Femtosecond carrier relaxation dynamics and photoinduced phase separation in κ-(BEDT-TTF)2Cu[N(CN)2]X (X=Br,Cl)

We investigate the relaxation dynamics of nonequilibrium carriers in organic conductors κ-(BEDT-TTF)(2)Cu[N(CN)(2)]X (X=Br and Cl) using ultrafast time-resolved optical spectroscopy. The dynamics for both salts show similar temperature dependences, which is well characterized by the carrier relaxation across the pseudogap (PG) of the magnitude Δ(PG) ≈ 16 meV for Br salt and 7.0 meV for Cl salt. On the other hand, only the Br salt shows an abrupt increase of the decay time at low temperature, indicating an additional decay component associated with the superconducting (SC) gap below T(c). The fluence dependent dynamics at low temperature evidences the superposition of the SC component onto the PG component. These results indicate a metallic-insulating phase separation in the Br salt triggered by photoexcited nonequilibrium carriers.

Surface of room-temperature-stable electride [Ca24Al28O64]4+(e-)4: preparation and its characterization by atomic-resolution scanning tunneling microscopy

The nanocage compound crystal [Ca24Al28O64]4+(e-)4 (C12A7:e-) is a room-temperature-stable electride. Although bulk C12A7:e- exhibits metallic conduction, the surface of an as-prepared sample or one prepared by mechanical fracture in ultrahigh vacuum is almost insulating and exhibits distinct non-ohmic contact. We studied whether the intrinsic surface of this electride exhibits metallic conduction or not by examining various conditions for preparing the intrinsic surface. A combination of sputtering with thermal annealing led to the emergence of metallic conductivity in a specific condition. Suitably prepared surfaces revealed ohmic contact even in an ambient atmosphere. Atomic-resolution scanning tunneling microscopy (STM) images of the surfaces were consistent with a structural model in which the cage structure in the bulk C12A7:e- electride is conserved at the surface.

Models of stoichiometric and oxygen-deficient surfaces of subnanoporous 12CaO·7Al 2 O 3

Surface structures of stoichiometric and oxygen-deficient complex subnanoporous oxide 12CaO·7Al 2 O 3 (C12A7) are generated by simulating lattice rupture under the influence of an external strain. Extra-framework anions are found to serve as buffers, maintaining stability of the lattice cages in both elastic and inelastic stretching regimes. Modification of the local atomic structure in the near-surface region reduces the band gap in stoichiometric insulating C12A7. On the contrary, the band gap appears in the oxygen-deficient form of C12A7, which is metallic in the bulk. This is due to formation of the surface electron traps, which differ both in the type of the local atomic structure and stability of the electronic states. The implications of this electronic structure for the surface chemical and electron emission properties are discussed.

Chiral charge-density waves

We discovered the chirality of charge-density waves (CDW) in 1T-TiSe₂ by using STM and time-domain optical polarimetry. We found that the CDW intensity becomes Ia₁∶Ia₂∶Ia₃ = 1∶0.7 ± 0.1∶0.5 ± 0.1, where Ia(i) (i=1,2,3) is the amplitude of the tunneling current contributed by the CDWs. There were two states, in which the three intensity peaks of the CDW decrease clockwise and anticlockwise. The chirality in CDW results in the threefold symmetry breaking. Macroscopically, twofold symmetry was indeed observed in optical measurement. We propose the new generalized CDW chirality H(CDW) ≡ q₁·(q₂×q₃), where q(i) are the CDW q vectors, which is independent of the symmetry of components. The nonzero H(CDW)-the triple-q vectors do not exist in an identical plane in the reciprocal space-should induce a real-space chirality in CDW system.

Dynamics of a paired optical vortex generated by second-harmonic generation

We study the dynamics of a paired optical vortex (OV) generated by second-harmonic generation (SHG) using sub-picosecond pulses. By changing the position of a thin nonlinear crystal along the propagation direction, we observe a rotation of two vortices with changing separation distance. The dynamics is well explained by SHG with a beam walk-off, which introduces a contamination of zero-order Laguerre-Gaussian beam (LG(0)) together with topological charge doubling. The quantitative analysis indicates that the rotation angle of the OVs manifests the Gouy phase while the splitting provides the walk-off angle of the crystal. We also show that the subtraction of LG(0) is realized by the superposition of LG(0) with an anti-balanced phase in the pump.

