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Electron microscopy determination of crystallographic polarity of aluminum nitride thin films

Kuwano N, Kaur J, Rahmah S

Micron, 2019 01;116:80-83.
PMID: 30321742 DOI: 10.1016/j.micron.2018.09.014

Aluminum nitride (AlN) crystallizes usually in the wurtzite structure (P63mc) and it has a crystallographic polarity. In this work, the polarity in AlN was characterized by using several methods of transmission electron microscopy (TEM) in order to examine their applicability. AlN was deposited by metalorganic vapor phase epitaxy (MOVPE), followed by annealing at 1550 °C. TEM samples were prepared by using a focused ion beam (FIB) mill. Observation was performed with microscopes of JEM-2100, JEM-ARM200 F and FEI Titan Cubed G2 at Kyushu University (Japan), and the following results were obtained. (1) Conventional TEM imaging: Under a diffraction condition with hkil = 0002, inversion domains or an inversion domain boundary (IDB) was observed. (2) Scanning TEM (STEM) High-Angle Annular Dark Field (HAADF) imaging: Even when atomic column images of Al and N are not resolved completely from each other, the polarity was determined from the shape of atomic column images. (3) Scanning moire fringe imaging: The moire fringe pattern indicated the position of IDB and determine the direction of polarity. (4) Convergent beam electron diffraction (CBED): CBED was applicable for determination of the polarity in AlN at the acceleration voltage of 120 kV. Hence the polarity, direction of polarity and inversion domain boundary was determined using advanced TEM methods.
Fulltext Physicochemical characterization and rheological properties of magnetic elastomers containing different shapes of corroded carbonyl iron particles

Burhannuddin NL, Nordin NA, Mazlan SA, Aziz SAA, Kuwano N, Jamari SKM, et al.

Sci Rep, 2021 Jan 13;11(1):868.
PMID: 33441824 DOI: 10.1038/s41598-020-80539-z

Carbonyl iron particles (CIPs) is one of the key components in magnetic rubber, known as magnetorheological elastomer (MRE). Apart from the influence of their sizes and concentrations, the role of the particle' shape is pronounced worthy of the attention for the MRE performance. However, the usage of CIPs in MRE during long-term applications may lead to corrosion effects on the embedded CIPs, which significantly affects the performance of devices or systems utilizing MRE. Hence, the distinctions between the two types of MRE embedded in different shapes of spherical and plate-like CIPs, at both conditions of non-corroded and corroded CIPs were investigated in terms of the field-dependent rheological properties of MRE. The plate-like shape was produced from spherical CIPs through a milling process using a rotary ball mill. Then, both shapes of CIPs individually subjected to an accelerated corrosion test in diluted hydrochloric (HCl) at different concentrations, particularly at 0.5, 1.0, and 1.5 vol.% for 30 min of immersion time. Eight samples of CIPs, including non-corroded for both CIPs shapes, were characterized in terms of a morphological study by field emission scanning electron microscope (FESEM) and magnetic properties via vibrating sample magnetometer (VSM). The field-dependent rheological properties of MREs were analyzed the change in the dynamic modulus behavior of MREs via rheometer. From the application perspective, this finding may be useful for the system to be considered that provide an idea to prolong the performance MRE by utilizing the different shapes of CIPs even when the material is fading.
Fulltext Green Synthesis of Magnetite (Fe3O4) Nanoparticles Using Seaweed (Kappaphycus alvarezii) Extract

Yew YP, Shameli K, Miyake M, Kuwano N, Bt Ahmad Khairudin NB, Bt Mohamad SE, et al.

Nanoscale Res Lett, 2016 Dec;11(1):276.
PMID: 27251326 DOI: 10.1186/s11671-016-1498-2

In this study, a simple, rapid, and eco-friendly green method was introduced to synthesize magnetite nanoparticles (Fe3O4-NPs) successfully. Seaweed Kappaphycus alvarezii (K. alvarezii) was employed as a green reducing and stabilizing agents. The synthesized Fe3O4-NPs were characterized with X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-Vis), Fourier transform infrared (FT-IR), and transmission electron microscopy (TEM) techniques. The X-ray diffraction planes at (220), (311), (400), (422), (511), (440), and (533) were corresponding to the standard Fe3O4 patterns, which showed the high purity and crystallinity of Fe3O4-NPs had been synthesized. Based on FT-IR analysis, two characteristic absorption peaks were observed at 556 and 423 cm(-1), which proved the existence of Fe3O4 in the prepared nanoparticles. TEM image displayed the synthesized Fe3O4-NPs were mostly in spherical shape with an average size of 14.7 nm.
Fulltext Plasma acetylcholine and nicotinic acid are correlated with focused preference for photographed females in depressed males: an economic game study

Kubo H, Setoyama D, Watabe M, Ohgidani M, Hayakawa K, Kuwano N, et al.

