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Background: Health consciousness in daily life is very important because lifestyle habits, such as dietary and exercise habits, sleep, and smoking, are involved in the development and progression of lifestyle-related diseases, such as cancer, heart diseases, stroke, liver diseases, kidney diseases, and diabetes. Purpose: In this study, we surveyed to see if the health consciousness increased and what behaviors in daily life changed in students of a nursing school (Seiwa Nursing College, Tokyo, Japan) after they learned medical care knowledge required to become a nurse. Results: After learning medical care knowledge for 3 years, the students were found to have a higher level of health consciousness in the third year than they did in the first year. They applied the medical care knowledge they learned in daily life. All data were collected in 2019. Conclusions: The medical care knowledge learned in a nursing school was demonstrated to serve as information to increase the health consciousness.

Colloidal photonic crystals, which are three-dimensional periodic structures of monodisperse submicron-sized particles, are expected to be suitable for novel photonic applications and color materials. In particular, nonclose-packed colloidal photonic crystals immobilized in elastomers exhibit significant potential for use in tunable photonic applications and strain sensors that detect strain based on color change. This paper reports a practical method for preparing elastomer-immobilized nonclose-packed colloidal photonic crystal films with various uniform Bragg reflection colors using one kind of gel-immobilized nonclose-packed colloidal photonic crystal film. The degree of swelling was controlled by the mixing ratio of the precursor solutions, which used a mixture of solutions with high and low affinities for the gel film as the swelling solvent. This facilitated color tuning over a wide range, enabling the facile preparation of elastomer-immobilized nonclose-packed colloidal photonic crystal films with various uniform colors via subsequent photopolymerization. The present preparation method can contribute to the development of practical applications of elastomer-immobilized tunable colloidal photonic crystals and sensors.

Mesenchymal stromal cells (MSCs) differentiation into different lineages is precisely controlled by signaling pathways. Given that protein kinases play a crucial role in signal transduction, here we show that Microtubule Associated Serine/Threonine Kinase Family Member 4 (Mast4) serves as an important mediator of TGF-β and Wnt signal transduction in regulating chondro-osteogenic differentiation of MSCs. Suppression of Mast4 by TGF-β1 led to increased Sox9 stability by blocking Mast4-induced Sox9 serine 494 phosphorylation and subsequent proteasomal degradation, ultimately enhancing chondrogenesis of MSCs. On the other hand, Mast4 protein, which stability was enhanced by Wnt-mediated inhibition of GSK-3β and subsequent Smurf1 recruitment, promoted β-catenin nuclear localization and Runx2 activity, increasing osteogenesis of MSCs. Consistently, Mast4−/− mice demonstrated excessive cartilage synthesis, while exhibiting osteoporotic phenotype. Interestingly, Mast4 depletion in MSCs facilitated cartilage formation and regeneration in vivo. Altogether, our findings uncover essential roles of Mast4 in determining the fate of MSC development into cartilage or bone.

The passive production of synthesis gas from liquid methanol using a packed bed of porous material particles supporting a catalyst is investigated. Heating of the upper portion of a vertical tube packed with the porous particles where the bottom is immersed in liquid methanol is expected to cause steady upward fluid flow due to capillary action enhanced by evaporation. The emergence of a dry region and a resulting increase in temperature can produce synthesis gas due to catalytic reaction, which then flows out of the top end of the tube. In the proposed process, the capillary force, which is dependent on the local liquid content in the porous bed, is balanced locally with the gravitational force and the viscous forces acting on the liquid and vapor. The distributions of the liquid content, flow rates, pressures, and temperatures of liquid and vapor along the tube axis are calculated using a one-dimensional model based on the mass, force, and energy balances for each phase. The experimental results indicate the validity of the process, that is, the induction of steady fluid flow, the emergence of a dry region, temperature increase to the reaction level, and the products of the reacted gases. The behavior of liquid-vapor flow induced by phase-change in a packed bed and the factors that characterize the process and affect the performance are discussed.

Quenching of a stainless-steel rod with a porous ceramic structure, i.e. honeycomb porous plate (HPP), attached to its lower surface was investigated in distilled water under saturated conditions at atmospheric pressure. The experiments were performed on bare surface (BS) and on a TiO2 nanoparticle-deposited surface (NPDS). When the HPP was attached, the quenching rate increased significantly on both tested surfaces. The quench time for the NPDS with the HPP was 28-times shorter than that for the bare stainless-steel surface. The results suggested that the combination of the HPP ability to transport water to the heat-transfer surface by capillary action, and the increase of surface roughness, capillarity and wettability properties by the deposited nanoparticle layer were responsible for the enhancement obtained.

