCTs can be improved by using established methods to achieve true randomization, blinding of the participants and study personnel, publishing the trial protocol and avoiding selective reporting of the outcomes, and reporting the trial as recommended in the Consolidated Standards of Reporting Trials statement. CLINICAL RELEVANCE: Clinicians should be aware that RCTs that do not use or report proper randomization and allocation concealment may overestimate the treatment effects.

Differential Diagnoses of Pediatric Upper Limb Masses.

PURPOSE: Upper limb masses are one of the most common presentations in the outpatient setting. However, there is a paucity of information in the literature regarding the epidemiology of upper-extremity masses in the pediatric population. The aim of this study was to determine the differential diagnoses and clinical characteristics in children aged ≤18 years presenting with upper limb masses. METHODS: A retrospective review of patients aged ≤18 years managed at our institution over a 5-year period was performed. We obtained information on patient demographics, clinical features, radiological investigations, intraoperative features, and histology. We also evaluated the correlation between the clinical and histopathological diagnoses in patients who underwent surgery. RESULTS: There were 141 upper limb masses in our series. The mean age at presentation was 12 years (SD, 5 years). The most common presenting complaints were asymptomatic swelling, pain, and paresthesia. The majority (128; 91%) of tumors were benign; there were 5 locally aggressive tumors and 6 malignant tumors. The dominant hand was involved in 60 patients. Of 140 patients, 43 (31%) patients had surgery. The procedures included incisional biopsy, excisional biopsy, wide resection, and reconstruction. One patient required a below elbow amputation for an osteosarcoma. CONCLUSIONS: Ten percent of cases represented malignant or locally aggressive disease. We have used our observations to develop a clinical algorithm that can assist clinicians in evaluating and managing children and adolescents presenting with upper-extremity masses. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic IV.

Evolution of adsorption heights in the on-surface synthesis and decoupling of covalent organic networks on Ag(111) by normal-incidence X-ray standing wave.

Structural characterization in on-surface synthesis is primarily carried out by Scanning Probe Microscopy (SPM) which provides high lateral resolution. Yet, important fresh perspectives on surface interactions and molecular conformations are gained from adsorption heights that remain largely inaccessible to SPM, but can be precisely measured with both elemental and chemical sensitivity by Normal-Incidence X-ray Standing Wave (NIXSW) analysis. Here, we study the evolution of adsorption heights in the on-surface synthesis and post-synthetic decoupling of porous covalent triazine-phenylene networks obtained from 2,4,6-tris(4-bromophenyl)-1,3,5-triazine (TBPT) precursors on Ag(111). Room temperature deposition of TBPT and mild annealing to ∼150 °C result in full debromination and formation of organometallic intermediates, where the monomers are linked into reticulated networks by C-Ag-C bonds. Topologically identical covalent networks comprised of triazine vertices that are interconnected by biphenyl units are obtained by a thermally activated chemical transformation of the organometallic intermediates. Exposure to iodine vapor facilitates decoupling by intercalation of an iodine monolayer between the covalent networks and the Ag(111) surface. Accordingly, Scanning Tunneling Microscopy (STM), X-ray Photoelectron Spectroscopy (XPS) and NIXSW experiments are carried out for three successive sample stages: organometallic intermediates, covalent networks directly on Ag(111) and after decoupling. NIXSW analysis facilitates the determination of adsorption heights of chemically distinct carbon species, i.e. in the phenyl and triazine rings, and also for the organometallic carbon atoms. Thereby, molecular conformations are assessed for each sample stage. The interpretation of experimental results is informed by Density Functional Theory (DFT) calculations, providing a consistent picture of adsorption heights and molecular deformations in the networks that result from the interplay between steric hindrance and surface interactions. Quantitative adsorption heights, i.e. vertical distances between adsorbates and surface, provide detailed insight into surface interactions, but are underexplored in on-surface synthesis. In particular, the direct comparison with an in situ prepared decoupled state unveils the surface influence on the network structure, and shows that iodine intercalation is a powerful decoupling strategy.

Radioscaphoid Impingement after Volar Plate Fixation and Bone Grafting of a Non-United Scaphoid Fracture.

Volar plate fixation (VPF) of scaphoid fractures has received increased attention over the past decade. The purported benefits over headless screw fixation are increased rigidity, better purchase of small fragments, the ability to prevent extrusion of bone graft, and to act as a buttress against excessive scaphoid flexion. We report a case of symptomatic radioscaphoid impingement presenting two years after successful VPF for a non-united scaphoid fracture. We performed an arthoscopic evaluation, synovectomy and chondroplasty, followed by open radial styloidectomy and implant removal. This article highlights the pertinent clinical features, relevant imaging, and key intra-operative findings. We have analyzed the factors that led to this complication and have highlighted several technical tips to minimize radiocarpal impingement and ongoing chondral damage.

Stimuli-Responsive Chiroptical Switching.

"Chirality" governs many fundamental properties in chemistry and biochemistry. While early investigations on stereochemistry are primarily dedicated to static chirality, there is an increasing interest in the field of dynamic chirality (chiral switches). These chiral switches are essential in controlling the directionality in molecular motors. Dynamic chiralities are equally crucial in switchable stereoselectivity, switchable asymmetric catalysis and enantioselective separation. Herein, we limit our discussion to recent advances on stimuli-induced chiroptical switching of axial, helical, and planar chirality in response to external stimuli. We also discuss a few examples of applications of the switchable chirality.