Pulsating aurora from electron scattering by chorus waves.

Auroral substorms, dynamic phenomena that occur in the upper atmosphere at night, are caused by global reconfiguration of the magnetosphere, which releases stored solar wind energy. These storms are characterized by auroral brightening from dusk to midnight, followed by violent motions of distinct auroral arcs that suddenly break up, and the subsequent emergence of diffuse, pulsating auroral patches at dawn. Pulsating aurorae, which are quasiperiodic, blinking patches of light tens to hundreds of kilometres across, appear at altitudes of about 100 kilometres in the high-latitude regions of both hemispheres, and multiple patches often cover the entire sky. This auroral pulsation, with periods of several to tens of seconds, is generated by the intermittent precipitation of energetic electrons (several to tens of kiloelectronvolts) arriving from the magnetosphere and colliding with the atoms and molecules of the upper atmosphere. A possible cause of this precipitation is the interaction between magnetospheric electrons and electromagnetic waves called whistler-mode chorus waves. However, no direct observational evidence of this interaction has been obtained so far. Here we report that energetic electrons are scattered by chorus waves, resulting in their precipitation. Our observations were made in March 2017 with a magnetospheric spacecraft equipped with a high-angular-resolution electron sensor and electromagnetic field instruments. The measured quasiperiodic precipitating electron flux was sufficiently intense to generate a pulsating aurora, which was indeed simultaneously observed by a ground auroral imager.

Oxygen torus and its coincidence with EMIC wave in the deep inner magnetosphere: Van Allen Probe B and Arase observations.

We investigate the longitudinal structure of the oxygen torus in the inner magnetosphere for a specific event found on 12 September 2017, using simultaneous observations from the Van Allen Probe B and Arase satellites. It is found that Probe B observed a clear enhancement in the average plasma mass (M) up to 3-4 amu at L = 3.3-3.6 and magnetic local time (MLT) = 9.0 h. In the afternoon sector at MLT ~ 16.0 h, both Probe B and Arase found no clear enhancements in M. This result suggests that the oxygen torus does not extend over all MLT but is skewed toward the dawn. Since a similar result has been reported for another event of the oxygen torus in a previous study, a crescent-shaped torus or a pinched torus centered around dawn may be a general feature of the O+ density enhancement in the inner magnetosphere. We newly find that an electromagnetic ion cyclotron (EMIC) wave in the H+ band appeared coincidently with the oxygen torus. From the lower cutoff frequency of the EMIC wave, the ion composition of the oxygen torus is estimated to be 80.6% H+, 3.4% He+, and 16.0% O+. According to the linearized dispersion relation for EMIC waves, both He+ and O+ ions inhibit EMIC wave growth and the stabilizing effect is stronger for He+ than O+. Therefore, when the H+ fraction or M is constant, the denser O+ ions are naturally accompanied by the more tenuous He+ ions, resulting in a weaker stabilizing effect (i.e., larger growth rate). From the Probe B observations, we find that the growth rate becomes larger in the oxygen torus than in the adjacent regions in the plasma trough and the plasmasphere.

Effect of dasatinib in a xenograft mouse model of canine histiocytic sarcoma and in vitro expression status of its potential target EPHA2.

Canine histiocytic sarcoma (HS) is an aggressive and highly metastatic tumor. Previously, the kinase inhibitor dasatinib was shown to have potent growth inhibitory activity against HS cells in vitro, possibly via targeting the EPHA2 receptor. Here, the in vivo effect of dasatinib in HS cells was investigated using a xenograft mouse model. Moreover, the expression status of EPHA2 was examined in six HS cell lines, ranging from insensitive to highly sensitive to dasatinib. In the HS xenograft mouse model, dasatinib significantly suppressed tumor growth, as illustrated by a decrease in mitotic and Ki67 indices and an increase in apoptotic index in tumor tissues. On Western blot analysis, EPHA2 was only weakly detected in all HS cell lines, regardless of sensitivity to dasatinib. Dasatinib likely results in the inhibition of xenograft tumor growth via a mechanism other than targeting EPHA2. The findings of this study suggest that dasatinib is a targeted therapy drug worthy of further exploration for the treatment of canine HS.

Selective growth inhibition by suppression of F1Fo ATPase in canine malignant melanoma cell lines.

