Direct measurement of 1-mN-class thrust and 100-s-class specific impulse for a CubeSat propulsion system

This paper presents the development of a thrust stand to enable direct measurement of thrust and specific impulse for a CubeSat propulsion system during firing. The thrust stand is an inverted pendulum and incorporates a mass balance for direct in situ mass measurement. The proposed calibration procedure allows precise performance characterization and achieves a resolution of 80 μN thrust and 0.01 g mass loss, by taking into account the drift of the thrust-stand zero caused by propellant consumption. The performance of a water micro-resistojet propulsion system for CubeSats was directly characterized as a proof of concept of the thrust stand. Continuous profiles of thrust, specific impulse, and mass consumption were acquired under various conditions in a single firing test. A thrust from 1 mN to 10 mN and a specific impulse from 45 s to 100 s with a maximum measurement uncertainty of ±15.3% were measured for the throat Reynolds number in the range 100-400.

Inhibition of Trigeminal Respiratory Activity by Suckling

The trigeminal motor system is involved in many rhythmic oral-motor behaviors, such as suckling, mastication, swallowing, and breathing. Despite the obvious importance of functional coordination among these rhythmic activities, the system is not well-understood. In the present study, we examined the hypothesis that an interaction between suckling and breathing exists in the brainstem, by studying the respiratory activity in trigeminal motoneurons (TMNs) during fictive suckling using a neonatal rat in vitro brainstem preparation. The results showed that fictive suckling, which was neurochemically induced by bath application of N-methyl-D,L-aspartate and bicuculline-methiodide, or by local micro-injection of the same drugs to the trigeminal motor nucleus, inhibited the inspiratory activities in both respiration TMNs and respiratory rhythm-generating neurons. Under patch-clamp recording, fictive suckling caused membrane potential hyperpolarization of respiration TMNs. We conclude that the brainstem preparation contains an inhibitory circuit for respiratory activity in the trigeminal motor system via the rhythm-generating network for suckling. Abbreviations: BIC, bicuculline methiodide; GABA, gamma aminobutyric acid; NMA, N-methyl-D,L-aspartate; NMDA, N-methyl-D-aspartate; and TMN, trigeminal motoneuron.

Expressions of isopeptide bonds and corneodesmosin in middle ear cholesteatoma

OBJECTIVE

Isopeptide bonds form cross-links between constituent proteins in the horny layer of the epidermis. Corneodesmosin (CDSN) is a major component of corneodesmosomes, which bind corneocytes together. Both play important roles in maintaining epidermal barrier functions. In the present study, we investigated the expressions of isopeptide bonds, CDSN, and related enzymes in middle ear cholesteatoma in comparison with the skin.

DESIGN

Prospective case series of patients with middle ear cholesteatoma.

SETTING

Tertiary medical institute.

PARTICIPANTS

Cholesteatoma and normal postauricular skin were collected from patients with acquired middle ear cholesteatoma during tympanomastoidectomy.

MAIN OUTCOME MEASURES

Expression of e-(g-glutamyl)lysine isopeptide bonds was examined by immunohistochemistry; Expressions of transglutaminase (TGase)1, TGase2, TGase3, and TGase5 by immunohistochemistry and quantitative RT-PCR (qRT-PCR); expression of CDSN by immunohistochemistry, qRT-PCR, and Western blot; and expressions of tissue kallikrein-related peptidase (KLK)5, KLK7, KLK14, and serine peptidase inhibitor Kazal type 5 (SPINK5) by qRT-PCR.

RESULTS

TGase2 was higher (P=0.0046) and TGase5 was lower (P=0.0008) in cholesteatoma than in the postauricular skin. Immunoreactivity for isopeptide bonds was localized in the granular and horny layers, and was not different between the two tissues. Immunoreactivity for CDSN was localized in the granular layer, and was lower in cholesteatoma than in the skin (P=0.0090). Western blot and qRT-PCR confirmed that the expression of CDSN was lower in cholesteatoma than in the skin. Expressions of KLK5, KLK7, KLK14, or SPINK5 were not different between the two tissues.

