Search

BACKGROUND: Work-related musculoskeletal disorders are prevalent in dental hygienists. Although engineering controls and ergonomic training is available, it is unclear why this intransigent problem continues. One possible barrier is that a comprehensive, standardized protocol for evaluating dental hygiene work does not exist. OBJECTIVE: This study aimed to generate a valid and reliable observational protocol for the assessment of dental hygiene work. METHODS: An iterative process was used to establish and refine an ecologically valid video acquisition and observation protocol to assess key activities, tasks, and performance components of dental hygiene work. RESULTS: Good inter-rater reliability was achieved across all variables when the final coding scheme was completed by three independent raters. CONCLUSIONS: This work provides an exemplar of the process required to generate a comprehensive protocol for evaluating the work components of a particular job, and provides standardized nomenclature for use by scientists and practitioners interested in understanding and addressing the pervasive issue of work-related disorders in dental hygienists.

In ingot casting, it is important to predict and control segregation and casting defects that occur during the solidification process, because they have a significant effect on the quality of the steel ingot. In some special steels, in typical Fe-C-Cr-Mo type high carbon tool steels, macro-segregation tends to be more pronounced due to their wide solid-liquid coexistence temperature range and molten steel properties such as relatively higher liquid viscosity than basic carbon steels. In order to investigate segregation and defect formation phenomena during solidification, many experiments have been conducted using specially designed laboratory scale model ingots that can induce partial difference of solidification to cause macrosegregation phenomena. However, these kind of experimental approaches for special steels are less conducted and influence of alloy types on the macrosegregation behaviour is still not well understood. In this study, a model ingot which have a steel chill ring in the middle region of a mullite mold was prepared, then Fe-0.45C(mass%) carbon steel, Fe-1C-1.8Cr(mass%) bearing steel and Fe-1C-8Cr-2Mo(mass%) high carbon tool steel were cast into 30kg ingots and the macrosegregation behaviour was investigated.

MHPS and MHI suggest HP/IP/LP separate casing and one bearing/rotor (one bearing between two casings) type steam turbine. To design this type of shaft arrangement, journal bearing that supports high specific load with superior oil film static and dynamic characteristics is demanded. In this paper, it is shown that 610 mm diameter direct lubricated two pads bearing which can operate at high specific load has been developed. Also, it is confirmed that its good bearing characteristics in full scale test.

Early stage oral cancer can be cured with oral brachytherapy, but whole-body radiation exposure status has not been previously studied. Recently, the International Commission on Radiological Protection Committee (ICRP) recommended the use of ICRP phantoms to estimate radiation exposure from external and internal radiation sources. In this study, we used a Monte Carlo simulation with ICRP phantoms to estimate whole-body exposure from oral brachytherapy. We used a Particle and Heavy Ion Transport code System (PHITS) to model oral brachytherapy with 192Ir hairpins and 198Au grains and to perform a Monte Carlo simulation on the ICRP adult reference computational phantoms. To confirm the simulations, we also computed local dose distributions from these small sources, and compared them with the results from Oncentra manual Low Dose Rate Treatment Planning (mLDR) software which is used in day-to-day clinical practice. We successfully obtained data on absorbed dose for each organ in males and females. Sex-averaged equivalent doses were 0.547 and 0.710 Sv with 192Ir hairpins and 198Au grains, respectively. Simulation with PHITS was reliable when compared with an alternative computational technique using mLDR software. We concluded that the absorbed dose for each organ and whole-body exposure from oral brachytherapy can be estimated with Monte Carlo simulation using PHITS on ICRP reference phantoms. Effective doses for patients with oral cancer were obtained.

A successful health care provider may be described as a clinician capable of establishing a comprehensive diagnosis including identifying related risk factors. However, an equally important quality a clinician should possess is the ability to understand the experiences and feelings of others to allow better communication for better outcomes. It is likely that faculty empathy levels influence students' ability to demonstrate this attribute. The aim of this study was to assess the levels of empathy of dental faculty members relative to dental students at the Universidad San Sebastian in Chile. Using a cross-sectional design of survey-collected data collected with the Jefferson Scale of Empathy, the authors compared the perceptions of the dental faculty involved in teaching fourth- and fifth-year dental students (n=116) to the perceptions of basic and preclinical students (n=346) and clinical students (n=189). The data were collected in 2016-17. The results showed that the mean faculty scores were higher than that of the students in compassionate care (90.1%) and perspective adoption (89.7%); however, for putting oneself in the other's shoes, the faculty had a lower score (57.8%) than the clinical students (58.2%). Future investigations are needed to understand the impact of faculty empathy scores on students and whether pedagogical interventions can increase empathy scores.