One strategy for dealing with severe accidents is in-vessel retention (IVR) of corium debris. In-vessel retention consists of external cooling of the reactor vessel in order to remove decay heat from the molten core by lower head of the vessel. In this system, it is important to establish techniques to (1) cool the high-temperature reactor vessel in order to change the boiling regime from film boiling to nucleate boiling as soon as possible, because the heat transfer coefficient for film boiling is very low, and (2) enhance the critical heat flux (CHF), because heat removal is limited by the occurrence of the CHF condition at the outer surface of the reactor vessel. Furthermore, approaches for increasing the IVR capability must be simple and installable at low cost. Regarding (2) CHF enhancement, we have demonstrated CHF enhancement of a large heated surface by a honeycomb porous plate (HPP) in saturated pool boiling of distilled water. In the present paper, we focus on the quenching behavior of a honeycomb porous plate on a nanoparticle-deposited surface. As a result, the quenching period was significantly reduced by approximately 22% as compared to the case of bare surface (without surface modification) due to the combination of nanoparticle deposition and a honeycomb porous plate.

Background There is no available data on the occurrence rate of a converged alveolar canal, the detailed three-dimensional (3D) courses of alveolar canals/grooves (ACGs), or the contribution of each superior alveolar nerve to each area in the maxilla. This study aimed to clarify the 3D courses of ACGs, the relationship between ACGs and superior alveolar nerves, and the contribution of posterior superior alveolar nerves (PSANs) using computed tomography (CT) with histological analysis. Methods During the gross anatomy course at Niigata University, we investigated nine human cadavers. Results All anterior and posterior ACGs converged into the common alveolar canal, which contained blood vessels and several nerve bundles surrounded by perineurium, located at the nasal floor near the pyriform aperture. Histometrical analysis clarified that 16.3% of the nerve bundles in this canal were derived from PSANs, and 67% of the bundles were dispersed while they coursed down to the nasal floor. There seems to be no relationship between the density of nerve bundles in the canal and the number of remaining anterior teeth. Conclusions Data obtained from observing the detailed 3D courses of anterior and posterior ACGs, and their relationship with superior alveolar nerves, suggest that PSANs partially contribute to the nociception of the anterior teeth.

Glycogen is the stored form of glucose and plays a major role in energy metabolism. Recently, it has become clear that enzymatically synthesized glycogen (ESG) has biological functions, such as the macrophage-stimulating activity. This study aimed to evaluate the effect of ESG on osteogenesis. MC3T3-E1 cells were cultured with ESG, and their cell proliferative activity and osteoblast differentiation were measured. An in vivo study was conducted in which ESG pellets with BMP-2 were grafted into mouse calvarial defects and histomorphometrically analyzed for the new bone formation. To confirm the effect of ESG on bone growth in vivo, ESG was orally administered to pregnant mice and the femurs of their pups were examined. We observed that ESG stimulated cell proliferation and enhanced messenger RNA expression of osteocalcin and osteopontin in MC3T3-E1 cells. ESG was taken up by the cells associated with GLUT-1 and activated the Akt/GSK-3β pathway. In vivo, the new bone formation in the calvarial defect was significantly accelerated by ESG and the maternal administration of ESG promoted fetal bone growth. In conclusion, ESG stimulates cell proliferation and differentiation of preosteoblasts via the activation of Akt/GSK-3β signaling and promotes new bone formation in vivo, suggesting that ESG could be a useful stimulant for osteogenesis.

Heat treatment by superheated steam has been utilized in several industrial fields including sterilization, desiccation, and cooking. Saturated and superheated steam is used in a number of home appliances, such as humidifiers, steam cookers, and steam irons. In these applications, in order to save electricity, it is necessary to produce steam on demand. Therefore, quick start-up and cut-off responses are required. However, most electrically energized steam generators require a relatively long time to generate steam due to the large heat capacities of the water in the container. We proposed a new method using containing porous material to generate saturated or superheated steam quickly. Steam may be generated rapidly using containing porous material because the heat capacity of the water in the meniscus is extremely small. The main objective of the present work was to show the performance of rapid steam generator we proposed and experimentally investigate the effect of the effective thermal conductivity of the porous material on the rapid and efficient generation of saturated and superheated steam. As a result, in order to generate superheated steam quickly and efficiently, the generator should be constructed from low-thermal-conductivity material. The energy utilization efficiency was analyzed based on a simplified one-dimensional model of the heat and fluid flow in the porous material, the calculated results were shown to be in good agreement with the experimental results. Based on the proposed model for the energy utilization efficiency on steam generation, the proposed rapid superheated steam generator is suitable for miniaturization.

Background Long-term changes of trabecular microstructure in human tooth extraction socket have not been investigated. Purpose To examine the trabecular microstructure of human residual ridges at various intervals following tooth extraction, and to determine whether bone remodeling activity can attain points of relative stability and when such points are reached. Materials and Methods Forty-four bone biopsy specimens were obtained from lower molar or premolar regions of residual ridges. Postextraction times ranged from 1.6 to 360 months. Samples were analyzed using micro-computed tomography and three-dimensional bone morphometry with histological analyses. Trabecular bone parameters were plotted against postextraction times, and a stepwise piecewise linear regression analysis was performed to determine at which points of time these parameters either increased or decreased. Results Using piecewise linear regression, “inflection points” were found in most trabecular bone parameters between 7 and 12 months postextraction. Among the residual ridge samples, woven trabecular structure became mature, consisting of thick lamellar trabeculae with sufficient bone density, under dynamic bone remodeling until the 7th to 12th month post-tooth extraction. After this period, the mature network structure remained stable with low remodeling activity. Conclusion Bone remodeling of trabecular structure in human residual ridge after tooth extraction had a stabilization period.

