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Many studies have focused on the stabilization of additive manufacturing (AM) in microgravity for its use in various space projects. Nevertheless, this paper presents a vital clue for innovating metal AM technologies from the perspective of high gravity. High-gravitational powder bed fusion has an excellent potential to address various challenges in AM, such as density enhancement, spatter suppression, and precise fabrication. This study summarizes an analogy among phenomena in different gravitational fields and establishes a combined machine for centrifuge and powder bed fusion. The results confirm the spatter suppression and fine-powder availability in high gravity, both theoretically and experimentally.

We present a rare case of synchronous mucinous borderline tumor of the ovary and low-grade appendiceal mucinous neoplasm (LAMN). We performed a left adnexectomy to diagnose the left ovarian borderline malignancy and an ileostomy because of the swollen appendix during the operation. It was diagnosed as left ovarian mucinous borderline malignancy and LAMN. LAMN causes peritoneal dissemination, ovarian metastasis, and peritoneal pseudomyxoma. The appendix and ovary are close to each other anatomically and can metastasize if there is a tumor in either. For ovarian mucinous tumors, it is necessary to search the gastrointestinal tract, especially the appendix, as the primary lesion. For appendix tumors, it is necessary to search for the ovary. Since LAMN may be associated with borderline ovarian malignancies, as in this case, there is a possibility of the duplication of tumors when searching for ovarian mucinous tumors as the primary tumor and if ovarian tumors are found. Since LAMN and mucinous ovarian tumors have similar histological features, immunohistochemical staining is useful for their differentiation because they show different immunostaining patterns.

Using powder-based directed energy deposition (DED), composite materials can easily be produced by mixing powders. In this study, a foam stainless block is fabricated through DED by combining SUS316L and titanium-hydride (TiH2) powders together. Although TiH2 successfully foams the melt pool and leaves many pores inside the deposit, it is difficult to enhance the porosity rate because the porous structure is destroyed when the upper layer is deposited. This study demonstrates a laser power control and deposition trajectory that can be used to create a low-density porous structure and measures the compression strength of the fabricated block.

Ultrasound-guided oocyte retrieval is a standard procedure for ovum pick up (OPU) during in vitro fertilization. Possible complications include tubo-ovarian abscesses (TOAs) in the fallopian tubes, and endometriosis may be associated with increasing the severity of pelvic infection. A 35-year-old woman who had been treated for infertility and endometriosis presented with abdominal pain that appeared several days after OPU. There were no significant changes in the size of both ovaries and fallopian tubes. A week later, transvaginal echography revealed right oviduct enlargement. Because conservative treatment with antibiotics before this revelation had not been successful, laparoscopy was performed for abscess drainage and/or excision of the adnexa. Intraoperative findings were an abscess in the right adnexa involving the ovary and fallopian tube. Preservation of the right fallopian tube was difficult due to the risk of prolonged infection, and a right appendectomy was performed. The diagnosis was a right TOA. Severe cases of pelvic infection after OPU may cause infertility. The presence of endometriosis may aggravate the infection, but the relationship between the extent of the endometriosis and the severity of the infection is not known. Even if the endometriosis is mild, as it was in this patient, surgical treatment should be considered if a severe infection occurs after OPU and conservative treatment is not effective.

Fusobacterium nucleatum (Fn) is generally an opportunistic oral pathogen that adheres to mammalian mucosal sites, triggering a host inflammatory response. In general, Fn is normally found within the human oral cavity; however, it was previously reported that Fn is a risk factor for certain respiratory diseases. Surprisingly, this was never fully elucidated. Here, we investigated the virulence potential of heat-killed Fn on primary human tracheal, bronchial, and alveolar epithelial cells. In this study, we measured the secretion of inflammatory- (IL-8 and IL-6), stress- (total heme and hydrogen peroxide), and cell death-related (caspase-1 and caspase-3) signals. We established that the inflammatory response mechanism varies in each epithelial cell type: (1) along tracheal cells, possible Fn adherence would trigger increased heme secretion and regulated inflammatory response; (2) along bronchial cells, potential Fn adherence would simultaneously initiate an increase in secreted H2O2 and inflammatory response (ascribable to decreased secreted heme amounts); and (3) along alveolar cells, putative Fn adherence would instigate the increased secretion of inflammatory responses attributable to a decrease in secreted heme levels. Moreover, regardless of the epithelial cell-specific inflammatory mechanism, we believe these are putative, not harmful. Taken together, we propose that any potential Fn-driven inflammation along the respiratory tract would be initiated by differing epithelial cell-specific inflammatory mechanisms that are collectively dependent on secreted heme.