CONCLUSIONS

These results indicate that the production of CDSN is likely to be suppressed in cholesteatoma, which would account, at least in part, for the mechanical fragility and increased permeability of the cholesteatoma epithelium.

Studies on the validity of urinary enzyme assay in the diagnosis of drug-induced renal lesions in rats

The validity of urinary enzyme assays in the diagnosis of renal lesions was studied in rats for evaluation in comparison with other tests such as urinalysis and serum biochemical assay. Tubular damages of slight or severe degree were induced by daily intramuscular administration of 500 mg/kg or 1,000 mg/kg of kanamycin (KM) for 7 and 6 days respectively. Glomerular lesions were induced subcutaneous injection of 30 mg/kg of puromycin (PM) for 6 days. The enzymes, assayed daily before and after the onset of administration, were lactic dehydrogenase (LDH), aspartate aminotransferase (GOT), alkaline phosphatase (AI-P), acid phosphatase (Ac-P), leucin aminopeptidase (LAP) and γ-glutamyl transpeptidase (γ-GT). The distribution of these enzymic activities in the kidneys was histochemically examined. Assays of LDH and GOT on the kidney tissue homogenate were also conducted. Histological alterations of the kidneys were examined in the rats sacrificed after termination of administration.

Significant elevation of the LDH and GOT urine levels were observed within 24 hours in rats treated with 500 mg/kg of KM with the high enzyme levels being maintained throughout the administration period, while the other enzymes remained within pretreatment levels or were only slightly elevated. Serum urea nitrogen (BUN) and creatinine levels remained unchanged with no abnormality being found in the urinalysis of this group. In the group treated with 1,000 mg/ kg of KM, concomitant rising of all urine enzyme levels was observed, with elevation of the LDH and GOT levels being extreme while the BUN and serum creatinine levels rose only at the termination of the administration period. The BUN level rose earlier than did most of the urinary enzymes in puromycin-treated rats.

Depletion of LDH activity was histochemically demonstrated in the kidneys where no histological alteration was observable, while the activities of AI-P, γ-GT, and LAP showed no distinct changes until the tabular destruction became severe. Upon termination of both KM and PM administration, the depletion of LDH and GOT activities was noted in a kidney homogenate assay for the enzymes.

These results clearly showed that among the enzymes studied, the LDH and GOT urine levels are the most sensitive indicators for detecting proximal tubular lesions induced by KM. It was further demonstrated that the urinary enzyme assay in combination with serum BUN measurement is an effective examination for distinguishing tubular from glomerular lesions.

Increased permeability of the epithelium of middle ear cholesteatoma

OBJECTIVE

We investigated the electrical impedance of and the expressions of tight junction molecules in the cholesteatoma epithelium to provide supporting evidence for the acid lysis theory of bone resorption in middle ear cholesteatoma.

METHODS

Study subjects were patients with primary acquired middle ear cholesteatoma and those with non-cholesteatomatous chronic otitis media who underwent tympanomastoidectomy. The electrical impedance of the cholesteatoma epithelium was measured during tympanomastoidectomy by loading alternating currents of 320 Hz and 30.7 kHz. The expressions of tricellulin (MARVELD2), claudin-1 (CLDN1) and claudin-3 (CLDN3) were examined by fluorescence immunohistochemistry and quantitative reverse transcription-polymerase chain reaction.

RESULTS

The electrical impedance of the cholesteatoma epithelium was significantly lower than that of the post-auricular skin and external auditory canal skin at both 320 Hz and 30.7 kHz. Immunoreactivity for MARVELD2, CLDN1 and CLDN3 was localised mainly in the granular layer, and to lesser degree, in the horny and spinous layers in both the cholesteatoma tissue and post-auricular skin. Fluorescence intensity was moderate for MARVELD2, weak for CLDN1 and strong for CLDN3. The expressions of MARVELD2, CLDN1 and CLDN3 mRNA were significantly lower in the cholesteatoma tissue than in the post-auricular skin.

