Soft-stable interface in grasping multiple objects by wiring-tension.

Efficiently manipulating objects in a group state poses an emerging challenge for soft robot hands. Overcoming this problem necessitates the development of hands with highly stable structures to bear heavy loads and highly compliant designs to universally adapt to various object geometries. This study introduces a novel platform for the development of robot hands aimed at manipulating multiple objects in each trial. In this setup, the objects come into soft contact with an elastic wire affixed to the finger skeletons. This combination results in a harmonious hybrid finger, inheriting both the soft, flexible properties of the wire and the robust stability provided by the finger skeleton. To facilitate this approach, a theoretical model was proposed to estimate the kinematics of manipulating multiple objects using wiring-based fingers. Based on this model, we designed a hybrid gripper comprising two wiring-based fingers for conducting experimental evaluations in manipulating four groups of samples: a pair of bevel gears, a pair of bevel gears plus a pneumatic connector, a pair of glue bottles, and a pair of silicon bottles. The experimental results demonstrated that our proposed gripper reached good performance with high success rates in durability tests conducted at various lifting velocities and high adaption with objects in soft-friendly ways. These findings hold promise for efficiently manipulating multiple complex objects in each trial without the need for complex control systems.

Mechanics of wet adhesion in soft interaction with patterned morphology.

Locking surfaces with a wet interface can enhance interactions between a grasped object and a soft pad. This paper presents a mechanical approach to understanding the role of morphological design in achieving wet adhesion for secure grasping by a soft pad. Two conditions were compared in modeling wet interfaces between an object and a soft pad: a pad with a flat surface, and a pad with a micropatterned surface. The latter was designed and analyzed based on the wet attachment between the surface of a tree-frog's toes and its substrate. In this model, we proposed a method to estimate the contact force in both normal and tangential directions between a soft pad with a micropattern surface and a rigid flat surface substrate. A square mold containing 3600 85 µm × 85 µm cells interspaced by grooves 15 µm wide and 15 µm deep was fabricated, using e-beam technology, as the micropattern pad. The generated normal and tangential contact forces of the pad with a micropattern surface, and a pad with a flat surface were measured in both normal and tangential directions under wet conditions. Experimental results showed good agreement with theoretical results, indicating that the micropattern significantly enhanced the contact force of the pad by approximately two-fold for the normal and 1.2- to 1.4-fold for the tangential force. This theoretical approach can be potentially utilized to investigate the association of soft pad morphology with wet adhesion, and enhance efficient grasping by soft robotic hands in wet and high-moisture environments.

Ocular surface rehabilitation: Application of human amniotic membrane in high-risk penetrating keratoplasties.

BACKGROUND: Human amniotic membrane is a versatile tool for management of ocular surface disorders. This study evaluates the effect of cryopreserved human amniotic membrane (hAM) on one-year survival of penetrating keratoplasties (PKP) in high-risk recipients. METHOD: This is a retrospective noncomparative cohort study of 58 consecutive eyes undergoing PKP with concurrent placement of a self-retained cryopreserved hAM (PROKERA®) at a tertiary care center from January 2009 to July 2010. RESULTS: Mean patient age was 66.7 ± 17.2 years and 30 (54%) were males. 51 eyes were pseudophakic and one aphakic. 27 eyes were glaucomatous; 24 had glaucoma drainage device and 2 had previous endocyclophotocoagulation. 12 patients had PKP for the first time and 46 had repeat PKP (average number of prior PKP = 1.63 ± 1.1, range: 1-5). Risk factors for graft failure included repeat PKP (79.3%), corneal neovascularization (51.7%), preexisting glaucoma (46.6%), and presence of anterior synechiae (37.9%). Both First Transplant and Repeat Transplant groups had similar survival rates until 6 months after transplant (75% vs 74%, odds ratio = 1.06, p = 1.00). At 12 months, First Transplant group showed a better survival rate (67% vs 43%, odds ratio = 2.60, p = 0.20). Eyes with >3 risk factors had a higher graft failure rate (odds ratio = 5.81, p = 0.003). CONCLUSION: Survey of the literature suggests that high-risk PKP with concurrent hAM placement demonstrate comparable graft survival. Presence of multiple risk factors is associated with poor survival.

