Harnessing Green Electricity from Food: A Split Black Gram-Based Triboelectric Nanogenerator for a Self-Powered Autonomous Lighting System and Portable Electronics.

Triboelectric nanogenerators (TENGs) represent a promising solution to mounting environmental concerns associated with battery disposal amid the escalating demand for portable electronics. However, prevailing TENG fabrication predominantly relies on nonbiodegradable, nonbiocompatible, and synthetic materials, posing a grave ecological threat. To mitigate this, there is a pressing need to develop eco-friendly and green TENGs leveraging sustainable, naturally occurring materials. This study pioneers the use of split black gram (SBG) as a tribo-positive material for TENGs. SBG's effectiveness as a tribo-positive material stems from its abundance of oxygen-containing functional groups, as confirmed by FTIR analysis, facilitating electron donation during the triboelectric process. SBG offers compelling advantages, including widespread availability, cost-effectiveness, biodegradability, and hydrophobic and adhesive properties due to its richness in starch and protein, positioning it as an optimal choice for eco-conscious TENG manufacturing. The fabrication process of an SBG-TENG is not only economical and facile but also solvent-free, requiring no specialized tools. Demonstrating commendable performance, the SBG-TENG achieves a maximum power density of 15.36 µW/cm2 at 1 MΩ, with an open circuit voltage of 84 V and short circuit current of 28 µA, comparable to recent studies. In practical applications, the SBG-TENG seamlessly integrates with LEDs and portable electronic devices via a full bridge rectifier, successfully powering them postcapacitor charging. Moreover, an autonomous lighting system is developed by embedding the SBG-TENG in a foot mat, enabling wireless light control through human stepping on the mat, introducing power-saving functionality for residential and office environments. In essence, the introduction of the SBG-TENG not only delivers cost-effectiveness but also minimizes the environmental impact by harnessing sustainable energy from food sources.

Self-expanding versus balloon expandable stent for intracranial arterial stenosis: A systematic review and meta-analysis.

BACKGROUND AND PURPOSE: There are limited data regarding the comparison of balloon expandable stents (BES) and self-expanding stents (SES) for the treatment of intracranial arterial stenosis. METHODS: We conducted a systematic review to identify studies that compared SES and BES in patients with symptomatic intracranial arterial stenosis. Data were extracted from relevant studies found through a search of PubMed, Scopus, and Web of Science until from January 1, 2010 to September 28, 2023. Statistical pooling with random-effects meta-analysis was undertaken to compare the rates/severity of postprocedure stenosis, technical success, 30-day stroke and/or death, cumulative clinical endpoints, and restenosis rates. RESULTS: A total of 20 studies were included. The standardized mean difference (SMD) for postprocedure stenosis (%) was significantly lower (SMD: -0.52, 95% confidence interval [CI]: -0.79 to -0.24, p < .001, 10 studies involving 1515 patients) with BES. The odds for 30-day stroke and/or death were significantly lower (odds ratio [OR] 0.68, 95% CI: 0.50-0.94, p = .019, 15 studies involving 2431 patients), and cumulative clinical endpoints on follow-up were nonsignificantly lower (OR 0.64, 95% CI: 0.30-1.37, p = .250, 10 studies involving 947 patients) with BES. The odds for restenosis during follow-up were significantly lower (OR 0.50, 95% CI: 0.31-0.80, p = .004, 13 studies involving 1115 patients) with BES. CONCLUSIONS: Compared with SES, BES were associated with lower rates of postprocedure 30-day stroke and/or death with lower rates of restenosis during follow up and the treatment of symptomatic intracranial arterial stenosis.

Intracranial atherosclerotic disease: current management strategies.