CONCLUSIONS

These results indicate the increased permeability of the cholesteatoma epithelium and suggest that this change is, at least partially, dependent on the decrease in the expressions of the tight junction molecules. This evidence supports the acid lysis hypothesis of bone resorption in cholesteatoma.

Crystallization of high-quality protein crystals using an external electric field

The effect of a 20 kHz external electric field on the quality of tetragonal hen egg white (HEW) lysozyme crystals was investigated using X-ray diffraction rocking-curve measurements. The full width at half-maximum was found to be larger for high-order reflections but smaller for low-order reflections. In particular, it was revealed that a large amount of local strain is accumulated in tetragonal HEW lysozyme crystals grown under an applied field at 20 kHz. Comparison with previous results obtained for crystals grown with an applied field at 1 MHz [Koizumi, Uda, Fujiwara, Tachibana, Kojima & Nozawa (2013).J. Appl. Cryst.46, 25–29] indicated that improvement of the protein crystal quality could be achieved by selection of an appropriate frequency for the applied electric field, which has a significant effect on the growth of the solid.

Wearable blood flowmeter appcessory with low-power laser Doppler signal processing for daily-life healthcare monitoring

A new appcessory for monitoring peripheral blood flow in daily life consists of a wearable laser Doppler sensor device and a cooperating smart phone application. Bluetooth Low Energy connects them wirelessly. The sensor device features ultralight weight of 15 g and an intermittent signal processing technique that reduces power consumption to only 7 mW at measurement intervals of 0.1 s. These features enable more than 24-h continuous monitoring of peripheral blood flow in daily life, which can provide valuable vital-sign information for healthcare services.

Elastic constants in orthorhombic hen egg-white lysozyme crystals

The ultrasonic sound velocities of cross-linked orthorhombic hen egg-white lysozyme (HEWL) crystals, including a large amount of water in the crystal, were measured using an ultrasonic pulse-echo method. As a result, seven elastic constants of orthorhombic crystals were observed to be C11 = 5.24 GPa, C22 = 4.87 GPa, C12 = 4.02 GPa, C33 = 5.23 GPa, C44 = 0.30 GPa, C55 = 0.40 GPa, and C66 = 0.43 GPa, respectively. However, C13 and C23 could not be observed because the suitable crystal planes could not be cut from bulk crystals. We conclude that the observed elastic constants of the cross-linked crystals are coincident with those of the intrinsic crystals without cross-linking. Moreover, the characteristics of the elastic constants in orthorhombic HEWL crystals are due to the fact that the shear elastic constants, C44, C55, and C66, are softer than in tetragonal crystals. That is, the shear components, C44, C55, and C66, are one half of those of the tetragonal crystals.

Improvement of crystal quality for tetragonal hen egg white lysozyme crystals under application of an external alternating current electric field

X-ray diffraction rocking-curve measurements were performed on tetragonal hen egg white lysozyme (HEWL) crystals grown with and without application of an external alternating current (AC) electric field, and then the crystal quality was assessed by the FWHMs of each rocking-curve profile. The FWHMs for HEWL crystals grown with an external electric field were smaller than those for crystals grown without. In particular, the average FWHM for the 12 12 0 reflection with an external electric field (0.0034°) was significantly smaller than that without (0.0061°). This indicates that the crystal quality of HEWL crystals was improved by application of the external AC electric field. This crystallization technique can be expected to enhance the resolution of protein molecule structure analysis by X-ray diffraction.

Control of Gibbs free energy relationship between hen egg white lysozyme polymorphs under application of an external alternating current electric field

The distribution of phases between bulk (tetragonal structure) and spherulitic crystals for hen egg white lysozyme was controlled under application of an external alternating current electric field. The distribution of phases differed depending on differences in the magnitude of the electrostatic energy contribution to the respective chemical potentials of the two solid phases. Therefore, the Gibbs free energy relationship between the two solid phases could be controlled by changing the frequency of the applied external electric field. Such a method of controlling the Gibbs free energy relationship among polymorphs would be adaptable to many kinds of protein.