The subject was a 53-year-old male. An alveolar bone sample was obtained from the site of the lower left first molar, before dental implant placement. Although the details of the trabecular structure were not visible with conventional computed tomography, micro-computed tomography (microCT) three-dimensional images of the alveolar bone biopsy sample showed several plate-like trabeculae extending from the lingual cortical bone. Histological observations of the bone sample revealed trabeculae, cuboidal osteoblasts, osteoclasts and hematopoietic cells existing in the bone tissue at the implantation site. Bone metabolic markers and calcaneal bone density were all within normal ranges, indicating no acceleration of the patient’s bone metabolism.Using microCT, and histological and histomorphometrical techniques, a great deal of valuable information about the bone tissue was obtained from a biopsy sample extracted from the patient’s planned implant site.

Alveolar cancellous bone biopsy samples were extracted during dental implant preparation for investigating microstructural changes due to menopause and relationships between these changes and bone turnover markers.Subjects were 18 women receiving mandibular implants: premenopausal (n = 5), early postmenopausal (≤5 years; n = 3), and late postmenopausal (5 years; n = 10). Bone turnover markers were measured and the samples analyzed using microscopic computerized tomography and 3-dimensional bone morphometry.The alveolar bone volume was significantly less in late postmenopausal women than in premenopausal ones. The trabeculae in early postmenopausal women were more separated and rod-like than in premenopausal ones (P.05). Each alveolar bone parameter was significantly (P.05) related to at least 1 bone turnover marker.Alveolar cancellous bone structure begins changing even in early postmenopausal women, and this structure varies in close relationship to bone turnover markers.

Purpose The aim of this study was to develop and apply a new method for easy intraoperative adjustment of a provisional fixed full-arch restoration, in order to allow immediate implant loading following computer-guided surgery, regardless of any implant positioning errors compared to the virtual planning. Methods In accordance with the NobelGuide™ protocol, a provisional restoration for immediate loading of six maxillary implants was prepared prior to surgery. Because small shifts between the planned and the actual implant positions were to be expected, the provisional restoration was not fabricated directly on temporary cylinders as a conventional one-piece superstructure, but was divided into two portions: six custom made abutments and a long span fixed restoration which were left unconnected. After implantation, the custom abutments were attached to the six implants to be immediately loaded, and the superstructure was cemented simultaneously to all abutments using dual cure resin cement. After the excess cement was cleaned and polished, the superstructure was then reseated. Passive fit was achieved between implants and the superstructure. Conclusion The superstructure described in this article can be easily seated and adjusted to accommodate any possible shifts in implant positioning occurring during computer-guided surgery. Through this method uneventful immediate implant loading can be achieved in a reasonable operative time.

目的：自立して社会生活を送る一般的な高齢者の義歯に対する主観的評価と「咬めること」，「食事中に外れないこと」，「痛くないこと」の3要因ならびに歯の欠損形態，咀嚼可能な食品との関連を明らかにすることを目的とした．方法：対象は，平成19年度厚生科学研究「口腔保健と全身的な健康状態の関係について」の調査に参加した，新潟市在住で義歯を装着している79～80歳の256名とした．義歯の満足度と「咬めること」，「外れにくいこと」，「痛みがないこと」についてVAS値でアンケートを行った．さらに，欠損形態を宮地分類でグループ化し，義歯満足度との関連を調べた．また，15品目の食品が咀嚼可能かを調べた．結果：義歯の満足度は，「咬めること」，「外れにくいこと」，「痛みがないこと」との間に相関があったが，一つの項目のみが突出して高い関連を示すことはなかった．宮地分類と義歯に対する満足度との間に，関連は認められなかった．義歯の満足度（VAS値）により分けた4群間では，不良群で咬める食品数が有意に低かった．結論：義歯の満足度を高めるには，咬めて，外れにくく，使用時に痛みのないことが必要であることが確認された．一方，今回の調査からは義歯の満足度と宮地分類との間には関連が認められなかった．これは，難しい欠損形態でも義歯の製作や調整次第で，満足が得られる可能性を示唆すると考えられた．

