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Flip angle (FA) measurements using the actual flip angle imaging (AFI) method may induce significant errors in ultrahigh fields. We aimed to develop a method for detecting errors in FA measurements using phase information at 7 tesla. We performed computer simulations to elucidate the relationship between the FA calculation errors and the phase difference between the two AFI source images. We then examined whether a method based on the phase difference could detect FA calculation errors and determine the prescribed nominal FA of the scanner for accurate measurements in phantoms and healthy volunteers. The simulations confirmed that the calculated FA values erroneously decreased when the longitudinal magnetization and phase in one of the source images were inverted. Tests on phantoms and human subjects demonstrated that the phase difference information between the source images with a cut-off of 90° could readily detect FA calculation errors in the AFI method.

Differentiation between multiple system atrophy (MSA) and other spinocerebellar degenerations showing cerebellar ataxia is often difficult. Hence, we investigated whether magnetic resonance diffusion kurtosis imaging (DKI) could detect pathological changes that occur in these patients and be used for differential diagnosis.Thirty-six subjects (12 patients with MSA accompanied by predominant cerebellar ataxia [MSA-C], 10 patients with spinocerebellar ataxias [SCAs] or sporadic adult-onset ataxia of unknown etiology [SAOA], and 14 healthy controls) were examined using 1.5- or 3-T magnetic resonance scanners. From the DKI data, the mean kurtosis, fractional anisotropy, and mean diffusivity values of the pontine crossing tract (PCT), middle cerebellar peduncle, and cerebellum were automatically measured, and the ratios against the values of the corpus callosum were calculated.We found significant decreases in mean kurtosis and fractional anisotropy ratios in the PCT and middle cerebellar peduncle, and a significant increase in the mean diffusivity ratio in the PCT in the MSA-C group, as compared with the SCA/SAOA and control groups (p0.027-0.001). Among these metrics, there were no significant differences in the diagnostic performance. By contrast, the ratios in the cerebellum showed no significant differences between the MSA-C and SCA/SAOA groups but were significantly altered when compared with the controls (p0.001).Quantitative DKI analyses can be used to differentiate between patients with MSA-C and those with SCA/SAOA.

Several qualitative features distinguish bipedal from quadrupedal locomotion in mammals. In this study we show quantitative differences between quadrupedal and bipedal gait in the Japanese monkey in terms of gait patterns, trunk/hindlimb kinematics, and electromyographic (EMG) activity, obtained from 3 macaques during treadmill walking. We predicted that as a consequence of an almost upright body axis, bipedal gait would show properties consistent with temporal and spatial optimization countering higher trunk/hindlimb loads and a less stable center of mass (CoM). A comparatively larger step width, an ~9% longer duty cycle, and ~20% increased relative duration of the double-support phase were all in line with such a strategy. Bipedal joint kinematics showed the strongest differences in proximal, and least in distal, hindlimb joint excursions compared with quadrupedal gait. Hindlimb joint coordination (cyclograms) revealed more periods of single-joint rotations during bipedal gait and predominance of proximal joints during single support. The CoM described a symmetrical, quasi-sinusoidal left/right path during bipedal gait, with an alternating shift toward the weight-supporting limb during stance. Trunk/hindlimb EMG activity was nonuniformally increased during bipedal gait, most prominently in proximal antigravity muscles during stance (up to 10-fold). Non-antigravity hindlimb EMG showed altered temporal profiles during liftoff or touchdown. Muscle coactivation was more, but muscle synergies less, frequent during bipedal gait. Together, these results show that behavioral and EMG properties of bipedal vs. quadrupedal gait are quantitatively distinct and suggest that the neural control of bipedal primate locomotion underwent specific adaptations to generate these particular behavioral features to counteract increased load and instability. NEW & NOTEWORTHY Bipedal locomotion imposes particular biomechanical constraints on motor control. In a within-species comparative study, we investigated joint kinematics and electromyographic characteristics of bipedal vs. quadrupedal treadmill locomotion in Japanese macaques. Because these features represent (to a large extent) emergent properties of the underlying neural control, they provide a comparative, behavioral, and neurophysiological framework for understanding the neural system dedicated to bipedal locomotion in this nonhuman primate, which constitutes a critical animal model for human bipedalism.

OBJECTIVES Nasal passages adjust the temperature of inhaled air to reach the required body temperature for the lungs. The nasal regions of primates including humans are believed to have experienced anatomical modifications that are adaptive to effective conditioning of the atmospheric air in the habitat for a given species. Measurements of the nasal temperature are required to understand the air-conditioning performance for a given species. Unfortunately, repeated direct measurements within the nasal passage have been technically precluded in most nonhuman primates. MATERIALS AND METHODS Computational fluid dynamics (CFD) simulation is a potential approach for examining the temperature profile in the nasal passage without any direct measurements. The CFD simulation model mainly comprises a computational model to simulate physiological mechanisms and a wall model to simulate the nasal passage's anatomical and physical properties. We used a computational model developed for humans and examined corrections for the developed wall model based on human properties for predicting its performance in Japanese macaques. RESULTS This study confirmed that the epithelium layer thickness of the wall model affects the accuracy of the predictions for macaques. A convenient correction of the thickness based on body mass allows us to simulate the actual air temperature profile in macaques' nasal passage. DISCUSSION The CFD simulations of the wall model corrected with body mass can be applied to other nonhuman primates and mammals. This convenient corrective approach allows us to examine the functional contributions of a specific morphology to the air-conditioning performance without any direct measurements to improve our understanding of primates' functional morphology and physical adaptations to the temperature environment in their habitat.