Glaucoma management in Boston keratoprosthesis type I recipients.

PURPOSE OF REVIEW: To review the literature on management of glaucoma in Boston keratoprosthesis type I recipients. RECENT FINDINGS: Glaucoma is a prevalent and important cause of permanent loss of sight in Boston keratoprosthesis recipients. The management of glaucoma is challenging as there are no reliable and accurate means to monitor the intraocular pressure (IOP) in these patients, and no standardized protocols exist regarding management. Because a significant number of patients require glaucoma drainage device placement, further studies are needed to determine ways to reduce the risk of shunt-associated complications. Surgical adjustments including posterior shunt placement, adjunctive corneal patch graft, and selection of a different size bandage contact lens can help reduce shunt-associated complications. Anterior segment optical coherence tomography is useful in elucidating the mechanisms of failure to control IOP. Continual innovations in imaging and IOP measurement technologies will assist surgeons' preoperative planning and postoperative management. SUMMARY: In keratoprosthesis recipients, glaucoma often leads to permanent loss of sight. It is imperative that these patients be monitored with vigilance by a multidisciplinary team to prevent progression. Pooled data from multiple centers and technologic innovations will assist the surgeon to design a surgical approach and postoperative management regimen for the individual recipient.

Descemet stripping with automated endothelial keratoplasty: A comparative study of outcome in patients with preexisting glaucoma.

PURPOSE: To compare postoperative complications after Descemet stripping with automated endothelial keratoplasty (DSAEK) in patients with and without glaucoma. METHODS: For this retrospective study a series of 298 DSAEK cases performed at the Doheny Eye Institute were taken, we compared postoperative complications in eyes with glaucoma on medication (55) or with previous glaucoma surgeries (64) with a time-matched group of all other DSAEK cases (179, control). RESULTS: With a mean follow-up of 1.85 ± 1.12 years, the complication rates were 12.8%, 11.1%, and 26.8% for postoperative graft detachment, graft failure, and IOP elevation, respectively. Graft detachment was an independent risk factor for graft failure (odds ratio OR = 12.35, 95% confidence interval CI [5.46-27.90], P < 0.001). Graft detachment was not associated with either history of glaucoma or glaucoma surgery (P > 0.05). Glaucoma on medication had no increased risks of graft failure compared to normal eyes (P = 0.38). However, increased risk of failure was seen in eyes with prior incisional glaucoma surgeries (OR = 4.26, 95% CI [1.87-9.71], P < 0.001). Medically managed glaucoma has increased risks of postoperative IOP elevation (OR = 2.39, 95% CI [1.25-4.57], P = 0.013), whereas surgically managed glaucoma has no significant elevation (P = 0.23). Elevation of IOP was not significantly correlated with graft failure (P = 0.21). CONCLUSION: DSAEK is the preferred treatment for corneal endothelial dystrophy. We observed that having glaucoma or glaucoma surgery is not associated with graft detachment. A history of glaucoma surgery and postoperative graft detachment appeared to be important risk factors for graft failure. And more studies are indicated to study long-term IOP evolution in post-DSAEK patients and its association with graft survival.

Strategies for local gene therapy of corneal allograft rejection.

Penetrating keratoplasty is the most common type of tissue transplant in humans. Irreversible immune rejection leads to loss of vision and graft failure. This complex immune response further predisposes future corneal transplants to rejection and failure. A diverse armamentarium of surgical and pharmacologic tools is available to improve graft survival. In this review, we will discuss the various gene therapeutic strategies aimed at potentiating the anterior chamber-associated immune deviation to extend graft survival.

Applications of optical coherence tomography in cataract surgery.