Directed energy deposition (DED), an additive manufacturing process, is a suitable approach for freeform production with metallic materials. By generating a melt pool with a high-power laser beam, injected material powder is contentiously laminated on a baseplate by melting and solidifying. Although all supplied powder should be molten and solidified in order to reduce the material waste, powder distribution is difficult to converge owing to turbulence around the melt pool. Furthermore, an inappropriate powder supply easily leads to sputter generation, which also increases the material waste. In this study, the gas flow under a powder nozzle was analyzed by a computational fluid dynamics (CFD) simulation in order to achieve a high convergence in the powder supply. By measuring the powder distribution with a laser light sheet system and conducting deposition tests, the powder distribution and supply efficiency were experimentally evaluated. According to a gas-solid multiphase-flow simulation, the convergence distance of the powder flow should be shorter than the laser beam focus distance to improve the powder convergence with a lower gas-flow rate. Moreover, the powder nozzles were redesigned by taking the simulation results into consideration, and deposition tests were conducted to evaluate the powder supply efficiency, porosity rate, and penetration rate. The experimental result of the designed nozzle shows a clear improvement in the powder supply efficiency from 50.2 to 66.0%.

Directed energy deposition (DED), which is one of additive manufacturing processes applicable to metals, is suitable to produce a large-scale complex-shaped part in aerospace and automobile industries. However, mechanical characteristics in a DED-produced part often varies according to the thermal conduction at each deposition point. To ensure quality uniformity in a DED-produced part, a cooling process also should be actively performed to control the thermal condition. This study evaluates variation in crystal structure in parts produced with DED applying a coolant system. By performing the cooling process at certain intervals during deposition, the variations in Vickers hardness and crystal structure are effectively suppressed in DED of Inconel 625.

Background/aim Human chronic periodontitis is a major health problem. Although some oral bacteria have been reported to be putative pathogens, Epstein-Barr virus (EBV) is reported to be associated with the progression of periodontitis. However, the role of EBV in the aetiology of periodontitis is unknown. Therefore, we investigated periodontal pathogenesis of EBV to confirm whether EBV-encoded latent membrane protein 1 (LMP1) induces Interleukin-8 (IL8) production in human gingival cells. Materials and methods Real-time polymerase chain reaction, luciferase assay, enzyme-linked immunosorbent assay (ELISA), and western blotting were performed for determining IL8 mRNA expression, nuclear factor kappa B (NF-ĸB) transcription, IL8 production, and the phosphorylation of NF-ĸB p65 and Inhibitor of kappa B alpha (IĸBα), respectively, in Ca9-22 human gingival epithelial cells. Two LMP1 mutants lacking C-terminal activating region (CATR) domains responsible for activating NF-ĸB were used. Results Extremely high IL8 production was induced by LMP1 in time- and dose-dependent manner, where simultaneous phosphorylation of NF-κB p65 and IĸBα and transcription of NF-ĸB were observed. On the contrary, IL8 production and NF-ĸB transcription were drastically inhibited by dominant negative mutant of IĸBα. Moreover, the LMP1 mutants failed to induce IL8 production. Conclusion Our findings suggest that due to CATR domains, LMP1 contributes to the progression of periodontitis via IL8 production attributable to NF-ĸB activation.

Direct energy deposition (DED) is one of additive manufacturing processes, which achieves high production efficiency by supplying material powder and irradiating high-power laser beam to a baseplate at the same time. Furthermore, the DED has a potential to produce a functional material by blending various material powders. Although a metal foam structure is well-known because of its beneficial functionality such as light-weight, the complicated foaming process requires a special equipment and long processing time. This paper proposes a simple fabrication method for metal foam structure by applying a blowing agent into DED. Metal foam structure can be produced by foaming the meltpool with titanium hydride which releases hydrogen in a high temperature environment. The proposed method certainly produces a foam structure in stainless steel by blending titanium hydride powder into stainless powder for DED.

Directed energy deposition is an additive manufacturing process which produces deposits by irradiating laser beam on the baseplate and supplying material powder to the meltpool. Although the material powder is generally conveyed with carrier-gas flow, the powders diffuse and some of them do not reach to the meltpool. In order to suppress the waste of materials, the particle movement should be analyzed and modified not only from the viewpoint of deposition conditions but also the nozzle design. Against this background, this paper presents analytical and measurement results of powder distribution under the nozzle and proposes a nozzle design to reduce the waste of material powder based on a gas-solid multiphase-flow simulation. The experimental result of designed nozzle certainly shows high powder supply efficiency of 74.8%, whereas that of the conventional nozzle is 52.6%.