Cell type-specific localization of optineurin in the striatal neurons of mice: implications for neuronal vulnerability in Huntington's disease

Striatal neuropathology of Huntington's disease (HD) involves primary and progressive degeneration of the medium-sized projection neurons, with relative sparing of the local circuit interneurons. The mechanism for such a patterned cell loss in the HD striatum continues to remain unclear. Optineurin (OPTN) is one of the proteins interacting with huntingtin and plays a protective role in several neurodegenerative disorders. To determine the cellular localization pattern of OPTN in the mouse striatum, we employed a highly sensitive immunohistochemistry with the tyramide signal amplification system. In this study, we show that OPTN appeared as a cytoplasmic protein within the subsets of the striatal neurons. Of particular interest was that OPTN was abundantly expressed in the interneurons, whereas low levels of OPTN were observed in the medium projection neurons. This cell type-specific distribution of OPTN in the striatum is strikingly complementary to the pattern of neuronal loss typically observed in the striatum of patients with HD. We suggest that OPTN abundance is an important cellular factor in considering the cell type-specific vulnerability of striatal neurons in HD.

Control of effect on the nucleation rate for hen egg white lysozyme crystals under application of an external ac electric field

The effect of an external ac electric field on the nucleation rate of hen egg white lysozyme crystals increased with an increase in the concentration of the precipitant used, which enabled the design of an electric double layer (EDL) formed at the inner surface of the drop in the oil. This is attributed to the thickness of the EDL controlled by the ionic strength of the precipitant used. Control of the EDL formed at the interface between the two phases is important to establishing this novel technique for the crystallization of proteins under the application of an external ac electric field.

Alpha2-adrenoceptors coordinate swallowing and respiration

Because the discoordination between swallowing and respiration may cause severe respiratory disorders such as aspiration pneumonia, understanding the neuronal mechanisms underlying such coordination is important. Recently, it was reported that medullary noradrenergic neurons are involved in evoking esophageal-gastric relaxation reflex, leading to a hypothesis that such neurons are also involved in swallowing-respiration coordination. We tested this hypothesis using an in vitro brain-stem preparation obtained from neonatal rats. A temporal inhibition of respiratory rhythm was consistently observed when swallowing activity was induced by electrical stimulations to the supralaryngeal nerve. We found that a broad adrenergic receptor agonist, norepinephrine, markedly blocked the swallowing-induced temporal inhibition of respiration. Further studies revealed that swallowing-induced respiratory inhibition is blocked by an alpha2-adrenergic receptor agonist and enhanced by an alpha2-adrenergic receptor antagonist, indicating an important role of alpha2-adrenergic receptors in regulation of the coordination between swallowing and respiration in vitro.

Regulation of Trigeminal Respiratory Motor Activity in the Brainstem

The trigeminal motor system participates in the control of respiration as well as suckling and mastication. However, the central mechanism underlying respiratory activity in trigeminal motoneurons is not well-understood. In this study, we aimed to elucidate brainstem circuitry for rhythm generation and signal transmission of trigeminal respiratory activity in in vitro neonatal rat brainstem-spinal cord preparations. We further examined the role of midline-crossing trigeminal interneurons in the bilateral synchronization of respiratory and suckling activity in trigeminal motor nerves. The results of brainstem-sectioning experiments indicated that respiratory rhythms were generated in the medulla and ipsilaterally transmitted to trigeminal motoneurons in the pons. We conclude that the trigeminal motor system, as well as the hypoglossal and phrenic motor system, is regulated by medullary respiratory networks, and that pontine interactions between bilateral trigeminal interneurons are not critical for the generation or synchronization of trigeminal respiratory activity, but are crucial for trigeminal suckling activity.

Elastic constants in tetragonal hen egg-white lysozyme crystals containing large amount of water

Transverse sound velocity of cross-linked tetragonal hen egg-white (HEW) lysozyme crystals containing large amount of water in the crystal was measured using ultrasonic pulse-echo method. All elastic constants of cross-linked crystals were observed to be C11=C22=5.50 GPa, C12=4.33 GPa, C13=C23=3.94 GPa, C33=5.22 GPa, C44=C55=0.68 GPa, and C66=0.84 GPa, respectively. We found that the elastic constants of the cross-linked crystals are identical to those of the intrinsic ones without cross-linking. Moreover, we found that tetragonal HEW lysozyme crystals that enclose large amount of water show decreased elastic constants (softening). In particular, the shear elastic constants C44=C55 and C66 showed more softening effect comparing with other elastic components.