Canine malignant melanoma (CMM) is a highly aggressive and fatal neoplasm. To identify potential therapeutic compounds and/or targets, 320 compounds were screened for their growth inhibitory activity in a CMM line (CMM-1) using a chemical library known to target specific signaling pathways/cell growth-related molecules. Among the compounds screened, the F1Fo ATPase inhibitor oligomycin showed potent growth inhibitory effects in CMM-1 cells, while exhibiting less toxic effects in a non-neoplastic control cell line (MDCK cells). The growth inhibitory effect of oligomycin A was then examined using six CMM lines and MDCK cells. Three CMM lines were highly sensitive to oligomycin A, with around 3000-20 000 times lower IC50 compared with oligomycin A-resistant CMM lines and MDCK cells. Oligomycin A-sensitive CMM-1 cells exhibited much greater oligomycin A-induced decreases in cellular ATP compared to oligomycin A-resistant cell lines. Although the oligomycins are clinically unsuitable because of its in vivo toxicity, these findings implicate the potential of F1Fo ATPase as a therapeutic target in a subset of CMM.

Collaborative Research Activities of the Arase and Van Allen Probes.

This paper presents the highlights of joint observations of the inner magnetosphere by the Arase spacecraft, the Van Allen Probes spacecraft, and ground-based experiments integrated into spacecraft programs. The concurrent operation of the two missions in 2017-2019 facilitated the separation of the spatial and temporal structures of dynamic phenomena occurring in the inner magnetosphere. Because the orbital inclination angle of Arase is larger than that of Van Allen Probes, Arase collected observations at higher L -shells up to L ∼ 10 . After March 2017, similar variations in plasma and waves were detected by Van Allen Probes and Arase. We describe plasma wave observations at longitudinally separated locations in space and geomagnetically-conjugate locations in space and on the ground. The results of instrument intercalibrations between the two missions are also presented. Arase continued its normal operation after the scientific operation of Van Allen Probes completed in October 2019. The combined Van Allen Probes (2012-2019) and Arase (2017-present) observations will cover a full solar cycle. This will be the first comprehensive long-term observation of the inner magnetosphere and radiation belts.

Association between Sarcopenia, Its Defining Indices, and Driving Cessation in Older Adults.

OBJECTIVES: Driving a car is essential for older adults to support their activities of daily living and maintain their quality of life. However, physical function - which often declines with age - is a key factor to determine whether older adults can continue driving safely. As such, we sought to examine the association between sarcopenia and driving cessation in older adults. DESIGN: A prospective study. SETTING: A community setting. PARTICIPANTS: We conducted a study including 2,874 older adult participants from the community (mean age: 71.0 ± 4.7 years [range: 65-93 years], women: 36.3%). MEASUREMENTS: We assessed whether they were still driving at baseline examination as well as their degree of sarcopenia. Sarcopenia was assessed according to the clinical definition provided by the EWGSOP2 by measuring muscle mass, muscle strength, and physical performance represented by gait speed. Driving cessation was determined based on driving status at the initial visit and at a follow-up examination approximately 15 months later. RESULTS: At the baseline assessment, there were 62 participants (2.2%) with confirmed sarcopenia and 23 participants (0.8%) with severe sarcopenia. Participants were classified into either the ongoing driving (n = 2816) or driving cessation (n = 58) group. Low muscle strength and low muscle mass were associated with driving cessation (low muscle strength: odds ratio [OR] 2.09, 95% confidence interval [CI] 1.13-3.87; low muscle mass: OR 2.00, 95% CI 1.04-3.85). Slow gait was not associated with driving cessation (OR 1.35, 95% CI 0.68-2.69). Significantly, sarcopenia was associated with driving cessation (confirmed sarcopenia: OR 4.48, 95% CI 1.63-12.29; severe sarcopenia: OR 4.46, 95% CI 1.21-16.41). CONCLUSIONS: Sarcopenia is associated with an increased likelihood of driving cessation in community-dwelling older adults. Evaluation of physical function related to sarcopenia would be useful for judgment of the ability to drive safely among older adults.

Penetration of MeV electrons into the mesosphere accompanying pulsating aurorae.