There was an error published in [Journal of Experimental Biology (2015) 218, 2394-2401][1] ([doi:10.1242/jeb.118059][2]). The authors mistakenly transposed the citations of two references on p. 2400 in the Materials and Methods. The corrected text before equations 12 and 13 should read: ‘The

Cerebrovascular reactivity (CVR) to acetazolamide (ACZ) on single-photon emission computed tomography (SPECT) can be used to assess the severity of chronic cerebral ischemia; however, this is an invasive method. We examined whether whole-brain magnetic resonance angiography (MRA) at 7T could non-invasively detect impaired CVR in patients with chronic cerebral ischemia by demonstrating the leptomeningeal collaterals (LMCs).Fifty-seven patients with symptomatic unilateral cervical stenosis underwent whole-brain time-of-flight MRA at 7T and cerebral perfusion SPECT before/after the ACZ challenge. MRA images were visually assessed based on 6-point grading systems to evaluate the development of LMCs toward the middle cerebral artery (MCA) and antegrade flow of MCA. CVR of the affected side was calculated from the SPECT data. Subsequently, we compared the LMC grades on MRA with CVR on SPECT.CVR was significantly lower in grades ≥ 2 of LMCs than in grades 0-1 (P 0.05) when applying LMCs from the anterior cerebral artery (ACA) and/or posterior cerebral artery (PCA). These differences were more evident than those in the grading of the antegrade MCA flow. The LMC grades from ACA/PCA readily detected reduced CVR (18.4%) with a sensitivity/specificity of 0.79/0.82.The development of LMCs on whole-brain MRA at 7T can non-invasively detect reduced CVR with a high sensitivity/specificity in patients with unilateral cervical stenosis.

In stroke patients, muscle tone on the unaffected side is often increased during voluntary tasks. This is known as a mirror movement and might be an impediment to function recovery, but its neural background is still unclear. In this study, we investigated the effect of unilateral muscle hypertonia on ipsilateral cortical activity and contralateral motor function. Fourteen right-handed healthy young subjects lifted a weight of 10% body weight with the right upper limb to increase muscle tone (weight task), while no weight lifting was set as the control 'nonweight' task. We recorded the motor-evoked potential (MEP), resting motor threshold and H-reflex from the left flexor carpi radialis muscle during both tasks. To estimate the functional effect of the weight task, subjects performed the 'Purdue pegboard test', consisting of examination for 30 seconds (peg-30) and assembly for 60 seconds (peg assembly). Left-hand grip strength was also measured. When subjects performed the weight task, the MEP amplitude increased significantly and the MT decreased significantly. There was no significant difference of H-reflex amplitude between the two tasks. No significant difference of the peg-30 score was observed between weight and nonweight tasks, but the peg assembly score was significantly lower during the weight task. Grip strength showed a significant increase during the weight task. These results indicate that the present weight load model may have the potential to advance our understanding of the mechanisms underlying mirror movements after stroke.

Background The severity of chronic cerebral ischemia can be assessed using cerebrovascular reactivity (CVR) to acetazolamide (ACZ) challenge, which is measured by single-photon emission computed tomography (SPECT); however, this is an invasive method. We investigated whether intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) can assess impaired CVR in preoperative patients with chronic cerebral ischemia and compared it to SPECT-CVR. Methods Forty-seven patients with unilateral cervical carotid artery stenosis underwent diffusion-weighted MRI with 11 b-values in the range of 0–800 s/mm2 and cerebral perfusion SPECT with the ACZ challenge. The perfusion fraction (f) and diffusion coefficient (D) of the IVIM parameters were calculated using a bi-exponential model. The f and D values and these ratios of the ipsilateral middle cerebral artery territory against the contralateral side were compared with the CVR values of the affected side calculated from the SPECT data. Results The IVIM-f and D values in the affected side were significantly higher than those in the unaffected side (median: 7.74% vs. 7.45%, p = 0.027; 0.816 vs. 0.801 10−3mm2/s, p Conclusion The IVIM perfusion parameter, f, can noninvasively assess impaired CVR with high sensitivity and specificity in patients with unilateral cervical carotid artery stenosis.

