Enhanced Non-Contact Grip Force and Swirl Stability by a Combined Venturi-Vortex Air Head.

A combination of the venturi module and the vortex cup was proposed to solve vortex instability and to enhance grip capacity. Mounting a venturi suction pad inside the vortex cup improved vacuum generation efficiency. When the vortex cup properly maintained the non-contact air gap and generated an equivalent vacuum to achieve a sealing effect around the open gap of the suction pad, the combined head improved grip capacity and stabilized the non-contact environment. Furthermore, the flow patterns around the venturi chamber and the swirl inside the vortex cup were analyzed based on the design elements of each module. In a module that integrated some of the venturi's features internally, increased air consumption of the vortex cup was required than that of the venturi. However, it supported a wide range of non-contact grips. The coupled model effectively protected the vacuum suction features of the venturi suction pad in all non-contact environments in that range.

3-month surgical outcomes of Implantable Collamer Lens implantation for myopic regression after laser vision correction surgeries: a retrospective case series.

BACKGROUND: To investigate the surgical outcomes of implantable collamer lens (ICL) implantation in eyes with residual myopia after primary laser vision correction (LVC) surgeries. METHODS: This study included patients who underwent ICL implantation and had a history of LVC surgery, including photorefractive keratectomy (PRK) or laser-assisted in situ keratomileusis (LASIK). Visual acuity and refractive error were assessed pre and 3-months postoperatively and the efficacy and safety indices calculated accordingly. RESULTS: A total of 30 eyes of 17 patients were included in this study. At 3 months, the mean logMAR uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and spherical equivalent were - 0.03 ± 0.11 (include logMAR), - 0.04 ± 0.09 (include logMAR), and - 0.06 ± 0.33 diopters (D), respectively. The 3-month Snellen UDVA was better than 20/20 for 83% of eyes, and 97% of eyes showed an unchanged or improved CDVA after surgery. The mean efficacy and safety indices were 1.11 ± 0.22 and 1.13 ± 0.20, respectively. Further, 93 and 100% of eyes were within ±0.5 and ± 1.0 D of the attempted spherical equivalent refraction, respectively. CONCLUSIONS: ICL implantation in eyes with myopic regression after previous LVC surgery showed safe, effective, and predictable outcomes. TRIAL REGISTRATION: retrospectively registered.

Critical Energy Dissipation in a Binary Superfluid Gas by a Moving Magnetic Obstacle.

We study the critical energy dissipation in an atomic superfluid gas with two symmetric spin components by an oscillating magnetic obstacle. Above a certain critical oscillation frequency, spin-wave excitations are generated by the magnetic obstacle, demonstrating the spin superfluid behavior of the system. When the obstacle is strong enough to cause density perturbations via local saturation of spin polarization, half-quantum vortices (HQVs) are created for higher oscillation frequencies, which reveals the characteristic evolution of critical dissipative dynamics from spin-wave emission to HQV shedding. Critical HQV shedding is further investigated using a pulsed linear motion of the obstacle, and we identify two critical velocities to create HQVs with different core magnetization.

Clinical outcomes of immediate transepithelial photorefractive keratectomy after suction loss during small-incision lenticule extraction.

PURPOSE: To investigate the surgical outcomes of immediate transepithelial photorefractive keratectomy (PRK) after suction loss during small-incision lenticule extraction (SMILE) and compare the outcomes with those of uneventful SMILE. SETTING: Eyereum Eye Clinic, Seoul, South Korea. DESIGN: Retrospective case series. METHODS: This study included 24 eyes of 12 patients who had uneventful SMILE in one eye and immediate transepithelial PRK after the development of suction loss during the lenticule cut in the contralateral eye. Visual acuity assessments, manifest refraction, and measurements of corneal wavefront aberrations were performed preoperatively and 6 months postoperatively. RESULTS: At 6 months, the mean uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and spherical equivalent were -0.04 ± 0.05, -0.09 ± 0.05, and -0.02 ± 0.24 diopter (D), respectively, in the transepithelial PRK group and -0.10 ± 0.07, -0.06 ± 0.07, and -0.04 ± 0.17 D, respectively (P = .036, P = .109, and P = .671, respectively), in the uneventful SMILE group. The 6-month Snellen UDVA was better than 20/20 for 11 (92%) and 12 (100%) of eyes in the transepithelial PRK and uneventful SMILE groups, respectively. All 24 eyes showed unchanged or improved CDVA and a significant increase in the total corneal higher-order aberrations postoperatively. Corneal spherical aberrations exhibited a significant postoperative increase only in the transepithelial PRK group. CONCLUSIONS: Immediate transepithelial PRK after early suction loss during SMILE might be safe and effective, with refractive outcomes that are comparable with those after uneventful SMILE.

