Transfer of orbital angular momentum of light to plasmonic excitations in metamaterials.

The emergence of the vortex beam with orbital angular momentum (OAM) has provided intriguing possibilities to induce optical transitions beyond the framework of the electric dipole interaction. The uniqueness stems from the OAM transfer from light to material, as demonstrated in electronic transitions in atomic systems. In this study, we report on the OAM transfer to electrons in solid-state systems, which has been elusive to date. Using metamaterials (periodically textured metallic disks), we show that multipolar modes of the surface electromagnetic excitations (so-called spoof localized surface plasmons) are selectively induced by the terahertz vortex beam. Our results reveal selection rules governed by the conservation of the total angular momentum, which is confirmed by numerical simulations. The efficient transfer of light's OAM to elementary excitations in solid-state systems at room temperature opens up new possibilities of OAM manipulation.

Changes in higher-order aberrations after scleral buckling surgery for rhegmatogenous retinal detachment.

PURPOSE: To evaluate changes in higher-order aberrations (HOAs) after scleral buckling surgery for the treatment of rhegmatogenous retinal detachment (RD). DESIGN: Prospective observational comparative case series. PARTICIPANTS: The study included 67 eyes of 67 rhegmatogenous RD patients undergoing scleral buckling surgery, and the fellow normal eyes comprised the control group. Twenty-seven eyes were treated with the segmental buckling procedure and 40 eyes received the encircling buckling procedure alone. METHODS: Hartmann-Shack wavefront analysis was performed at 2 weeks, 1 month, and 3 months postoperatively. MAIN OUTCOME MEASURE: Time course of changes in HOAs. RESULTS: Scleral buckling surgery significantly increased HOAs at 2 weeks (P<0.0001), 1 month (P<0.0005), and 3 months (P<0.05) postoperatively as compared with the control group. At 3 months postoperatively, the HOAs were significantly lower in the encircling group than in the segmental buckling group (P<0.05). The vertical coma (Zernike Z(3)(-1)) became negative (significantly lower than zero, P<0.01) in patients who received segmental buckling in the upper quadrant. The ocular HOAs and logarithm of the minimum angle of resolution best-corrected visual acuity significantly correlated at 3 months postoperatively (third-order root mean square [RMS]: r = 0.445, P<0.0005; fourth-order RMS: r = 0.489, P<0.0001). CONCLUSIONS: Scleral buckling surgery significantly increased HOAs. The segmental buckling procedure increased the HOAs to a greater extent and for a longer duration than the encircling procedure. The direction of coma aberration corresponded to the location of the segmental buckle. The increase in HOAs can be one of the factors responsible for visual disturbances after scleral buckling surgery.

Changes in corneal topography after 25-gauge transconjunctival sutureless vitrectomy versus after 20-gauge standard vitrectomy.

PURPOSE: To evaluate the changes in regular and irregular corneal astigmatism after 25-gauge transconjunctival sutureless vitrectomy and 20-gauge standard vitrectomy. DESIGN: Prospective observational comparative case series. PARTICIPANTS: Thirty-two eyes of 32 patients undergoing 25-gauge transconjunctival sutureless vitrectomy and 25 eyes of 24 patients undergoing 20-gauge standard vitrectomy. METHODS: Corneal topography was obtained preoperatively and at 2 weeks and 1 month postoperatively. MAIN OUTCOME MEASURES: The dioptric data of the central 3-mm zone of the cornea were decomposed using Fourier harmonic analysis into spherical power, regular astigmatism, asymmetry, and higher-order irregularity. RESULTS: None of the 4 Fourier indices changed throughout the observation period in the 25-gauge group. In the 20-gauge group, regular astigmatism, asymmetry, and higher-order irregularity were increased significantly at 2 weeks after vitrectomy (P<0.05, Wilcoxon signed-ranks test) and returned to preoperative levels by 1 month. The spherical power in the 20-gauge group did not change after surgery. For regular astigmatism, asymmetry, and higher-order irregularity, the 20-gauge group showed significantly greater surgically induced changes than the 25-gauge group (P<0.05, Mann-Whitney U test). CONCLUSIONS: Twenty-five-gauge transconjunctival sutureless vitrectomy does not induce significant changes in corneal topography and exerts little influence on the optical quality of the cornea.