Direct lubricated tilting two pads bearing with 890 mm diameter for large steam turbine was developed. Its performance, both static and dynamic characteristics, and reliability were tested with full scale test, after confirmation by thermo-hydrodynamic calculation coupled with finite element method deformation analysis, to evaluate deformations of the bearing pads. As a result of full scale test, it was confirmed that all of the target values were satisfied. In the same manner, robustness tests, changing the tilt angle of the shaft and supply oil condition were also conducted, and sufficient safety operations of the test bearing were also confirmed. Compared to the conventional bearings, the friction loss of the developed bearing was less than half of other types, such as flooded type, or direct lubricated four pads bearing.

DAT54 is a new near a heat resistant Ti alloy developed for disk applications in the compressor part of jet engines. DTA54 with bimodal microstructure shows a good balance of fatigue strength and creep life, and performs better than Ti-6242s up to 873 K. However, the influence of microstructure on properties, especially the effect of the morphology of primary a on fatigue crack growth resistance is not understood. In this study, samples with different types of microstructure were prepared by applying different heat treatment temperatures, and the influence of microstructure on fatigue crack growth properties at ambient temperature and 823 K was investigated. Influence of environment was also investigated by testing in vacuum and in air condition. Acicular microstructure shows lower fatigue crack growth rates in Paris’ region than the bimodal microstructures at 823 K. For the bimodal structures, aspect ratio of primary a do not have apparent influence on fatigue crack growth rates in Paris’ region, whereas fatigue threshold (DKth) seems to be affected by the morphology of primary a.

This paper introduces inverse active filters employing operational transconductance amplifiers (OTAs) and grounded capacitors. The filter circuits can realise inverse low-pass, inverse band-pass and inverse high-pass transfer functions by addition of the circuit currents. Additionally, the circuit parameters ω0, Q and H can be set orthogonally or independently by adjusting the bias currents of the OTAs. The inverse filter circuits enjoy very low sensitivities to active and passive components. The achievement examples are given together with simulation results by PSPICE.

This article presents a realisation of an electronically tunable first-order all-pass circuit employing a differential voltage current conveyor (DVCC), an operational trans-conductance amplifier (OTA) and two MOS conductance. The circuit can realise two all-pass characteristics by choosing the current output of the OTA. Additionally, the circuit parameters ω0 and H can be set independently by tuning the circuit active components electronically. Sensitivity analysis shows that the circuit enjoys very low sensitivity to the circuit components. An example is given together with simulated results by PSPICE.

Seeded crystal growth of Zinc oxide (ZnO) by the closed ampoule chemical vapor transport (CVT) is carried out using polyvinyl alcohol (PVA) as a transport agent. Under the conditions of TS=1100 °C, ΔT=10 K and the amount of PVA=0.13–0.91 mg/cm3, single-crystalline ZnO was grown continuously on the ZnO seed-crystal, of which the surface was (0 0 0 1) Zn-face. The grown crystals had well-marked growth facets belonged to {1 0 1¯0} and {1 0 1¯ 1} faces. The color of the crystals was changed from pale yellow to dark orange-red depending on the amount of PVA. Typical electron density and the Hall mobility of the crystals were 1×1017 cm−3 and 2×102 cm2/V s at 300 K, respectively.

This paper introduces a novel current-mode biquadratic circuit using plus type differential voltage current conveyors (DVCCs) and grounded passive components. The circuit is constructed with two plus type dual current output DVCCs (DO-DVCCs), two grounded capacitors and two resistors. The circuit can realize multiple circuit transfer functions by choosing the appropriate input and output terminals. Additionally, the circuit parameters Q and ω 0 can be set orthogonally by adjusting the passive components. The biquadratic circuit enjoys very low sensitivities to the circuit components. An example is given together with simulated results by PSPICE.