Estrogen deficiency-induced postmenopausal osteoporosis has become a worldwide problem, inducing low bone mass and microarchitectural deterioration of the bone scaffolding in the vertebrae and long bones. With the prevalence of such osteoporosis on the increase, the influence of this estrogen deficiency on the jaw bones has drawn the attention of researchers and clinicians in the field of dentistry. The aim of this article is therefore to review the microstructural changes occurring after ovariectomy in the jaw bones of animal subjects. Induced estrogen deficiency clearly led to structural changes in the jaw bones and alveolar bone of animal subjects (rats and monkeys). Severe bone loss in the rat alveolar bone was principally caused by high bone resorptive activity. This activity accelerated greatly immediately after ovariectomy, and was then followed by more moderate resorptive activity, which continued over an extended period. Additionally, occlusal hypofunction further greatly accelerated the fragility of the alveolar bone structure in ovariectomized rats. Microstructural damage also seen in the alveolar bone of ovariectomized monkeys was found to be directly connected to their systemic osteoporosis. Recent investigations of the relationship in humans between systemic osteoporosis and jaw bone loss have also suggested that a connection may exist between these two. However, more research is required to confirm this connection in humans as well.

Summary Objective To examine changes appearing in the alveolar bone following the removal of the mechanical stress of occlusal loading, as well as the added influence of estrogen deficiency on such changes. Design The right mandibular molars of female rats were extracted. After 8 weeks, 12 animals were ovariectomized (OVX), and the other 12 were subjected to sham surgery (sham). Four weeks after surgery, all rats were sacrificed. The left-half and right-half maxillas of the sham group (the sham-occluded side and the sham-extruded side, respectively) and right-half maxilla of OVX group (the OVX-extruded side) were examined by histological observation and bone histomorphometry. Results The vertical height of alveolar bone in the sham-extruded and the OVX-extruded sides increased as compared with that of the sham-occluded side. In both extruded sides, active bone formation occurred on the surface of the alveolar bone facing the periodontal ligament, but the bone marrow was expanded and the bone volume had decreased in the internal area of the alveolar bone. In the OVX-extruded side, the bone marrow expanded more remarkably than that of the sham-extruded side, and the highest percentage of osteoclast surface was detected. Conclusions Around the extruded teeth, there were regional differences in bone dynamics between the internal area of the alveolar bone and the bone surface facing the periodontal ligament, and estrogen deficiency seems to have caused further loss of bone volume in the interior of the alveolar bone supporting the extruded tooth.

In order to prove osteocytic osteolysis in vivo, human parathyroid hormone (hPTH (1-34), 749 ng/h), or only solvent of the same volume, was continuously administered to 8-month-old rats by an infusion pump for 4 weeks, and then structural changes in osteocytes in the cortical bones of the tibiae were analyzed morphometrically, histologically, and histochemically. Based on contact microradiography (CMR) observations, the osteocyte lacunae in the PTH group tended to be enlarged, compared with those of the control, while the average lacuna area was 137.0 microm2 in the PTH group versus 93.9 microm2 in the control, suggesting evidence of osteocytic osteolysis. Acid phosphatase enzyme histochemical localization was observed in some osteocytes in the PTH group; therefore, lysosome systems may participate in the osteolytic mechanisms. On histological samples stained with hematoxylin-eosin or toluidine blue, the lacunae of the controls were surrounded by narrow areas of matrices both positive for hematoxylin and metachromatic for toluidine blue, while belt-like areas positive for hematoxylin were observed around the PTH-group lacunae. These findings suggested that, after osteocytic osteolysis, regenerated bone matrices may be added to the walls of osteocytes that possess enlarged lacunae.

症例の概要: 症例は16歳の両側性唇顎口蓋裂の女性. 212が欠如, 上顎の劣成長が著しく, 上顎左側中切歯切縁が下顎前歯よりも15mm後退し, 顎裂部も陥凹していた.考察: 患者は固定性補綴物を望んでいたが, 矯正治療前の所見では, 固定性ブリッジは不可能と考えられた. しかし, 補綴担当医として顎裂部への骨移植および転位している矮小歯の欠損部への自家移植を提案したところ, これらが受け入れられ, 最終的に患者の希望する固定性ブリッジによる補綴治療を行うことができた.結論: よい治療結果を得るためには, 補綴医ができる限り早期に唇顎口蓋裂治療チームに加わり, 補綴学的な見地から治療方針決定に関与していくことが肝要であることが示された.

Objective. Trabecular structural changes in the jaw after long-term estrogen deficiency are not well understood. Therefore, we sought to observe the changes in rat alveolar bone for 1 year. Methods. Six-month-old female rats were ovariectomized (OVX) or underwent a sham operation. After 1 year, bone histomorphometry and a node-strut analysis were performed on the interradicular septum of the mandibular first molar by using micro computed tomography and confocal laser scanning microscopy. Statistical analysis was carried out by using analysis of variance. Results. The alveolar trabeculae of rats in the sham group had network structures, whereas the trabeculae of rats in the OVX group became fragmented. The trabecular bone volume, number, and thickness in the OVX group were significantly lower than those found in the sham group, and the trabecular separation was 4-fold higher in the OVX group than in the sham group. Bone resorptive and formative activity appeared to be moderately higher in the OVX group than in the sham group, but only the difference in bone formation was of statistical significance. Conclusion. By 1 year after ovariectomy, bone loss and trabecular fragmentation had occurred in the rat mandibular alveolar bone. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2003;95:495-502)