Diagnostic value of spinal MR imaging in spontaneous intracranial hypotension syndrome

BACKGROUND AND PURPOSE

Spontaneous intracranial hypotension (SIH) presents with orthostatic headache, and the diagnosis is made on the basis of low CSF pressure and brain MR imaging findings characteristic of the disorder. However, a broad spectrum of symptoms and MR imaging findings of SIH is recognized, and some cases have no typical MR imaging abnormalities. SIH is believed to be caused by CSF leakage from the spinal dural sac, whereas the usefulness of MR imaging of the spine remains unclear. Our aim was to elucidate the diagnostic value of brain and spinal MR imaging

MATERIALS AND METHODS

The sensitivities for the detection of SIH were retrospectively evaluated in 18 patients with SIH treated in our institutions between January 1998 and August 2007.

RESULTS

Brain MR imaging detected abnormalities in 15 of the 18 patients (83%): diffuse pachymeningeal enhancement in 15 (83%), descent of the cerebellar tonsil in 13 (72%), brain stem sagging in 13 (72%), enlargement of the pituitary gland in 12 (67%), and subdural fluid collection in 13 (72%). Spinal MR imaging detected abnormalities in 17 of the 18 patients (94%): distention of the epidural veins in 14 (78%), epidural fluid collection on fat-saturated T2-weighted images in 16 (89%), and abnormal visualization of the nerve root sleeve in only 1 (6%). The sensitivity for SIH was 83% for brain MR imaging and 94% for spinal MR imaging.

CONCLUSIONS

Spinal MR imaging is useful for the diagnosis of SIH, especially in the early stage.

An uncommon cleft subtype of unilateral cleft lip and palate

The finding that the vomer plays a crucial role in maxillary growth suggests that the bilateral cleft configuration of unilateral cleft lip and palate (UCLP), in which the vomer is detached from the non-cleft-side secondary hard palate, negatively influences palatal development, and this hypothesis was tested. Sixty persons with complete UCLP, including those with the vomer detached from (n = 30, b-UCLP) and attached to (n = 30, u-UCLP) the secondary hard palate, were analyzed morphologically, with the use of cast models taken at 10 days, 3 mos, and 12 mos of age. The anterio-posterior palatal length at 12 mos of age in those with b-UCLP was significantly shorter than that in those with u-UCLP, by 8.7% (p < 0.05). In addition, palatal width development in the first year in those with b-UCLP was also significantly retarded. These results suggest that the uncommon bilateral cleft subtype in UCLP should be included in the cleft classification.

Angiomyolipoma of the tongue

We present a rare case of angiomyolipoma of the tongue in a 23-year-old man. The clinical appearance was of a small, solitary, well-demarcated, painless mass. The oral angiomyolipoma followed a benign course with no recurrence after excision.

Spatial and functional architecture of the mammalian brain stem respiratory network: a hierarchy of three oscillatory mechanisms