This paper introduces a versatile current-mode biquadratic circuit using second generation current-controlled current conveyors (CCCIIs). The circuit is constructed with two plus type multiple current output CCCIIs (MO-CCCIIs) and two grounded capacitors. The circuit can realize low-pass, band-pass, high-pass, band-stop and all-pass transfer functions by choosing appropriate input and output terminals without any component matching conditions. Additionally, the circuit parameters Q and ω0 can be set orthogonally by adjusting the bias currents of the MO-CCCIIs and grounded capacitors. The biquadratic circuit enjoys very low sensitivities to the circuit components. Some examples are given together with simulated results by PSPICE.

This paper presents a realization of a current-mode biquad filter using operational transconductance amplifiers (OTAs) and a dual current output second generation current conveyor (DO-CCII). The proposed filter is constructed with two multiple current output OTAs (MO-OTAs), one OTA, one DO-CCII and two grounded capacitors. The circuit can realize low-pass, band-pass, high-pass, band-stop and all-pass transfer functions by choosing appropriate current outputs without any matching conditions of the circuit elements. And the characteristic parameters ω0 and Q can be tuned orthogonally through adjusting the bias currents of the OTAs. The biquad filter enjoys very low sensitivities with respect to the circuit elements. An example is given together with simulated results by PSPICE. The filter circuit configuration is well suited for implementation in both bipolar and CMOS technologies.

The infrared absorption enhancement phenomenon in the normal configuration of vacuum-evaporated metal films on a transparent substrate is known to depend not only on the metal film morphology but also on the local structures of metal particles. To date, however, few studies have examined the effect of local structure on the phenomenon. Size distributions of islands and gaps, along with the volume fractions of Ag in thin films, were measured using scanning electron microscopy as a function of film thickness. The local structure of Ag nano clusters deposited on silicon substrates was investigated using a total conversion electron yield X-ray absorption fine structure (XAFS) method at the Ag K-edge. We observed a correlation between the electromagnetic field intensity at the surface as evaluated by IR measurement and the coordination numbers evaluated by XAFS. We found that the film morphology had a greater effect on resonant and nonresonant contributions than did the local structure of a particle. Copyright © 2006 John Wiley & Sons, Ltd.

This paper presents a realization of voltage-mode and current-mode active-only biquad circuits with a two-integrator loop-structure. The circuits are constructed solely with operational amplifiers (OAs) and operational transconductance amplifiers (OTAs). The biquad circuits can realize the multiple circuit transfer functions, and the circuit parameters can be tuned orthogonally through adjusting the transconductance gains of the OTAs. Also, these biquad circuits enjoy very low sensitivities with respect to the circuit active elements. Some examples are given together with simulated results by PSPICE. The circuit configurations are very suitable for implementation on both bipolar and CMOS technologies.

To complete a subchannel analysis code for prediction of thermal–hydraulic behavior of a coolant in BWR fuel rod bundle, an accurate estimation of fluid transfer between subchannels is essential. Under two-phase gas–liquid flow conditions, the fluid transfer is usually subdivided into turbulent mixing, void drift and diversion cross-flow. We focused on the turbulent mixing in this study. Until now, experimental data on two-phase turbulent mixing rate have been obtained exclusively for simpler channels with two subchannels alone, and prediction methods of the mixing rates have been proposed based on such data. In order to obtain data necessary to validate the prediction methods, we newly constructed a vertical test channel simulating a BWR fuel rod bundle, which contained six rods in a rectangular array and two kinds of six subchannels. Using this channel, flow distributions and turbulent mixing rates of both gas and liquid phases were measured for single-phase water and two-phase air–water flows under a hydrodynamic equilibrium flow condition at ambient pressure. In this paper, the experimental data on turbulent mixing rates in comparison with the data for two-subchannel system at 0.34 MPa obtained by others are presented and discussed.

This paper presents a realization of a current-mode active-only biquad with a two-integrator loop structure. The proposed circuit is constructed solely with operational amplifiers (OAs) and operational transconductance amplifiers (OTAs). The circuit can realize low-pass, band-pass, high-pass, band-stop and all-pass transfer functions, and the circuit characteristics can be electronically tuned by adjusting the transconductance gains of the OTAs. An example is given together with simulated results by PSPICE. The circuit configuration is very suitable for implementation in both bipolar and CMOS technologies.

