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2.
Sci Rep ; 7(1): 930, 2017 04 19.
Article in English | MEDLINE | ID: mdl-28424473

ABSTRACT

III-V semiconductors have been intensively studied with the goal of realizing metal-oxide-semiconductor field-effect transistors (MOSFETs) with high mobility, a high on-off ratio, and low power consumption as next-generation transistors designed to replace current Si technology. Of these semiconductors, a narrow band-gap semiconductor InAs has strong Rashba spin-orbit interaction, thus making it advantageous in terms of both high field-effect transistor (FET) performance and efficient spin control. Here we report a high-performance InAs nanowire MOSFET with a gate-all-around (GAA) structure, where we simultaneously control the spin precession using the Rashba interaction. Our FET has a high on-off ratio (104~106) and a high field-effect mobility (1200 cm2/Vs) and both values are comparable to those of previously reported nanowire FETs. Simultaneously, GAA geometry combined with high- κ dielectric enables the creation of a large and uniform coaxial electric field (>107 V/m), thereby achieving highly controllable Rashba coupling (1 × 10-11 eVm within a gate-voltage swing of 1 V), i.e. an operation voltage one order of magnitude smaller than those of back-gated nanowire MOSFETs. Our demonstration of high FET performance and spin controllability offers a new way of realizing low-power consumption nanoscale spin MOSFETs.

3.
Orthop Traumatol Surg Res ; 102(5): 583-7, 2016 09.
Article in English | MEDLINE | ID: mdl-27317638

ABSTRACT

BACKGROUND: Surgical treatment is recommended for type 5 acromioclavicular joint dislocation on Rockwood's classification. We believe that anatomic repair of the coracoclavicular ligaments best restores the function of the acromioclavicular joint. We attempted to correctly reconstruct the anatomy of the coracoclavicular ligaments under arthroscopy, and describe the minimally invasive arthroscopic procedure. MATERIALS AND METHODS: There were 22 patients; mean age at surgery, 38.1 years. Mean time to surgery was 13.2 days. Mean follow-up was 3 years 2 months. The palmaris longus tendon was excised from the ipsilateral side to replace the conoid ligament, while artificial ligament was used for reconstructing the trapezoid ligament. Both ligament reconstructions were performed arthroscopically. No temporary fixation of the acromioclavicular joint was performed. RESULTS: On postoperative radiographic evaluation, 4 patients showed subluxation and 2 showed dislocation of the acromioclavicular joint; the other 16 patients had maintained reduction at the final consultation. MR images 1year after surgery clearly revealed the reconstructed ligaments in 19 patients. Only 1 patient showed osteoarthritis of the acromioclavicular joint. CONCLUSION: Although it requires resection of the ipsilateral palmaris longus for grafting, we believe that anatomic reconstruction of both coracoclavicular ligaments best restores the function of the acromioclavicular joint. LEVEL OF EVIDENCE: 4.


Subject(s)
Acromioclavicular Joint/surgery , Arthroscopy/methods , Joint Dislocations/surgery , Ligaments, Articular/surgery , Adult , Aged , Female , Follow-Up Studies , Humans , Male , Middle Aged , Treatment Outcome
4.
J Hum Hypertens ; 30(6): 379-85, 2016 06.
Article in English | MEDLINE | ID: mdl-26538381

ABSTRACT

Primary aldosteronism due to unilateral aldosterone-producing adenoma (APA) is a surgically curable form of hypertension. Bilateral APA can also be surgically curable in theory but few successful cases can be found in the literature. It has been reported that even using successful adrenal venous sampling (AVS) via bilateral adrenal central veins, it is extremely difficult to differentiate bilateral APA from bilateral idiopathic hyperaldosteronism (IHA) harbouring computed tomography (CT)-detectable bilateral adrenocortical nodules. We report a case of bilateral APA diagnosed by segmental AVS (S-AVS) and blood sampling via intra-adrenal first-degree tributary veins to localize the sites of intra-adrenal hormone production. A 36-year-old man with marked long-standing hypertension was referred to us with a clinical diagnosis of bilateral APA. He had typical clinical and laboratory profiles of marked hypertension, hypokalaemia, elevated plasma aldosterone concentration (PAC) of 45.1 ng dl(-1) and aldosterone renin activity ratio of 90.2 (ng dl(-1) per ng ml(-1 )h(-1)), which was still high after 50 mg-captopril loading. CT revealed bilateral adrenocortical tumours of 10 and 12 mm in diameter on the right and left sides, respectively. S-AVS confirmed excess aldosterone secretion from a tumour segment vein and suppressed secretion from a non-tumour segment vein bilaterally, leading to the diagnosis of bilateral APA. The patient underwent simultaneous bilateral sparing adrenalectomy. Histopathological analysis of the resected adrenals together with decreased blood pressure and PAC of 5.2 ng dl(-1) confirmed the removal of bilateral APA. S-AVS was reliable to differentiate bilateral APA from IHA by direct evaluation of intra-adrenal hormone production.