Mammalian central pattern generators (CPGs) producing rhythmic movements exhibit extremely robust and flexible behavior. Network architectures that enable these features are not well understood. Here we studied organization of the brain stem respiratory CPG. By sequential rostral to caudal transections through the pontine-medullary respiratory network within an in situ perfused rat brain stem-spinal cord preparation, we showed that network dynamics reorganized and new rhythmogenic mechanisms emerged. The normal three-phase respiratory rhythm transformed to a two-phase and then to a one-phase rhythm as the network was reduced. Expression of the three-phase rhythm required the presence of the pons, generation of the two-phase rhythm depended on the integrity of Bötzinger and pre-Bötzinger complexes and interactions between them, and the one-phase rhythm was generated within the pre-Bötzinger complex. Transformation from the three-phase to a two-phase pattern also occurred in intact preparations when chloride-mediated synaptic inhibition was reduced. In contrast to the three-phase and two-phase rhythms, the one-phase rhythm was abolished by blockade of persistent sodium current (I(NaP)). A model of the respiratory network was developed to reproduce and explain these observations. The model incorporated interacting populations of respiratory neurons within spatially organized brain stem compartments. Our simulations reproduced the respiratory patterns recorded from intact and sequentially reduced preparations. Our results suggest that the three-phase and two-phase rhythms involve inhibitory network interactions, whereas the one-phase rhythm depends on I(NaP). We conclude that the respiratory network has rhythmogenic capabilities at multiple levels of network organization, allowing expression of motor patterns specific for various physiological and pathophysiological respiratory behaviors.

Sodium hyaluronate eye drops prevent late-onset bleb leakage after trabeculectomy with mitomycin C

PURPOSE

To evaluate the efficacy of sodium hyaluronate eye drops for prevention of late-onset bleb leakage after trabeculectomy with mitomycin C (MMC).

METHODS

Sixty-eight patients (68 eyes) who had trabeculectomy with MMC from March 1995 to February 2002 at the Marui Eye Clinic or the Department of Ophthalmology, Fukushima Medical University Hospital were examined in this study. Twenty-two were treated postoperatively with sodium hyaluronate eye drops (sodium hyaluronate group) and 46 eyes were not treated postoperatively (control group). The blebs were classified according to the avascular area, epithelial defect and degree of bleb wall leakage. Both groups were assigned classes (0, avascular or partial avascular bleb; 1, avascular or partial avascular bleb with an epithelial defect; 2, avascular or partial avascular bleb with oozing; 3, avascular or partial avascular bleb with a point of leakage).

RESULTS

Follow-up duration ranged from 10 to 116 months (mean+/-SD, 57.6+/-30.5). The incidence of reclassification from class 1 to class 0 was significantly greater in the sodium hyaluronate group (four of six class 1 eyes improved to class 0 after application of sodium hyaluronate eye drops) than in the control group (zero of 10 eyes) (P=0.008). And, the incidence of reclassification from class 1 to class 2 or class 3 was significantly smaller in the sodium hyaluronate group (one of six eyes) than in the control group (nine of 10 eyes) (P=0.008).

CONCLUSIONS

Sodium hyaluronate eye drops may prevent late-onset bleb leakage after trabeculectomy with MMC.

Intrinsic bursters increase the robustness of rhythm generation in an excitatory network

The pre-Botzinger complex (pBC) is a vital subcircuit of the respiratory central pattern generator. Although the existence of neurons with pacemaker-like bursting properties in this network is not questioned, their role in network rhythmogenesis is unresolved. Modeling is ideally suited to address this debate because of the ease with which biophysical parameters of individual cells and network architecture can be manipulated. We modeled the parameter variability of experimental data from pBC bursting pacemaker and nonpacemaker neurons using a modified version of our previously developed pBC neuron and network models. To investigate the role of pacemakers in networkwide rhythmogenesis, we simulated networks of these neurons and varied the fraction of the population made up of pacemakers. For each number of pacemaker neurons, we varied the amount of tonic drive to the network and measured the frequency of synchronous networkwide bursting produced. Both excitatory networks with all-to-all coupling and sparsely connected networks were explored for several levels of synaptic coupling strength. Networks containing only nonpacemakers were able to produce networkwide bursting, but with a low probability of bursting and low input and output ranges. Our results indicate that inclusion of pacemakers in an excitatory network increases robustness of the network by more than tripling the input and output ranges compared with networks containing no pacemakers. The largest increase in dynamic range occurs when the number of pacemakers in the network is greater than 20% of the population. Experimental tests of our model predictions are proposed.