PURPOSE OF REVIEW: The rapid emergence and widespread adoption of optical coherence tomography (OCT) has spurred the development of many ophthalmic applications. Spectral domain OCT provides high-resolution in-vivo images of both anterior and posterior segments of the eye. Innovations in anterior segment OCT (AS-OCT) aim to improve refractive accuracy and reduce surgical risks. This review focuses on the utility of AS-OCT in cataract surgery for preoperative assessment, intraoperative assistance, and postoperative management to improve surgical outcomes. RECENT FINDINGS: Recent advances in AS-OCT for preoperative planning include characterization of dry eye and ocular surface conditions, calculation of intraocular lens (IOL) power, delineation of anterior chamber structures, and assessment of risk factors for postoperative complications. Successful intraoperative use of AS-OCT has been described for in-vivo assessment of clear cornea wound architecture and OCT-guided femtosecond laser-assisted cataract surgery. The essential roles of OCT in managing postoperative complications include characterization of maculopathy or corneal wound integrity, assessment of IOL stability or optical changes, and evaluation of laser-assisted in situ keratomileusis flaps after cataract surgery. SUMMARY: In its rapidly evolving state, the utility of OCT in cataract surgery continues to broaden with applications from preoperative planning, intraoperative image-based treatments, and postoperative care. We advocate the judicious use of OCT, wherever clinically indicated, because routine use may not be clinically necessary or economically feasible for each stage of cataract evaluation and management.

Imaging studies in a case of infectious scleritis after pterygium excision.

A 44-year-old woman presented with a painful red eye for 2 weeks. Ultrasound biomicroscopy and optical coherence tomography were instrumental in the diagnosis and management of this case of infectious scleritis associated with previous pterygium excision complicated by choroidal and retinal detachments.

Correlation between optical coherence tomography-derived assessments of lower tear meniscus parameters and clinical features of dry eye disease.

PURPOSE: To measure the correlation between subjective symptom score, conventional clinical tests, and Fourier-domain optical coherence tomography (FD-OCT) of lower tear meniscus parameters in patients with dry eye disease. METHODS: Eighteen patients with dry eye disease requiring medical therapy and/or punctal occlusion were recruited for this prospective, nonrandomized, observational case series. Severity of symptoms of dry eye disease was assessed using the Indiana University Dry Eye Questionnaire 2002. Clinical assessments were completed using slit-lamp biomicroscopy, rose bengal dye staining, fluorescein tear breakup time (TBUT), and a 5-minute Schirmer test with topical anesthesia. The lower tear meniscus was imaged using an FD-OCT system with 5-µm axial resolution and measured manually by a masked grader using computer calipers. Correlation was assessed using Spearman correlation coefficient (ρ). RESULTS: The mean (±SD) scaled symptom score was 58 ± 21, with a range of 0 to 100. Vital staining test averaged 1.7 ± 3.4, TBUT averaged 4.4 ± 1.8 seconds, and Schirmer tests averaged 10.2 ± 8.1 mm. As determined by optical coherence tomography, the meniscus height was 228 ± 153 µm, depth was 127 ± 79 µm, and cross-sectional area was 0.018 ± 0.021 mm. Optical coherence tomography meniscus area was negatively correlated with the symptom questionnaire score (P < 0.01) and positively correlated with Schirmer test results (P < 0.01). There was no significant correlation between symptom score and rose bengal staining, TBUT, or Schirmer test results (P > 0.01). CONCLUSIONS: Lower tear meniscus measurement with FD-OCT is an objective noninvasive test that correlates well with symptoms of dry eye disease and the Schirmer test.

Early surgical debridement in the management of infectious scleritis after pterygium excision.

PURPOSE: The purpose of this study was to report outcomes of infectious scleritis after pterygium surgery, managed with antibiotic therapies and early scleral debridement. METHODS: Retrospective chart review of 13 consecutive cases of infectious scleritis after pterygium excision between 1999 and 2009 was conducted. Collected data included prior medical and surgical history, latency period between pterygium surgery and presentation of infectious scleritis, culture and histopathologic findings, antibiotic regimen, length of hospital stay, visual acuity before and after treatment, and complications. RESULTS: Median follow-up was at 14 months. Twelve patients underwent prompt surgical debridement after infectious scleritis diagnosis (median, 2.5 days). Debridement was delayed in one patient. Median hospital stay was 3 days. Best-corrected visual acuity improved in ten patients, remained stable in one patient, and decreased in two patients following treatment. Complications included scleral thinning requiring scleral patch graft (1/13), glaucoma (3/13), and progression to phthisis bulbi (1/13). No patients required enucleation. CONCLUSIONS: In contrast to the generally poor outcomes in the literature, early surgical debridement of pterygium-associated infectious scleritis appears to offer improved prognosis.

Between-grader repeatability of tear meniscus measurements using Fourier-domain OCT in patients with dry eye.