The short-term joint immobilization induces a decrease of corticospinal excitability; however, detailed time course of the immobilization-induced central nervous system changes and their extent have not yet been clarified. To evaluate the time course of changes in corticospinal excitability during forearm/hand immobilization for 24 h and investigate the effect on muscle strength, adhesive casting tape was used to immobilize the nondominant forearm/hand. The amplitude of the motor-evoked potential of the flexor pollicis brevis muscle induced by transcranial magnetic stimulation was measured during immobilization and after cast removal. The muscle strength was evaluated after the termination of immobilization. The resting motor-evoked potential recorded from flexor pollicis brevis muscle showed a significant decrease 3 h after initiation of immobilization and gradually declined further until the end of immobilization. It then increased over 2 h after cast removal, but was still significantly below baseline. However, no significant difference from baseline was observed at 3 h. Both pinch power and integrated electromyogram were significantly reduced by immobilization, and then gradually returned to baseline after the cast was removed. These results indicate that short-term forearm/hand immobilization rapidly reduces corticospinal excitability, and this change is rapidly reversed after resumption of movement.

Background and Purpose— The oxygen extraction fraction (OEF) is an effective metric to evaluate metabolic reserve in chronic ischemia. However, OEF is considered to be accurately measured only when using positron emission tomography (PET). Thus, we investigated whether OEF maps generated by magnetic resonance quantitative susceptibility mapping (QSM) at 7 Tesla enabled detection of OEF changes when compared with those obtained with PET. Methods— Forty-one patients with chronic stenosis/occlusion of the unilateral internal carotid artery or middle cerebral artery were examined using 7 Tesla-MRI and PET scanners. QSM images were obtained from 3-dimensional T2*-weighted images, using a multiple dipole-inversion algorithm. OEF maps were generated based on susceptibility differences between venous structures and brain tissues on QSM images. OEF ratios of the ipsilateral middle cerebral artery territory against the contralateral side were calculated on the QSM-OEF and PET-OEF images, using an anatomic template. Results— The OEF ratio in the middle cerebral artery territory showed significant correlations between QSM-OEF and PET-OEF maps ( r =0.69; P r =0.79; P =0.004), although showing significant systematic biases for the agreements. An increased QSM-OEF ratio of >1.09, as determined by receiver operating characteristic analysis, showed a sensitivity and specificity of 0.82 and 0.86, respectively, for the substantial increase in the PET-OEF ratio. Absolute QSM-OEF values were significantly correlated with PET-OEF values in the patients with increased PET-OEF. Conclusions— OEF ratios on QSM-OEF images at 7 Tesla showed a good correlation with those on PET-OEF images in patients with unilateral steno-occlusive internal carotid artery/middle cerebral artery lesions, suggesting that noninvasive OEF measurement by MRI can be a substitute for PET.

Objective To investigate the correlation between changes of contralesional cortical excitability evaluated by transcranial magnetic stimulation (TMS) and functional recovery in patients with hemiparetic stroke. Methods Eight inpatients (mean age: 75.9±13.8 years) with mild to moderate hemiparesis were enrolled. TMS was delivered to the optimal scalp position over the contralesional (ipsilateral to the paresis) primary motor cortex (M1) to activate the unaffected flexor carpi radialis muscle (FCR) while the patient picked up a wooden block with the affected hand. The amplitude of the motor-evoked potential (MEP) was measured and then was divided by the resting MEP amplitude (MEP ratio). For evaluation of motor function, we tested grip strength (GS), performed the upper extremity motor section of the Fugl-Meyer Assessment (FMA-UE), and performed the Purdue Pegboard Test (PPT) when the patients were admitted to our hospital (T1) and 2 months after admission (T2). Results The MEP ratio was significantly decreased at the second examination. The partial correlations between the MEP ratio and FMA-UE at T1, and PPT of an affected hand at T2 were observed while controlling for the period after stroke onset as the confounding variable. Conclusion The reduction of contralesional cortical hyperactivity is related to the functional recovery in part, but not related with the period after stroke onset. This suggests that enhanced reduction of contralesional M1 hyperactivity contributes to functional recovery after stroke.

Purpose The Bayesian estimation algorithm improves the precision of bolus tracking perfusion imaging. However, this algorithm cannot directly calculate Tmax, the time scale widely used to identify ischemic penumbra, because Tmax is a non-physiological, artificial index that reflects the tracer arrival delay (TD) and other parameters. We calculated Tmax from the TD and mean transit time (MTT) obtained by the Bayesian algorithm and determined its accuracy in comparison with Tmax obtained by singular value decomposition (SVD) algorithms. Methods The TD and MTT maps were generated by the Bayesian algorithm applied to digital phantoms with time-concentration curves that reflected a range of values for various perfusion metrics using a global arterial input function. Tmax was calculated from the TD and MTT using constants obtained by a linear least-squares fit to Tmax obtained from the two SVD algorithms that showed the best benchmarks in a previous study. Correlations between the Tmax values obtained by the Bayesian and SVD methods were examined. Results The Bayesian algorithm yielded accurate TD and MTT values relative to the true values of the digital phantom. Tmax calculated from the TD and MTT values with the least-squares fit constants showed excellent correlation (Pearson's correlation coefficient = 0.99) and agreement (intraclass correlation coefficient = 0.99) with Tmax obtained from SVD algorithms. Conclusions Quantitative analyses of Tmax values calculated from Bayesian-estimation algorithm-derived TD and MTT from a digital phantom correlated and agreed well with Tmax values determined using SVD algorithms.