The mechanistic insight of a specific interaction between 15d-Prostaglandin-J2 and eIF4A suggests an evolutionary conserved role across species.

15-deoxy-delta 12,14-prostaglandin J2 (15d-PGJ2) is an anti-inflammatory/anti-neoplastic prostaglandin that functions through covalent binding to cysteine residues of various target proteins. We previously showed that 15d-PGJ2 mediated anti-inflammatory responses are dependent on the translational inhibition through its interaction with eIF4A (Kim et al., 2007). Binding of 15d-PGJ2 to eIF4A specifically blocks the interaction between eIF4G and eIF4A, which leads to the formation of stress granules (SGs), which then cluster mRNAs with inhibited translation. Here, we show that the binding between 15d-PGJ2 and eIF4A specifically blocks the interaction between the MIF4G domain of eIF4G and eIF4A. To reveal the mechanism of this interaction, we used computational simulation-based docking studies and identified that the carboxyl tail of 15d-PGJ2 could stabilize the binding of 15d-PGJ2 to eIF4A through arginine 295 of eIF4A, which is the first suggestion that the 15d-PGJ2 tail plays a physiological role. Interestingly, the putative 15d-PGJ2 binding site on eiF4A is conserved across many species, suggesting a biological role. Our data propose that studying 15d-PGJ2 and its targets may uncover new therapeutic approaches in anti-inflammatory drug discovery.

eIF2A, an initiator tRNA carrier refractory to eIF2α kinases, functions synergistically with eIF5B.

The initiator tRNA (Met-tRNA i Met ) at the P site of the small ribosomal subunit plays an important role in the recognition of an mRNA start codon. In bacteria, the initiator tRNA carrier, IF2, facilitates the positioning of Met-tRNA i Met on the small ribosomal subunit. Eukarya contain the Met-tRNA i Met carrier, eIF2 (unrelated to IF2), whose carrier activity is inhibited under stress conditions by the phosphorylation of its α-subunit by stress-activated eIF2α kinases. The stress-resistant initiator tRNA carrier, eIF2A, was recently uncovered and shown to load Met-tRNA i Met on the 40S ribosomal subunit associated with a stress-resistant mRNA under stress conditions. Here, we report that eIF2A interacts and functionally cooperates with eIF5B (a homolog of IF2), and we describe the functional domains of eIF2A that are required for its binding of Met-tRNA i Met , eIF5B, and a stress-resistant mRNA. The results indicate that the eukaryotic eIF5B-eIF2A complex functionally mimics the bacterial IF2 containing ribosome-, GTP-, and initiator tRNA-binding domains in a single polypeptide.

Critical Spin Superflow in a Spinor Bose-Einstein Condensate.

We investigate the critical dynamics of spin superflow in an easy-plane antiferromagnetic spinor Bose-Einstein condensate. Spin-dipole oscillations are induced in a trapped condensate by applying a linear magnetic field gradient and we observe that the damping rate increases rapidly as the field gradient increases above a certain critical value. The onset of dissipation is found to be associated with the generation of dark-bright solitons due to the modulation instability of the counterflow of two spin components. Spin turbulence emerges as the solitons decay because of their snake instability. We identify another critical point for spin superflow, in which transverse magnon excitations are dynamically generated via spin-exchanging collisions, which leads to the transient formation of axial polar spin domains.

Observation of vortex-antivortex pairing in decaying 2D turbulence of a superfluid gas.

In a two-dimensional (2D) classical fluid, a large-scale flow structure emerges out of turbulence, which is known as the inverse energy cascade where energy flows from small to large length scales. An interesting question is whether this phenomenon can occur in a superfluid, which is inviscid and irrotational by nature. Atomic Bose-Einstein condensates (BECs) of highly oblate geometry provide an experimental venue for studying 2D superfluid turbulence, but their full investigation has been hindered due to a lack of the circulation sign information of individual quantum vortices in a turbulent sample. Here, we demonstrate a vortex sign detection method by using Bragg scattering, and we investigate decaying turbulence in a highly oblate BEC at low temperatures, with our lowest being ~0.5T c , where T c is the superfluid critical temperature. We observe that weak spatial pairing between vortices and antivortices develops in the turbulent BEC, which corresponds to the vortex-dipole gas regime predicted for high dissipation. Our results provide a direct quantitative marker for the survey of various 2D turbulence regimes in the BEC system.

Observation of von Kármán Vortex Street in an Atomic Superfluid Gas.