BACKGROUND AND OBJECTIVE: To examine the between-grader repeatability of height, depth, and cross-sectional area measurements of the lower tear meniscus, using a Fourier-domain optical coherence tomography (OCT) system. PATIENTS AND METHODS: A total of 16 patients with dry eye had the lower tear meniscus of the right eye imaged twice in rapid succession. The tear meniscus height, depth, and cross-sectional area were measured by two masked graders using computer calipers. The between-grader variability, calculated using the pooled coefficient of variation (CV%), assessed the repeatability of the measurements. RESULTS: The between-grader CV% was 12.1%, 15.7%, and 19.5% for height, depth, and area, respectively. The between-image variability was 17.1%, 13.4%, and 35.4% for height, depth, and area, respectively. The overall intraclass correlation was 99%. There was no systematic bias between the two graders. CONCLUSION: Fourier-domain OCT demonstrates good between-grader and between-image repeatability in measuring the height, depth, and cross-sectional area of the tear meniscus in patients with dry eye. Measurement variability was primarily due to the difference between images rather than graders.

Electron attachment to sulfur oxyhalides: SOF2, SOCl2, SO2F2, SO2Cl2, and SO2FCl attachment rate coefficients, 300-900 K.

Electron attachment to SOF(2), SOCl(2), SO(2)F(2), SO(2)FCl, and SO(2)Cl(2) was studied with two flowing-afterglow Langmuir-probe apparatuses over the temperature range 300-900 K. Attachment rate coefficients at 300 K are k(a) = 2.6+/-0.8x10(-10)(SOF(2)), 1.8+/-0.5x10(-8)(SOCl(2)), 4.8+/-0.7x10(-10)(SO(2)F(2)), 2.4+/-0.7x10(-9)(SO(2)Cl(2)), and 2.0+/-0.6x10(-7) cm(3) s(-1)(SO(2)FCl). Arrhenius plots of the data imply activation energies of 56+/-22 meV(SOF(2)), 92+/-40(SO(2)F(2)), 44+/-22 meV(SOCl(2)), and 29+/-15 meV(SO(2)Cl(2)). The rate coefficients for SO(2)FCl decrease slightly with temperature, commensurate with the decrease in the capture rate coefficient. Electron attachment to SOF(2) and SO(2)F(2) is nondissociative, while reaction with SOCl(2), SO(2)FCl, and SO(2)Cl(2) is dissociative. Dissociative attachment is dominated by channels arising from S-Cl bond cleavage but also includes a minor channel forming a dihalide product ion. Branching fraction data are reported for the dissociative attachment channels.

Applications of nanobiotechnology in ophthalmology--Part I.

Much progress has been achieved in the field of nanotechnology and its applications in ophthalmology. It is evident that drug delivery, gene therapy, implantable devices and regenerative medicine are some of the key areas of active research. To the best of our knowledge, there is limited review work on this subject area in the current literature. To assist the interested clinicians and scientists, this bipartite commentary will focus the discussion on emerging researches in nano-ophthalmology and other enabling technologies that soon may be available in the clinician's armamentarium to maintain and restore eye sight. This installment will focus on recent discoveries in drug delivery, gene therapy, imaging and visual prostheses; the second installment will discuss the impact of nanotechnology on artificial environment, cell-nanostructure interaction, other enabling nano-ophthalmic technologies, and safety and biocompatibility of nanostructures. We will take this opportunity to introduce some exciting nano-ophthalmic applications under investigation in our laboratory. The accomplishments by the scientific community are tremendous and the future prospects are wide open.

Management of Corneal Graft Rejection - A Case Series Report and Review of the Literature.

PURPOSE: To report long-term results in a case series of patients treated with systemic immune suppression for prevention of penetrating keratoplasty (PKP) graft rejection. DESIGN: Retrospective noncomparative chart review. PARTICIPANTS: Three patients presented with PKP graft failure. METHODS: Patients received oral prednisone, azathioprine and cyclosporine to prevent rejection of repeat corneal transplant. Patients received repeat PKP and graft outcome was reported. MAIN OUTCOME MEASURES: Visual acuity and graft survival were recorded. RESULTS: Mean age was 55 years, two male and one female. Mean follow-up period was 37 months (range 24-46). All three patients completed the treatment protocol with minimal adverse effects. All grafts remained clear over observational period. CONCLUSION: Our study suggests that systemic immune suppression with 2 or more agents may be helpful to prevent corneal graft rejection in high-risk patients.