An association between postmenopausal osteoporosis and tooth loss has been proposed. However, histomorphometrical changes in alveolar bone following estrogen deficiency are rarely reported with data on microtrabecular structural changes. To clarify the relationship between estrogen deficiency and tooth loss, we histomorphometrically analyzed the trabecular structural changes of mandibular alveolar bone in ovariectomized rats. Twenty-four adult female Fischer rats were used. Eight rats were sacrificed on day 0 (baseline). The remaining 16 rats were divided into two groups. One group was ovariectomized bilaterally (OVX) and the other group was subjected to sham surgery (Sham). After administration of tetracycline and calcein, the animals were sacrificed 60 days after surgery. Bone histomorphometry, node-strut analysis and measurement of thickness of alveolar bone proper were performed on the interradicular septum of the first molar on the sagittal surface. The trabecular bone volume and trabecular number of the OVX group were significantly lower than those of the baseline and Sham groups. All of the bone resorptive and formative parameters of the OVX group were significantly higher (about one-and-a-half times) than those of the Sham group. Several osteoclasts were seen lining the irregular, eroded surface facing the bone marrow in the OVX group. Furthermore, the OVX group tended to have low microtrabecular stiffness and showed significantly thinner distal alveolar bone proper than in the baseline and Sham groups. In summary, estrogen deficiency caused osteoporotic changes and thin alveolar bone proper in the interradicular septum of rat first molar. This phenomenon might accelerate destruction of alveolar bone and tooth loss, especially in elderly women affected by periodontal disease.

Changes in cancellous bone of the rat mandibular condyle following estrogen deficiency were histomorphometrically examined with 120-day-old female Fischer rats. Sixty-four animals were either ovariectomized bilaterally (ovx) or subjected to sham surgery (sham), and eight from each group were killed at 7, 14, 30, and 60 days after surgery. Seven intact animals were killed on day 0. Before killing, tetracycline and calcein were administered to all animals. Following histological observation, bone histomorphometry of the mandibular condyle was done using a confocal laser scanning microscope and an image analyzer. The sampling site was divided into two regions for analysis: (1) a "subchondral region," formed by the region connected to cartilage; and (2) a "central region," formed by the region beneath the former. The changes in these two regions were analyzed separately. In the sham group's condyle, the bone volume of the subchondral and central regions increased with the passage of time, although the bone turnover became low. This bone gain could be due to the effects of growth and the mechanical stimulus by occlusal load. In the subchondral region of the ovx group's condyle, the bone volume decreased significantly at 7 days, but recovered to reach approximately the same value as the sham group from 14 days onward. In the central region of the ovx group's condyle, the bone volume was unchanged, but revealed a significantly lower value than that of the sham group at 60 days (p < 0.01). Thus, ovariectomy inhibited bone gain, which was observed in the sham group's condyle even though there was no bone loss. On the other hand, the trabecular separation in the ovx's condyle of both the subchondral and central regions increased considerably and small marrow cavities interconnected to form a large bone marrow. Therefore, the ovx rat mandibular condyles dynamically altered their structures under the effects of estrogen deficiency and occlusal loads. Consequently, estrogen deficiency induced transient subchondral bone loss and recovery, whereas, in the central region, it inhibited bone gain. This suggests that mechanical loading modulates the normal ovx-induced bone loss found in other parts of the skeleton.

Limitation of mouth opening, one of the symptoms of TMD, is commonly estimated by measuring the range of motion of the mandible (ROM). The values of ROM in previous studies show that ROM becomes smaller by fixation of the head while being recorded. Recently it has become obvious that the head postures, such as head extension, have a great effect on the stomatognathic function.In this study, we investigated the influence of head extension and body posture on ROM to find out the reliability of measured ROM as a diagnostic aid in TMD and the mechanism of mouth opening; and simultaneously, we observed the EMG activity of the anterior belly of digastric muscle (Da).The results were as follows:1. As the head was extended, the ROM increased significantly. It is considered that the space under the mandible increased by head extension enables wider mandibular movement. This suggests that more consideration should be given to the head posture to obtain accurate ROM records of individuals.2. The muscle activity of Da also increased significantly with head extended mouth opening. This confirms that Da plays an important role in mandibular rotation of maximum mouth opening.

This study examined relationships between starting points of head and mandibular movements in 11 female control subjects and 10 TMD patients showing disc displacement with reduction during consecutive open-close movements, using a six-degree-of-freedom measuring device. During the first mandibular opening cycle, in the TMD group, head movement was significantly preceded in relation to mandibular movement when compared with the control group, and major differences in onset were seen between maximum and minimal values at the beginning of mandibular movements. After the second cycle, significant differences in starting points were not evident. In TMD patients showing disc displacement with reduction, in the first cycle, at the commencement of opening movements, it is proposed that the head precedes the mandible in order to compensate for irregular condylar movements, and the degree of the condylar movement irregularity might affect the onset relation between the head and the mandible.