Pulsating aurorae (PsA) are caused by the intermittent precipitations of magnetospheric electrons (energies of a few keV to a few tens of keV) through wave-particle interactions, thereby depositing most of their energy at altitudes ~ 100 km. However, the maximum energy of precipitated electrons and its impacts on the atmosphere are unknown. Herein, we report unique observations by the European Incoherent Scatter (EISCAT) radar showing electron precipitations ranging from a few hundred keV to a few MeV during a PsA associated with a weak geomagnetic storm. Simultaneously, the Arase spacecraft has observed intense whistler-mode chorus waves at the conjugate location along magnetic field lines. A computer simulation based on the EISCAT observations shows immediate catalytic ozone depletion at the mesospheric altitudes. Since PsA occurs frequently, often in daily basis, and extends its impact over large MLT areas, we anticipate that the PsA possesses a significant forcing to the mesospheric ozone chemistry in high latitudes through high energy electron precipitations. Therefore, the generation of PsA results in the depletion of mesospheric ozone through high-energy electron precipitations caused by whistler-mode chorus waves, which are similar to the well-known effect due to solar energetic protons triggered by solar flares.

Cognitive Frailty as a Risk Factor for Incident Disability During Late Life: A 24-Month Follow-Up Longitudinal Study.

OBJECTIVES: Association between cognitive frailty as identified by a new operational definition and incident disability in the community setting remains unclear. This will be the catalyst for preventive interventions designed to treat adverse health problems among elderlies. DESIGN: A 24-month follow-up longitudinal study on a community-based cohort. SETTING: Community-setting. PARTICIPANTS: Participants included a total of 9,936 older adults aged 65 years or older. MEASUREMENTS: Frailty was characterized as slow walking speed or/and muscle weakness represented by grip strength. Cognitive function was assessed according to several tests. Cognitive impairment was defined below the age-education reference threshold. Participants were categorized into the four groups: robust, cognitive impairment alone, frailty alone, and cognitive frailty (both frail and cognitive impairment). Incident disability data was extracted from the Japanese Long-Term Care system. RESULTS: The prevalence of cognitive frailty was 11.2%. The cumulative incidence rates of incident disability in each group were also estimated (robust, 9.6/1,000 person-years (95% CI 7.9 to 11.7); cognitive impairment, 21.3/1,000 person years (95% CI 16.3 to 27.7); frailty, 45.4/1,000 person years (95% CI 39.5 to 52.3); and cognitive frailty, 79.9/1,000 person years (95% CI 68.6 to 93.1)). Adjusted Cox proportional hazard model revealed that the cognitive frailty group had the highest hazard ratio (HR 3.86, 95%CI 2.95 - 5.05, P < 0.001). CONCLUSIONS: A proper operational definition was developed to determine cognitive frailty among elderlies. Cognitive frailty is more associated with incident disability in community-setting than cognitive impairment or physical frailty alone.

Multiple time-scale beats in aurora: precise orchestration via magnetospheric chorus waves.

The brightness of aurorae in Earth's polar region often beats with periods ranging from sub-second to a few tens of a second. Past observations showed that the beat of the aurora is composed of a superposition of two independent periodicities that co-exist hierarchically. However, the origin of such multiple time-scale beats in aurora remains poorly understood due to a lack of measurements with sufficiently high temporal resolution. By coordinating experiments using ultrafast auroral imagers deployed in the Arctic with the newly-launched magnetospheric satellite Arase, we succeeded in identifying an excellent agreement between the beats in aurorae and intensity modulations of natural electromagnetic waves in space called "chorus". In particular, sub-second scintillations of aurorae are precisely controlled by fine-scale chirping rhythms in chorus. The observation of this striking correlation demonstrates that resonant interaction between energetic electrons and chorus waves in magnetospheres orchestrates the complex behavior of aurora on Earth and other magnetized planets.

Canine squamous cell carcinoma cell lines with high expression of survivin are sensitive to survivin inhibitor YM155.