Certification of standard reference materials containing bitter orange.

A suite of three dietary supplement standard reference materials (SRMs) containing bitter orange has been developed, and the levels of five alkaloids and caffeine have been measured by multiple analytical methods. Synephrine, octopamine, tyramine, N-methyltyramine, hordenine, total alkaloids, and caffeine were determined by as many as six analytical methods, with measurements performed at the National Institute of Standards and Technology and at two collaborating laboratories. The methods offer substantial independence, with two types of extractions, two separation methods, and four detection methods. Excellent agreement was obtained among the measurements, with data reproducibility for most methods and analytes better than 5% relative standard deviation. The bitter-orange-containing dietary supplement SRMs are intended primarily for use as measurement controls and for use in the development and validation of analytical methods.

Ocular surface reconstruction: recent advances and future outlook.

PURPOSE OF REVIEW: Ocular surface disorder underlies a diverse group of prevalent diseases in the United States, caused by biological aging, autoimmune conditions, trauma, or iatrogenic factors. Left untreated, these conditions can progress to vision loss or destruction of the globe itself. This review discusses the most recent and relevant clinical and experimental advances in the treatment options for ocular surface disorders. RECENT FINDINGS: Current literature suggests that recent progress in tissue bioengineering, and molecular and cellular biology research presents many potential interventional therapies for ocular surface diseases. Depending on the pathogenesis of each condition, treatment options include bioengineered amniotic membrane graft, limbal stem cell transplantation, conjunctival and extraocular tissue transplantation, multiagent immunosuppressant therapy, and bioartificial devices such as lacrimal gland microdevices and keratoprostheses, or tissue adhesives. SUMMARY: Much progress has been made in the fields of microbiology, stem-cell research, tissue engineering, and bioartificial devices for the treatment of the heterogeneous group of ocular surface disorders. Intensive efforts are underway to ensure the adaptation and accessibility of these therapeutic options to the general population.

Biliary duct ablation with N-butyl cyanoacrylate.

PURPOSE: To assess the efficacy of percutaneous insertion of n-butyl cyanoacrylate (NBCA) in the ablation of bile ducts in patients with persistent postsurgical bile leaks in which traditional means of treatment have failed. MATERIALS AND METHODS: Ablation of bile ducts with NBCA was performed in six patients (two men and four women). The average length of follow-up was 27 months (range, 13-46 months). Four patients presented after hepatic lobectomy with a persistent bile leak, one patient presented after cholecystectomy with a chronically obstructed bile duct, and one patient presented after cholecystectomy from intraoperative bile duct injury. After access to the biliary system was obtained, a cholangiogram was obtained. After the desired duct was isolated, it was copiously irrigated with saline solution. A glue solution containing NBCA glue, Ethiodol, and tantalum powder was delivered into the duct through a polyethylene catheter that had been irrigated with dextrose solution. RESULTS: Four patients had problems arising from isolated segmental ductal systems that had no communication with the normal biliary ductal system and were treated successfully on the first attempt. In two patients, there was communication to the main biliary ductal system and a persistent bile leak occurred that required placement of a coil and a second final gluing procedure. The only complication observed was unintentional spillage of glue into the main biliary system in one patient, which was ultimately clinically insignificant. CONCLUSIONS: The use of NBCA glue in obliteration of bile ducts is a safe procedure with excellent results in patients with complications from isolated segmental ducts. Although a repeat procedure may be necessary if the duct communicates with the main biliary tree, the procedure can decrease the morbidity associated with chronic external biliary drainage.

Silicon nanowire synthesis by a vapor-liquid-solid approach.

Synthesis of silicon nanowires is studied by using a vapor-liquid-solid growth technique. Silicon tetrachloride reduction with hydrogen in the gas phase is used with gold serving as catalyst to facilitate growth. Only a narrow set of conditions of SiCl4 concentration and temperature yield straight nanowires. High concentrations and temperatures generally result in particulates, catalyst coverage and deactivation, and coatinglike materials.