Carrier dynamics in an organic magnetic superconductor and related salts κ, λ-(BETS)(2)MCl(4) (M = Fe, Ga)

In order to compare the carrier dynamics and reveal the origin of differences in their electrical behaviour, time-resolved reflectivity changes were measured on single crystals of the title compounds. The observed relaxation behaviour explained well their electrical behaviour, and indicated that different conduction mechanisms dominated κ- and λ-type BETS salts, irrespective of local spins, at about 8-100 K; the electrical behaviour of the κ-type salts is governed by relaxation times of carriers and/or density of states at the Fermi levels, while that of the λ-type salts is dominated by the latter.

Coherent transfer of orbital angular momentum to excitons by optical four-wave mixing

We demonstrate the coherent transfer of optical orbital angular momentum (OAM) to the center of mass momentum of excitons in semiconductor GaN using a four-wave mixing (FWM) process. When we apply the optical vortex (OV) as an excitation pulse, the diffracted FWM signal exhibits phase singularities that satisfy the OAM conservation law, which remain clear within the exciton dephasing time (approximately 1ps). We also demonstrate the arbitrary control of the topological charge in the output signal by changing the OAM of the input pulse. The results provide a way of controlling the optical OAM through carriers in solids. Moreover, the time evolution of the FWM with OAM leads to the study of the closed-loop carrier coherence in materials.

Preparation and characterization of beta-tricalcium phosphate co-doped with monovalent and divalent antibacterial metal ions

Ag(+) and Zn(2+) or Cu(2+) ions were co-doped with beta-tricalcium phosphate (AgZn-TCP and AgCu-TCP), and their substitution models, antimicrobial activities, mechanisms and cytotoxicities were investigated. The lattice constants (a-axis and c-axis) of AgZn-TCP and AgCu-TCP decreased linearly with the amount of Zn(2+) or Cu(2+) ions up to 9.09 mol.%, which indicated that Ag(+) ions were doped at the Ca(4) site and a vacancy in the beta-TCP structure, and Zn(2+) or Cu(2+) ions were doped at the Ca(5) site. Antibacterial activities of AgZn-TCP and AgCu-TCP on Escherichia coli and Staphylococcus aureus were higher than those of Ag(+) ions-doped beta-TCP (Ag-TCP) and pure beta-TCP. These antimicrobial activities suggested that an interaction occurred between bacteria and Ag(+), Zn(2+) and Cu(2+) ions eluted from AgZn-TCP and AgCu-TCP and between bacteria and the free radicals generated by antibacterial agents or in bacterial cells. AgZn-TCP and AgCu-TCP can be used over long periods of time with high antimicrobial activity, because the rate at which Ag(+) ions are released from AgZn-TCP and AgCu-TCP is slower than that at which Ag(+) ions are released from Ag-TCP. However, it is necessary to determine the suitable amounts of Ag(+), Zn(2+) and Cu(2+) ions in AgZn-TCP and AgCu-TCP by considering both their antimicrobial activities and cytotoxicities, because beta-TCP doped with a large amount of these metal ions exhibits cytotoxicity. Furthermore, AgZn-TCP and AgCu-TCP are considered to be promising materials for use in various fields.

Pressure and magnetic field tuned quantum critical point in the Kondo antiferromagnet CePtZn

We report magnetization, heat capacity and electrical resistivity measurements on CePtZn, which crystallizes in the orthorhombic TiNiSi type structure. Magnetization and electrical resistivity on the iso-structural series of compounds Ce(1-x)La(x)PtZn (x = 0.1, 0.2 0.5 and 1) were also carried out. The electrical resistivity of CePtZn was also measured in external magnetic fields up to 12 T and under pressures up to 2.66 GPa. We find that CePtZn is a dense Kondo lattice, ordering antiferromagnetically at T(N) = 1.7 K, with a comparable Kondo temperature. The magnetic transition temperature, T(N), is continuously suppressed both by the magnetic field and pressure and [Formula: see text] around 5-6 T and at 1.2 GPa, respectively. Non-Fermi liquid behavior of resistivity at 4 T and 1.2 GPa and logarithmic divergence of the heat capacity, C(4f)/T, at 6 T in a limited temperature region strongly suggest the emergence of a quantum critical point as [Formula: see text].