Subject(s)
Adrenal Cortex Neoplasms/diagnosis , Adrenal Cortex Neoplasms/surgery , Adrenalectomy/methods , Adrenocortical Adenoma/diagnosis , Adrenocortical Adenoma/surgery , Aldosterone/blood , Biomarkers, Tumor/blood , Blood Specimen Collection/methods , Organ Sparing Treatments , Adrenal Cortex Neoplasms/blood , Adrenal Cortex Neoplasms/metabolism , Adrenocortical Adenoma/blood , Adrenocortical Adenoma/metabolism , Adult , Aldosterone/metabolism , Biomarkers, Tumor/metabolism , Biopsy , Diagnosis, Differential , Humans , Immunohistochemistry , Male , Predictive Value of Tests , Tomography, X-Ray Computed , Treatment Outcome , Veins
5.
Horm Metab Res ; 47(11): 826-32, 2015 Oct.
Article in English | MEDLINE | ID: mdl-26305168

ABSTRACT

Approximately 10% of cases of hypertension in Japan are caused by primary aldosteronism (PA), amounting to about 4 million patients in total. Primary aldosteronism due to unilateral aldosterone hypersecretion is potentially curable by adrenalectomy. The clinical benefits of identifying and treating PA have been reported internationally, but its cost-effectiveness is unclear. We examined whether diagnosing and treating hidden PA in hypertensive population was cost-effective compared with suboptimal treatment. Our hypothetical patient was a 50-year-old man diagnosed with stage I-III hypertension. We established a Markov decision model based on plausible clinical pathways and prognoses of PA. We applied cost-effectiveness analysis comparing a comprehensive diagnostic strategy for PA (measurement of plasma aldosterone/renin ratio, 2 loading tests, imaging, and selective adrenal venous sampling) with a suboptimal strategy to manage hypertension by medication unless the typical signs of PA or other complication were manifest. Outcome measures were expected costs, expected effectiveness, and incremental cost-effectiveness ratio. The robustness of the findings was established by one-way and scenario sensitivity analyses. The comprehensive PA diagnostic strategy increased the expected costs by 64 004 JPY and expected life-years by 0.013 compared with standard treatment. The incremental cost-effectiveness ratio for the diagnosis of PA was 4 923 385 JPY per year. Our findings were sensitive to the outcomes of screening and treatment, and the costs of continuous or periodic medication for hypertension and the treatment of stroke and its complications.


Subject(s)
Cost-Benefit Analysis , Hyperaldosteronism/diagnosis , Hyperaldosteronism/therapy , Humans , Hyperaldosteronism/economics , Japan , Male , Markov Chains , Middle Aged
6.
Dis Esophagus ; 28(8): 728-34, 2015.
Article in English | MEDLINE | ID: mdl-25286827

ABSTRACT

Using a large animal model, we examined whether circumferential stricture after esophageal endoscopic submucosal dissection (ESD) can be treated by grafting a bioabsorbable esophageal patch. Circumferential ESD was performed on the thoracic esophagus in pigs (n = 6) to create a stricture, for which one of the following interventions was performed: (1) the stricture site was longitudinally incised, and an artificial esophageal wall (AEW) was grafted after placing a bioabsorbable stent (AEW patch group, n = 3); (2) endoscopic balloon dilation (EBD) was performed every other week after stricture development (EBD group, n = 3). In both groups, esophageal fluoroscopy was performed 8 weeks after the interventions, and the esophagus was excised for histological examination of the patched site. In the AEW patch group, esophageal fluoroscopy revealed favorable passage through the patched site. Histologically, the mucosal epithelium and lamina propria had regenerated as in the normal area. In the EBD group, the circumferential stricture site showed marked thickening, and there were hypertrophic scars associated with epithelial defects on the luminal surface. Histologically, defects of the mucosal epithelium and full-thickness proliferation of connective tissue were observed. AEW patch grafting was suggested to be a potentially novel treatment strategy for post-ESD esophageal circumferential stricture.