Heat treatment by superheated steam has been utilized in several industrial fields including sterilization, desiccation, and cooking. In particular, cooking by superheated steam is receiving increased attention because it has advantages of reducing the salt and fat contents in foods as well as suppressing the oxidation of vitamin C and fat. In this application, quick startup and cut-off responses are required. Most electrically energized steam generators require a relatively long time to generate superheated steam due to the large heat capacities of the water in container and of the heater. Zhao and Liao (2002) introduced a novel process for rapid vaporization of subcooled liquid, in which a low-thermal-conductivity porous wick containing water is heated by a downward-facing grooved heating block in contact with the upper surface of the wick structure. They showed that saturated steam is generated within approximately 30 seconds from room-temperature water at a heat flux 41.2 kW/m 2 . In order to quickly generate superheated steam of approximately 300°C, which is required for cooking, the heat capacity of the heater should be as small as possible and the imposed heat flux should be so high enough that the porous wick is able to dry out in the vicinity of the contact with the heater and that the resulting heater temperature becomes much higher than the saturation temperature. The present paper proposes a simple structured generator to quickly produce superheated steam. Only a fine wire heater is contacted spirally on the inside wall in a hollow porous material. The start-up, cut-off responses and the rate of energy conversion for input power are investigated experimentally. Superheated steam of 300°C is produced in approximately 19 seconds from room-temperature water for an input power of 300 W. The maximum rate of energy conversion in the steady state is approximately 0.9.

Cleft lip and palate patients show several characteristic clinical and functional findings, such as:a. Cross bite, open bite and unstable occlusion in ICP.b. Tight upper lip, midface retrusion and scar contracted vestibular sulcus.c. Malposition of teeth, oronasal fistula and velopharyngeal incompetence.d. Relapse of teeth and segment.To consider a prosthodontic therapy to be successful, two factors must be satisfied:1. Reconstruction for optimum occlusion: stable occlusion in ICP and anterior guidanceproviding harmonious jaw movement.2. Prosthesis must satisfy requests of esthetics, comfort, simplicity and durability.In this study, the clinical and prosthetic findings of 10 patients before and after prosthetictreatment were compared.Results:1. All patients were satisfied with the given prosthodontic treatment.2. In 2 patients, both factors were established.In 4 patients who had anterior malocclusion, stable occlusion in ICP was established, butoptimum anterior guidance was not.In 4 patients who had severe malocclusion, optimum occlusion was not established with oralreconstruction.3. Many patients who had upper malpositioned teeth, oronasal fistula, relapse of teeth andsegment showed that their prostheses were more complicated and larger.Therefore, we reconfirm that prosthodontists, oral surgeons and orthodontists must coordinate and discuss how to accomplish a successful rehabilitation of cleft lip and palate patients.

Objective The objective was to study the radiological and histologic changes in the mandibular cortices of ovariectomized monkeys. Study design Twelve female, adult, Cynomolgus monkeys ( Macaca fascicularis ) were used. Under anesthesia, 1 group was bilaterally ovariectomized (OVX), and the other (control group) underwent sham surgery. Seventy-six weeks after surgery, the monkeys were humanely killed, their mandibles were excised, and their mandibular inferior cortices (MIC) and adjacent cortices were examined histologically and with panoramic radiographs and micro computed tomography. Results Striped shadows were seen on the endosteal side of the OVX cortices on panoramic radiographs. Histologic observation revealed many enlarged pores with eroded surfaces and calcein labeling (indicating osteon remodeling) in the OVX cortices. Conclusions In the MIC and adjacent cortices of OVX monkeys, enlarged Haversian canals were seen and there were indications of a high rate of bone turnover. The enlarged Haversian canals resulted in striped shadows and unclear endosteal margins on radiographic images.

Epidemiological studies have shown that post-menopausal women who do not use an estrogen supplement have fewer teeth than those who do. We hypothesized that changes in the dentition of post-menopausal women might be due to alveolar bone alterations by estrogen deficiency. To clarify this, we analyzed the microstructural alveolar bone changes in ovariectomized monkeys and compared these with their lumbar bone mineral density. The % of baseline bone mineral density showed a significant decrease in the ovariectomized group as compared with the controls. The second-molar interradicular septa in ovariectomized monkeys showed a significantly decreased nodes number, cortices number, and an increased structural model index value. More pores were seen in the ovariectomized group at the top of the septa. This study demonstrated that, in such monkeys, estrogen deficiency led to fragility of the trabecular structure of the molar alveolar bone, and such fragility was inversely correlated with lumbar bone mineral density.