We report on the experimental observation of vortex cluster shedding from a moving obstacle in an oblate atomic Bose-Einstein condensate. At low obstacle velocities v above a critical value, vortex clusters consisting of two like-sign vortices are generated to form a regular configuration like a von Kármán street, and as v is increased, the shedding pattern becomes irregular with many different kinds of vortex clusters. In particular, we observe that the Stouhal number associated with the shedding frequency exhibits saturation behavior with increasing v. The regular-to-turbulent transition of the vortex cluster shedding reveals remarkable similarities between a superfluid and a classical viscous fluid. Our work opens a new direction for experimental investigations of the superfluid Reynolds number characterizing universal superfluid hydrodynamics.

eIF2A mediates translation of hepatitis C viral mRNA under stress conditions.

Translation of most mRNAs is suppressed under stress conditions. Phosphorylation of the α-subunit of eukaryotic translation initiation factor 2 (eIF2), which delivers initiator tRNA (Met-tRNA(i)) to the P site of the 40S ribosomal subunit, is responsible for such translational suppression. However, translation of hepatitis C viral (HCV) mRNA is refractory to the inhibitory effects of eIF2α phosphorylation, which prevents translation by disrupting formation of the eIF2-GTP-Met-tRNA(i) ternary complex. Here, we report that eIF2A, an alternative initiator tRNA-binding protein, has a key role in the translation of HCV mRNA during HCV infection, in turn promoting eIF2α phosphorylation by activating the eIF2α kinase PKR. Direct interaction of eIF2A with the IIId domain of the HCV internal ribosome entry site (IRES) is required for eIF2A-dependent translation. These data indicate that stress-independent translation of HCV mRNA occurs by recruitment of eIF2A to the HCV IRES via direct interaction with the IIId domain and subsequent loading of Met-tRNA(i) to the P site of the 40S ribosomal subunit.

Minocycline inhibition of photoreceptor degeneration.

OBJECTIVE: To determine whether systemic minocycline can protect photoreceptors in experimental retinal detachment (RD). METHODS: Retinal detachment was induced in mice by subretinal injection of sodium hyaluronate, 1.4%. In 1 experiment, mice received daily injections of minocycline (group 1) or saline (group 2). In a second experiment, mice were treated with minocycline or saline beginning 24 hours prior, immediately after, or 24 hours after experimental RD. In both experiments, photoreceptor cell survival and apoptosis were assessed by immunohistochemistry with primary antibodies against photoreceptor cell markers, rod rhodopsin, and cone opsin, and by terminal deoxynucleotidyl transferase-mediated dUTP-biotin end labeling. RESULTS: Photoreceptor cell apoptosis was detected at day 1 after experimental RD, with apoptotic cells peaking in number at day 3 and dropping by day 7. Treatment with minocycline significantly reduced the number of apoptotic photoreceptor cells associated with RD when given 24 hours before or even 24 hours after RD. CONCLUSIONS: Our data suggest that minocycline may be useful in the treatment of photoreceptor degeneration associated with RD, even when given up to 24 hours after RD. CLINICAL RELEVANCE: Use of minocycline in patients with macula-off RD may prevent photoreceptor apoptosis and glial cell proliferation, improving final visual outcomes.

Proline-rich transcript in brain protein induces stress granule formation.

The repression of translation in environmentally stressed eukaryotic cells causes the sequestration of translation initiation factors and the 40S ribosomal subunit into discrete cytoplasmic foci called stress granules (SGs). Most components of the preinitiation complex, such as eIF3, eIF4A, eIF4E, eIF4G, and poly(A)-binding protein, congregate into SGs under stress conditions. However, the molecular basis of translation factor sequestration into SGs has not been clearly elucidated. Here, we report that proline-rich transcript in brain (PRTB) protein interacts with eIF4G and participates in SG formation. PRTB was recruited to SG under sodium arsenite and heat stress conditions. When overexpressed, PRTB inhibited global translation and formed SGs containing TIA-1, eIF4G, and eIF3. Knockdown of PRTB reduced the SG formation induced by sodium arsenite. These results suggest that PRTB not only is a component of SG formed by cellular stresses but also plays an important role in SG formation via an interaction with the scaffold protein eIF4G, which is associated with many translation factors and mRNAs.

Modified external needle drainage of subretinal fluid in primary rhegmatogenous retinal detachment: a prospective, consecutive, interventional, single-surgeon study.