Direct observation of the coexistence of the pseudogap and superconducting quasiparticles in Bi2Sr2CaCu2O8 + y by time-resolved optical spectroscopy

We report the ultrafast optical response of quasiparticles (QPs) in both the pseudogap (PG) and superconducting (SC) states of an underdoped Bi2Sr2CaCu2O8 + y (Bi2212) single crystal measured with the time-resolved pump-probe technique. At a probe energy variant planck's over omegapr = 1.55 eV, it is found that the reflectivity change DeltaR/R changes its sign at exactly Tc, which allows the direct separation of the charge dynamics of PG and SC QPs. Further systematic investigations indicate that the transient signals associated with PG and SC QPs depend on the probe beam energy and polarization. By tuning them below Tc, two distinct components can be detected simultaneously, providing evidence for the coexistence of PG and SC QPs.

Hyperglycemia and the outcome of pediatric cardiac surgery patients requiring peritoneal dialysis

OBJECTIVE

To study the nature of the association between glycemia and ICU mortality in pediatric cardiac surgery patients treated with peritoneal dialysis (PD).

MATERIALS AND METHODS

Retrospective observational study in the ICU of a tertiary hospital involving forty pediatric cardiac surgery patients treated with PD. We selected patients requiring PD, extracted glucose measurements and nutritional intake data during ICU stay and calculated mean and maximum blood glucose values i) during ICU stay; ii) during dependence on PD; and iii) during independence from PD. We statistically assessed the relationship between glycemia-related variables and ICU mortality.

MEASUREMENTS AND RESULTS

Twenty-two patients treated with PD died (mortality 55%). In the PD cohort, 9725 blood glucose measurements were performed (every 3.3 hours on average). The mean glycemia during dependence on PD was significantly higher in non-survivors than survivors (p<0.0001), but not during independence from PD (p=0.49). The area under the receiver operator characteristic curve for the mean glycemia during dependence on PD was significantly greater than that obtained during independence from PD. Even after adjustment for severity of illness using multivariate logistic analysis, the mean glycemia and calorie intake during PD were significant and independent predictors of ICU mortality.

CONCLUSIONS

A higher mean blood glucose concentration during PD, but not during PD-free periods was associated with greater ICU mortality. Mean glycemia and calorie intake during PD were significant and independent predictors of ICU mortality.

A comparison of intra-articular hyaluronan injection accuracy rates between three approaches based on radiographic severity of knee osteoarthritis

OBJECTIVE

To compare the accuracy rates of intra-articular hyaluronic acid (HA) injections for osteoarthritis (OA) of the knee between the modified Waddell approach (an anteromedial approach with manipulative ankle traction at 30 degrees of knee flexion), an anteromedial approach with the subjects seated (hereinafter the seated anteromedial approach) and a lateral patellar approach based on the Kellgren-Lawrence (K-L) radiographic grade (II, III and IV).

DESIGNS

Fifty patients with knee OA received HA injections through the three approaches. The accuracy rates were confirmed with a single radiograph after injections of a mixture of radiographic contrast medium.

RESULTS

In the K-L grade IV cases (n=11), the accuracy rates through the modified Waddell approach (11 out of 11, 100%) were significantly higher than those through the seated anteromedial approach (six out of 11, 55%) and the lateral patellar approach (six out of 11, 55%) (P=0.035). No significant differences were detected in the accuracy rates of the participants classified as grade II (n=21) or III (n=18) cases between the modified Waddell approach (86% and 78%, respectively), the seated anteromedial approach (71% and 56%, respectively) and the lateral patellar approach (86% and 61%, respectively) (P>0.05).

CONCLUSION

Although previous studies have been conducted on the accuracy of needle placement into the intra-articular space of the knee, no evaluations were performed with the results categorized by radiographic severity. This study highlighted the need for clinicians to change the approach employed for HA injections, according to the severity of knee OA.

Influence of concomitant heeled footwear when wearing a lateral wedged insole for medial compartment osteoarthritis of the knee

OBJECTIVE

To compare the influence of concomitant heeled footwear when wearing a lateral wedged insole for medial compartment of osteoarthritis (OA) of the knee, between everyday walking shoes for outdoor use and socks or flat footwear without a heel for indoor use.

DESIGN

A total of 227 outpatients were prospectively randomized and treated with a neutral wedged insole inserted into shoes (placebo with shoes; n=45), a wedged insole inserted into shoes (inserted insole with shoes; n=45), a sock-type ankle supporter with a wedged insole when wearing socks or flat footwear (inserted insole without shoes; n=46), a subtalar strapped insole when wearing shoes (strapped insole with shoes; n=45), and the strapped insole with socks or flat footwear (strapped insole without shoes; n=46). The Lequesne index of knee OA at week 12 was compared with the baseline in each treatment group.