A stroke due to underlying intracranial large artery occlusion, which is atherosclerotic in nature, is known as intracranial atherosclerotic disease (ICAD). It is important to recognize that ischaemic stroke due to ICAD differs from extracranial disease and other stroke aetiologies and requires a nuanced approach. It is a significant cause of stroke worldwide, and severe symptomatic ICAD can present challenges from a therapeutic standpoint, including recurrent ischaemic stroke despite optimal management. Furthermore, exploring the underlying pathophysiological mechanisms responsible for the disease may be necessary while considering treatment options. This narrative review aims to provide an all-encompassing overview of this disease. Epidemiology and clinical pathophysiology will be explored in detail. The findings of large clinical trials will serve as a guide to finding the most optimized management strategies. Another critical question that arises is the treatment of acute ischaemic stroke due to large vessel occlusion with underlying intracranial atherosclerosis, is the treatment and clinical diagnosis the same as for other aetiologies of stroke (i.e. extracranial disease and nonvalvular atrial fibrillation)? Consequently, secondary prevention of patients with ischaemic stroke or transient ischaemic attack will be divided into medical therapy, risk factor control, and endovascular and surgical treatment options.

Tensile Properties of In Situ 3D Printed Glass Fiber-Reinforced PLA.

A 3D printed composite via the fused filament fabrication (FFF) technique has potential to enhance the mechanical properties of FFF 3D printed parts. The most commonly employed techniques for 3D composite printing (method 1) utilized premixed composite filaments, where the fibers were integrated into thermoplastic materials prior to printing. In the second method (method 2), short fibers and thermoplastic were mixed together within the extruder of a 3D printer to form a composite part. However, no research has been conducted on method 3, which involves embedding short fibers into the printed object during the actual printing process. A novel approach concerning 3D printing in situ fiber-reinforced polymer (FRP) by embedding glass fibers between deposited layers during printing was proposed recently. An experimental investigation has been undertaken to evaluate the tensile behavior of the composites manufactured by the new manufacturing method. Neat polylactic acid (PLA) and three different glass fiber-reinforced polylactic acid (GFPLA) composites with 1.02%, 2.39%, and 4.98% glass fiber contents, respectively, were 3Dprinted. Tensile tests were conducted with five repetitions for each sample. The fracture surfaces of the samples were then observed under scanning electron microscopy (SEM). In addition, the porosities of the 3D printed samples were measured with a image processing software (ImageJ 1.53t). The result shows that the tensile strengths of GFPLA were higher than the neat PLA. The tensile strength of the composites increased from GFPLA-1 (with a 1.02% glass fiber content) to GFPLA-2.4 (with a 2.39% glass fiber content), but drastically dropped at GFPLA-5 (with a 4.98% glass fiber content). However, the tensile strength of GFPLA-5 is still higher than the neat PLA. The fracture surfaces of tensile samples were observed under scanning electron microscopy (SEM). The SEM images showed the average line width of the deposited material increased as glass fiber content increased, while layer height was maintained. The intralayer bond of the deposited filaments improved via the new fiber embedding method. Hence, the porosity area is reduced as glass fiber content increased.

Factors leading to the academic failure of undergraduate medical students - Predict early to prevent.

Objectives: The main objective of the study was to explore the factors to predict academic failure before the first major assessment. Methods: An exploratory qualitative study was conducted from March 2021 to August 2021 at Riphah International University. Using the purposive sampling technique, 16 students and seven teachers were included in the study. Eight online interviews were conducted with students who were academic failures and two focus group discussions were held with eight high achievers and seven teachers. The data was analyzed and thematic analysis was done. Results: Thematic analyses deduced relevant themes which were: Educational Journey Does past matter? Essential for learning, Personality and psychological make-up, and assessment of behaviour. The factors identified were performance record, learning difficulty, educational dislocation, missionless and purposeless, against free will, tuition, poor self-regulation, low effort, procrastination, non-reflective practice, cognitive load mismanagement, limited remediation, hesitant help-seeking, low self-efficacy, introvert behaviour, demotivation, emotional imbalance, observation of student behaviour, assessment of assigned task. Conclusion: Academic failure can be predicted early and salvaged.