Primary germinoma arising from the midbrain

A 29-year-old man presented with diplopia, dysarthria, anisocoria, oculomotor nerve paralysis, abducens nerve paralysis, right facial palsy, and spastic hemiparetic gait. Magnetic resonance imaging (MRI) showed a homogenously enhanced mass in the midbrain. MRI-guided stereotactic biopsy was performed, and the histologic diagnosis was pure germinoma. The tumor disappeared after chemotherapy and radiotherapy. Germinoma should be included in the differential diagnosis of midbrain lesions in young adults. MRI-guided stereotactic biopsy provided a helpful diagnostic clue in a patient with a midbrain lesion.

Observation of all the components of elastic constants using tetragonal hen egg-white lysozyme crystals dehydrated at 42% relative humidity

Success in measuring transverse sound velocity allowed us to determine, for the first time, all six elastic constants of a protein crystal. An ultrasonic pulse-echo method was used to perform sound velocity measurements on tetragonal hen egg-white (HEW) lysozyme crystals that were partially dehydrated at 42% relative humidity. The measurements were performed using the (110), (101), and (001) crystallographic faces. Thus, all six elastic constants of the dehydrated tetragonal HEW lysozyme crystals were determined: C11=C22=12.44 GPa, C12=7.03 GPa, C13=C23=8.36 GPa, C33=12.79 GPa, C44=C55=2.97 GPa, and C66=2.63 GPa. In addition, for the hydrated crystals, the longitudinal sound velocities along the [110] direction and the direction normal to the (101) face were measured. From these results, all the components of elastic constants in the hydrated crystals were extrapolated.

Comparative strength of metal-ceramic and metal-composite bonds after extended thermocycling

The relative strengths of ceramic-to-metal and composite-to-metal bonds were compared after prolonged thermocycling. A total of 104 cast discs were produced from a gold alloy (Pontor LFC). A ceramic material (Duceragold) was fused to 24 discs to assess the strength of the metal-ceramic bond. An indirect composite material (New Metacolor Infis) was bonded to the remaining discs after surface preparation by Rocatec tribochemical coating, tin plating and priming with a phosphate conditioner [10-methacryloyloxydecyl dihydrogen phosphate (MDP), Cesead II], priming with a thione conditioner (V-Primer) or no treatment (unprimed control). Shear bond strengths were determined before and after thermocycling at 20,000 and 100,000 cycles. Pre-thermocycling bond strengths were ranked in the order: metal-ceramic (40.5 MPa); Rocatec treatment (33.1 MPa) and tin plating-MDP (31.0 MPa); V-Primer (20.9 MPa); and control (11.9 MPa). The bond strengths of the first three groups were not significantly different after 20,000 thermocycles, whereas those of the V-Primer and control groups were significantly reduced. After extended thermocycling (100,000 cycles) the metal-ceramic group had the highest mean shear bond strength (28.5 MPa; P < 0.05), followed by the Rocatec (23.9 MPa) and tin plating-MDP (22.1 MPa) groups. The metal-ceramic bond was the most durable, although its strength was reduced by 29.6% after extended thermocycling. On the basis of these results, we recommend the Rocatec and tin plating-MDP systems for composite-to-metal bonding. Metal-ceramic bonding, however, is superior to metal-composite bonding within the limitation of the current experiment.

Effect of intracrystalline water on longitudinal sound velocity in tetragonal hen-egg-white lysozyme crystals

Longitudinal sound velocity of tetragonal hen-egg-white (HEW) lysozyme crystals was measured during air drying by ultrasonic pulseecho method. The sound velocity increases with exposure to open air and approaches a constant value. The maximum value is approximately 2900 m/s that is about 1.6 times as much as that of original one before drying. In addition, the sound velocity clearly recovers to original one after immersing the dried crystal in solution. Therefore, the sound velocity in tetragonal HEW lysozyme crystals can be reversibly changed due to dehydration and rehydration. These changes in sound velocity are discussed in the light of water-mediated intramolecular and intermolecular interactions in the crystals.