Treatment of unresectable canine squamous cell carcinoma (SCC) remains challenging and new therapeutic strategies are needed. Survivin is a member of the inhibitor of apoptosis protein family and its inhibitor, YM155, is a potential anti-tumour agent. In the present study, 10 canine tumour cell lines (representing eight different tumour types) were screened for sensitivity to YM155; the drug potently inhibited the growth of the HAPPY SCC cell line. The growth inhibitory properties of YM155 were then examined in more detail using a panel of seven SCC cell lines. YM155 inhibited the growth of the cell lines HAPPY and SQ4; in contrast to the other lines in the panel, these two cell lines had high levels of expression of survivin. In HAPPY cells, YM155 inhibited expression of the survivin gene at the transcriptional level. In contrast, YM155 down-regulated survivin at the post-transcriptional level in SQ4 cells. YM155 suppressed cell growth in HAPPY cells, mostly via induction of apoptosis, but this was not the case in SQ4 cells. Two canine SCC cell lines with high cellular expression of survivin were sensitive to YM155. The possible underlying mechanisms of the cytotoxic effect of YM155 in these cell lines were different. One cell line had down-regulation of survivin mRNA and protein expression, associated with induction of apoptotic cell death. The other cell line had post-transcriptional down-regulation of survivin expression and subsequent induction of non-apoptotic cell death. Targeting survivin with YM155 is a potential approach for the treatment of canine SCCs with high expression of survivin.

Moyamoya disease. Posterior cerebral artery occlusion and pattern-reversal visual-evoked potential.

Although vascular abnormality in moyamoya disease predominates in the anterior and middle cerebral arteries, the posterior cerebral artery (PCA) has been found to be involved in the course of the disease. To explore PCA occlusion by noninvasive means, we studied visual-evoked potentials in the patients with PCA occlusion (occlusive group), as well as in those without PCA occlusion (nonocclusive group). The results were compared with those of other examinations that also detected an occipital lobe pathologic condition. Abnormalities of those examinations were highly specific to PCA occlusion. Positron emission tomography and pattern-reversal visual-evoked potentials yielded high incidence of abnormality in the occlusive group (86% and 75%, respectively), and expressed the side of PCA occlusion if the occlusion was unilateral. Since pattern-reversal visual-evoked potentials is popular and a low-cost examination compared with positron emission tomography, we conclude that pattern-reversal visual-evoked potentials is the most practical mean to explore PCA occlusion in the course of moyamoya disease.

Hodgkin's disease expressing follicular dendritic cell marker CD21 without any other B-cell marker: a clinicopathologic study of nine cases.

Reed-Sternberg (RS) and Hodgkin's (H) cells are considered to be the neoplastic cells in Hodgkin's disease (HD). Although most data suggest their lymphoid origin, the nature of these cells still remains a subject of controversy. Recently, a number of RS cells have been found to express an antigen that is also present on follicular dendritic cells (FDCs), asserting FDCs as the possible progenitor cells of H-RS cells. This prompted us to investigate whether these CD21-positive cases had distinct clinicopathologic characteristics. In a series of 94 examined cases of HD, we identified 9 CD21-positive ones (4 of 37 cases of nodular sclerosis, 1 of 41 mixed cellularity, and 4 of 12 lymphocyte depletion HD) without any other B-cell marker on paraffin sections. The patients varied in age from 16 to 82 years (median, 50 years) and included six men and three women. They had superficial or mesenteric lymphadenopathy without hepatosplenomegaly. Peripheral blood leukocytosis was seen in three patients. The clinical course was indolent, and all patients but one achieved an initial complete response with HD-based treatment regimens, although three of them relapsed. Morphologically, two subgroups could be delineated. Six of the cases were characterized, besides by the classic RS cells, by a varying number of the cells with the distinctive walnutlike or cerebrumlike nuclei and cytologically with cytoplasmic processes. Their fine structural examination also revealed villous processes, but no desmosomes. The other three cases had multinucleated RS cells often with triangular nuclei, but not cytoplasmic processes. The percentage of CD21-positive tumor cells ranged from less than 10% to 60% among the H-RS cells. These RS cells were positive for CD30 (9 of 9), CD15 (7 of 9), CD68 (1 of 8), fascin (8 of 8), S-100 protein (1 of 7), and epithelial membrane antigen (2 of 8) on paraffin sections. Notably, of eight cases examined on frozen sections, two showed immunostaining for DRC1, CD35, R4/23, and Ki-M4p. Only CD35 was also detected in the other two cases. Genotypic investigation showed germline configuration of the T-cell receptor beta and gamma chain genes and the immunoglobulin heavy chain gene in all eight cases examined. In situ hybridization showed Epstein-Barr virus sequences in four cases, three of which were examined by the terminal region analysis and showed the Epstein-Barr virus to be monoclonal. We concluded that in a small proportion (9.6%) of HD, H-RS cells might be derived from FDCs and that they appear to represent a distinct pathologic variant based on morphologic and phenotypic traits within the framework of HD.