3D-Printed Fiber-Reinforced Polymer Composites by Fused Deposition Modelling (FDM): Fiber Length and Fiber Implementation Techniques.

Fused Deposition Modelling (FDM) is an actively growing additive manufacturing (AM) technology due to its ability to produce complex shapes in a short time. AM, also known as 3-dimensional printing (3DP), creates the desired shape by adding material, preferably by layering contoured layers on top of each other. The need for low cost, design flexibility and automated manufacturing processes in industry has triggered the development of FDM. However, the mechanical properties of FDM printed parts are still weaker compared to conventionally manufactured products. Numerous studies and research have already been carried out to improve the mechanical properties of FDM printed parts. Reinforce polymer matrix with fiber is one of the possible solutions. Furthermore, reinforcement can enhance the thermal and electrical properties of FDM printed parts. Various types of fibers and manufacturing methods can be adopted to reinforce the polymer matrix for different desired outcomes. This review emphasizes the fiber types and fiber insertion techniques of FDM 3D printed fiber reinforcement polymer composites. A brief overview of fused deposition modelling, polymer sintering and voids formation during FDM printing is provided, followed by the basis of fiber reinforced polymer composites, type of fibers (synthetic fibers vs. natural fibers, continuous vs. discontinuous fiber) and the composites' performance. In addition, three different manufacturing methods of fiber reinforced thermoplastics based on the timing and location of embedding the fibers, namely 'embedding before the printing process (M1)', 'embedding in the nozzle (M2)', and 'embedding on the component (M3)', are also briefly reviewed. The performance of the composites produced by three different methods were then discussed.

Takayasu's Arteritis With Acute Severe Aortic Regurgitation Requiring a Bio-Bentall Procedure.

Aortitis is a rare form of vasculitis that is associated with significant morbidity and mortality through the development of aneurysms, aortic rupture, dissection, and thrombotic occlusions. Common causes for non-infectious large vessel vasculitis include Takayasu's arteritis and giant cell arteritis. Delayed diagnosis and treatment can be devastating, resulting in lifelong disability or death. Here we present an unfortunate case of Takayasu's arteritis with aortitis and acute severe aortic regurgitation in a young patient requiring an emergent Bio-Bentall procedure and bowel resection.

Deep Learning for EEG Seizure Detection in Preterm Infants.

EEG is the gold standard for seizure detection in the newborn infant, but EEG interpretation in the preterm group is particularly challenging; trained experts are scarce and the task of interpreting EEG in real-time is arduous. Preterm infants are reported to have a higher incidence of seizures compared to term infants. Preterm EEG morphology differs from that of term infants, which implies that seizure detection algorithms trained on term EEG may not be appropriate. The task of developing preterm specific algorithms becomes extra-challenging given the limited amount of annotated preterm EEG data available. This paper explores novel deep learning (DL) architectures for the task of neonatal seizure detection in preterm infants. The study tests and compares several approaches to address the problem: training on data from full-term infants; training on data from preterm infants; training on age-specific preterm data and transfer learning. The system performance is assessed on a large database of continuous EEG recordings of 575[Formula: see text]h in duration. It is shown that the accuracy of a validated term-trained EEG seizure detection algorithm, based on a support vector machine classifier, when tested on preterm infants falls well short of the performance achieved for full-term infants. An AUC of 88.3% was obtained when tested on preterm EEG as compared to 96.6% obtained when tested on term EEG. When re-trained on preterm EEG, the performance marginally increases to 89.7%. An alternative DL approach shows a more stable trend when tested on the preterm cohort, starting with an AUC of 93.3% for the term-trained algorithm and reaching 95.0% by transfer learning from the term model using available preterm data. The proposed DL approach avoids time-consuming explicit feature engineering and leverages the existence of the term seizure detection model, resulting in accurate predictions with a minimum amount of annotated preterm data.

Hypoxia induced up-regulation of tissue factor is mediated through extracellular RNA activated Toll-like receptor 3-activated protein 1 signalling.