Sci Rep, 2021 01 26;11(1):2199.
PMID: 33500434 DOI: 10.1038/s41598-020-75115-4

Interpersonal difficulties are often observed in major depressive disorder (MDD), while the underlying psychological and biological mechanisms have not yet been elucidated. In the present case-control study, a PC-based trust game was conducted for 38 drug-free MDD patients and 38 healthy controls (HC). In the trust game, participants invested money in a partner (trusting behaviors), and also rated each partner's attractiveness (preference for others). In addition, blood biomarkers including metabolites were measured. Both MDD and HC males exhibited more trusting behaviors compared to females. MDD males' preference for ordinary-attractive partners (lay-person photographs) was lower than HC males, whereas their preference for high-attractive females (fashion-model photographs) was similar levels to HC males. This tendency in MDD males could reflect a "focused (narrowed) preference for females". As for blood biomarker analysis, the levels of 37 metabolites including acetylcholine, AMP, GMP, nicotinic acid and tryptophan were significantly different between two groups. Interestingly, among male participants, acetylcholine and nicotinic acid were negatively correlated with the level of focused preference for photographed females. In sum, we have revealed some behavioral, psychological and biological traits of trusting behaviors and preference for others especially in MDD males. Larger studies should be conducted to validate our preliminary findings.
Fulltext Development and validation of the 22-item Tarumi's Modern-Type Depression Trait Scale: Avoidance of Social Roles, Complaint, and Low Self-Esteem (TACS-22)

Kato TA, Katsuki R, Kubo H, Shimokawa N, Sato-Kasai M, Hayakawa K, et al.

Psychiatry Clin Neurosci, 2019 Aug;73(8):448-457.
PMID: 30900331 DOI: 10.1111/pcn.12842

AIM: Understanding premorbid personality is important, especially when considering treatment selection. Historically, the premorbid personality of patients with major depression in Japan was described as Shuchaku-kishitsu [similar to Typus melancholicus], as proposed by Shimoda in the 1930s. Since around 2000, there have been increased reports in Japan of young adults with depression who have had premorbid personality differing from the traditional type. In 2005, Tarumi termed this novel condition 'dysthymic-type depression,' and more recently the condition has been called Shin-gata/Gendai-gata Utsu-byo [modern-type depression (MTD)]. We recently developed a semi-structured diagnostic interview to evaluate MTD. Development of a tool that enables understanding of premorbid personality in a short time, especially at the early stage of treatment, is desirable. The object of this study was to develop a self-report scale to evaluate the traits of MTD, and to assess the scale's psychometric properties, diagnostic accuracy, and biological validity.
METHODS: A sample of 340 participants from clinical and community settings completed measures. Psychometric properties were assessed with factor analysis. Diagnostic accuracy of the MTD traits was compared against a semi-structured interview.
RESULTS: The questionnaire contained 22 items across three subscales, thus we termed it the 22-item Tarumi's Modern-Type Depression Trait Scale: Avoidance of Social Roles, Complaint, and Low Self-Esteem (TACS-22). Internal consistency, test-retest reliability, and convergent validity were all satisfactory. Among patients with major depression, the area under the curve was 0.757 (sensitivity of 63.1% and specificity of 82.9%) and the score was positively correlated with plasma tryptophan.
CONCLUSION: The TACS-22 possessed adequate psychometric properties and diagnostic accuracy in an initial sample of Japanese adults. Additional research on its ability to support clinical assessment of MTD is warranted.
Fulltext Blood biomarkers of Hikikomori, a severe social withdrawal syndrome

Hayakawa K, Kato TA, Watabe M, Teo AR, Horikawa H, Kuwano N, et al.

Sci Rep, 2018 02 13;8(1):2884.
PMID: 29440704 DOI: 10.1038/s41598-018-21260-w

Hikikomori, a severe form of social withdrawal syndrome, is a growing social issue in Japan and internationally. The pathophysiology of hikikomori has not yet been elucidated and an effective treatment remains to be established. Recently, we revealed that avoidant personality disorder is the most common comorbidity of hikikomori. Thus, we have postulated that avoidant personality is the personality underpinning hikikomori. First, we herein show relationships between avoidant personality traits, blood biomarkers, hikikomori-related psychological features, and behavioural characteristics assessed by a trust game in non-hikikomori volunteers. Avoidant personality traits were negatively associated with high-density lipoprotein cholesterol (HDL-C) and uric acid (UA) in men, and positively associated with fibrin degeneration products (FDP) and high sensitivity C-reactive protein (hsCRP) in women. Next, we recruited actual individuals with hikikomori, and compared avoidant personality traits, blood biomarkers, and psychological features between individuals with hikikomori and age-matched healthy controls. Individuals with hikikomori had higher avoidant personality scores in both sexes, and showed lower serum UA levels in men and lower HDL-C levels in women compared with healthy controls. This is the first report showing possible blood biomarkers for hikikomori, and opens the door to clarify the underlying biological pathophysiology of hikikomori.