Identification of dislocations in large tetragonal hen egg-white lysozyme crystals by synchrotron white-beam topography

Large tetragonal hen egg-white (HEW) lysozyme crystals have been grown by a salt concentration-gradient method. The grown crystals, of thicknesses greater than 1.5 mm, were observed by means of X-ray topography using white-beam synchrotron radiation. Line contrasts clearly appeared on the Laue topographs. Extinction of the line images was observed in specific reflections. These results mean that the observed lines correspond to dislocation images. From the extinction criterion it is shown that the predominant dislocations are of screw character with <110> Burgers vectors. In addition, dislocation loops with [001] Burgers vectors have been found in a tetragonal HEW lysozyme crystal including some cracks. These results are discussed in the light of dislocation elastic energy and slip systems in the crystals.

Effect of serotonin (5-HT) on trigeminal rhythmic activities generated in in vitro brainstem block preparations

We used rat isolated brainstem block preparations to analyze the functional roles of serotonin receptors in the generation of trigeminal rhythmic activities. We previously reported that trigeminal rhythmic activities could be induced by some pharmacological applications in an isolated brainstem preparation with a rostral boundary at the border between the inferior and superior colliculus, and a caudal border at the level of the rostral facial nucleus. However, the same stimulation did not induce trigeminal rhythmic activities in a whole brainstem block preparation with the same rostral boundary and a caudal border at the obex level. In the present study, both the 5-HT(1A) phthalimido-butyl-piperazine, and the 5-HT(2C) agonist, 1-2,5-dimethoxy-4-iodophenyl-2-aminopropane, combined with N-methyl-D,L-aspartate and bicuculline, elicited trigeminal rhythmic activities in a whole brainstem block preparation. Our results suggest that serotonin has both facilitation and inhibition effects on the generation of trigeminal rhythmic activities in an isolated brainstem block preparation in vitro.

High serum levels of additional IL-18 forms may be reciprocally correlated with IgE levels in patients with atopic dermatitis

We established an ELISA system for determination of as yet unidentified species of interleukin 18 (IL-18), named IL-18 type 2, in human serum. Serum IL-18 levels and their effect on IgE levels were examined in 18 patients with atopic dermatitis (AD) with no other allergic symptoms. Three of these patients showed high IL-18 type 2 concentrations (25-100 ng/ml) in their blood serum, and this IL-18 type 2 was detectable only with our established ELISA system. In contrast, the level of the conventional form of IL-18 (type 1) was found to be 50-400 pg/ml in all patients by the commercially available ELISA. The levels of type 1 IL-18 showed no correlation with those of type 2 and approximately 2-fold higher in AD patients than in normal subjects. IL-12 p40 and IgE levels were correlated in the patients with no IL-18 type 2, and interestingly, relatively low IgE concentrations were detected in the three IL-18 type 2-positive patients. They showed considerable levels of IL-12 p40 unlike normal subjects. The IFNgamma-inducing activity of IL-18 type 2 was >100-fold less potent by weight ratio than that of a recombinant 'active' IL-18 preparation, even after the treatment with Caspase 1. Although the relationship between AD and serum IgE levels is not clear cut, IL-18 type 2 appears to play some roles in the Th2-polarization involving IgE production in association with immune responses occurring in local inflammatory milieu such as atopic lesions.

[Noninvasive higher-order brain-function imaging by near-infrared spectroscopy]

The simultaneous position encoding method for optical topography was developed. Each channel has dual-wavelength optics to separately determine the changes in oxy-hemoglobin and deoxy-hemoglobin concentrations around their isobestic points at 805 nm. Part of the incident light penetrates the scalp and skull and is reflected from brain tissues including the cerebral cortex. Any change in the light extinction is mainly due to changes in the oxy-hemoglobin and/or the deoxy-hemoglobin concentration during the activation of a functional area linked to a neuronal activity. Unlike conventional functional imaging methodologies, it can be used for behavioral studies because the flexible optical fibers allow a subject to move, and a very light and compact system can be made. Noninvasive dynamic optical topography has a wide variety of applications from basic science to clinical medicine. Several applications, such as the study of the Broca and Wernicke language areas, the assessment of the dominant hemisphere of the brain, epilepsy focus determination, and sleep studies are reported. We also tested a 14-month-old baby with a extremely abnormal brain.