Sterile Inflammation (SI), a condition where damage associated molecular patterns (DAMPs) released from dying cells, leads to TLR (Toll-like receptor) activation and triggers hypoxemia in circulation leading to venous thrombosis (VT) through tissue factor (TF) activation, but its importance under acute hypoxia (AH) remains unexplored. Thus, we hypothesized that eRNA released from dying cells under AH activates TF via the TLR3-ERK1/2-AP1 pathway, leading to VT. Animals were exposed to stimulate hypoxia for 0-24 h at standard temperature and humidity. RNaseA and DNase1 were injected immediately before exposure. TLR3 gene silencing was performed through in vivo injection of TLR3 siRNA. 80 µg/kg BW of isolated eRNA and eDNA were injected 6 h prior to sacrifice. Antigens of TF pathway were determined by ELISA and TF activity by a chromogenic assay. AH exposure significantly induced release of SI markers i.e. eRNA, eDNA, HMGB1 and upregulated TLR3, ERK1/2 (Extracellular signal-regulated kinases), AP1 (Activator Protein-1) and TF, whereas RNaseA pre-treatment diminished the effect of AH, thus inhibiting TF expression as well as activity during AH. Hence, we propose a possible mechanism of AH-induced TF activation and thrombosis where RNaseA can become the novel focal point in ameliorating therapy for AH induced thrombosis.

Microwave Irradiation Synthesis and Characterization of Reduced-(Graphene Oxide-(Polystyrene-Polymethyl Methacrylate))/Silver Nanoparticle Nanocomposites and their Anti-Microbial Activity.

Herein, we report a facile process for the preparation of styrene and methyl-methacrylate copolymer nanocomposites containing reduced graphene oxide and silver nanoparticles ((R-(GO-(PS-PMMA))/AgNPs)) by using (i) microwave irradiation (MWI) to obtain R-(GO-(PS-PMMA))/AgNPs and (ii) the in situ bulk polymerization technique to produce RGO/AgNPs-(PS-PMMA). Various characterization techniques, including FT-IR, XPS, Raman spectroscopy, XRD, SEM, HR-TEM, DSC, and TGA analysis, were used to characterize the prepared nanocomposites. The Berkovich nanoindentation method was employed to determine the hardness and elastic modulus of the nanocomposites. The results showed that the MWI-produced nanocomposites were found to have enhanced morphological, structural, and thermal properties compared with those of the nanocomposites prepared by the in situ method. In addition, the antibacterial activity of the prepared nanocomposites against the E. coli HB 101 K-12 was investigated, whereby an inhibition zone of 3 mm (RGO/AgNPs-(PS-PMMA) and 27 mm (R-(GO-(PS-PMMA))/AgNPs) was achieved. This indicates that the MWI-prepared nanocomposite has stronger antibacterial activity than the in situ-prepared nanocomposite.

Association of Glycated Haemoglobin and Serum Apolipoproteins with Diabetic Retinopathy: An Indian Overview.