Most 3-dimensional (3D) finite element analyses (FEAs) simplify the cancellous bone to a block and completely ignore its trabecular structure. Thus, a 3D FEA was performed to compare the peri-implant stress distribution of a model in which the trabecular structure was accurately simulated (precise model) with that of a model with a homogenous cancellous bone component (simplified model). In contrast to the simplified model, the distribution patterns and higher stresses in the precise model may explain the overall bone resorption at the implant-bone interface in load-related implant failures. Further studies using data from the jawbone and a more detailed implant simulation are planned.

To clarify the relationship between estrogen deficiency and tooth loss, we analyzed the trabecular structural changes of mandibular alveolar bone in ovariectomized rats. Two months after ovariectomy, the bone resorptive activity remarkably accelerated and caused high bone turnover. On the other hand, one year after ovariectomy, bone loss and trabecular fragmentation occurred in the alveolar bone, although the accelerated degree of bone resorptive activity was moderate. If elderly women could experience similar changes on their alveolar bone, we must pay more attention to the bone resorption presently after menopause and the trabecular fragility long after menopause.

We investigated the ability of synchrotron radiation computed tomography (SR-CT) to demonstrate trabecular microstructure, detail of trabecular surfaces, and mineralization of bones. Eight rat vertebrae, six rat tibiae, and eight minipig vertebrae were scanned using SR-CT at the synchrotron radiation facility Super Photon ring-8GeV (SPring-8). Images obtained using conventional micro-CT, scanning electron microscopy (SEM), and contact microradiography (CMR) were compared with the SR-CT images. SR-CT showed high image quality without visible partial volume effect. Three-dimensional SR-CT revealed shallow concavities in the bone surface, which were considered to correspond to osteoclastic resorption areas, as well as the connectivity, anisotropy, and shape (rod- or platelike) of trabeculae. Two-dimensional SR-CT showed different density along the surface of the trabecular bone, indicating the degree of bone mineralization. In conclusion, SR-CT seems to be a useful tool for delineating trabecular surfaces, evaluating bone mineralization, and revealing precise trabecular structure.

The effects of estrogen deficiency on the mandible have been indicated; however, there have been only a few reports on the mandibular condyle. To clarify the region-specific changes of condyles following estrogen deficiency, we histomorphometrically studied the anterior and posterior regions of condyles in sham-operated (Sham) and ovariectomized (Ovx) female Fischer rats, since it has been reported that rat occlusal force loads mainly onto the anterior part of the condyle. The anterior and posterior regions of condyles showed significantly different bone dynamics. The bone volume in the anterior region of the Sham group increased to 79.9% with aging, but that of the posterior region remained at ca. 60%. In the Ovx group, the bone volume of the posterior region significantly declined to 42.7% until 60 days post-ovariectomy, although no changes occurred in the anterior region. As compared with the Sham counterparts, both regions of the Ovx group showed high bone turnover and revealed significantly low bone volume at 60 days (p < 0.01). Regional differences between anterior and posterior regions were more emphasized in the Ovx than in the Sham group. The osteoclast number and amount of eroded surface in the Ovx were higher in the posterior than in the anterior region, with significance at 30 and/or 60 days (p < 0.05). The mineralized surface at 14 days and the bone formation rate at 60 days in the Ovx posterior region were significantly lower than those in the Ovx anterior region (p < 0.05). Consequently, a net bone loss occurred in the posterior region of the mandibular condyle in ovariectomized rats, owing to region specificity and estrogen deficiency.

Intermittent administration of human parathyroid hormone (1-34) (PTH) increases bone mass in lumbar vertebrae and long bones of osteoporotic experimental animals. However, whether PTH has the same effect on jaw bones remains unclear. This study determined the effect of intermittent administration of PTH on rat mandibular condyle affected by estrogen deficiency. Fifty 6-month-old rats were either sham operated or ovariectomized, then divided into five groups depending on surgical procedure and hormone administration: sham + vehicle (SV), OVX + vehicle (OV), OVX + PTH 6 micrograms/kg once per week (OP6-1), OVX + PTH 60 micrograms/kg once per week (OP60-1), and OVX + PTH 20 micrograms/kg three times per week (OP20-3). PTH or vehicle was injected intermittently for 6 months in 5 rats of each group either immediately after surgery in a preventive administration experiment, or injected starting 6 months after surgery in a therapeutic administration experiment. The mandibles were excised, and bone morphometry was performed using confocal laser scanning microscopy and soft X-ray images. In both experiments, the bone volume of the OV groups was significantly lower than that of the SV group (P0.01); also, depending on dose and frequency, the bone volume of the OP group was higher than that of the OV group, particularly in the OP20-3 group. The value of mineralized surface of the OP groups was significantly higher than that of the OV group (P0.01), whereas the value of eroded surface of the OP groups was not significantly higher than that of the OV group. This study indicates that preventive and therapeutic intermittent administration of PTH in ovariectomized rats increase the bone formation in rat mandibular condyle without accelerating bone resorptive activity. This anabolic effect was best induced by the injection mode of 20 micrograms/kg three times per week.

