Using Convolutional Neural Networks to Measure the Physiological Age of Caenorhabditis elegans.

Caenorhabditis elegans (C. elegans) is a popular and excellent model for studies of aging due to its short lifespan. Methods for precisely measuring the physiological age of C. elegans are critically needed, especially for antiaging drug screening and genetic screening studies. The effects of various antiaging interventions on the rate of aging in the early stage of the aging process can be determined based on the quantification of physiological age. However, in general, the age of C. elegans is evaluated via human visual inspection of morphological changes based on personal experience and subjective judgment. For example, the rate of motor activity decay has been used to predict lifespan in early- to mid-stage aging. Using image processing, the physiological age of C. elegans can be measured and then classified into periods or classes from childhood to elderhood (e.g., 3 periods comprising days 0-2, 4-6 and 10-12) by using texture entropy (Shamir, L. et al., 2009). Our dataset consists of 913 microscopic images of C. elegans, with approximately 60 images per day from day 1 to day 14 of adulthood. We present quantitative methods to measure the physiological age of C. elegans with convolution neural networks (CNNs), which can measure age with a granularity of days rather than periods. The methods achieved a mean absolute error (MAE) of less than 1 day for the measured age of C. elegans. In our experiments, we found that after training and testing our dataset, 5 popular CNN models, 50-layer residual network (ResNet50), InceptionV3, InceptionResNetV2, 16-layer Visual Geometry Group network (VGG16) and MobileNet, measured the physiological age of C. elegans with an average testing MAE of 1.58 days. Furthermore, based on the results, we propose two models, one model for linear regression analysis and the other model for logistic regression, that combine a CNN model and a new attribute: curved_or_straight. The linear regression analysis model achieved a test MAE of 0.94 days; the logistic regression model achieved an accuracy of 84.78 percent with an error tolerance of 1 day.

Changes in the axial orientation of the zygapophyseal joint in the subaxial cervical spine from childhood to middle-age, and the biomechanical implications of these changes.

The objective of this study was to investigate the effect of age on facet orientation (FO) of the cervical spine during development, maturation, and degeneration. Computed tomography (CT) data of the cervical spine of 131 subjects without pathology of the cervical spine were analyzed. Subjects were categorized as: pediatric (n=36, 8-16years old), young adult (n=33, 18-24years old), and middle-age (n=62, 40-59years old). Serial CT scans were reconstructed by image processing. The FO in the axial plane was measured bilaterally at each vertebral level from C3/4 to C6/7. Differences in FO were analyzed between the 3 groups. The degree of external rotation of FO significantly decreased at C3/4 and C4/5 with increasing in age, and maximum external rotation was observed at C5/6. The external rotation at C6/7 increased from pediatric to young adulthood, but decreased from young adults to middle-aged adults. The dominant external rotation was seen in C4/5 and C5/6 in the pediatric age group, C5/6 and C6/7 in young adults, and C4/5 and C5/6 in middle-aged adults. These results lead us to conclude that FO in the axial plane exhibits significant differences with age. The degree of external rotation with respect to FO at each vertebral level is comparable to changes in cervical spinal dynamics with age. Hence, FO in the axial plane is a biomechanical parameter that can be used to assess changes in the cervical spinal during maturation and degeneration.

Clinical Pathway in the Treatment of Nocardial Brain Abscesses following Systemic Infections.

Nocardial infections are commonly encountered in patients with immunocompromised states. Cerebral nocardiosis is an uncommon clinical entity, representing only 2% of all cerebral abscesses. It has a higher mortality rate, especially for multiple cerebral lesions in immunocompromised hosts following systemic infections. However, an optimal treatment policy to deal with these immunocompromised patients in Asia is still lacking. We retrospectively reviewed the subjects with nocardial brain abscesses from 2001 to 2011 at our medical center. All of them had multiple brain abscesses, underlying with immunocompromised state following systemic infections. All cases were under steroid control due to their comorbidities for more than six months. The comorbidities and misdiagnosis often lead to poor prognosis. The change in the environments of the microorganisms caused by immunosuppressive agents and multiple antibiotic uses may play an important role in this critical disorder. Aggressive craniotomy should be performed in time to avoid grievous neurological outcomes. Our conclusion is that early diagnosis and appropriate antibiotic uses should be implemented promptly, and aggressive craniotomy should be performed for nocardial brain abscesses in subjects with systemic infections under an immunocompromised status.

Minimally invasive decompression with posterior column reinforcement for the treatment of symptomatic osteoporotic fracture with spinal stenosis in lumbar vertebrae.

An osteoporotic fracture (OF) in the second to fifth lumbar vertebrae with spinal stenosis may be an indication for surgical treatment, but carries the risks of instability or instrumentation failure. Modified surgical procedures have been developed to manage patients with challenging OF. We retrospectively studied 12 patients (three male, nine female; mean age±standard deviation=73.5±7.2 years) who underwent minimally invasive decompression and posterior column reinforcement with polymethylmethacrylate. During a mean follow-up period of 24.8±3.1 months, pain severity and functional impairment were both significantly reduced, as measured by the visual analog scale and the Oswestry disability index. Nine patients (75%) experienced a satisfactory outcome while the other three (25%) were unchanged. Plain radiographs showed stable spinal alignment and immobilization of flexion-extension within the PMMA construct. Five complications were managed successfully, including one by revision surgery. These procedures are a feasible surgical option in the elderly population studied.

Comparison of the kinematic features between the in vivo active and passive flexion-extension of the subaxial cervical spine and their biomechanical implications.