Supplemental Digital Content is available in the text., Background and Purpose— The frictional force because of blood flow may dislodge masses present on the surface of a plaque. Such frictional force is calculated as wall shear stress (WSS) using computational fluid dynamics. The aims of the present study were to determine whether, in addition to carotid plaque intensity on T1-weighted magnetic resonance (MR) imaging, WSS calculated using computational fluid dynamics analysis for carotid arteries is associated with development of an embolism during exposure of carotid arteries during carotid endarterectomy. Methods— One hundred patients with internal carotid artery stenosis (≥70%) underwent carotid plaque imaging with MR, and 54 patients with a vulnerable plaque (intraplaque hemorrhage or lipid/necrotic core) displayed as a high-intensity lesion underwent additional cervical 3-dimensional MR angiography. The maximum value of WSS within the most severe stenotic segment of the internal carotid artery was calculated using MR angiography. Transcranial Doppler monitoring of microembolic signals (MES) in the ipsilateral middle cerebral artery was performed during carotid endarterectomy. Results— Although none of the 46 patients with a nonvulnerable carotid plaque had MES during exposure of carotid arteries, 24 of the 54 patients with a vulnerable carotid plaque (44%) had MES. Logistic regression analysis showed that higher plaque intensity (P=0.0107) and higher WSS (P=0.0029) were significantly associated with the development of MES. When both cutoff points of plaque intensity and WSS in the receiver operating characteristic curves for predicting development of MES were combined, specificity (from 63% to 93%) and positive predictive value (from 66% to 90%) became greater than those for plaque intensity alone. Conclusions— In addition to carotid plaque intensity on T1-weighted MR imaging, WSS calculated using computational fluid dynamics analysis for carotid arteries is associated with development of an embolism during exposure of carotid arteries during carotid endarterectomy.

We compared the time-course of satellite cell (SC) activation between eccentric and concentric contractions in the vastus lateralis (VL) muscle after step exercise. Young adults participated in a 30-min step up/down exercise which mainly involved concentric contractions with the right VL muscle and eccentric contractions with the left VL muscle. The concentric and eccentric contraction phases of the VL muscles were identified by changes in the electromyogram (EMG) and knee joint angle. Biopsy samples were taken from both VL muscles at three time periods: before the exercise and 2 and 5 days after the exercise. We found that the numbers of SCs were significantly increased in the type IIa fibers of the left VL at 2 and 5 days after the exercise. The expression of both hepatocyte growth factor (HGF) and myogenic differentiation 1 (MyoD) mRNA had significantly increased in the left VL at 2 and 5 days after the exercise and in the right VL at 5 days after the exercise. The expression of transient receptor potential canonical (TRPC) 1 mRNA also increased in the left VL at 2 days after exercise. These results indicate that eccentric contraction can effectively activate SC proliferation for up to 5 days after exercise. Similar changes in HGF, MyoD and TRPC1 mRNA expression suggest that HGF/c-Met signal activation through cation influx has a major impact on skeletal muscle SC activation in response to eccentric exercise.

BACKGROUND: Stent placement is thought to obstruct the inflow of blood to an aneurysm. However, we introduced parent artery expansion and demonstrated that this may reduce the blood flow by the stent. In our previous study using idealized shapes, the results showed that flow reduction was greater than 22.2%, even if the expansion rate was only 6%. Furthermore, the parent artery expansion is predominantly caused by the effect of flow reduction as compared to that of flow reduction due to the obstruction of flow under stent placement. However, a realistic shape is complex and the blood flow also becomes complex flow. It is not understood whether the results of flow in the idealized shape are reflective of flow from a realistic 3D model. Therefore, we examined the effect of parent artery expansion using a realistic model. OBJECTIVE: The aim is to clarify the effects of parent artery expansion on inflow rate, wall shear stress, and oscillatory shear index.METHODS: We used a patient-specific geometry of a human internal carotid artery with an aneurysm. The geometry of parent artery expansion due to oversized stent constructed based on the voronoi diagram. We performed calculations in the unsteady-state situations using constructed models. RESULTS: The complexity of the flow in the aneurysm decreases in case of expanded parent artery. The inflow rate decreases by 33.6% immediately after parent artery expansion alone without a stent. The effect of the parent artery expansion on flow reduction is larger than that of the obstruction flow by stent placement. In addition, wall shear stress and oscillatory shear index on the aneurysm wall decrease by change in blood flow due to the parent artery expansion. CONCLUSION: The effects of the parent artery expansion in a realistic aneurysm model with different stent lengths were evaluated on the basis of a numerical simulation. Although the flow was complex, the parent artery expansion with stent reduces the inflow to the aneurysm and wall shear stress and oscillatory shear index on the aneurysm. Therefore, we suggest that changes in the blood flow because of the parent artery expansion may be identified and, sometimes, is more effective than the obstruction flow due to the stent placement.

