All-optical single-sideband frequency upconversion utilizing the XPM effect in an SOA-MZI.

An all-optical single sideband (OSSB) frequency upconverter based on the cross-phase modulation (XPM) effect is proposed and experimentally demonstrated to overcome the power fading problem caused by the chromatic dispersion of fiber in radio-over-fiber systems. The OSSB frequency upconverter consists of an arrayed waveguide grating (AWG) and a semiconductor optical amplifier Mach-Zehnder interferometer (SOA-MZI) and does not require an extra delay line used for phase noise compensation. The generated OSSB radio frequency (RF) signal transmitted over single-mode fibers up to 20 km shows a flat electrical RF power response as a function of the fiber length. The upconverted electrical RF signal at 48 GHz shows negligible degradation of the phase noise even without an extra delay line. The measured phase noise of the upconverted RF signal (48 GHz) is -74.72 dBc/Hz at an offset frequency of 10 kHz. The spurious free dynamic range (SFDR) measured by a two-tone test to estimate the linearity of the OSSB frequency upconverter is 72.5 dB·Hz2/3.

Pilot Safety Study of a Microfabricated Device for Anterior Stromal Puncture to Treat Corneal Epithelial Disease in the Optical Axis.

PURPOSE: Anterior stromal puncture is an inexpensive and widely used technique at the slit lamp to treat recurrent corneal erosions (RCE), common sequelae of corneal abrasions, trauma, and epithelial basement membrane dystrophies (EBMDs). The purpose of this study was to determine safety of a novel anterior stromal micropuncture device (termed a "plexitome") for use in the optical axis of the cornea. METHODS: We performed an IRB-approved clinical pilot study on 45 patients with diverse corneal pathologies to determine the safety of the plexitome device and examined corneal healing responses clinically for a minimum of 30 days after treatment. Follow on efficacy data was collected for treated patients with RCE. Micropuncture treatment was performed either through loose epithelial tissue or after debridement using a cotton tip at the slit lamp. After "imprinting," patients were treated with topical medications including antibiotics, hypertonic saline/ointment, bandage contact lenses, and/or patching according to the treating physician's routine care for the condition. RESULTS: Micropuncture using the "plexitome" device did not create visible scars in the corneal stroma of the 45 patients treated and followed for at least 30 days. Photographic evidence of imprinting was seen at in 1 patient at 30 days. There were no significant adverse events associated with treatment. CONCLUSIONS: Micropuncture of the cornea using the "plexitome" device does not create optically evident anterior stromal scarring after treatment. Micropuncture using the device may be an effective way of treating RCE and other corneal manifestations of EBMD in the optical axis, which is not currently possible using standard anterior stromal puncture methods.

Tape-splint tarsorrhaphy technique to manage exposure keratopathy in a patient refusing surgical intervention.

This case report describes the benefits of a unique tape-splinting technique to serve as a nonsurgical tarsorrhaphy in the management of exposure keratopathy in a patient who refuses surgical intervention.

Orbital emphysema as a result of chest tube placement for recurrent pneumothorax.

Orbital emphysema refers to the presence of air or gas within the orbital soft tissue space. Although orbital fracture due to trauma is the most common cause, iatrogenic orbital emphysema from chest tube insertion is a rare but potentially serious complication from the treatment of pneumothorax. Symptoms can range from mild crepitus of the periorbital region to permanent vision loss secondary to central retinal artery occlusion or optic neuropathy, a result of orbital compartment syndrome. Management is dependent on the presence of orbital signs and vision loss. Herein, we present a rare case of orbital emphysema in the setting of pneumothorax and chest tube insertion in a 62 year-old patient admitted to the hospital floor. Presenting symptoms included vision loss and bilateral orbital edema, while physical exam revealed complete ptosis of the right eye with diffuse periorbital emphysema and crepitus. Diagnosis was confirmed clinically and with CT head and orbits. The patient's vision loss was felt to be secondary to ptosis; thus, interventions were not necessary and his condition resolved with observation. The present case and associated literature review highlights orbital emphysema as a complication of chest tube insertion and pneumothorax, as well as the drastic complications of the condition if left untreated.

Integration of Large-Area Halide Perovskite Single Crystals and Substrates via Chemical Welding Using an Ionic Liquid for Applications in X-ray Detection.