PURPOSE: We describe surgical outcomes in a single-surgeon, consecutive series of patients who received scleral buckle placement for primary retinal detachment using a modified external needle drainage technique. METHODS: Eighty-two eyes of 80 patients with primary retinal detachment underwent scleral buckle placement with modified external needle drainage. Preoperative, postoperative, and surgical data were collected. Regression analysis was used to evaluate the association between preoperative clinical data and number of surgeries. RESULTS: The retinal detachment most commonly involved 41% to 50% of the retina. Seventy-six eyes (92.7%) were repaired after 1 surgical procedure, 98.8%, after 2 procedures, and 100%, after 3 procedures. No preoperative clinical variables were found to be significantly correlated with the number of surgeries performed. Vision improved an average of 0.3 logarithm of the minimal angle of resolution or 3 lines of vision (P < 0.001). One eye (1.2%) developed a localized subretinal hemorrhage at the drainage site that resolved spontaneously. CONCLUSIONS: The modified external needle drainage technique used during scleral buckle placement appears to be safe and effective in patients with primary retinal detachment.

Anti-inflammatory lipid mediator 15d-PGJ2 inhibits translation through inactivation of eIF4A.

The signaling lipid molecule 15-deoxy-delta 12,14-prostaglandin J2 (15d-PGJ2) has multiple cellular functions, including anti-inflammatory and antineoplastic activities. Here, we report that 15d-PGJ2 blocks translation through inactivation of translational initiation factor eIF4A. Binding of 15d-PGJ2 to eIF4A blocks the interaction between eIF4A and eIF4G that is essential for translation of many mRNAs. Cysteine 264 in eIF4A is the target site of 15d-PGJ2. The antineoplastic activity of 15d-PGJ2 is likely attributed to inhibition of translation. Moreover, inhibition of translation by 15d-PGJ2 results in stress granule (SG) formation, into which TRAF2 is sequestered. The sequestration of TRAF2 contributes to the anti-inflammatory activity of 15d-PGJ2. These findings reveal a novel cross-talk between translation and inflammatory response, and offer new approaches to develop anticancer and anti-inflammatory drugs that target translation factors including eIF4A.

A modified iris repair technique and capsular tension ring insertion in a patient with coloboma with cataracts.

PURPOSE: We describe our successful experience using a capsular tension ring (CTR) and iris repair during cataract surgery in a patient with bilateral coloboma. METHODS: A 67-year-old woman had no history of trauma, but had zonular deficiency and inferonasal iris defects in both eyes. An extracapsular cataract extraction and intraocular lens (IOL) scleral fixation was performed in the left eye. A CTR was implanted in the right eye through a sclerocorneal incision. After the IOL was placed centrally in the capsular bag, two paracenteses were made at the limbus (5 o'clock and 7 o'clock). A long, straight needle was passed through the 7 o'clock paracentesis site into a angled, blunt tipped 27 gauge needle inserted from the 5 o'clock paracentesis. The two needles were pulled out at 5 o'clock. After inserting the long needle into the blunt tipped needle at 7 o'clock, both were passed back through the 7 o'clock paracentesis site. The needles were pulled out again at the 5 o'clock paracentesis site tied. Equal tension was used to tie both sides. RESULTS: Visual acuity improved to 20/20 in the right eye. CONCLUSIONS: Both capsular tension ring implantation and iris repair was successfully performed at the time of cataract surgery in a coloboma patient, which resulted in improvements in visual function and cosmesis.

Neovascularization in branch retinal vein occlusion combined with arterial insufficiency.

The aim of this study is to elucidate the association of neovascularization in branch retinal vein occlusion (BRVO) combined with major arterial insufficiency (MAI), compared with BRVO alone. The authors retrospectively reviewed the charts, color photographs, and fluorescein angiograms of 304 patients (308 eyes) who had BRVO from 1990 to 2002 at Hanyang University hospital. Patients with BRVO combined with MAI and patients with BRVO alone were differentiated by angiographic appearance. Of the 308 eyes, 12 (3.9%) had neovascularization, all of which were in the 56 eyes of the MAI group for which the neovascularization rate was 21.4%. Neovascularization in BRVO was more strongly associated with the non-perfusion caused by MAI, rather than with the extent of the non-perfusion area that originated from retinal capillary obstruction. MAI is considered as a risk factor for neovascularization and hence could be a prognostic factor.

Transscleral fixation of a dislocated IOL through sclerotomy.

We describe a technique for knotting a suture to the haptic of a dislocated intraocular lens (IOL) through a sclerotomy site without removing an IOL in 4 patients. The suture was knotted to the haptic from outside the sclera. The remaining suture material was tied together and buried in the sclerotomy site. To prove that we could suture to the haptic safely, experiments were carried out using 4 scleral shells of donor eyes. No complications occurred, and good visual recovery was achieved. In this method, the haptic can be tied safely through the sclerotomy site and reduce the risk for knot-related complications. To our knowledge, this approach has not been reported.