Retention and removal of a new viscous dispersive ophthalmic viscosurgical device during cataract surgery in animal eyes.

AIMS: To assess the retention and removal properties of a new viscous dispersive ophthalmic viscosurgical device (OVD), DisCoVisc, in comparison with those of cohesive (Provisc), dispersive (Viscoat), and viscoadaptive (Healon5) OVDs. METHODS: In 20 porcine eyes, cataract surgery was simulated using one of the four OVDs which were stained with fluorescein for better visualisation. Three parameters were measured. Firstly, the presence/absence of OVDs in the chamber at the completion of phacoemulsification was recorded. Secondly, the time until the OVDs were completely removed from the anterior chamber using the phaco needle was measured. Thirdly, after intraocular lens (IOL) implantation, the time needed to completely remove the OVDs from the chamber with irrigation/aspiration tip was recorded. RESULTS: At the completion of phacoemulsification, the OVDs retained in 0% (0/5) for Provisc, 80% (4/5) for Healon5, 100% (5/5) for DisCoVisc, and 100% (5/5) for Viscoat. The retention of OVDs during phacoemulsification was greatest with Viscoat followed by, in descending order, DisCoVisc, Healon5, and Provisc. The removal of OVDs after IOL implantation took longest with Viscoat followed by Healon5, DisCoVisc, and Provisc. CONCLUSION: The viscous dispersive DisCoVisc showed excellent retention during phacoemulsification, while its removal after IOL implantation was very easy. When compared with the viscoadaptive Healon5, DisCoVisc was retained better in the chamber and was easier to remove. These features of DisCoVisc should be highly advantageous when considering covering the entire cataract surgery procedure with a single OVD.

Investigation of new cytogenetic biomarkers specific to high-LET radiation using in vivo and in vitro exposed human lymphocytes.

PURPOSE: To find detectable cytogenetic biomarkers that can offer information about the radiation quality of in vivo exposure retrospectively. MATERIALS AND METHODS: Chromosome-type aberrations of peripheral lymphocytes of uterine cancer patients that received internal gamma- and external X-ray therapy or carbon beam therapy and of victims severely exposed to neutrons and gamma-rays in a criticality accident that occurred in Tokai-mura, Japan were analysed. Data obtained from in vitro irradiation experiments using 60Co gamma-rays and 10 MeV neutrons were compared with the in vivo exposure data. RESULTS: The ratio of acentric rings to dicentric chromosomes (termed RaD ratio) and that of excess fragments to dicentrics (termed EfD ratio) showed significant (p < 0.05) differences between the two groups of cancer patients, and these ratios for accidental victims were in between the values of the two groups of cancer patients. The in vitro studies using doses equivalent to 1 - 3 Gy of gamma-rays have confirmed that the EfD ratios were increased with the high LET (linear energy transfer) and RaD ratios decreased. CONCLUSION: The present data show that the RaD and EfD ratios can be used as cytogenetic biomarkers of exposure to high-LET radiation at least within a few years of exposure.

Prevention of growth of metastases in rat liver by perioperative immunoactivation.