The large carrier lifetime mobility product and strong stopping power for high-energy X-rays make halide perovskites an attractive candidate for next-generation X-ray detectors. In particular, high-energy X-rays in the range of several tens of keV require halide perovskite absorber layers with thicknesses exceeding a few millimeters. To avoid carrier scattering caused by grain boundaries at such thicknesses, the utilization of single crystals is desirable. Large-area single crystals are predominantly grown in a freestanding form, and integration onto a substrate is necessary for the fabrication of commercial devices. However, an effective method for integrating large single crystals onto a substrate has not yet been developed. In this study, a large-area (20 cm2) MAPbBr3 single crystal is bonded to an indium tin oxide (ITO) substrate using an ionic liquid, showing strong adhesion strength of 164 kPa. X-ray detectors based on ITO/MAPbBr3 single crystal bonded by methylammonium acetate achieved excellent sensitivity of 91,200 µC Gyair-1 cm-2, the highest among substrate-integrated halide perovskite single crystal X-ray detectors.

Implementation of the Corneal Sweep Test in the Diagnosis of Recurrent Corneal Erosion: A 2-Year Retrospective Study.

PURPOSE: The purpose of this study was to evaluate the incidence and epidemiology of recurrent corneal erosion within a clinical population using standard diagnostic techniques and a new technique called the corneal sweep test (CST). METHODS: A retrospective chart review was conducted on 58 eyes of 51 patients with the diagnosis of recurrent corneal erosion from July 2018 to June 2020. All underwent a thorough history and physical examination. The CST was performed as a confirmatory test and on any patient who lacked visible corneal pathology. RESULTS: The CST was necessary on 49 of the 58 eyes to help confirm the diagnosis of a corneal erosion. Among them, 34 had an occult corneal erosion, which is defined as having a normal-appearing cornea on slitlamp examination but found to have loose corneal epithelium with the CST. Clear corneal cataract surgery (28 eyes, 48.2%) was the most common presumed mechanism of injury, with 20 (71.4%) developing symptoms only after cataract surgery. All 20 eyes had an erosion located directly over a clear corneal cataract incision. CONCLUSIONS: The CST is a new and effective technique to help diagnose corneal erosions in the absence of visible corneal findings. Clear corneal cataract surgery is an under-recognized but important risk factor to consider because the incision can be the source for an erosion. Using the CST could lead to a paradigm shift in the way clinicians approach RCEs and patients with a persistent ocular pain syndrome.

Malignant glaucoma presenting with uncontrolled intraocular pressure and myopic refractive surprise after cataract surgery.

We present a seemingly typical case of bilateral angle closure with elevated intraocular pressures. After cataract surgery, there was axial shallowing, escalating intraocular pressure, anterior displacement of the IOL, and myopic shift in the left eye. Irido-zonulo-hyaloido-vitrectomy resolved the angle closure, normalized intraocular pressure, and corrected the myopic shift.

Tape Splint Tarsorrhaphy for Persistent Corneal Epithelial Defects.

PURPOSE: To report outcomes of tape splint tarsorrhaphy (TST) for persistent corneal epithelial defects (PCED). DESIGN: Retrospective, interventional case series. METHODS: The study population was consecutive patients with a PCED (14 days or longer) treated at a tertiary cornea clinic with TST. Patients with a corneal epithelial defect that did not respond to treatment with a bandage contact lens were included. Patients with a follow-up time of less than 3 months were excluded. Time to PCED resolution was the main outcome measure. RESULTS: Thirty-four eyes of 33 patients (mean age 62.9 ± 17.8 years; range, 27-90 years) were included in this study. The main etiologies of the PCED were post keratoplasty (n = 15), herpes simplex virus (n = 4), superficial keratectomy (n = 3), neurotrophic cornea (n = 4), fungal keratitis (n = 2), exposure keratopathy (n = 2), failed graft (n = 1), peripheral ulcerative keratitis (n = 1), rosacea (n = 1), and stitch abscess (n = 1). Mean ± SD time from PCED presentation to TST was 58.9 ± 106.3 days (range, 14-390 days). The mean ± SD area of the PCED was 25.1 ± 15.7 mm2 (range, 0.50-42.0 mm2). After TST, resolution of the PCED was achieved in 29/34 eyes (85.3%) without the need for additional interventions within 22.5 ± 24.3 days (range, 2-105 days). The mean ± SD logMAR best-corrected visual acuity improved significantly from 1.11 ± 0.41 to 0.83 ± 0.70 (P = .02). There were no complications attributed to TST and 2 patients elected to discontinue due to discomfort. CONCLUSIONS: TST achieved resolution of PCEDs secondary to various etiologies in 85.3% of eyes, with significant improvement in vision demonstrated. This simple, inexpensive, noninvasive technique may be considered for patients with PCEDs.