RESULTS

Twenty patients withdrew from the study, and the 207 patients who completed the 12-week study were evaluated. At the final assessment, participants wearing the inserted insole without shoes (P=0.003), the strapped insole with shoes (P<0.0001), and the strapped insole without shoes (P<0.0001) demonstrated significantly improved Lequesne index scores in comparison with their baseline assessments. No significant differences were found in the placebo (P=0.16) or the inserted insole with shoes (P=0.2) groups.

CONCLUSION

Concomitant heeled footwear may decrease the efficacy of an inserted lateral wedged insole. The optimal usage of a lateral wedged insole for knee OA would be the combination with socks or flat footwear without heels.

Room Temperature-Stable Electride as a Synthetic Organic Reagent: Application to Pinacol Coupling Reaction in Aqueous Media

Room temperature-stable inorganic electride [Ca(24)Al(28)O(68)](4+)4e(-) was employed for a pinacol coupling reaction in aqueous media. Ca-Al-O gel formed by the destruction of the crystal structure of an electride by water media played a key role in transferring the electron to electrophilic aldehydes. Aromatic aldehydes reacted smoothly with moderate to high yields.

Glial fibrillary acidic protein (gfap ) and anti-gfap autoantibody in canine necrotising meningoencephalitis

To establish clinical markers for canine necrotising meningoencephalitis (NME) and to elucidate its pathogenesis, glial fibrillary acidic protein (GFAP) and anti-GFAP autoantibodies were measured in the cerebrospinal fluid (CSF) of 32 dogs with NME, 23 dogs with other inflammatory central nervous system (CNS) diseases, 27 dogs with miscellaneous CNS diseases and 25 healthy dogs, including five pugs. The dogs with NME had the highest levels of anti-GFAP autoantibodies. The diagnostic sensitivity and specificity of anti-GFAP autoantibodies for NME were 91 per cent and 73 per cent, respectively. Some of the dogs with NME and the healthy pugs, had high CSF concentrations of GFAP, suggesting a breed-specific fragility of astrocytes. The leakage of GFAP and the development of autoimmunity may be key to understanding the pathogenesis of NME.

Modulation of host genes by mammalian transposable elements

Interspersed repetitive sequences are major components of eukaryotic genomes. They comprise about 50% of the mammalian genome. They interact with the whole genome and influence its evolution. They do this in many ways, e.g. by serving as recombination hotspots, providing a mechanism for genomic shuffling and a source of 'ready-to-use' motifs for new transcriptional regulatory elements, polyadenylation signals, and protein-coding sequences. In this review we discuss the consequences of exaptation of sequences originated in tansposable elements with focus on events that influence protein coding genes.

Heme Arginate Pretreatment Attenuates Pulmonary NF-κB and AP-1 Activation Induced by Hemorrhagic Shock via Heme Oxygenase-1 Induction

Hemorrhagic shock followed by resuscitation (HSR) induces oxidative stress that leads to acute lung injury. Heme oxygenase-1 (HO-1), the rate-limiting enzyme in heme catabolism, is induced by oxidative stress and is thought to play an important role in the protection from oxidative tissue injuries. We previously demonstrated that HO-1 induction by heme arginate (HA), a strong inducer of HO-1, ameliorated HSR-induced lung injury and inflammation. Cellular redox state is known to modulate the DNA biding activity of the transcription factors; nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1). In the present study, we treated rats with HA (30 mg/kg of hemin) 18 h prior to HSR and examined its effect on the DNA binding activity of NF-kappaB and AP-1 at 1.5 h after HSR. HSR significantly increased the DNA binding activity of NF-kappaB as well as AP-1, while HA pretreatment markedly attenuated the activities of these transcription factors. In contrast, administration of tin mesoporphyrin, a specific competitive inhibitor of HO activity, to HA-pretreated animals abolished the suppressive effect of HA on the activities of NF-kappaB and AP-1, and increased these activities to almost the same level as those in HSR animals. Our findings indicate that HA pretreatment can significantly suppress the increased activity of NF-kappaB and AP-1 induced by HSR by virtue of its ability to induce HO-1. Our findings also suggest that HO-1 induced by HA pretreatment ameliorates HSR-induced lung injury at least in part mediated through the suppression of the activities of these transcription factors.

Prediction of future scotoma on conventional automated static perimetry using frequency doubling technology perimetry

AIM

To see if scotoma detected with frequency doubling technology (FDT) is confirmed by Humphrey field analyser (HFA) 3 years later.