INTRODUCTION: India is presently facing an epidemic of diabetes mellitus and the risks of chronic complications from the disease are associated with the duration of the disease as well as the degree of hyperglycaemia. Diabetic retinopathy is a known microvascular complication of diabetes mellitus and is the most common cause of blindness in the western countries.Apolipoproteins are the protein component of lipoproteins. Apart from acting as structural proteins, they also act as cofactors to various enzymes. AIM: To measure the levels of serum apolipoproteins and glycated haemoglobin in cases of diabetic retinopathy and to assess their association with the stages of diabetic retinopathy. MATERIAL AND METHODS: The 135 diabetic cases [with (110) and without (125) retinopathy] attending the Ophthalmology OPD of this tertiary care hospital were included in the present study. Following retinoscopy, the patients were classified as Non-Proliferative Diabetic Retinopathy (NPDR) (n=75) and Proliferative Diabetic Retinopathy (PDR) (n=35). The controls (n=100) were age and sex matched patients who did not have diabetes. The cases and controls were assessed for HbA1c, total cholesterol, triglycerides, HDL cholesterol, Apo A-I and Apo B-100. RESULTS: The HbA1c was found to be higher in diabetics without retinopathy (7.02%) as compared to controls (5.58%) (p<0.05) and the highest value was seen in the mild NPDR group (8.82%). The mean value of Apo A-I was found to be lowest in the diabetics without retinopathy at 88 mg/dl and the highest in severe NPDR at 167 mg/dL. The mean value of Apo B-100 was found to be highest in severe NPDR at 114 mg/dL. The mean value of HDL cholesterol was lowest in moderate NPDR at 36.6 mg/dl. Total cholesterol was highest in severe NPDR at 280.88mg/dl while triglyceride was highest in severe NPDR at 286.4mg/dl. CONCLUSION: In our study, the level of HbA1c was found to range from 5.58% in non-diabetic to 8.82% in mild NPDR. There was a clear association between Apo B-100 and total cholesterol, triglycerides with the highest value of each parameter seen in the severe NPDR group. There was a discordance noted in the levels of HDL and Apo A-I in various groups. Apo B-100 values may be of value in prognosis of diabetic retinopathy as higher values may result in progression of the disease. Further studies involving Lp(a) and homocysteine may be required in cases of diabetic retinopathy.

Exploring temporal information in neonatal seizures using a dynamic time warping based SVM kernel.

Seizure events in newborns change in frequency, morphology, and propagation. This contextual information is explored at the classifier level in the proposed patient-independent neonatal seizure detection system. The system is based on the combination of a static and a sequential SVM classifier. A Gaussian dynamic time warping based kernel is used in the sequential classifier. The system is validated on a large dataset of EEG recordings from 17 neonates. The obtained results show an increase in the detection rate at very low false detections per hour, particularly achieving a 12% improvement in the detection of short seizure events over the static RBF kernel based system.

Mixed Phenotypic Acute Leukemia Presenting as Mediastinal Mass-2 Cases.

Mixed phenotype acute leukemia symbolizes a very small subset of acute leukemia that simply cannot be allocated as lymphoid or myeloid lineage. The 2008 World Health Organisation classification established stringent standard for diagnosis of mixed phenotype acute leukemia, accentuating myeloperoxidase for myeloid lineage, cytoplasmic CD3 for T lineage and CD19 with other B markers for B lineage obligation. Mixed phenotype leukemia is rare and 3-5 % of acute leukmias of all age groups, is associated with poor outcome with overall survival of 18 months. We wish to present two cases of mixed phenotypic acute leukemia who presented with mediastinal masses, were suspected to be T cell lymphoma/leukemia clinically and radiologically. In one case, tissue diagnosis was given as lymphoma for which treatment was given. These cases show that patients diagnosed as lymphoma on histopathology can be cases of mixed phenotype acute leukemia and varying specific treatment protocols and follow up are required. Awareness of these entities will help in proper diagnosis and treatment.

Grading hypoxic-ischemic encephalopathy severity in neonatal EEG using GMM supervectors and the support vector machine.

OBJECTIVE: This work presents a novel automated system to classify the severity of hypoxic-ischemic encephalopathy (HIE) in neonates using EEG. METHODS: A cross disciplinary method is applied that uses the sequences of short-term features of EEG to grade an hour long recording. Novel post-processing techniques are proposed based on majority voting and probabilistic methods. The proposed system is validated with one-hour-long EEG recordings from 54 full term neonates. RESULTS: An overall accuracy of 87% is achieved. The developed grading system has improved both the accuracy and the confidence/quality of the produced decision. With a new label 'unknown' assigned to the recordings with lower confidence levels an accuracy of 96% is attained. CONCLUSION: The statistical long-term model based features extracted from the sequences of short-term features has improved the overall accuracy of grading the HIE injury in neonatal EEG. SIGNIFICANCE: The proposed automated HIE grading system can provide significant assistance to healthcare professionals in assessing the severity of HIE. This represents a practical and user friendly implementation which acts as a decision support system in the clinical environment. Its integration with other EEG analysis algorithms may improve neonatal neurocritical care.