Major intraabdominal operations result in immunodepression. In addition, manipulation of malignant tumors may release tumor cells into the systemic and portal circulation. The additive effects of immunodepression and tumor cell release during surgical treatment for gastrointestinal cancer may increase the metastases of tumor to the liver. We, therefore, studied the inhibitory effect of immunoactivator OK-432 on the growth of the liver metastases in the perioperative period using a model in which rat ascites hepatoma AH-130 cells transplanted into the portal venous system consistently induce hepatic metastases. Forty-four male Donryu rats were assigned to a test group and a control group. The test group of 24 rats was treated with OK-432 (0.5 mg/day administered i.p.) for 7 days before tumor implantation, and the control group of 20 rats was treated with 0.2 ml of saline i.p. for the same number of days as the test group. The number of hepatic metastatic lesions at 14 days after tumor implantation amounted to 71.5 +/- 45.9 (SD) in the test group of 8 rats and 149.3 +/- 61.9 in the control group of 8 rats. The mean values of survival days after tumor implantation in the test group of 9 rats and the control group of 6 rats were 33.4 +/- 8.1 and 21.8 +/- 6.9, respectively. The values of OKT4+ in peripheral blood T-cell subsets in the test group of 7 rats and in the control group of 6 rats were 51.9 +/- 7.0 and 41.8 +/- 7.2%, respectively. These data showed significant differences between the two groups. Perioperative immunoactivation with OK-432 pretreatment reduced the incidence of liver metastases developed in rats given injections of tumor cells. We believe that the perioperative period is critical for the implantation and growth of metastases and that correction of perioperative immunodepression may favorably affect the development of metastatic disease and survival. This model may have relevance to the adjuvant treatment of human gastrointestinal cancer.

Radiosensitivity of skin fibroblasts from atomic bomb survivors with and without breast cancer.

Fibroblasts were established in vitro from skin biopsies obtained from 55 women and 1 man with or without breast cancer and with or without exposure to radiation from the atomic bomb explosion in Hiroshima. The radiosensitivity of these cells was evaluated by clonogenic assays after exposure to X-rays or to fission neutrons from a 252Cf source. Data were fitted to a multitarget model, S/S0 = A [1 - (1 - ekD)N], for both X-ray and neutron dose-survival curves. A single hit model, S/S0 = AekD, fits the neutron dose-survival responses as well. There were no differences in the means or variances of radiosensitivity between exposed and nonexposed groups or between patients with or without breast cancer. Hence, although the sample is not large, it provides no support for the hypothesis that atomic bomb radiation preferentially induces breast cancer in women whose cells in vitro are sensitive to cell killing by radiation.

Transient interhemispheric neuronal synchrony correlates with object recognition.

Object recognition might be achieved by the recreation of a meaningful internal image from visual fragments. This recreation might be achieved by neuronal synchronization that has been proposed as a solution for the perceptual binding problem. In this study, we evaluated synchronization between the occipitotemporal regions bilaterally using electroencephalograms during several visual recognition tasks. Conscious recognition of familiar objects spanning the visual midline induced transient interhemispheric electroencephalographic coherence in the alpha band, which did not occur with meaningless objects or with passive viewing. Moreover, there was no interhemispheric coherence when midline objects were not recognized as meaningful or when familiar objects were presented in one visual hemifield. These data suggest a close link between site-specific interregional synchronization and object recognition.

Inhibition of post-ischemic reperfusion injury of the kidney by diamine oxidase.

To elucidate the role of histamine in the pathogenesis of post-ischemic reperfusion injury of tissues, the effect of diamine oxidase (DAO) was studied on the changes in renal functions induced by 30 min occlusion followed by reperfusion of the renal vessels of unilaterally nephrectomized rats. Kinetic analysis using radiolabeled albumin revealed that vascular permeability of the kidney increased markedly after reperfusion. Although the intensity of neutrophil-dependent chemiluminescence of the blood remained unchanged during the occlusion, it increased significantly after reperfusion. Histological examination revealed a marked degeneration of glomeruli and proximal tubules in the reperfused kidney. Transtubular transport of phenolsulfophthalein (PSP) decreased markedly after reperfusion with concomitant increase in plasma levels of creatinine. Intravenously administered DAO markedly inhibited the reperfusion-induced increase in vascular permeability, preserved the structure of the kidney and normalized the rate of clearance of PSP and creatinine. Combined use of diphenylhydramine and ranitidine also inhibited the reperfusion injury of the kidney. These results suggested that histamine and its receptors might play critical roles in post-ischemic reperfusion injury of the kidney.

A new method using F-waves to measure muscle fiber conduction velocity (MFCV).