METHODS

Subjects were first examined with the screening C-20-1 program of FDT. The visual field was examined annually for 4 years using HFA program C30-2. The central 58 test points in HFA were assigned to one of the 17 clusters corresponding to FDT test points. Each cluster was represented as the lowest probability symbol of total deviation (TD) of the HFA test points included in the cluster. Clusters were graded normal, suspected scotoma, and scotoma depending on probability of TD-5% or more, 5%-1%, less than 1%, respectively. Relative risk (RR) of abnormality on FDT for future scotoma on HFA was estimated.

RESULTS

80 eyes of 42 patients were followed up for 4 years. While 4.0% of normal clusters of HFA with normal FDT results developed into scotoma cluster, 20.8% of normal clusters with abnormal FDT results developed into scotoma cluster with HFA at the third year. RR for future scotoma was 5.24 (95% CI, 2.75 to 10.0, p<0.05).

CONCLUSION

An abnormal result in FDT shows a high risk of future scotoma on HFA after 3 years even if the original HFA perimetry showed normal results.

A 2-year follow-up of a study to compare the efficacy of lateral wedged insoles with subtalar strapping and in-shoe lateral wedged insoles in patients with varus deformity osteoarthritis of the knee

OBJECTIVE

This study was conducted in order to assess the effect of wearing a lateral wedged insole with a subtalar strap for 2 years in patients with osteoarthritis varus deformity of the knee (knee OA).

DESIGN

The setting was an outpatient clinic. The efficacies of the strapped insole and a traditional shoe insert wedged insole (the inserted insole), as a positive control, were compared at the baseline and after 2 years of treatment. Randomization was performed according to birth date. The 61 female outpatients with knee OA who completed a prior 6-month study were asked to wear their respective insoles continuously as treatment during the course of the 2-year study. The femorotibial angle (FTA) was assessed by standing radiographs obtained while the subjects were barefoot and the Lequesne index of the knee OA at 2 years was compared with those at baseline in each insole group.

RESULTS

There were 61 patients in the original study, but 13 patients (21.3%) did not want to wear the insole continuously and five (8.2%) withdrew for other reasons. The 42 patients who completed the 2-year study were evaluated. At the 2-year assessment, participants wearing the subtalar strapped insole (n=21) demonstrated significantly decreased FTA (P=0.015), and significantly improved Lequesne index (P=0.031) in comparison with their baseline assessments. These significant differences were not found in the group with the traditional shoe inserted wedged insole (n=21).

CONCLUSION

Only those participants using the subtalar strapped insole demonstrated significant change in the FTA in comparison with the baseline assessments. If the insole with a subtalar strap maintains FTA for more than 2 years, it may restrict the progression of degenerative articular cartilage lesions of knee OA.

A 90-day oral toxicity study of beta-carotene derived from Blakeslea trispora, a natural food colorant, in F344 rats

A subchronic oral toxicity study of beta-carotene derived from Blakeslea trispora, a natural food colorant, was performed with groups of 10 male and 10 female F344 rats fed the agent at dietary levels of 0%, 0.2%, 1.0% and 5.0% for 90 days. There were no treatment-related adverse effects with regard to body weight, food and water consumption, urinalysis, ophthalmology, hematology, serum biochemistry, and organ weight data. On clinical observation, red coloring of fur was noted in both sexes of the 1.0% and 5.0% group rats, with red feces observed in all treated group animals, and necropsy revealed all rats of the treated groups to have reddish coloration of the contents of the gastro-intestinal tract, due to the pigmentation and thus lacking toxicological significance. On histopathological examination, sporadic spontaneous lesions known to occur in this strain of rats were the only findings, with no specific relation to the test substance. Thus, the no-observed-adverse-effect-level (NOAEL) was judged to be a dietary level of at least 5.0% (3127 mg/kg body weight/day for males, 3362 mg/kg body weight/day for females) for beta-carotene derived from B. trispora under the present experimental conditions.

Influences on lactate levels in children early after cardiac surgery: prime solution and age

OBJECTIVE

Hyperlactataemia is often seen after cardiac surgery in children and is associated with an increased risk of adverse outcome, especially in infants and young children. However, we noticed that many older children after cardiac surgery had elevated lactate levels in the absence of other markers of oxygen debt or cardiovascular instability and had an uncomplicated postoperative course. Many older children undergo surgery without blood products being used in the cardiopulmonary bypass (CPB) circuit prime. The aim of this study was to determine whether lactate levels in children after CBP are influenced by age and/or pump prime solutions.