Association Of Tricuspid Regurgitation And Severity Of Mitral Stenosis In Patients With Rheumatic Heart Disease.

BACKGROUND: Rheumatic heart disease is a common ailment in Pakistan and Mitral stenosis is its flag bearer Severity of mitral stenosis is the key factor in deciding for mitral valve surgery. METHODS: This case series study was conducted at Ayub Teaching Hospital .Cases of Rheumatic heart disease with mitral stenosis were diagnosed clinically. 2D echocardiography was used to find severity of mitral stenosis. Data was entered into SPSS-17.0 and results were recorded and analysed. Pearson's two tailed correlation was used to find the correlation between presence of tricuspid regurgitation in patients with severe mitral stenosis, p was <0.05. RESULTS: A total 35 patients with pure mitral stenosis were included in study, out of which 8 were male and 27 were females. Mean age in males was 34.5±15.85 years while in females it was 31±8 years. Twenty-two out of 35 (62.86%) patients had tricuspid regurgitation while 13 out 35 (37.14%) had no tricuspid regurgitation. Mean (MVA) mitral valve area in patients with tricuspid regurgitation was 0.84±0.3 cm2 while mean (MVA) mitral valve area in patients without tricuspid regurgitation was 1.83±0.7 cm2. Mean left atrial (L.A) size was 45.23±1.5 mm2 in patients with tricuspid regurgitation, while it was 44.13±6.14 mm2 in patients without tricuspid regurgitation. Mean RSVP was 57.5mmHg in patients with tricuspid regurgitation while RSVP could not be calculated in patients without tricuspid regurgitation. CONCLUSIONS: It was concluded that tricuspid regurgitation was strongly associated with severe mitral stenosis as almost all patients with severe mitral stenosis had tricuspid regurgitation and none of the patients with mild mitral stenosis had tricuspid regurgitation.

Classification of hypoxic-ischemic encephalopathy using long term heart rate variability based features.

Hypoxic-ischemic HI injury at the time of birth could lead to severe neurological dysfunction at an older age. Therapeutic hypothermia can be used to treat HI if severity of injury is determined within 6 hours of birth. EEG is generally used to assess the brain injury but it is neither widely recorded after birth nor is the expertise to interpret it commonly available. This study presents a novel system to classify HI injury using heart rate variability. The system makes decisions based on long-term statistical features extracted from the short-term HRV features. The preliminary results show the promising performance and robustness of the proposed method given a poor quality dataset. This tool can serve as decision support system in remote maternity units to help clinical staff to initiate hypothermia.

A simple and convenient method for the simultaneous in vitro study of metformin and glimepiride tablets.

A simple and convenient method was developed for the simultaneous determination of metformin HCl and glimepiride in tablet dosage form of different pharmaceuticals companies. This method was validated and proved to be applicable for assay determination in intermediate and finished staged. More over a single medium dissolution of metformin HCl and glimepiride was established and the media was evaluated for comparative studies for different formulations. Reverse phase HPLC equipped with UV detector was used for the determination of metformin HCl and glimepiride. A mixture of acetonitrile and ammonium acetate buffer 0.05M pH 3.0 was used as mobile phase at flow rate of 1.0ml/min. Promocil C18 5µ 100Aº 4.6 x 100mm C18 silica column was used and detection was carried out at 270nm. Method was found to be linear over the range of 4ppm to 16ppm for glimepiride and 170ppm to 680ppm for metformin HCl. Regression co-efficient were found to be 0.9949 and 0.9864 for glimepiride and metformin HCl respectively. Dissolution was performed in 500ml 0.2% sodium lauryl sulfate at 37°C for 45min using paddle apparatus. Dissolution of glimepiride was found to be 98.60% and 101.08% in Orinase Met1 tablet and Amaryl M tablet respectively whereas metformin was found 99.41% and 98.59% in Orinase Met 1 tablet and Amaryl M tablet. RSD for all the dissolutions was less than 2.0% after completion.