Nodal cytotoxic lymphoma spectrum: a clinicopathologic study of 66 patients.

The expression of cytotoxic granule-associated proteins has been reported in some T-cell or natural killer (NK)-cell lymphomas of mostly extranodal origin, but rarely of nodal origin except for anaplastic large cell lymphoma (ALCL) and Hodgkin's disease (HD). This study analyzed 66 nodal lymphomas expressing T-cell intracellular antigen-1 (TIA-1) and/or granzyme B to characterize the clinicopathologic spectrum of these neoplasms. Four main groups could be delineated. The first group consisted of p80/anaplastic lymphoma kinase (ALK)-positive ALCL (n = 35). The patients were 2 to 62 years of age (median age, 16 years), and the lymphomas pursued a relatively indolent clinical course. The tumors were phenotypically of either T- or null-cell type with constant expression of CD30, epithelial membrane antigen (EMA), and p80/ALK, but not CD15 or BCL2. None harbored Epstein-Barr virus (EBV). The second group consisted of peripheral T/NK-cell lymphoma, the nodal high-grade cytotoxic type (n = 13). The patients were 29 to 72 years in age (median age, 55 years), and the tumors pursued an aggressive clinical course. The tumors often showed pleomorphic, anaplastic, or centroblastoid morphology, and were featured by either EBV association or CD56 expression. The third group consisted of peripheral T-cell lymphoma, of the nodal low-grade cytotoxic type (n = 8). The patients, three men and five women, were 31 to 75 years old (median age, 61 years). Notably, six of them exhibited lymphoepithelioid (Lennert's) lymphoma. The fourth group consisted of cytotoxic Hodgkin's-like ALCL/HD (n = 10), included seven cases of Hodgkin's-like ALCL and three cases of HD, and was characterized by the presence of Reed-Sternberg cells and often the CD15+ phenotype. The patients were all men except for one woman, and they ranged in age from 24 to 84 years (median age, 62 years). The link among these four groups was reinforced by the presence of a highly characteristic large cell with horseshoelike or reniform nuclei-the frequent expression of CD30 and EMA-and the often lack of T-cell receptor-alphabeta. In this series, the expression of p80/ALK and CD56 was also associated with favorable and poor prognoses respectively (p<0.001, log-rank test).

Mediastinal diffuse large cell lymphoma of B-cell type with azurophilic granules.

A case of diffuse large cell lymphoma of B-cell type with unusual azurophilic granules is reported. Lymphoma occurred primary in the upper anterior mediastinum and was suggested to be of thymic origin. Histologically, lymphoma cells showed diffuse proliferation and were large in size, frequently with multilobulated nuclei. In imprint preparations stained by May-Giemsa, most lymphoma cells had basophilic cytoplasm with azurophilic granules. Cytochemical studies showed the granules to be negative for PAS, peroxidase, acid phosphatase, and beta-glucuronidase. Electron-dense granules and electron-lucent granules were found on ultrastructural analysis. The cells were characterized as B-cell type by immunophenotypes of L26+, CD20+, CD21-, CD22+, and PCA1+, the possession of surface monotypic IgA kappa immunoglobulin, and a genotype of immunoglobulin heavy and kappa light chain gene rearrangements.

Location of the preepiglottic space and its relationship to the paraglottic space.

An investigation was carried out to determine the location of the preepiglottic space (PES) and its relationship to the paraglottic space (PGS). Excised human adult larynges served as materials for this study. The distribution of the PES of the larynx was determined histologically in 3 whole organ serial sections: sagittal, horizontal, and coronal. The results are summarized as follows. 1) The PES exists not only anterior, but also posterolateral and inferolateral to the epiglottis. 2) Its posterior end is located in the vicinity of the anteroposterior midpoint of the thyroid lamina. 3) The PES is adjacent to the PGS posteroinferiorly and is separated by fibrous tissue (the thyroglottic ligament). Posterosuperiorly, the 2 spaces are not clearly delineated from each other.

Histopathologic study of carcinoma of the hypopharynx: implications for conservation surgery.