In order to e xecute various finite-difference method applications on large-scale parallel computers with a reasonable cost of computer resources, a framework using an adaptive mesh refinement (AMR) technique has been developed. AMR can realize high -resolution simulations while saving computer resources by generating and removing hierarchica l grids dynamically. In the AMR frame work, a dynamic domain decomposition (DDD) technique, as a dynamic load balancing method, is also implemented to correct the computational load imbalance between each process associated with parallelization. By performing a 3D AM R test simulation, it is confirmed that dynamic load balancing can be achieved and execution time can be reduced by introducing the DDD technique.

Background: Infarcts in the lateral striate artery (LSA) territory can be caused by several pathological changes, including lipohyalinosis and microatheroma. However, fluid dynamic effects on these changes remain unknown. Thus, we investigated whether the fluid dynamic metrics of the LSAs were altered in patients with acute ischemic stroke using computational fluid dynamics (CFD) analysis. Methods: Fifty-one patients with acute ischemic stroke confined in the basal ganglia and/or corona radiata underwent high-resolution magnetic resonance angiography (HR-MRA) at 7T. We performed CFD analyses to obtain indices including the wall shear stress (WSS), WSS gradient (WSSG), and flow velocity (FV) and compared these values between the ipsilesional and contralesional sides in the patients with infarcts in the LSA or non-LSA territories. Results: In patients with LSA-territory infarcts, the WSS, WSSG, and FV values were significantly lower in the ipsilesional LSAs than in the contralesional LSAs (P = .01-.03), while these values in the proximal middle cerebral arteries showed no significant lateralities. In contrast, in patients with non-LSA-territory infarcts, there were no significant lateralities in the metrics between the ipsilesional and contralesional sides. Conclusions: The CFD analyses using HR-MRA revealed significantly low WSS and WSSG values of the ipsilesional LSAs compared with that of the contralesional side in patients with LSA-territory infarcts, suggesting that fluid dynamic factors of LSAs can be one of the risk factors for LSA-territory infarctions.

Knowing the detailed responses associated with the environment of our closest living relative allows us to comprehend more data about apes which may be useful to conclude hypotheses regarding the behavior of early hominins. The difference between humans and apes toward the adaptability to the living environment is caused by the difference among both bodies’ biological functions such as the nasal cavity biological function. Indeed, the temperature and the humidity of the inhaled air are adjusted by the heat and the water exchange in the nasal cavity wall's surface. In order to understand the nasal cavity functions for the adjustment of the temperature and the humidity of the inhaled air, it is necessary to know the flow distribution during breathing process. To do so, a noninvasive measurement is hard to be held. Therefore, this study simulates a laminar steady airflow, in a realistic adult male chimpanzee's nasal cavity shape reconstructed from Computed Tomography (CT) images, using CFD. So far, an airflow study related to chimpanzee's nasal cavity has not been previously reported. We present for the first time a computer simulation of a realistic chimpanzee's nasal cavity flow. This study uses a model with heat and humidity transport. The governing equations include a continuum equation and the equations describing momentum, energy, and water transport. The findings are in agreement with the expected results directly inferred from the biological function of the nasal cavity itself.

Bipedal (Bp) locomotion is one of the most characteristic motor behaviors in human beings. Innate quadrupedal (Qp) four-legged animals also often walk bipedally. The walking posture, however, is significantly different between the two. This suggests that although both have a potential to walk bipedally, however, the human has a body scheme suitable for Bp locomotion, probably its skeletal system. The skeletal system includes the lumbar lordosis, sacral kyphosis, a round pelvis, a large femur neck angle, short feet, and so on. To verify this hypothesis, we compared kinematic and EMG activities between rats and humans during Qp and Bp locomotion on a treadmill belt. The rat is a representative Qp animal, but it is able to acquire Bp walking capability with motor learning. Although the mobile ranges of the hindlimb joint are different during each locomotor pattern between rats and humans, both showed replicable flexion and extension excursion patterns for each joint depending on the locomotor phase. There are many phase-locked EMG bursts between rats and humans during the same walking task and these are observed in the proximal rather than the distal muscles. This suggests that both rats and humans utilize similar neuronal systems for the elaboration of Qp and Bp locomotion. It was interesting that both subjects showed more muscle activities during non-natural locomotor patterns; Qp < Bp for rats and Bp < Qp for humans. This indicates that rat Bp and human Qp walking need more effort and we may be able to find its reason in their skeletal system.