The mixture of Agrimonia pilosa Ledeb. and Salvia miltiorrhiza Bunge. extract produces analgesic and anti-inflammatory effects in a collagen-induced arthritis mouse model.

Pain and inflammation typically manifest in patients with arthritis. It is now widely known that Agrimonia pilosa Ledeb (AP) and Salvia miltiorrhiza Bunge (SM) exert anti-inflammatory and antinociceptive effects. We have previously reported that the mixture extract (ME) from AP and SM produces antinociceptive and anti-inflammatory effects in gout arthritis and monoiodoacetate (MIA)-induced arthritis models. In the present study, we assessed the antinociceptive and anti-inflammatory effects on the collagen-induced arthritis (CIA) model. The antinociceptive effects in mice were measured using the von Frey test. ME administered once or for one week (once per day) once, and one-week reduced the pain in a dose-dependent manner (from 50 to 100 mg/kg) in the CIA-induced osteoarthritis (OA) model. ME treatment also reduced tumor necrosis factor (TNF)-α and C-reactive protein (CRP) levels in plasma and ankle tissues. Furthermore, COX-1, COX-2, NF-κB, TNF-α, and IL-6 expressions were attenuated after ME treatment. In most experiments, the antinociceptive and anti-inflammatory effects induced by ME treatment were almost equal to or slightly better than those induced by Perna canaliculus (PC) treatment, which was used as a positive control. Our results suggest that ME possesses antinociceptive and anti-inflammatory effects, indicating its potential as a therapeutic agent for arthritis treatment.

Characterization of a new bacteriocin, Carocin D, from Pectobacterium carotovorum subsp. carotovorum Pcc21.

Two different bacteriocins, carotovoricin and carocin S1, had been found in Pectobacterium carotovorum subsp. carotovorum, which causes soft-rot disease in diverse plants. Previously, we reported that the particular strain Pcc21, producing only one high-molecular-weight bacteriocin, carried a new antibacterial activity against the indicator strain Pcc3. Here, we report that this new antibacterial activity is due to a new bacteriocin produced by strain Pcc21 and named carocin D. Carocin D is encoded by the caroDK gene located in the genomic DNA together with the caroDI gene, which seems to encode an immunity protein. N-terminal amino acid sequences of purified carocin D were determined by Edman degradation. In comparison with the primary translation product of caroDK, it was found that 8 amino acids are missing at the N terminus. This finding proved that carocin D is synthesized as a precursor peptide and that 8 amino acids are removed from its N terminus during maturation. Carocin D has two putative translocation domains; the N-terminal and C-terminal domains are homologous to those of Escherichia coli colicin E3 and Pseudomonas aeruginosa S-type pyocin, respectively. When caroDK and caroDI genes were transformed into carocin D-sensitive bacteria such as Pcc3, the bacteria became resistant to this bacteriocin. Carocin D has one putative DNase domain at the extreme C terminus and showed DNase activity in vitro. This bacteriocin had slight tolerance to heat but not to proteases. The caroDK gene was present in only 5 of 54 strains of P. carotovorum subsp. carotovorum. These results indicate that carocin D is a third bacteriocin found in P. carotovorum subsp. carotovorum, and this bacteriocin can be readily expressed in carocin D-sensitive nonpathogenic bacteria, which may have high potential as a biological control agent in the field.

Microbiological assessment in strawberry production and recommendations to establish a good agricultural practice system.

This study conducted microbiological assessment in tunnel style strawberry greenhouses and packaging centers and suggested recommendations to establish a good agricultural practice for strawberry production. The samples from irrigation water, workers' gloves, harvest bins, soil, strawberry leaves and strawberries in greenhouses, packers' gloves, conveyor belts, packaging tables, and door knobs of entrances in packaging centers were collected. Bacterial cell counts of aerobic plate counts, coliforms, Escherichia coli, E. coli O157:H7, Salmonella, Staphylococcus aureus, and Bacillus cereus were then enumerated on appropriate selective media. In general, bacterial populations were similar (p ≥ 0.05) among strawberry greenhouses but not among packaging houses. E. coli and E. coli O157:H7 were negative in all samples, and low levels of Salmonella and B. cereus were detected. However, high bacterial cell counts of aerobic plate counts, coliforms, and S. aureus were found in most samples. These results suggest that food safety practice in strawberry greenhouses and packaging centers should be improved, and the results may be useful in the establishment of a good agricultural practice system for strawberry production.