A total of 38 specimens obtained by laryngopharyngectomy were subjected to a whole organ section study. Of the 38, 31 were pyriform sinus (PS), three were postcricoid (PC), and four were posterior wall (PW) carcinomas. The results were as follows. 1) The thyroid cartilage was involved much more frequently than the other laryngeal cartilages. 2) Joint involvements were infrequent. 3) The interarytenoid, thyroarytenoid, and lateral cricoarytenoid muscles frequently were invaded by PS carcinomas, whereas PC carcinomas frequently involved the interarytenoid and posterior cricoarytenoid muscles. 4) The recurrent laryngeal nerve (RLN) was involved in all PC T3 cases, but RLN involvement was rare in PS cases. 5) Involvements of the paraglottic space and periarytenoid region were closely related to fixation of the larynx on the affected side (hemilarynx) in PS carcinomas. 6) Neither hemilarynx fixation nor PS apex involvement was a reliable landmark for determining the exact extent of laryngeal involvement. 7) Conservation surgery could have been employed in 18 of the 38 cases.

Vocal function following hemilaryngectomy.

Vocal function following hemilaryngectomy was investigated in 54 cases in which a superiorly based sternohyoid muscle flap was used for glottic reconstruction. Four types of material were employed for covering the muscle flap: hypopharyngeal mucosa, lip mucosa, thyroid perichondrium, and island cervical skin flap. The vocal function varied greatly from individual to individual; however, the following tendencies were observed in many cases: 1) the glottis did not close completely; 2) supraglottic structures (false fold, arytenoid region, and epiglottis) were hyperfunctional and vibrated instead of or together with the unaffected vocal fold; 3) vibrations of the laryngeal structures were irregular; 4) maximum phonation time was short; 5) mean airflow rate was high; 6) fundamental frequency and intensity ranges of phonation were limited; 7) the voice was rough, breathy, and/or strained; and 8) cases with poor vocal function were most frequent in the skin flap group and least frequent in the lip mucosa group.

Deglutition following supraglottic horizontal laryngectomy.

In order to determine factors that may contribute to deglutition problems following supraglottic horizontal laryngectomy or its modified techniques, clinical records of 38 patients were studied. Contribution of the following factors was investigated: age; sex; tumor classification; radical neck dissection; extent of and symmetry in removal of the aryepiglottic folds, arytenoid cartilages, and false folds; removal of the base of the tongue, hyoid bone, and a part of the vocal folds; extent of removal of the epiglottis and thyroid cartilage; cricopharyngeal myotomy; and some complications and concomitant diseases. The results suggest that removal of the arytenoid cartilage and asymmetrical removal of the false folds contribute to deglutition problems. We conclude that the standard supraglottic horizontal laryngectomy associated with surgical approximation of the larynx to the base of the tongue and cricopharyngeal myotomy does not usually cause serious deglutition problems. When the arytenoid cartilage is removed, reconstruction of the structure is required for the prevention of severe aspiration.

Posterior glottis. Morphological study in excised human larynges.

Two sets of investigations were conducted with excised human larynges. The glottis was closely observed and photographed from above and below in three conditions: neutral, adduction, and abduction. The structure surrounding the posterior glottis was histologically investigated in the same three conditions. The results are as follows. The structure surrounding the posterior glottis consists of three portions: the posterior wall of the glottis, the lateral wall of the posterior glottis, and the cartilaginous portion of the vocal fold. During vocal fold adduction, the posterior part of the larynx closes completely not at the glottis but at the supraglottis, resulting in formation of a conic space in the posterior glottis that can be viewed only from below. The posterior glottis accounts for approximately 35% to 45% of the entire glottic length and 50% to 65% of the entire glottic area. The mucosa of the posterior glottis has ciliated epithelium. The lamina propria consists of two layers. The posterior glottis can be regarded as a respiratory glottis.

Distribution of elastic cartilage in the arytenoids and its physiologic significance.

An investigation of the distribution of the elastic cartilage in the arytenoids was performed on excised human adult and newborn larynges. The distribution of elastic cartilage in the arytenoids was investigated histologically in two serial sections: horizontal and coronal. The behavior of the elastic cartilage portion of the arytenoids was investigated histologically under the conditions of adduction and abduction. The results are summarized as follows. 1) Elastic cartilage is found not only at the tip of the vocal process but at the superior portion of the arytenoid cartilage from the vocal process to the apex. 2) This phenomenon is observed at birth. 3) The vocal process bends at the elastic cartilage portion during adduction and abduction. The sides of the arytenoids come into contact mainly at the elastic cartilage portion. 4) Elastic cartilage appears to play an important role in the physiologic functioning of the arytenoid.