We are flat-faced hominins with an external nose that protrudes from the face. This feature was derived in the genus Homo, along with facial flattening and reorientation to form a high nasal cavity. The nasal passage conditions the inhaled air in terms of temperature and humidity to match the conditions required in the lung, and its anatomical variation is believed to be evolutionarily sensitive to the ambient atmospheric conditions of a given habitat. In this study, we used computational fluid dynamics (CFD) with three-dimensional topology models of the nasal passage under the same simulation conditions, to investigate air-conditioning performance in humans, chimpanzees, and macaques. The CFD simulation showed a horizontal straight flow of inhaled air in chimpanzees and macaques, contrasting with the upward and curved flow in humans. The inhaled air is conditioned poorly in humans compared with nonhuman primates. Virtual modifications to the human external nose topology, in which the nasal vestibule and valve are modified to resemble those of chimpanzees, change the airflow to be horizontal, but have little influence on the air-conditioning performance in humans. These findings suggest that morphological variation of the nasal passage topology was only weakly sensitive to the ambient atmosphere conditions; rather, the high nasal cavity in humans was formed simply by evolutionary facial reorganization in the divergence of Homo from the other hominin lineages, impairing the air-conditioning performance. Even though the inhaled air is not adjusted well within the nasal cavity in humans, it can be fully conditioned subsequently in the pharyngeal cavity, which is lengthened in the flat-faced Homo. Thus, the air-conditioning faculty in the nasal passages was probably impaired in early Homo members, although they have survived successfully under the fluctuating climate of the Plio-Pleistocene, and then they moved "Out of Africa" to explore the more severe climates of Eurasia., ヒトの鼻腔機能はチンパンジーに及ばない -それでも、原人は出アフリカを遂げた-. 京都大学プレスリリース. 2016-03-25.

The nasal cavity performs several important functions for the inhaled air, such as temperature and humidity adjustments. Although it is necessary to obtain velocity, temperature, and humidity distributions during inhalation in order to understand the nasal cavity's functions, it is difficult to measure them noninvasively in the nasal cavity. Therefore, we have continued to study nasal flow simulation with heat and humidity transport. In such a simulation, the governing equations include a continuum equation and the equations describing momentum, energy, and water transport. The temperature and humidity of the inhaled air are adjusted by heat and water exchange on the nasal cavity wall's surface. Therefore, in the simulation, these roles of the wall in the energy and water transport equations were included as the boundary conditions. Although in related studies of nasal flow simulation with heat and humidity transport, the nasal cavity wall's surface temperature and humidity were constant, here they were treated as degrees of using Newton's cooling law. A flow including temperature and humidity in a realistic human nasal cavity shape was simulated. The simulation results agreed well with the measurements reported by Keck at al. Therefore, this study concludes that our model can simulate the heat and humidity exchange occurring in the nasal cavity. In addition, it was found that the temperature and humidity adjustment functions worked effectively in the front and narrow regions of the nasal cavity.

The purpose of the present study was to establish a rat bipedal walking model to examine the effects of bipedal walking on the central nervous system by training rats to perform bipedal walking over a period of 3 months. The characteristics of bipedal walking were investigated using kinematic and electromyographic methods in established bipedal walking models. Stable bipedal walking was achieved in rats by training them to stand with an upright posture and to walk with the hindlimbs using bipedal-walking training equipment to obtain a water reward. A stable head position in the rat bipedal walking model was attained primarily by closing the swing-phase period with a large angular change in the hip, knee, and ankle joints. The EMG burst pattern of the knee extensor (m. rectus femoris) and the erector muscle of the spine (m. longissimus) during bipedal walking was similar to that during quadrupedal walking in rats. We established two bipedal walking models using normal and forelimb-amputated rats. Comparative studies of these two bipedal walking models are expected to provide the information about the influence of forelimb movements on neuronal control of bipedal walking.

We evaluate the performance of a parallel 3D finite-difference method (FDM) simulation of seismic wave propagation using the Intel Xeon Phi coprocessor. Since a continued decrease in the byte/flop ratio of future machines is forecast, program optimization with a decrease byte/flop ratio was applied by fusing the original major kernel and omitting the storing and loading of intermediate variables. We confirm that 1) MPI/OpenMP hybrid parallel computing with hyper-threading is more efficient than pure MPI parallel computing and 2) the performance of the FDM simulation with a splitting of triple DO loops is 1.3 times faster than the modified code with triple DO loops, while no performance acceleration is achieved with a fused double DO-loop calculation. We consider that loop distribution optimization is effective for prefetching and the thread parallelization of each loop by its use and reuse on cache data.

Electron projection lithography (EPL) is a realistic technology for the 65nm node and below, as a complementary technology of optical lithography especially for contacts and gate layers because of its high resolution and large process margin. Nikon has developed an EPL exposure tool as an electron-beam (EB) stepper and the first generation EB stepper; NSR-EB1A is now almost completed as an R&D tool for the 65nm technology node. Using a ϕ200mm reticle, a 20mm×25mm exposure field is realized. Full-field exposure performance of NSR-EB1A is shown. A 70nm isolated line and 1:1 nested lines are simultaneously resolved, as are 50nm 1:2 nested lines. 60nm contact holes are resolved with a depth of focus over a 10μm range and dosage window over ±6%. Stitching accuracy is about 20nm (3σ) and the single machine overlay is about 30nm (mean + 3σ). These data mean sufficient performance for device manufacturing of the 65nm technology node. The concept of a large subfield is one candidate for resolution and throughput e...