Cataract incision-related corneal erosion: recurrent corneal erosion because of clear corneal cataract surgery.

Three patients developed recurrent corneal erosions (RCEs) over their cataract surgery corneal incisions. These cataract incision-related corneal erosions (CIRCEs) resulted in pain after cataract surgery. None had any physical findings for corneal erosion; thus, a new technique called the corneal sweep test was developed to identify the erosion. To the authors' knowledge, this is the first time this association between the clear corneal cataract incision and RCEs has been reported. Considering the high number of cataract surgeries performed around the world, it is important for ophthalmologists to recognize CIRCEs as a potential cause of ocular discomfort after clear corneal cataract surgery.

Trailing-haptic-first modification of double-needle intrascleral haptic fixation technique.

The Yamane double-needle intrascleral haptic fixation technique for posterior chamber intraocular lens (IOL) fixation in the setting of absent or inadequate capsule support is a minimally invasive IOL fixation technique that requires scleral incisions using needles to externalize the IOL haptics. Despite being a seemingly easy and intuitive procedure, there are significant challenges when learning this technique. The most difficult step is threading the trailing haptic with the needle for fixation. If using an IOL with weak haptics, this step can result in haptic kink or breakage, which renders the haptics useless for this technique and necessitating explantation of the IOL. Even when an IOL with strong and rigid haptics is used, the rigid haptics make threading the trailing haptic the most difficult step. The trailing-haptic-first technique is a distinct modification that enhances the ease and success of the double-needle technique.

Wound-healing response and refractive regression after conductive keratoplasty.

PURPOSE: To characterize the histological changes that occur after conductive keratoplasty (CK) using a rabbit model. SETTING: LSU Eye Center and Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, School of Medicine, New Orleans, Louisiana, USA. METHODS: Conductive keratoplasty was performed on 24 eyes of 12 New Zealand albino rabbits. In each eye, 24 spots were placed in a cross-corneal manner using 3 optical zones at 6.0, 7.0, and 8.0 mm. Eyes were assessed with corneal topography weekly. Rabbits were humanely killed 2, 4, 6, and 8 weeks postoperatively. The eyes were then enucleated and processed for histopathology and immunohistochemical analysis. RESULTS: All eyes showed an initial mean steepening of the corneal curvature of 2.24 diopters (D) 2 weeks postoperatively. Corneal topography revealed a 26%, 36%, and 39% regression of the refractive results at 4, 6, and 8 weeks, respectively. Immunohistochemical analysis demonstrated keratocyte apoptosis, myofibroblast appearance, and upregulation of chondroitin sulfate, MMP-1, and collagen III in the area surrounding the tip in each spot. CONCLUSION: The histological changes that occur after CK may be responsible for the well-established regression of its refractive effect. A better understanding of the wound-healing response after CK is necessary to improve the long-term stability of the procedure.

Double-chop: Modified-chop technique eliminating ultrasonic energy and vacuum for lens fragmentation.

Ultrasound (US) energy and vacuum are necessary for most nuclear disassembly techniques, but the use of US energy and vacuum poses potential risks to intracameral structures, including the corneal endothelium, iris, zonular fibers, and posterior capsule. A wide range of techniques involve sculpting, chopping, prechopping, and femtosecond laser-assisted fragmentation. However, these techniques are limited by high US energy, high vacuum to grab and hold the lens, additional instrumentation, or cost. A modified chop approach that bypasses the traditional rules of chopping is presented. The approach is not only effective, but also potentially safer than current techniques because it exposes the eye to less US energy, less vacuum, and less intracapsular manipulation. FINANCIAL DISCLOSURE: The author has no financial or proprietary interest in any material or method mentioned.

Topical combination of NGF and DHA increases rabbit corneal nerve regeneration after photorefractive keratectomy.