Subject(s)
Absorbable Implants , Esophageal Stenosis/surgery , Esophagoscopy/methods , Esophagus/transplantation , Animals , Catheterization/instrumentation , Catheterization/methods , Cicatrix, Hypertrophic , Disease Models, Animal , Dissection/methods , Epithelium/physiology , Epithelium/surgery , Esophageal Stenosis/diagnostic imaging , Esophageal Stenosis/physiopathology , Esophagoscopy/instrumentation , Esophagus/diagnostic imaging , Esophagus/pathology , Fluoroscopy , Mucous Membrane/physiology , Mucous Membrane/surgery , Regeneration , Stents , Swine , Treatment Outcome
7.
J Neuroendocrinol ; 26(12): 909-17, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25283748

ABSTRACT

The oestrogen-induced luteinising hormone (LH) surge is evident in male primates, including humans, whereas male rodents never show the LH surge, even when treated with a preovulatory level of oestrogen. This suggests that the central mechanism governing reproductive hormones in primates is different from that in rodents. The present study aimed to investigate whether male Japanese monkeys conserve a brain mechanism mediating the oestrogen-induced LH surge via activation of kisspeptin neurones. Adult male and female Japanese monkeys were gonadectomised and then were treated with oestradiol-17ß for 2 weeks followed by a bolus injection of oestradiol benzoate. Both male and female monkeys showed an oestrogen-induced LH surge. In gonadectomised monkeys sacrificed just before the anticipated time of the LH surge, oestrogen treatment significantly increased the number of KISS1-expressing cells in the preoptic area (POA) and enhanced the expression of c-fos in POA KISS1-positive cells of males and females. The oestrogen treatment failed to induce c-fos expression in the arcuate nucleus (ARC) kisspeptin neurones in both sexes just prior to LH surge onset. Thus, kisspeptin neurones in the POA but not in the ARC might be involved in the positive-feedback action of oestrogen that induces LH surge in male Japanese monkeys, as well as female monkeys. The present results indicate that oestrogen-induced activation of POA kisspeptin neurones may contribute to the LH surge generation in both sexes. The conservation of the LH surge generating system found in adult male primates, unlike rodents, could be a result of the capability of oestrogen to induce POA kisspeptin expression and activation.


Subject(s)
Estradiol/analogs & derivatives , Kisspeptins/metabolism , Luteinizing Hormone/blood , Neurons/drug effects , Preoptic Area/cytology , Animals , Arcuate Nucleus of Hypothalamus/cytology , Arcuate Nucleus of Hypothalamus/drug effects , Arcuate Nucleus of Hypothalamus/physiology , Estradiol/blood , Estradiol/pharmacology , Female , Kisspeptins/biosynthesis , Macaca , Male , Neurons/metabolism , Neurons/physiology , Preoptic Area/drug effects , Preoptic Area/physiology
8.
Clin Radiol ; 69(12): 1273-9, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25246336

ABSTRACT

AIM: To evaluate radiation-induced myocardial damage after mediastinal radiotherapy using MRI. MATERIALS AND METHODS: Between May 2010 and April 2011, delayed contrast-enhanced MRI was performed for patients who had maintained a complete response to curative radiotherapy for oesophageal cancer for more than 6 months. The patients received radiotherapy with a median total dose of 66 Gy (60-70 Gy) for the primary tumour and metastatic lymph nodes. Images of MRI were analysed by a 17-segment method recommended by the American Heart Association. A segment included mainly in the 40 Gy dose line was defined as Segment 40 Gy, a segment included mainly in the 60 Gy dose line as Segment 60 Gy, and a segment out of the radiation fields as Segment OUT. The percentage of late gadolinium enhancement (LGE) was examined in those categories. The layer in which LGE was predominantly distributed was evaluated for each patient. RESULTS: Four hundred and eight segments in 24 patients were analysed. The median interval from completion of radiotherapy to MRI was 23.5 months (range 6-88 months). LGE was detected in 12 of the 24 patients. LGE was detected in 15.38% of Segment 40 Gy cases, 21.21% of Segment 60 Gy cases, and 0% of Segment OUT cases. LGE in mid-myocardial and subendocardial layers was detected in 11 patients and one patient, respectively. CONCLUSION: LGE suggesting radiation induced myocardial fibrosis was observed by performing delayed contrast-enhanced MRI. Care should be taken when planning radiotherapy to avoid late cardiac damage.