Direct energy deposition (DED) is a metal additive manufacturing process that involves the application of a large amount of heat energy, which generates a thermal gradient across the deposited part. This usually results in unexpected anisotropy and weakening of the deposited part due to residual pours. These problems need to be solved to ensure satisfactory results when using DED. This study led to the proposal of a simple heat treatment procedure for DED-produced parts in the form of a remelting process, which controls the metal crystal orientation and eliminates residual pours. The use of a high-power laser for remelting certainly obtained high-density metal structures with high hardness.

This paper presents a sensor-less on-line chatter detection method for a turning process by introducing a mechanical energy factor (MEF) and a mechanical power factor (MPF). The MEF and MPF serve as indexes for self-excited chatter and forced chatter, respectively. The indexes are based on the power-factor theory, which generally represents the electrical-power efficiency as having a correlation with the phase difference between the current and the voltage. By applying this theory to a mechanical system, the MEF and MPF can be employed to monitor the phase difference between the cutting force and the displacement/velocity of the tool system, respectively. By monitoring the phase difference, chatter vibration can be detected in time domain with a high response and small number of computations. The MEF and MPF can be calculated without using additional external sensors employing the sensor-less cutting-force estimation technique based on the disturbance observer. The monitoring performance of the proposed method was evaluated through several outside turning tests with a prototype precision lathe. The results showed that both the self-excited and forced chatters were successfully detected with unique thresholds, which did not depend on the cutting condition or the workpiece material.

Additive manufacturing is a technology that enables mass customization of products owing to its flexibility and is one of the key technologies used in Internet-of-Things-based manufacturing systems. In recent years, industrial applications of additive manufacturing have been increasing, and expanding into space manufacturing. However, the controllability of gravitational acceleration has not been well explored. In this study, a high-gravitational powder bed fusion system is developed, which produces a high-gravitational field via the application of centrifugal acceleration. It is evident that the powder bed quality is improved, and the spatter generation is dramatically suppressed on applying a high gravitational acceleration of up to 10+ G. The experimental evaluations demonstrate that a high gravitational field improves the surface quality, density, and hardness of the fabricated parts.

Background/Aim: Epstein-Barr virus (EBV) associates with human chronic periodontitis (CP) progression. We previously demonstrated that butyric acid (BA), produced by periodontopathic bacteria, induced EBV lytic switch activator BZLF1 expression. We investigated whether short chain fatty acids (SCFAs) in CP patients’ saliva enabled EBV reactivation. Materials and Methods: Saliva was collected from seven CP patients and five periodontally healthy individuals. SCFAs were quantified using HPLC. BZLF1 mRNA and its pertinent protein ZEBRA were determined with Real-time PCR and western blotting. Histone H3 acetylation (AcH3) was further examined. Results: BZLF1 mRNA expression and transcriptional activity in EBV-infected Daudi cells were induced only when treated with the CP saliva. Among SCFAs, BA alone correlated significantly with the BZLF1 transcription (r=0.88; p< 0.02). As expected, CP patients’ saliva induced AcH3. Conclusion: BA in saliva may play a role in EBV reactivation and hence contribute to EBV-related disease progression in CP patients.

Epstein-Barr virus (EBV) is associated with several disorders. EBV is known to modulate the proliferation and survival of hematopoietic cells such as B cells and T cells in human. However, the effects of EBV on hematopoiesis itself have not been investigated. To study EBV infection in murine models, their hematopoiesis must be humanized, since EBV infection is limited only in primates. To engraft the human hematopoiesis, NOD/Shi-scid-IL2rγnull (NOG) mice were used. Usually, the hematopoiesis humanized mice reconstitute only lymphoid cells, but myeloid cells are not. However, we revealed human macrophages (hMφ) and their precursor monocytes were increased in peripheral tissues of EBV-infected mice. Furthermore, our previous report indicated Mφ accumulation in spleen was essential for development of EBV-positive tumors, suggesting that EBV modulates human hematopoiesis in order to thrive. Interestingly, we revealed a dramatic increase of immature granulocytes only in bone marrow of EBV-infected mice. In addition, GM-CSF, a cytokine that is essential for differentiation of the myeloid lineage, was significantly increased in EBV-infected mice. These results were also reproduced in patients with EBV-related disorders. We suggest that the hematopoietic alterations during EBV-infection might contribute immune suppression to the development and exacerbation of EBV-related disorders.

Sapphire is an attractive engineering material for the cover glass of smartphones and wristwatches because of its high hardness and resistance to corrosion, wear, and heat. However, the high rate of tool wear and brittle chippings around the holes are serious problems associated with drilling sapphire. To enhance the accuracy and efficiency of the drilling process on sapphire, this paper presents a novel tool-path strategy using helical milling along with various tool path patterns. Experimental results show that the proposed method successfully reduces brittle chippings around the holes.