PURPOSE: To investigate the effect of nerve growth factor (NGF) in combination with docosahexaenoic acid (DHA) on corneal nerve regeneration in a rabbit model after PRK and correlate the findings with functional tear test. METHODS: Unilateral PRK was performed on 21 New Zealand albino rabbits. Three groups, each consisting of six rabbits, were randomized to receive twice-weekly treatments with DHA, NGF, or NGF plus DHA delivered by collagen shield. A fourth group, the control, received treatment with albumin. Rabbits were observed for 8 weeks, and tear secretion tests were conducted every 15 days. The eyes were prepared for immunostaining. Monoclonal antibodies for class II beta-tubulin, calcitonin gene-related peptide (CGRP), substance P (SP), and Ki-67 were used. Cell nuclei were stained with 4',6'-diamino-2-phenylindole (DAPI). Positive staining areas in relation to total area were calculated with image-analysis software. RESULTS: There were no significant differences in the tear-secretion test results among the four groups. However, none of the eyes treated with NGF plus DHA showed rose bengal staining 30 days after PRK, compared with 50% in the control group and 33% in the DHA-treated group. A higher percentage of Ki-67-positive cells, a marker of cell proliferation, was observed in the DHA plus NGF-and NGF-treated groups compared with DHA alone or the control. Eight weeks after PRK, tubulin-positive and CGRP-positive epithelial and subbasal nerve bundle areas were significantly higher in the DHA plus NGF group than in the control and NGF or DHA alone. No differences were noted in the SP-positive nerve bundles between the different treatments and the control treatment. CONCLUSIONS: NGF plus DHA treatment after PRK in rabbits is associated with increased corneal nerve surface area, increased epithelial proliferation, and decreased rose bengal staining compared with NGF, DHA, or vehicle control alone. The combination of NGF plus DHA yields faster nerve recovery after PRK and may have therapeutic usefulness in the treatment of post-PRK dry eye and other neurotrophic keratopathies.

Retractor lysis as prophylaxis for lower lid retraction following inferior rectus recession.

BACKGROUND: Lower lid retraction is a frequent complication of inferior rectus recession, especially of larger amounts. METHODS: With an incision through the palpebral conjunctiva, the lower lid retractors were lysed at the same anesthesia as inferior rectus recessions in a total of 20 patients (24 eyes). Included are 10 patients (12 eyes) described earlier and presented here with extended follow-up. Inferior rectus recessions ranged from 2 to 10 mm (mean, 4.2 mm). RESULTS: No patient had clinically apparent lid retraction or subjective complaints of lid deformity. Results were stable for 1 to 89 months (mean, 24.8 months) of follow-up. Three patients developed symblepharon, but surgical repair was required in only 1 case. CONCLUSION: Lower lid retractor lysis is a simple, safe, and effective procedure to prevent the lower lid retraction associated with inferior rectus recession.

Cross chop: Modified rotationless horizonal chop technique for weak zonules.

Cross chop is a modified horizontal chop technique that enables safe and efficient lens disassembly without torquing the lens within the capsular bag.

(2R,7S)-diacetoxytridecane: sex pheromone of the aphidophagous gall midge, Aphidoletes aphidimyza.

In a recent study, evidence was presented that females of the aphidophagous midge Aphidoletes aphidimyza (Rondi) (Diptera: Cecidomyiidae) release a sex pheromone to attract mates. Our objectives were to identify and bioassay the pheromone. Coupled gas chromatographic-electroantennographic detection(GC-EAD) analyses of untreated and hydrogenated pheromone extract on three fused-silica columns (DB-5, DB-23, DB-210) revealed a single compound that elicited responses from male antennae. Retention index calculations of this candidate pheromone (CP) suggested that it was a di-acetate. Considering that most of the presently identified cecidomyiid pheromones consist of a 13-carbon chain with (at least) one acetate group in C2, we synthesized 2,6-, 2,7-, 2,8-, 2,9-, 2,10-, 2,11-, and 2,12-diacetoxytridecane. In GC analyses of these compounds, only 2,7-diacetoxytridecane cochomatographed with CP on all columns. In laboratory two-choice experiments with stereospecifically synthesized stereoisomers, only (2R,7S)-diacetoxytridecane elicited significant anemotatic responses by male A. aphidimyza. In trapping experiments in greenhouse compartments, only traps baited with (2R,7S)-diacetoxytridecane captured significant numbers of male A. aphidimyza, clearly revealing the absolute configuration of the pheromone. Failure of the stereoisomeric mixture (containing all four stereoisomers including the pheromone) to attract males is due to inhibitory characteristics of the (2R,7R)- and (2S,7R)-stereoisomers. The pheromone of zoophagous A. aphidimyza resembles those from phytophagous cecidomyiid midges, suggesting a common, diet-independent pathway for pheromone biosyntheses.