Subject(s)
Cardiomyopathies/etiology , Cardiomyopathies/pathology , Esophageal Neoplasms/radiotherapy , Heart/radiation effects , Magnetic Resonance Imaging/methods , Myocardium/pathology , Radiation Injuries/complications , Aged , Contrast Media , Esophageal Neoplasms/complications , Female , Gadolinium , Humans , Image Enhancement/methods , Male , Radiotherapy/adverse effects , Radiotherapy Dosage , Reproducibility of Results , Tomography, X-Ray Computed/methods
10.
AJNR Am J Neuroradiol ; 35(12): 2293-301, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25082820

ABSTRACT

BACKGROUND AND PURPOSE: During surgery to treat an aneurysm in the anterior communicating artery, injury to the subcallosal artery, a perforator of the anterior communicating artery, may lead to infarction that produces basal forebrain amnesia after surgery. Our purpose was to examine whether 3D MR imaging can detect subcallosal artery infarction in patients with amnesia after surgery for an anterior communicating artery aneurysm. MATERIALS AND METHODS: We evaluated 3D-T2-weighted MR images obtained a median of 4 months after treatment of anterior communicating artery aneurysm for the presence of infarcted foci in 10 consecutive patients with postoperative amnesia. Because the subcallosal artery and its neighboring perforator, the recurrent artery of Heubner, were considered the most easily affected vessels during that surgery, we focused mainly on 8 regions of the subcallosal artery territory per hemisphere and 5 regions of the recurrent artery of Heubner territory per hemisphere. RESULTS: All 10 patients had infarcts in the territory of the subcallosal artery (median, 9 regions per patient), and most were bilateral (9 of 10 patients). Five patients had additional infarcted foci in the territory of the recurrent artery of Heubner (median, 1 region per patient), all unilateral. Among the regions perfused by the subcallosal artery, the column of the fornix was involved in all patients; the anterior commissure, in 9; and the paraterminal gyrus, in 8 patients. CONCLUSIONS: 3D MR imaging revealed subcallosal artery infarction, the distribution of which was mostly bilateral, presumably owing to the unpairedness of that artery, in patients with postoperative amnesia after anterior communicating artery aneurysm repair.


Subject(s)
Amnesia/etiology , Aneurysm, Ruptured/surgery , Imaging, Three-Dimensional/methods , Intracranial Aneurysm/complications , Intracranial Aneurysm/surgery , Magnetic Resonance Imaging/methods , Postoperative Complications/diagnosis , Aged , Basal Forebrain , Female , Humans , Male , Middle Aged , Retrospective Studies
11.
Ann Rheum Dis ; 73(9): 1695-9, 2014 Sep.
Article in English | MEDLINE | ID: mdl-24854356

ABSTRACT

OBJECTIVE: To determine whether serial ANA testing predicts biological disease modifying antirheumatic drugs (bDMARD)-associated ANA/dsDNA production in patients with rheumatoid arthritis (RA). METHODS: Serial autoantibody profiles, bDMARD treatment sequences and clinical data were collected from patients identified from our database that since 2005 received (i) a first bDMARD (tumour necrosis factor inhibitor (TNFi)) and (ii) tocilizumab and/or abatacept. RESULTS: Of over 1000 patients, 454 RA patients received a first TNFi. Infliximab group demonstrated higher ANA seroconversion rates (31.2%) compared with etanercept (11.8%) and adalimumab (16.1%) (p<0.001). Median (range) treatment duration prior to ANA seroconversion was 10.9 (1.3-80.0) months. Positive anti-dsDNA titres of IgG class (median (range) of 77 IU/mL (65-109)) were noted in six (7.2%) patients, within a median (range) of 2.0 (0.8-4.2) years. Three patients developed classifiable lupus. 4 of 74 (5.4%) primary non-responders and 24 of 111 (21.6%) secondary non-responders developed positive ANA antibodies after TNFi initiation (p=0.003). Seven (9.5%) tocilizumab-treated patients changed to positive ANA; five (8.6%) abatacept-treated patients changed to positive ANA status. CONCLUSIONS: This study demonstrates no utility of serial ANA/dsDNA testing that could be used to predict onset of seroconversion and therefore the development of lupus/vasculitis. An association however between seroconversion and the development of a secondary non-response to bDMARD therapy is suggested.