OBJECTIVE: First, to propose a new technique for measuring muscle fiber conduction velocity (MFCV). Second, to ascertain the validation of the new method that uses F-waves (F-MFCV) in healthy volunteers. Third, to examine the relationship between F-MFCV and motor nerve conduction velocity (MCV) in the same subjects. SUBJECTS AND METHODS: F-waves reflecting single motor units were recorded with a multi-channel surface electrode array and weak electrical stimulation to the median or ulnar nerves in 21 healthy volunteers. F-MFCVs of the abductor pollicis brevis (APB) and abductor digiti minimi (ADM) were calculated from the F-wave peak latency in each channel. MFCV during minimal voluntary contraction (V-MFVC) was measured in the same muscles. RESULTS: There was no significant difference between F-MFCV and V-MFCV in the muscles tested The mean F-MFCV value was similar to recently reported MFCV values generated by minimal voluntary contraction. No significant differences were found between the APB and ADM F-MFCVs, whereas the MCV of the ulnar nerve was faster than that of the median nerve. CONCLUSION: The MFCV in a single motor unit could be measured with a multi-channel surface electrode array by recording F-waves induced by weak stimulation. Since V-MFCV generated by minimal voluntary contraction is explained by the size principle, V-MFCV reflects small and slow conducting motor unit. There was no significant difference between F-MFCV and V-MFCV. It seemed that F-MFCV also reflected small motor unit. The reason for the lack of difference in the F-MFCVs of the ADM and APB is considered to be a relatively slow F-MFCV. Moreover, MCV reflected the speed of the fastest nerve fiber, whereas F-MFCV did not.

Expression of the putative membrane fatty acid transporter (FAT) in taste buds of the circumvallate papillae in rats.

The putative membrane fatty acid transporter (FAT) protein and its mRNA, originally expressed in adipose tissue, were found in the tongue of rats. Northern blot analysis showed a significant expression of FAT mRNA in the epithelial layer of circumvallate papillae. Immunohistochemical staining revealed that immunoreactivity for FAT is specifically localized in the apical part of taste bud cells, possibly gustatory cells, in the circumvallate papillae.

A human homolog of Drosophila warts tumor suppressor, h-warts, localized to mitotic apparatus and specifically phosphorylated during mitosis.

We identified a human homolog of Drosophila warts tumor suppressor gene, termed h-warts, which was mapped at chromosome 6q24-25.1. The h-warts protein has a serine/threonine kinase domain and is localized to centrosomes in interphase cells. However, it becomes localized to the mitotic apparatus, including spindle pole bodies, mitotic spindle, and midbody, in a highly dynamic manner during mitosis. Furthermore, h-warts is specifically phosphorylated in cells at mitotic phase, most likely by Cdc2 kinase. These findings suggest that h-warts functions as a component of the mitotic apparatus and is involved in proper progression of mitosis.

Characteristics of neutron beam generated by 500 MeV proton beam.

A neutron irradiation facility was constructed at PARMS, University of Tsukuba to produce an ultrahigh energy neutron beam with a depth dose distribution superior to an x-ray beam generated by a modern linac. This neutron beam was produced from the reaction on a thick uranium target struck by a 500 MeV proton beam from the booster synchrotron of the High Energy Physics Laboratory. The percentage depth dose of this neutron beam was nearly equivalent to that of x-rays around 20 MV and the dose rate was 15 cGy per minute. The relative biological effectiveness (RBE) of this neutron beam has been estimated using the cell inactivation effect and the HMV-I cell line. The survival curve of cells after neutron irradiation has a shoulder with n and Dq of 8 and 2.3 Gy, respectively. The RBE value at the 10(-2) survival level for the present neutron beam as compared with 137Cs gamma rays was 1.24. The results suggest that the biological effects of ultrahigh energy neutrons are not large enough to be useful, although the depth dose distribution of neutrons can be superior to that of high energy linac x-rays.

Compensation techniques in NIRS proton beam radiotherapy.