In Japan, the elderly population suffering from dementia is rapidly increasing. Several animal studies have indicated a relationship between reduced masticatory function in the elderly subject and cognitive impairment. However, epidemiological studies examining this have been scarce. Using an epidemiological approach, the present study investigated this relationship in 44 females with and 44 without dementia, all aged over 65 years. Age and basic activities of daily living, such as walking, eating, excreting, bathing and dressing, were matched in the two groups. Cognitive impairment of the subjects was measured using the revised Hasegawa Dementia Rating Scale. Masticatory function was assessed in terms of the number of teeth present, maximum bite force, occlusal contact area, and mastication score. The number of teeth present in cognitively normal subjects was significantly higher than in cognitively impaired subjects (P < 0.05). In addition, maximum bite force, occlusal contact area, and mastication scores of cognitively normal subjects were significantly higher than those of cognitively impaired subjects (P < 0.01). These results suggest that masticatory function in the elderly person is associated with cognitive status.

The precision with which images reflect tracer uptake in the myocardium has been studied. Additionally, the degree to which Tc methoxyisobutylisonitrile (99mTc-MIBI) in the liver gave the effect to a myocardial image has been examined. After administering Tc-MIBI to normal male rats, we compared the myocardial uptakes obtained using a gamma camera with the actual uptakes in the excised organs. Twenty-nine rats were used. Following imaging, the anterior view at 5, 10, 15, 30, 45, 60, 90 and 120 min after administration of the tracer, uptakes in the heart, lung, liver and blood were estimated with a well-type scintillation counter (WC) and represented as the percentage of the injected dose per gram of tissue (%ID/g). The regions of interest (ROIs) were placed on planar images (PI) and the uptake in each organ was estimated as the percentage of the injected dose per pixel (%ID/pixel). The ratios of PI-to-WC and heart-to-organ were also evaluated. Cardiac uptake with WC was maximum (1.581%+/-1.893%) at 10 min post-injection. On the other hand, that with PI was maximum (1.493%+/-0.598%) at 45 min post-injection, but there were significant differences between both measurements (PI/WC ratio: about 1.0 time). Pulmonary uptake with WC was the maximum at 5 min (0.808%+/-0.015%) post-injection, and decreased gradually. PI measurement showed the maximum value at 45 min (0.760%+/-0.012%). Hepatic uptake with WC was the maximum at 30 min (0.594%+/-0.254%). On the other hand, PI measurement showed the same pattern with WC, but these values were higher value than WC as the whole. PI measurement showed higher uptakes in each organ than WC measurement. It was concluded that uptakes or the heart-to-organ ratio obtained clinically with PI might not represent a value that is always accurate.

Proton and deuteron production has been observed in S+S and S+Pb collisions at 200 A·GeV and in Pb+Pb reactions at 158 A·GeV at the CERN SPS accelerator. For Pb+Pb triton production was also measured. The p and d spectra as well as the p and t spectra were observed in similar rapidity ranges and over similar ranges of transverse momenta per nucleon, making it possible to interpret the cross sections of the composite particles in terms of coalescence mechanisms. Volumes of homogeneity were extracted and compared to pion-pair HBT interferometry results. Special attention is given to the dependence on transverse mass, centrality and rapidity.

This paper introduces a current-mode biquadratic circuit employing current controlled current conveyors (CCCIIs) and grounded capacitors. The circuit can realize low-pass, band-pass, high-pass, band-stop and all-pass characteristics by suitably choosing or adding current outputs. Additionally, the circuit parameters ω0 and Q can be set orthogonally adjusting the bias currents of the CCCIIs. The biquadratic circuit enjoys very low sensitivity to the circuit components. The achievement examples are given together with simulation results by PSPICE.

$\pi^{-}\pi^{-}\pi^{-}$ correlations from Pb+Pb collisions at 158 GeV/c per nucleon are presented as measured by the focusing spectrometer of the NA44 experiment at CERN. The three-body effect is found to be stronger for PbPb than for SPb. The two-dimensional three-particle correlation function is also measured and the longitudinal extension of the source is larger than the transverse extension. 3pi- correlations from Pb+Pb collisions at 158 GeV/c per nucleon are presented as measured by the focusing spectrometer of the NA44 experiment at CERN. The three-body effect is found to be stronger for PbPb than for SPb. The two-dimensional three-particle correlation function is also measured and the longitudinal extension of the source is larger than the transverse extension.

We present results for the charged-particle multiplicity distribution at midrapidity in Au-Au collisions at square root of [s(NN)] = 130 GeV measured with the PHENIX detector at RHIC. For the 5% most central collisions we find dN(ch)/d eta(vertical line eta = 0) = 622+/-1(stat)+/-41(syst). The results, analyzed as a function of centrality, show a steady rise of the particle density per participating nucleon with centrality.