Subject(s)
Antibodies, Antinuclear/blood , Antirheumatic Agents/adverse effects , Arthritis, Rheumatoid/drug therapy , Biological Products/adverse effects , Lupus Erythematosus, Systemic/chemically induced , Vasculitis/chemically induced , Abatacept , Adolescent , Adult , Aged , Aged, 80 and over , Antibodies, Monoclonal, Humanized/adverse effects , Antirheumatic Agents/therapeutic use , Arthritis, Rheumatoid/immunology , Biological Products/therapeutic use , Biomarkers/blood , Cohort Studies , DNA/immunology , Drug Monitoring/methods , Female , Humans , Immunoconjugates/adverse effects , Lupus Erythematosus, Systemic/diagnosis , Male , Middle Aged , Prognosis , Tumor Necrosis Factor-alpha/antagonists & inhibitors , Vasculitis/diagnosis , Young Adult
12.
Phys Rev Lett ; 111(17): 170802, 2013 Oct 25.
Article in English | MEDLINE | ID: mdl-24206471

ABSTRACT

We demonstrate a zero-dead-time operation of atomic clocks. This clock reduces sensitivity to local oscillator noise, integrating as nearly 1/τ whereas a clock with dead time integrates as 1/τ(1/2) under identical conditions. We contend that a similar scheme may be applied to improve the stability of optical clocks.

13.
J Hum Hypertens ; 27(10): 612-6, 2013 Oct.
Article in English | MEDLINE | ID: mdl-23595158

ABSTRACT

Association of the C825T G-protein ß3 subunit (GNB3) gene polymorphism with cardiovascular disease (CVD) incidence was examined in a population-based longitudinal study of the Japanese individuals. The incidence of CVD (stroke and coronary heart disease (CHD)) was assessed in a cohort population (n=1524) consisting of participants of the 2001-2005 Funagata study through March 2008. Cumulative incidences according to genotype were compared with the Kaplan-Meier product-limit method. During the follow-up, 78 subjects experienced a CVD event (stroke: n=54; CHD: n=30; both consecutively: n=6). At the end of the follow-up (longest and median follow-up periods: 81 and 68 months, respectively), the cumulative incidence of CVD for the TT genotype was significantly higher than that of the C-carriers (0.077 vs 0.042, P=0.004). Blood pressures and the prevalence of hypertension were not different between the genotypes. Cox's proportional hazard analysis showed that the TT genotype is a significant risk factor for CVD (hazard ratio (HR)=1.82 (95% confidence interval (CI) 1.14-2.89); P=0.012) and stroke (HR=1.76 (95% CI: 1.01-3.07); P=0.048) incidences after adjustment for age, sex, hypertension, hyperlipidemia, diabetes, alcohol drinking and smoking at baseline. The TT genotype of the C825T GNB3 gene polymorphism was found to be a significant risk factor for the incidence of CVD and stroke independent of hypertension and other established CVD risk factors in a Japanese population.


Subject(s)
Cardiovascular Diseases/genetics , Heterotrimeric GTP-Binding Proteins/genetics , Hypertension/genetics , Polymorphism, Genetic , Aged , Asian People/genetics , Blood Pressure/genetics , Cardiovascular Diseases/ethnology , Cardiovascular Diseases/physiopathology , Chi-Square Distribution , Female , Gene Frequency , Genetic Predisposition to Disease , Humans , Hypertension/ethnology , Incidence , Japan/epidemiology , Kaplan-Meier Estimate , Longitudinal Studies , Male , Middle Aged , Multivariate Analysis , Phenotype , Prevalence , Proportional Hazards Models , Prospective Studies , Risk Factors
14.
Neuroscience ; 237: 151-60, 2013 May 01.
Article in English | MEDLINE | ID: mdl-23396087