Proton beam has the dose distribution advantage in radiation therapy, although it has little advantage in biological effects. One of the best advantages is its sharp fall off of dose after the peak. With proton beam, therefore, the dose can be given just to cover a target volume and potentially no dose is delivered thereafter in the beam direction. To utilize this advantage, bolus techniques in conjunction with CT scanning are employed in NIRS proton beam radiation therapy planning. A patient receives CT scanning first so that the target volume can be clearly marked and the radiation direction and fixation method can be determined. At the same time bolus dimensions are calculated. The bolus frames are made with dental paraffin sheets according to the dimensions. The paraffin frame is replaced with dental resin. Alginate (a dental impression material with favorable physical density and skin surface contact) is now employed for the bolus material. With fixation device and bolus on, which are constructed individually, the patient receives CT scanning again prior to a proton beam treatment in order to prove the devices are suitable. Alginate has to be poured into the frame right before each treatments. Further investigations are required to find better bolus materials and easier construction methods.

Biophysical characteristics of HIMAC clinical irradiation system for heavy-ion radiation therapy.

PURPOSE: The irradiation system and biophysical characteristics of carbon beams are examined regarding radiation therapy. METHODS AND MATERIALS: An irradiation system was developed for heavy-ion radiotherapy. Wobbler magnets and a scatterer were used for flattening the radiation field. A patient-positioning system using X ray and image intensifiers was also installed in the irradiation system. The depth-dose distributions of the carbon beams were modified to make a spread-out Bragg peak, which was designed based on the biophysical characteristics of monoenergetic beams. A dosimetry system for heavy-ion radiotherapy was established to deliver heavy-ion doses safely to the patients according to the treatment planning. A carbon beam of 80 keV/microm in the spread-out Bragg peak was found to be equivalent in biological responses to the neutron beam that is produced at cyclotron facility in National Institute Radiological Sciences (NIRS) by bombarding 30-MeV deuteron beam on beryllium target. The fractionation schedule of the NIRS neutron therapy was adapted for the first clinical trials using carbon beams. RESULTS: Carbon beams, 290, 350, and 400 MeV/u, were used for a clinical trial from June of 1994. Over 300 patients have already been treated by this irradiation system by the end of 1997.

Synthesis of 2-deoxy-2-[(2,2-difluoro-3-hydroxytetradecanoyl)amino]-3-O- [(R)-3-(tetradecanoyloxy)tetradecanoyl]-D-glucopyranose 4-phosphate.

2-Deoxy-2-[(2,2-difluoro-3-hydroxytetradecanoyl)amino]-3-O-[(R)-3- (tetradecanoyloxy)tetradecanoyl]-D-glucopyranose 4-phosphates (9H,L) were synthesized from allyl 2-amino-2-deoxy-4,6-O- isopropylidene-beta-D-glucopyranoside (1), (+/-)-3-[(benzyloxycarbonyl)oxy]-2,2-difluorotetradecanoic acid, and (R)-3- (tetradecanoyloxy)tetradecanoic acid. Both compounds 9H and 9L were more active than GLA-60 for the prostaglandin D2 releasing test on macrophages.

Effects of spontaneous respiration on right and left ventricular function: evaluation by respiratory and ECG gated radionuclide ventriculography.

To clarify the mechanism of inspiratory reduction of left ventricular (LV) stroke volume (SV) during spontaneous respiration, we measured right and left ventricular volume changes from expiration to inspiration using radionuclide ventriculography with respiratory gating technique. In this method, scintigraphic data were acquired in a list mode with ECG R wave triggers and respiratory volume curve derived from respiratory flowmeter. Cardiac cycles occurring during the second halves of inspiratory and expiratory phases were separately selected and used to produce multigated images for the respective phases. Twelve patients with normal LV ejection fraction (EF) (greater than 50%) and right ventricular (RV) EF (greater than 40%) and without pulmonary diseases were studied. LV end-diastolic volume (EDV) decreased during inspiration in all subjects (by 11 +/- 5%), whereas LV end-systolic volume (ESV) was insignificantly changed. Accordingly, LVSV decreased during inspiration in all subjects (by 17 +/- 7%). LVEF decreased from 64 +/- 6% during expiration to 60 +/- 6% during inspiration (p less than 0.001). In contrast to the left ventricle, RVEDV and RVSV increased during inspiration by 13 +/- 11% and 22 +/- 18%, respectively. RVESV did not change significantly. RVEF increased from 48 +/- 6% during expiration to 52 +/- 5% during inspiration (p less than 0.05). These results indicate that inspiratory reduction of LVSV during spontaneous respiration is due to a decrease in LVEDV which may be derived from an increase in RVEDV during inspiration through the mechanism of ventricular interdependence.