METHODS

We studied 100 children undergoing open heart surgery in a tertiary paediatric cardiac surgical unit. Fifty children were aged 2 months to 4 years (Group 1) and 50 were aged 4 years or older (Group 2). Blood samples were obtained from an arterial catheter and serum lactate levels were collected at the time of admission to the paediatric intensive care unit (PICU) and 4 hours later. The following data were collected from the medical records or laboratory databases: weight, age, lowest haemoglobin during CPB, total bypass time, aortic cross clamp time, priming solution used, length of postoperative ventilation and PICU stay, type of surgery and occurrence of adverse perioperative events, including cardiac arrest, need for extracorporeal support or death.

RESULTS

All children in Group 1 had a blood prime. All children in Group 2 had a bloodless prime. Although there were differences in the types of anomalies and surgical procedures performed, there were no significant differences between the two groups in terms of surgical complexity, CBP time, aortic cross clamp time and haemoglobin during CPB. Lactate levels in children in Group 2 were higher than in Group 1. Sixteen children (32%) in Group 2 had a lactate level of > 4 mmol/L, whereas only 3 children (6%) in Group 1 had a lactate level of > 4 mmol/L (Fisher's exact test p = 0.0002). Using multivariate analysis the pump prime solution was independently associated with high lactate levels after CPB.

CONCLUSIONS

Lactate levels after cardiac surgery in older children who have a bloodless prime may not have the same physiological or prognostic implications as in infants who have a blood prime.

An optimal duration of daily wear for an insole with subtalar strapping in patients with varus deformity osteoarthritis of the knee

OBJECTIVE

To assess the optimal duration of daily wear for a laterally wedged insole with subtalar strapping in subjects with medial compartment osteoarthritis of the knee (knee OA).

DESIGN

The setting was an outpatient clinic. Eighty-one patients with knee OA were prospectively randomized according to birth date and to either 2 weeks of treatment with a lateral wedge with subtalar strapping for less than 5 h (the short group), 5-10 h (the medium group) or greater than 10 h (the long group) each day, or to treatment with a subtalar strapping band without lateral wedge (the placebo group). Standing radiographs were used to analyze the femorotibial angle for each subject, both with and without their respective orthotic device. The remission scores of Lequesne index were compared among the four groups at the conclusion.

RESULTS

The short (n=21), medium (n=20) and long (n=18) groups demonstrated a significant greater valgus correction of the femorotibial angle than the placebo group (n=22) (P<0.0001). The remission score was significantly improved in the medium group compared to the placebo (P=0.001) and long (P=0.001) groups.

CONCLUSIONS

An optimal duration of insole with subtalar strapping wear for patients with varus deformity knee OA may be between 5 and 10 h each day.

A newly developed peripheral anterior chamber depth analysis system: principle, accuracy, and reproducibility

AIM

To develop a new, non-contact system for measuring anterior chamber depth (ACD) quantitatively, and to investigate its accuracy as well as interobserver and intraobserver reproducibility.

METHODS

The system scanned the ACD from the optical axis to the limbus in approximately 0.5 second and took 21 consecutive slit lamp images at 0.4 mm intervals. A computer installed program automatically evaluated the ACD, central corneal thickness (CT), and corneal radius of curvature (CRC) instantly. A dummy eye was used for investigating measurement accuracy. The effects of CT and CRC on the measurement results were examined using a computer simulation model to minimise measurement errors. Three examiners measured the ACD in 10 normal eyes, and interobserver and intraobserver reproducibility was analysed.

RESULTS

The ACD values measured by this system were very similar to theoretical values. Increase of CRC and decrease in CT decreased ACD and vice versa. Data calibration using evaluated CT and CRC successfully reduced measurement errors. Intraobserver and interobserver variations were small. Their coefficient variation values were 7.4% (SD 2.3%) and 6.7% (0.7%), and these values tended to increase along the distance from the optical axis.

CONCLUSION

The current system can measure ACD with high accuracy as well as high intraobserver and interobserver reproducibility. It has potential use in measuring ACD quantitatively and screening subjects with narrow angle.

Layer-doubling method in ADF-STEM image simulation

A layer-doubling method developed in LEED calculation is applied to the ADF-STEM image simulation. This approach makes it possible to simulate image intensities of systems having a repeated slab structure, such as embedded precipitates or defects, with a much higher efficiency because it does not require the diagonalization of repeated slabs. As a simple example of this method, channeling effects are calculated for a system with embedded crystalline displaced slabs for various different slab thicknesses.