Two-particle correlations of negative pions as a function of charged particle multiplicity are studied in Pb+Pb collisions at $\sqrt{s}=17.3$ GeV per nucleon using the NA44 experiment at the CERN Super Proton Synchrotron(SPS). We find that the source size parameters increase with the charged particle multiplicity. However the slope of the source size parameters plotted as a function of charged multiplicity is slightly larger at high multiplicity than at low multiplicity. The value of $\lambda$ is independent of charged multiplicity. For Pb+Pb collisions, $R_L$ is larger than $R_{TS}$ and $R_{TO}$ for all multiplicity intervals, whereas these three radius parameters were approximately equal in S+Nucleus collisions. The ratios ( $R_L/R_{TS}$ ) and ( $R_L/R_{TO}$ ) for Pb+Pb data show almost no dependence on charged multiplicity. The duration of pion emission $\Delta \tau$ is constant at 3.8 $\pm$ 1.1 fm/c as a function of the charged multiplicity in Pb+Pb collisions. Effective volume (V) is also calculated as V= $\pi\times R_{TS}^2\times R_L$ , assuming a cylindrically shaped source. We found, within the limited statistics, the effective volume rapidly increases at high multiplicity.

The invariant cross section as a function of transverse momentum for antideuterons produced in 158A GeV/c per nucleon Pb+Pb central collisions has been measured by the NA44 experiment at CERN. This measurement, together with a measurement of antiprotons, allows for the determination of the antideuteron coalescence parameter. The extracted coalescence radius is found to agree with the deuteron coalescence radius and radii determined from two particle correlations.

NA44 has measured proton and deuteron distributions from SS and SPb collisions at 200 GeV/ c and PbPb collisions at 158 GeV/ c . The mean p T of both protons and deuterons grows with system size but the deuterons are somewhat slower than the protons. The phase space density of protons falls with m T but increases for larger systems. The phase space density of p s is much lower than of protons while their average freeze-out radii are similar. The proton source size increases with system size but not as rapidly as the pion source. For PbPb collisions, all radii lie on a single curve.

K+K+ correlations from Pb+Pb collisions at the CERN experiment NA44 will be presented. NA44 is a focussing spectrometer that uses the 160 AGeV Pb beam at the SPS and specializes in the detection of a few artices near mid-rapidity. A comparison of the results from pion and kaon correlations will be made, and the mt dependence of hadron correlations will also be discussed.

NA44 has measured the invariant cross section of deuterons and tritons at non zero p t in 158 A·GeV lead on lead collisions at CERN SPS. Normalized transverse mass spectra and coalescence parameters versus p t have been calculated showing a significant transverse flow. Radius parameters have been extracted using a simple thermal coalescence model. Results from RQMD+coalescence calculations are compared to the data.

We report a measurement of the quantum efficiency of a charge coupled device (CCD) with a simple method and report a resultant quantum efficiency in the energy range from 0.47 to 9 keV. The CCD is a front side illuminated device and is fabricated by Hamamatsu Photonics K.K. The quantum efficiency for 4.5 keV x rays is 11% for the single pixel events, 33% for the spectroscopic events, and 60% for flux mode operation. We present the quantum efficiency as a function of the energy.

K−/K+ and p ¯ / p ratios measured in 158 A·GeV Pb+Pb collisions are shown as a function of transverse momentum PT and centrality in top 8.5% central region. Little centrality dependence of the K−/K+ and p ¯ / p ratios is observed. The transverse mass mT distribution and dN/dy of K+, K−, p and p ¯ around mid-rapidity are obtained. The temperature Tch and the chemical potentials for both light and strange quarks (μq, μs) at chemical freeze-out are determined by applying simple thermodynamical model to the present data. The resultant μq, μs and Tch are compared with those obtained from similar analysis of SPS S+A and AGS Si+A data. The chemical freeze-out temperature Tch at CERN energies is higher than thermal freeze-out temperature Tfo which is extracted from mT distribution of charged hadrons. At AGS energies Tch is close to Tfo.