Inhibition of lens opacification during the early stages of cataract formation.

PURPOSE: To characterize the time period during cataract formation in which administration of pantethine inhibits lens cell opacification in the selenite model for cataract. METHODS: Pantethine was administered to neonatal rat pups at selected time points from -0.5 to 17 hours with respect to injection of selenite at time = 0. The injection dose of pantethine was 820 mg/kg (1.5 mmol/kg) diluted in water at 410 mg/ml concentration. The injection dose of selenite was 3.28 mg/kg (19 mumol/kg) diluted in saline at 1.8 mg/ml concentration. Opacification was observed using a slit lamp microscope at selected time points over a 14-day period. Cataracts were staged using a classification of opacity from 0 (normal) to 6 (mature). RESULTS: The effect of pantethine was characterized by three different time periods: administration -0.5 to 6 hours with respect to selenite injection provided highly significant protection, P < 0.001; administration 8 hours after selenite provided significant protection, P < 0.005; administration 10 to 17 hours after selenite was not protective. CONCLUSIONS: The metabolite pantethine inhibited lens opacification during cataract formation in the selenite model. Even when pantethine was injected several hours after the administration of selenite, opacification was inhibited. Advanced stages of opacification were unresponsive to the administration of pantethine. The inhibitory effect of pantethine was statistically significant when administered during the earliest stage of opacification in the selenite model for cataract.

Lipophorin as a yolk protein precursor in the mosquito, Aedes aegypti.

We examined expression of the lipophorin (Lp) gene, lipophorin (Lp) synthesis and secretion in the mosquito fat body, as well as dynamic changes in levels of this lipoprotein in the hemolymph and ovaries, during the first vitellogenic cycle of females of the yellow fever mosquito, Aedes aegypti. Lipophorin was purified by potassium bromide (KBr) density gradient ultracentrifugation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Polyclonal antibodies were produced against individual Lp apoproteins, apolipoprotein-I (apoLp-I) and apolipoprotein-II (apoLp-II), with molecular weights of 240 and 75 kDa, respectively. We report here that in the mosquito A. aegypti, Lp was synthesized by the fat body, with a low level of the Lp gene expression and protein synthesis being maintained in pre- and postvitellogenic females. Following a blood meal, the Lp gene expression and protein synthesis were significantly upregulated. Our findings showed that the fat body levels of Lp mRNA and the rate of Lp secretion by this tissue reached their maximum at 18 h post-blood meal (PMB). 20-Hydroxyecdysone was responsible for an increase in the Lp gene expression and Lp protein synthesis in the mosquito fat body. Finally, the immunocytochemical localization of Lp showed that in vitellogenic female mosquitoes, this protein was accumulated by developing oocytes where it was deposited in yolk granules.

Treatment of low density lipophorin with lipoprotein lipase: diacylglycerol content has no effect on dissociation of apolipophorin III from low-density lipophorin.

The mechanism of the conversion of low-density lipophorin (LDLp) to high-density lipophorin (HDLp) in long-distance flight insects was investigated using a lipoprotein lipase from a bacterium, Alcaligenes sp. Diacylglycerol of LDLp was steadily hydrolyzed in vitro by the lipase, resulting in a 90% loss of diacylglycerol from LDLp during incubation. The "lipase-treated LDLp" thus obtained still contained associated apolipophorin-III (apoLp-III). These data suggest that the dissociation of apoLp-III is independent of the depletion of diacylglycerol from LDLp, and that the decrease in particle diameter caused by the depletion of diacylglycerol does not force the dissociation of apoLp-III from the lipophorin particle. Some physico-chemical properties of the lipase-treated LDLp were measured.