ABSTRACT

General anesthesia is occasionally associated with postoperative complications such as sleep disorder, drowsiness, or mood alterations. Hippocampal acetylcholine (ACh), the extracellular level of which increases during the dark (active) phase and decreases during the light (rest) phase in rats, is thought to be associated with locomotor activity and be crucial for learning and memory. Propofol, an intravenous anesthetic, is known to shift the circadian rhythms of physiological parameters including locomotor activity and body temperature in both rodents and humans, while the effects of volatile anesthetics on the circadian rhythm largely remain unclear. The present study examined the effects of isoflurane anesthesia on the diurnal changes in hippocampal ACh release and locomotor activity in rats. Rats were divided into three groups: a light-phase anesthesia group (LA group), a dark-phase anesthesia group (DA group), and a control group. They were exposed to a 12-h light/12-h dark environment and anesthetized with 1.4% isoflurane for 4h during the middle of the light phase (LA group) and dark phase (DA group). Simultaneous measurement of hippocampal ACh by microdialysis and locomotor activity were done for 60h under free-moving conditions. Hippocampal ACh release and locomotor activity showed a clear circadian rhythm. In the DA group, but not in the LA group, the diurnal variation in ACh release was significantly disturbed and a more than 2-h phase-advance in locomotor activity was observed. There was a significant correlation between hippocampal ACh release and locomotor activity, and isoflurane anesthesia disrupted it even after anesthesia was discontinued. This study revealed that the levels and circadian rhythms of hippocampal ACh release and locomotor activity were more sensitive to isoflurane anesthesia when it was administered during the active phase. Our findings suggest that anesthesia exerts differential effects on the regulation of circadian rhythms depending on the circadian phase.


Subject(s)
Acetylcholine/metabolism , Anesthetics, Inhalation/pharmacology , Circadian Rhythm/drug effects , Hippocampus/drug effects , Isoflurane/pharmacology , Motor Activity/drug effects , Analysis of Variance , Animals , Circadian Rhythm/physiology , Dose-Response Relationship, Drug , Male , Microdialysis , Rats , Rats, Wistar , Statistics as Topic
16.
Clin Exp Rheumatol ; 30(1): 85-92, 2012.
Article in English | MEDLINE | ID: mdl-22325923

ABSTRACT

OBJECTIVES: We simultaneously assessed ultrasonography (US) and magnetic resonance imaging (MRI) in comparison with histopathological changes in the knee joints of long-lasting arthritis patients. METHODS: We studied 15 patients with rheumatoid arthritis and 5 patients with osteoarthritis, who underwent total knee arthroplasty. On the day before surgery, the joints were examined by US and contrast-enhanced MRI. In US, synovitis was graded with 0-3 grey scale (GSUS) and power Doppler (PDUS). In MRI, synovitis was graded according to OMERACT-RAMRIS (grade 0-3). Synovial tissue samples were obtained during arthroplasty and evaluated on the basis of inflammatory cell infiltrates (grade 0-3), synovial lining layer thickness (grade 0-3) and vascularity (grade 0-3). RESULTS: Positive findings of PDUS and contrast-enhanced MRI were 45% and 85% of 20 operated joints, respectively. GSUS, PDUS and MRI synovitis were well correlated with overall histopathological grades of synovitis (Spearman correlation coefficients 0.48, 0.84 and 0.48, p<0.05, p<0.01 and p<0.05, respectively). Moreover, positive PDUS findings were closely associated with all pathological comportments of synovitis including inflammatory cell infiltrates, synovial lining layer thickness and vascularity. CONCLUSIONS: The present study revealed that positive PDUS findings more faithfully illustrated active synovitis than MRI, whereas contrast-enhanced MRI was more sensitive in detecting synovitis in patients with long-lasting arthritis. It is important to understand distinct features of the both modalities for clinical assessment of chronic joint diseases.


Subject(s)
Arthroplasty, Replacement, Knee , Knee Joint/surgery , Magnetic Resonance Imaging/methods , Synovitis/diagnosis , Ultrasonography, Doppler/methods , Adult , Aged , Aged, 80 and over , Arthritis, Rheumatoid/diagnostic imaging , Arthritis, Rheumatoid/pathology , Arthritis, Rheumatoid/surgery , Female , Humans , Knee Joint/diagnostic imaging , Knee Joint/pathology , Male , Middle Aged , Osteoarthritis/diagnostic imaging , Osteoarthritis/pathology , Osteoarthritis/surgery , Synovitis/diagnostic imaging , Synovitis/pathology , Synovitis/surgery
17.
Med Eng Phys ; 34(6): 725-32, 2012 Jul.
Article in English | MEDLINE | ID: mdl-21978914