Dynamic time warping based neonatal seizure detection system.

Neonatal seizures patterns evolve with changing frequency, morphology and propagation. This study is an initial attempt to incorporate the characteristics of temporal evolution of neonatal seizures into our developed neonatal seizure detector. The previously designed SVM-based neonatal seizure detector is modified by substituting the Gaussian kernel with the Gaussian dynamic time warping kernel, to enable the SVM to classify variable length sequences of feature vectors of neonatal seizures. The preliminary results obtained compare favorably with the conventional SVM. The fusion of the two approaches is expected to improve the current state of the art neonatal seizure detection system.

Periosteal Flap fixation of the Globe for Surgical Treatment of Severe Restrictive Strabismus: A Report of Eight Cases with Outcomes.

PURPOSE: Severe paretic and restrictive strabismus presents a challenging surgical problem. Despite aggressive, and often multiple, surgical attempts, patients can have recurrence of large angle binocular misalignments. In this paper, we present a series of patients who underwent apically-based orbital bone periosteal flap fixation of the globe in cases of restrictive strabismus due to isolated third-nerve and sixth-nerve palsies, multiple cranial nerve palsies, and severe ocular fibrosis syndrome. METHODS: We performed a retrospective study at our institution of patients who underwent a periosteal flap fixation. In all cases presented, the creation of the periosteal flap was performed by an orbital surgeon, and the strabismus surgery and follow-up data points were performed and collected by a strabologist. RESULTS: A total of 8 patients underwent a periosteal flap fixation of the globe. The mean age was 48 years old. Three patients had a third cranial nerve palsy, one patient had congenital fibrosis, one patient had sixth cranial nerve palsy, and three patients had multiple cranial nerve palsies. Five patients had a medial periosteal flap constructed, and 3 patients had a temporal periosteal flap. Seven of the 8 patients had stable postoperative strabometry (binocular misalignment) measurements. A single patient required an additional procedure secondary to postoperative drift (a mild recurrence of binocular misalignment). CONCLUSIONS: The surgical correction of severe paretic and restrictive strabismus is complex and can present a formidable challenge. The use of an orbital bone-based periosteal fixation flap, at our institution, has shown satisfactory outcomes not only with regard to improved postoperative deviation, but also, in that most patients required only this single procedure, usually after several prior unsuccessful interventions by standard strabismus surgery procedures.

Phosphorus-based functional groups as hydrogen bonding templates for rotaxane formation.

We report on the use of the hydrogen bond acceptor properties of some phosphorus-containing functional groups for the assembly of a series of [2]rotaxanes. Phosphinamides, and the homologous thio- and selenophosphinamides, act as hydrogen bond acceptors that, in conjunction with an appropriately positioned amide group on the thread, direct the assembly of amide-based macrocycles around the axle to form rotaxanes in up to 60% yields. Employing solely phosphorus-based functional groups as the hydrogen bond accepting groups on the thread, a bis(phosphinamide) template and a phosphine oxide-phosphinamide template afforded the corresponding rotaxanes in 18 and 15% yields, respectively. X-ray crystallography of the rotaxanes shows the presence of up to four intercomponent hydrogen bonds between the amide groups of the macrocycle and various hydrogen bond accepting groups on the thread, including rare examples of amide-to-phosphinamide, -thiophosphinamide, and -selenophosphinamide groups. With a phosphine oxide-phosphinamide thread, the solid-state structure of the rotaxane is remarkable, featuring no direct intercomponent hydrogen bonds but rather a hydrogen bond network involving water molecules that bridge the H-bonding groups of the macrocycle and thread through bifurcated hydrogen bonds. The incorporation of phosphorus-based functional groups into rotaxanes may prove useful for the development of molecular shuttles in which the macrocycle can be used to hinder or expose binding ligating sites for metal-based catalysts.