STUDY DESIGN: An in vivo motion analysis of active and passive kinematic cervical flexion-extension. OBJECTIVE: The study was aimed at investigating the differences between the active and passive kinematic sagittal motions of the subaxial cervical spine. SUMMARY OF BACKGROUND DATA: The biomechanical behavior of the cadaver spinal column is different from that of the in vivo spine. Two major issues were concerned: the complex neuromuscular control of the in vivo cervical spinal motion and the unknown true nature of the passive cervical spinal motion. The kinematic characteristics of active and passive spinal motions need to be clarified. METHODS: The active and passive motion patterns of the subaxial spine in the sagittal plane were recorded by digital video fluoroscopy. The motion of functional units from C3-C4 to C6-C7 of the cervical spine were processed using Image J, an image processing software, in both active and passive cervical motions. The Cobb's angle was measured in serial flexion and extension motions, and a comparison of this angle in both active and passive motions was made in 12 patients with degenerative disc herniation. RESULTS: The difference between active and passive gentle flexion was minimal, and the degree of their correlation was high. The differences in the degree of gentle extension between active and passive motion were variable, and their correlation was low. During early passive flexion, the degree of flexion at the upper level was less and that at the lower level was more as compared to that observed at the respective levels in early active flexion. CONCLUSION: In gentle flexion, the active and passive cervical spinal motions are closely approximated, which implies that the active neuromuscular control mainly plays the buffer-and-brake mechanism without placing additional load on the spine. In contrast, the degree of passive extension is limited, and active neuromuscular control may place additional load on the spine.

Axial and coronal orientation of subaxial cervical zygapophysial joints and their effect on axial rotation and lateral bending.

STUDY DESIGN: Computerized tomography and image processing methodologies were used to analyze the axial and coronal orientation of cervical zygapophysial joints in asymptomatic adults. Surface motions of axial rotation and lateral bending were simulated. OBJECTIVE: The study was designed to obtain the normal distribution and variation of facet orientation (FO) in axial and coronal planes to investigate factors affecting FO and to study the effects of FO on axial rotation and lateral bending. SUMMARY OF BACKGROUND DATA: The FO of the subaxial cervical spine is usually evaluated in the sagittal plane. Cervical spine axial and coronal FO is usually considered to be horizontal. The literature reveals no statistical data for axial or coronal FO. METHODS: Serial thin-sliced computed tomography scans of the cervical spine in asymptomatic adults were input into Image J, National Institutes of Health, image processing software. Bilateral zygapophysial joint angles from C2-C3 to C6-C7 were measured in the axial and coronal planes and collected from 100 subjects. The effect of gender, age, and correlation was analyzed. The surface motions of axial rotation and lateral bending were simulated in Abaqus CAE 6.5. Mathematical facet contact and range of motion were computed. RESULTS: The FO was widely distributed at each level. Gender had no significant association with FO. Age affected FO at most levels. Axial and coronal FO were significantly correlated. The zygapophysial joint of internally rotated/inverted FO contacted more perpendicularly to each other, and mathematical range of motion was smaller. CONCLUSION: The axial or coronal FO of the subaxial cervical spine was found with more variability. Age was significantly related to FO. Geometrically, internally rotated/inverted FO of axial rotation/lateral bending was morerestricted. The extent of axial rotation and lateral bending was correlated with each other.

Detection system built from commercial integrated circuits for real-time measurement of radiation dose and quality using the variance method.

A small, specialised amplifier using commercial integrated circuits (ICs) was developed to measure radiation dose and quality in real time using a microdosimetric ion chamber and the variance method. The charges from a microdosimetric ion chamber, operated in the current mode, were repeatedly collected for a fixed period of time for 20 cycles of 100 integrations, and processed by this specialised amplifier to produce signal pulse heights between 0 and 10 V. These signals were recorded by a multi-channel analyser coupled to a computer. FORTRAN programs were written to calculate the dose and dose variance. The dose variance produced in the ion chamber is a microdosimetric measure of radiation quality. Benchmark measurements of different brands of ICs were conducted. Results demonstrate that this specialised amplifier is capable of distinguishing differences of radiation quality in various high-dose-rate radiation fields including X rays, gamma rays and mixed neutron-gamma radiation from the research reactor at Texas A&M University Nuclear Science Center.

Camera self-calibration method suitable for variant camera constraints.

This paper presents a self-calibration algorithm that seeks the camera intrinsic parameters to minimize the sum of squared distances between the measured and reprojected image points. By exploiting the constraints provided by the fundamental matrices, the function to be minimized can be directly reduced to a function of the camera intrinsic parameters; thus variant camera constraints such as fixed or varying focal lengths can be easily imposed by controlling the parameters of the resulting function. We employed the simplex method to minimize the resulting function and tested the proposed algorithm on some simulated and real data. The experimental results demonstrate that our algorithm performs well for variant camera constraints and for two-view and multiple-view cases.

Spontaneous intracranial hemorrhage caused by pheochromocytoma in a child.

We report a 6-year-old boy who presented with left occipital spontaneous lobar hematoma and hypertension. Cerebral angiography failed to demonstrate a vascular malformation. Subsequently, a left adrenal tumor was found that proved to be a pheochromocytoma. This is the first report in the literature of a lobar hematoma in a child caused by a concomitant pheochromocytoma. In children with hypertension and resulting intracerebral hematoma, a pheochromocytoma should be considered in the differential diagnosis.