This study investigated developmental aspects of the acquisition of operant-trained bipedal (Bp) standing and Bp walking in the normally quadrupedal (Qp) juvenile Japanese monkey (M. fuscata). Four male monkeys (age: 1.6 to 2.4 years, body weight: 3.3 to 4.6 kg) were initially operantly trained to stand upright on a smooth floor and a stationary treadmill belt (width = 60 cm, walking length = 150 cm). They were then trained to walk bipedally on the moving treadmill belt (speed: 0.4–0.7 m/s). A regular training program (5 days/week; 30–60 min/day) was given to each monkey for the first 40 to 60 days, followed by less intensive training. After the beginning of locomotor training, upright postural stability and Bp walking capability were assessed kinematically for 592, 534, 526, and 537 days on monkeys A, B, C, and D, respectively. Left side- and back-views of the walking monkey were photographed (10 frames/s) and videotaped (250 frames/s). Stick figures of the head, body, and hindlimbs were drawn with reference to ink-marks positioned in front of the ear and over the pivot points of hindlimb joints. All kinematic data were digitized and analyzed using image-analyzing software. After sufficient physical growth and locomotor training, all the monkeys gradually acquired: (a) a more upright and a more stable posture with a constant body axis orientation during Bp locomotion; (b) a more stable and a stronger functional coupling between the body and hindlimb movements with a less anterior (A)-posterior (P) fluctuation of a body axis; (c) a smaller leftward (Lt)-rightward (Rt) displacement of the midline pelvic position, allowing the monkey to walk along a straight course; (d) a more coordinated relationship among hip-knee, knee-ankle, and ankle-metatarsophalangeal (MTP) joints; and finally (e) the acquisition of well-coordinated Bp walking even at high treadmill belt speeds up to 1.5 m/s. All of these results demonstrated the capability of the physically developing monkey to integrate the neural and musculoskeletal mechanisms required for sufficient coordination of upper (head, neck, trunk) and lower (hindlimbs) motor segments so that Bp standing and Bp walking could be elaborated.

The nasal passages mainly adjust the temperature and humidity of inhaled air to reach the alveolar condition required in the lungs. By contrast to most other nonhuman primates, macaque monkeys are distributed widely among tropical, temperate and subarctic regions, and thus some species need to condition the inhaled air in cool and dry ambient atmospheric areas. The internal nasal anatomy is believed to have undergone adaptive modifications to improve the air-conditioning performance. Furthermore, the maxillary sinus (MS), an accessory hollow communicating with the nasal cavity, is found in macaques, whereas it is absent in most other extant Old World monkeys, including savanna monkeys. In this study, we used computational fluid dynamics simulations to simulate the airflow and heat and water exchanges over the mucosal surface in the nasal passage. Using the topology models of the nasal cavity with and without the MS, we demonstrated that the MS makes little contribution to the airflow pattern and the air-conditioning performance within the nasal cavity in macaques. Instead, the inhaled air is conditioned well in the anterior portion of the nasal cavity before reaching the MS in both macaques and savanna monkeys. These findings suggest that the evolutionary modifications and coetaneous variations in the nasal anatomy are rather independent of transitions and variations in the climate and atmospheric environment found in the habitats of macaques.

BACKGROUND Stent placement for cerebral aneurysms leads to a decrease in blood flow. This occurs not only through the direct obstruction of flow but also by the expansion of the parent artery. The latter has been observed in several clinical studies. OBJECTIVE The goal of this study was to clarify the effects of parent artery expansion after stent treatment on the following: 1) decrease in blood flow to an aneurysm, 2) wall shear stress (WSS), and 3) oscillatory shear index (OSI). METHODS The parent artery geometry constructed U-shape. The aneurysm location with respect to the U-shaped parent artery was determined according to previous clinical data. We performed calculations in unsteady-state situations using constructed models. RESULTS Parent artery expansion with stent reduces blood inflow to an aneurysm and WSS of the aneurysm wall, in addition to increasing OSI. The aneurysm position affects the decrease of the inflow rate and WSS ratio and increases the OSI ratio. Expansion causes the majority of effects on flow reduction inside an aneurysm model. Thus, the expansion effects of all samples should not be neglected. CONCLUSION These data suggest that parent artery expansion and its effect should be measured and included in the total decrease in blood flow. Parent artery expansion may induce intimal hyperplasia, thus increasing the thickness of the aneurysm wall.