ABSTRACT

Pneumothorax is characterized by lung collapse and an alteration of lung geometry, resulting in alterations of the pulmonary artery blood flow. Though many clinical studies and animal experiments have investigated the effects of pneumothorax on the hemodynamics of pulmonary arteries, its precise effects remain unclear. In this patient-specific study, we investigated the effects of lung deformation and vascular resistance increases due to pneumothorax on the pulmonary blood flow during the acute phase and after recovery. Arterial geometry was extracted up to the fifth generation from computed tomography images, and reconstructed. Computational fluid dynamic analysis was performed, for an unsteady laminar flow with resistance at the outlets, in a reconstructed domain. The results demonstrated a change in flow structure during systole between the acute phase and recovery, and were associated with variations in the flow rate ratio between the right and left lungs. We observed a parabolic-like decrease of the volume flow rate ratio in the affected lung as the resistance increased. Thus, the systemic artery blood oxygenation will rely more on the unaffected lung leading to improved oxygenation of the blood under high resistance in the affected lung. These findings are significant in our understanding of ventilation function under a pneumothorax.


Subject(s)
Hemodynamics , Pneumothorax/physiopathology , Pulmonary Artery/physiopathology , Humans , Male , Middle Aged , Oxygen/metabolism , Pneumothorax/metabolism , Pulmonary Artery/metabolism , Regional Blood Flow
18.
Article in English | MEDLINE | ID: mdl-21809944

ABSTRACT

In this paper, we propose a novel patient-specific method of modelling pulmonary airflow using graphics processing unit (GPU) computation that can be applied in medical practice. To overcome the barriers imposed by computation speed, installation price and footprint to the application of computational fluid dynamics, we focused on GPU computation and the lattice Boltzmann method (LBM). The GPU computation and LBM are compatible due to the characteristics of the GPU. As the optimisation of data access is essential for the performance of the GPU computation, we developed an adaptive meshing method, in which an airway model is covered by isotropic subdomains consisting of a uniform Cartesian mesh. We found that 4(3) size subdomains gave the best performance. The code was also tested on a small GPU cluster to confirm its performance and applicability, as the price and footprint are reasonable for medical applications.


Subject(s)
Computer Simulation , Models, Biological , Respiratory Mechanics/physiology , Computer Graphics , Humans , Hydrodynamics , Models, Anatomic , Respiratory System/anatomy & histology
19.
Phys Rev Lett ; 107(13): 133001, 2011 Sep 23.
Article in English | MEDLINE | ID: mdl-22026848

ABSTRACT

We demonstrate a cold-atom interferometer gyroscope which overcomes accuracy and dynamic range limitations of previous atom interferometer gyroscopes. We show how the instrument can be used for precise determination of latitude, azimuth (true north), and Earth's rotation rate. Spurious noise terms related to multiple-path interferences are suppressed by employing a novel time-skewed pulse sequence. Extended versions of this instrument appear capable of meeting the stringent requirements for inertial navigation, geodetic applications of Earth's rotation rate determination, and tests of general relativity.

20.
West Indian Med J ; 60(1): 73-6, 2011 Jan.
Article in English | MEDLINE | ID: mdl-21809716

ABSTRACT

OBJECTIVE: In this study, eighteen patients who have had perilunate injury with dislocation or fracture, were evaluated and the patho-mechanics and surgical treatment were studied. SUBJECTS AND METHODS: According to the Green and O'Brien's classification, type 1 injury occurred in one patient, type 2 in nine, type 4A in five, type 4C in one and type 4D in one. The other one case could not be classified using the Green and O'Brien's criteria. RESULTS: According to the Evans scoring system, good results were achieved in thirteen patients, fair results, in four, poor results in one and very poor results in none. When the patho-mechanics was estimated based on the Mayfield's criteria, seventeen patients were classified as stage 3. However only one case was extremely unusual and should be classified as a subtype of stage 2. CONCLUSION: The results were good in the majority of patients who had repair of perilunate injury.


Subject(s)
Fractures, Bone/surgery , Joint Dislocations/surgery , Lunate Bone/injuries , Wrist Injuries/surgery , Adult , Aged , Female , Fractures, Bone/classification , Fractures, Bone/diagnostic imaging , Humans , Joint Dislocations/classification , Joint Dislocations/diagnostic imaging , Male , Middle Aged , Radiography , Treatment Outcome , Wrist Injuries/classification , Wrist Injuries/diagnostic imaging
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