Statement of problem. It is important for dentists to understand the effect of systemic hormonal change on the osseous oral structures. Purpose. This study examined the effect of aging and ovariectomy on rat mandibular condyle. Material and methods. Seventy-two 120-day-old female Fischer rats were killed at 7, 14, 30, and 60 days after bilateral ovariectomy or sham surgery. As the baseline control group, eight animals were killed on day 0 without surgeries. Changes in the bone mineral density and bone marrow area were detected through dual-energy x-ray absorptiometry and soft x-ray photography, respectively. Results. No significant difference of bone mineral density was found between the bilateral ovariectomy and sham surgery groups with dual-energy x-ray absorptiometry, probably because the thickness of cortical bone obscured any possible changes in trabecular bone. Age-related osteosclerotic changes were found in the sham group with soft x-ray photography. In contrast, the bilateral ovariectomy group showed little change in bone marrow area in relation to time course; on the other hand, the value of their bone marrow area became significantly larger than that of the sham surgery group from 14 days after ovariectomy onward. Conclusions. It was inferred that estrogen deficiency caused the significantly large marrow area found in the rat mandibular condyle. Although much more research is necessary, this study allowed us to speculate that osteoporotic changes may occur in the mandibular condyle of postmenopausal women. (J Prosthet Dent 1998;79:685-90.)

Although apparently phenotypically normal at birth, mice heterozygous for inactivation of the gene encoding parathyroid hormone-related peptide (PTHrP) develop haplotype insufficiency by 3 months of age. In addition to histologic and morphologic abnormalities similar to those seen in homozygous mutants, heterozygous animals demonstrated alterations in trabecular bone and bone marrow. These included metaphyseal bone spicules which were diminished in volume, irregularly distributed, and less well developed than those seen in age-matched controls as well as bone marrow, which contained an inordinate number of adipocytes. A substantial reduction in PTHrP mRNA was detected in heterozygous tissue, while circulating parathyroid hormone (PTH) and calcium concentrations were normal. Thus, while a physiologic concentration of PTH was capable of maintaining calcium homeostasis, it was incapable of compensating for PTHrP haploinsufficiency in developing bone. In normal animals, both PTHrP and the PTH/PTHrP receptor were expressed predominantly in chondrocytes situated throughout the proliferative zone of the tibial growth plate. In the metaphysis, the PTH/PTHrP receptor was identified on osteoblasts and preosteoblastic cells situated in the bone marrow, while PTHrP was expressed only by osteoblasts. These observations indicate that postnatal bone development involves susceptible pathways that display exquisite sensitivity to critical levels of PTHrP and imply that the skeletal effects of PTH are influenced by locally produced PTHrP. Moreover, identification of both the ligand and its N-terminal receptor in metaphyseal osteoblasts and their progenitors suggests an autocrine/paracrine role for the protein in osteoblast differentiation and/or function. Impairment in this function as a consequence of PTHrP haploinsufficiency may critically influence the course of bone formation, resulting in altered trabecular architecture and perhaps low bone mass and increased bone fragility.

The 13 C-NMR spectra of seven cavanine alkaloids isolated from Veratrum and Fritillaria plants were measured and their signals were assigned, and these results were applicated for structure elucidation of two new cevanine alkaloids, baimonidine and isoverticine, isolated from mature Fritillaria verticillata.

After acid hydrolysis of a glycosidic fraction from the aerial parts of Fritillaria camtschatcensis , in addition to solanidine, tomatidenol, and solasodine, two N -methyl-22,26-epiminocholestenes, hapepunine and anrakorinine, were isolated and their structures elucidated by physical and chemical methods.

Several characteristics of the sliding disintegration of Tetrahymena ciliary axonemes were found by turbidimetric assay, the ATP-regenerating system, and quantitative determination of the ATP concentration. At ATP concentrations exceeding 40 μM, the response in terms of turbidity was biphasic and could be divided into three phases. The dependence of each phase on ATP concentration was examined. The time duration of phase 2 increased with ATP concentration. When the ATP concentration was kept constant by the ATP-regenerating system, consisting of pyruvate kinase and phosphoenol pyruvate, the time duration of phase 2 increased with the concentration of phosphoenol pyruvate. On examining the change in turbidity with decreasing ATP concentration, the transition from phase 2 to phase 3 was found to occur at an ATP concentration of 40 μM. Dark-field and electron microscopy indicated the sliding disintegration to be closely correlated with the degree of tubidity. At phase 1, one or two doublets extruded from most of the axonemes, and disintegration failed to progress during phase 2. At the transition point from phase 2 to 3, at about 40 μM, ATP, other doublets were noted to extrude from the axonemes one after the other, causing turbidity to be minimal by the end of phase 3. The ATP concentration dependence of stepwise sliding disintegration suggests that each axoneme may possess the ability to regulate doublet microtubule sliding at lower or higher concentrations of ATP. In response to local differences or gradients of ATP concentration along the axoneme, the axonemes may cause localized sliding of doublets, thus subsequently generating active bending movement.