The distribution of choline acetyltransferase (ChAT)-containing neurons and serotonin (5-HT)-containing nerve fibers in the cat neostriatum was investigated by use of immunohistochemical techniques. Both ChAT- and 5-HT-staining techniques were applied to alternate brain sections, thereby allowing a precise comparison of the distribution pattern of ChAT-immunopositive cells (ChAT cells) and 5-HT-immunopositive fibers (5-HT fibers). In the neostriatum, ChAT cells were strongly stained throughout their cell bodies and proximal (first-order) dendrites. The majority of them were multipolar cells with a soma diameter of 20-50 microm (long axis)x10-30 microm (short axis). In the caudate nucleus, ChAT cells were evenly and diffusely distributed except for the dorsolateral region of its rostral half, in which latter region they were distributed in loosely formed clusters. In the rostral portion of the putamen, the density of ChAT-cell distribution was like that in the medial region of the caudate nucleus. In contrast, this distribution was more dense in the caudomedial region of the putamen, adjacent to the globus pallidus. 5-HT fibers in the neostriatum were dark-stained, of quite fine diameter (0.6 microm), and they contained small, round varicosities (diameter, usually 0.5-1.0 microm, but some1.0 microm). Such 5-HT fibers were distributed abundantly throughout the caudate nucleus and putamen. In the rostrocaudal portion of the caudate nucleus, their density was high in its dorsal and ventral components, and low in the middle component. Throughout the putamen, 5-HT fibers were distributed homogeneously in the mediolateral and dorsoventral directions. In the caudal portion of the putamen adjacent to the globus pallidus, the 5-HT fibers had a higher density while maintaining their homogenous distribution pattern. In the two main divisions of the striatum, the so-called 'patch' (acetylcholinesterase (AChE)-poor) and 'matrix' (AChE-rich) compartments, there was a near-even distribution of 5-HT fibers and terminals. The above results suggest that the 5-HT-dominated, raphe-striatal pathway is optimally arranged for modulating the activity of both the intrinsic and the projection neurons of the neostriatum.

Pieces of fetal spinal tissue were transplanted into the site of complete midthoracic spinal transections in neonatal rat pups (transplant rats). The development of locomotion in these animals was compared with that of unoperated control rats and rats that received spinal transections alone (spinal rats). Reflex, treadmill and overground locomotion, staircase descent, and horizontal ladder crossing for a water reward were tested in control, spinal, and transplant rats from 3 weeks to adulthood. All tests were readily performed by control animals. Most spinal rats were unable to make many linked weight-supported steps on these tasks. Transplant rats were variable in their locomotor capabilities, but a subset of rats were able to demonstrate coordinated and adaptable locomotion on these tasks. Some transplant rats performed better on more challenging tasks, suggesting that motor strategies for these tasks used different information, perhaps from descending systems. Transplanted tissue survived, and in most cases there was immunocytochemical staining of serotonergic fibers passing into and caudal to the transplant, supporting the conclusion that descending systems grew through the transplanted tissue. Integration with the host tissue was often poor, suggesting that nonspecific or trophic effects of the transplant might also contribute to the development of locomotor function. Therefore several mechanisms may contribute to the repair of injured spinal cord provided by transplants that permit the development of useful locomotion.

The aging society has rapidly progressed worldwide and the mortality and morbidity rates of aortic diseases are increasing. In particular, aortic aneurysm and aortic dissection are serious disorders. These may be fatal if their diagnosis and treatment are delayed. In 2006, guideline for the diagnosis and treatment of aortic aneurysm and aortic dissection was established in Japan [1]. In 2010, a guideline for the diagnosis and management of patients with thoracic aortic diseasewas established in the United States[2]. These guidelines pay particular attention to the diagnosis and treatment of aortic diseases. We investigated the possibility of estimating timedependent changes in these diseases using Computational Fluid Dynamics (CFD) simulation. This chapter describes the numerical simulations used for ulcer-like projections due to aortic dissections with complete thrombosis. By combining the results of CFD and diagnostic imaging, we can anticipate future improvements in diagnosis.

Percutaneous transluminal coronary angioplasty (PTCA) with stent implantation is widely used for the treatment of coronary stenosis. However, restenosis after stent implantation frequently reported by intravascular ultrasound evaluation. This may occur because of the reduced luminal area after implantation, insufficient stent expansion, or by the elastic recoil of the stent (ERS). Quantitative evaluation of stent expanding should provide further information on how to decrease the incidence of re-stenosis. Many previous studies have observed stent properties in 2D. However, the stent geometry is changed in 3D space, and 3D measurements will provide further information on factors such as the risk for asymmetric ERS. We performed 3D reconstruction using high spatial resolution images obtained with a Micro-CT system to observe the 3D expansion behavior of a test stent and quantitatively evaluate ERS. The expansion behavior of each structural component of the stent varied, as did the ERS and eccentricity. ERS ranged from 2.4% to 9.2% during observation form proximal and distal positions in each component. The greatest difference in ERS between 2D and 3D measurements was 5.2%. 3D measurements provide more information on ERS than 2D measurements. Our result shows the importance of the observation, and the evaluation by three dimensions.

The rat bipedal walking model (RBWM) refers to rats that acquired anatomical and functional characteristics for bipedal walking after the completion of a long-term motor training program. We recorded the Hoffmann reflex (H-reflex) of the forelimb and hindlimb in RBWM and control (not trained, normal) rats to evaluate the effects of bipedal walking on central nervous system (CNS) activity. The H-reflex recorded from the hindlimbs of the RBWM was significantly inhibited compared with that in the control. Furthermore, the inhibition of the H-reflex recorded from both forelimbs and hindlimbs by paired pulse stimulation tended to be enhanced in RBWM. These results indicate that bipedal walking or bipedal walking training cause functional changes in spinal reflex pathways in the CNS.