Samples of liver, renal cortex, and medulla were obtained from 55 forensic autopsies (0- to 95-yr-old Japanese). Metallothionein (MT) was determined by the Ag-hem or Cd-hem method. Zinc (Zn), copper (Cu), and cadmium (Cd) were determined by atomic absorption spectrophotometry. The mean levels of MT were 250 micrograms/g in the liver, and 394 micrograms/g (cortex) and 191 micrograms/g (medulla) in the kidney. Age-dependent changes were observed in both the liver and kidney. In the liver, MT level decreased during infancy and increased thereafter with age. Similar age-dependent changes in the levels of Zn and Cu were observed. In the kidney cortex, MT level increased with age, although no correlation was found after middle age. The levels of Cd and Zn also increased with age until middle age; however, they decreased thereafter. These results suggest that age-dependent changes in renal MT levels are associated with accumulation of Cd.

Recent results of analyses on hadron spectra from the focusing spectrometer experiment NA44 are presented. One-, two- and three-particle hadron spectra in the mid-rapidity region at CERN/SPS energy have been measured. The mT inverse-slopes of proton and anti-proton in collision systems from p+A to Pb+Pb are discussed. Spectra of deuteron, triton and anti-deuteron are presented, and the flow effect on the composite particle spectra are discussed. The two-particle interferometry analysis is made for the π±π± and K+K+ correlations in the central Pb+Pb collisions, and the dependences of interferometric parameters on the transverse mass and the multiplicity are discussed.

The physics emphases of the PHENIX collaboration and the design and current status of the PHENIX detector are discussed. The plan of the collaboration for making the most effective use of the available luminosity in the first years of RHIC operation is also presented., Comment: 5 pages, 1 figure. Further details of the PHENIX physics program available at http://www.rhic.bnl.gov/phenix/

We describe a start-timing detector for the PHENIX experiment at the relativistic heavy-ion collider RHIC. The role of the detector is to detect a nuclear collision, provide precise time information with an accuracy of 50ps, and determine the collision point along the beam direction with a resolution of a few cm. Technical challenges are that the detector must be operational in a wide particle-multiplicity range in a high radiation environment and a strong magnetic field. We present the performance of the prototype and discuss the final design of the detector., Comment: 12 pages, LaTeX, 9 gif and 4 ps figures. Submitted to NIM A

A 25-year-old woman with a large acoustic schwannoma underwent surgical excision 18 months after Gamma Knife radiosurgery because of transient expansion of the tumor causing ataxia. Histopathologial investigation by the TUNEL method revealed the presence of some apoptotic cells. The findings were compared with findings from a control group of 7 operated cases where radiosurgery had not been used. There was no apoptosis found in any of these cases. In addition, another case which resulted in a regrowing tumor following Gamma Knife treatment also showed no apoptosis. These findings suggest apoptosis may be a possible mechanism in reducing tumor size following Gamma Knife radiosurgery.

Results are presented for the ${}^{3}$He$(\ensuremath{\gamma},{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})$ reaction in the region 380 $l~{E}_{\ensuremath{\gamma}}l~700$ MeV, investigated with the use of a 10% duty factor tagged photon beam, in conjunction with the TAGX multiparticle spectrometer. The study of such multipion photoproduction reactions has motivated a number of chiral symmetric models, and is expected to provide an insight on the role of the $\ensuremath{\Delta}$ and ${N}^{*}$ resonances in the nuclear medium. From comparisons of the data with simple reaction simulations, it was found that the data were best fit with a combination of multibody phase space channels, quasifree $\ensuremath{\Delta}$ and ${N}^{*}$, and $\ensuremath{\Delta}\ensuremath{\Delta}$ production channels. The results are compared with other double pion photoproduction reactions on hydrogen and deuterium.

Transverse mass spectra of pions, kaons, and protons from the symmetric heavy-ion collisions 200AGeV S+S and 158AGeV Pb+Pb, measured in the NA44 focusing spectrometer at CERN, are presented. The mass dependence of the slope parameters provides evidence of collective transverse flow from expansion of the system in heavy-ion induced central collisions. {copyright} {ital 1997} {ital The American Physical Society}

A kinematically complete 4He(γ,pn)2H measurement was carried out in the photon energy (Eγ) range 145–425 MeV. The total cross section (σα) forms a prominent structure whose peak lies at Eγ ∼ 245 MeV (the pnd invariant mass of 3960 MeV/c2). The ratio σ α σ d , where σd is the deuteron photodisintegration cross section, shows a step-like rise to a value of 6 at Eγ ∼ 140 MeV.