Robust Output Feedback Control of Single-Link Flexible-Joint Robot Manipulator with Matched Disturbances Using High Gain Observer.

This article focuses on the output feedback control of single-link flexible-joint robot manipulators (SFJRMs) with matched disturbances and parametric uncertainties. Formally, four sensing elements are required to design the controller for single-link manipulators. We have designed a robust control technique for the semiglobal stabilization problem of the angular position of the link in the SFJRM system, with the availability of only a position sensing device. The sliding mode control (SMC) based output feedback controller is devised for SFJRM dynamics. The nonlinear model of SFJRM is considered to estimate the unknown states utilizing the high-gain observer (HGO). It is shown that the output under SMC using HGO-based estimated states coincides with that using original states when the gains of HGO are sufficiently high. Finally, the results are presented showing that the designed control technique works well when the SFJRM model is uncertain and matched perturbations are expected.

INFANTILE ALEXANDER'S DISEASE: A CASE WITH CHARACTERISTIC MRI FEATURES.

Alexander disease, less commoniy known as fibrinoid leukodystrophy is an extremely rare, non- familial, progressive, lethal leukodystrophy which is characterized predominantly by abnormalities of white matter in bilateral frontal regions. It usually presents early within first 2 years of life with clinical features of macrocephaly, recurrent seizures and psychomotor retardation. Diagnosis of this white matter disorder is possible with certain features seen on magnetic resonance imaging (MRI), even without the need for histological confirmation. Our case is a one year old male infant who presented with repeated episodes of focal seizures to the paediatrician. He was referred for an MRI and subsequently based on typical MRI findings the diagnosis of Alexander disease was made.

Aerococcus Urinae Endocarditis: A Case Report and Literature Review.

A 75-year-old male, with a past medical history of chronic kidney disease stage 3 (CKD3) and a recent diagnosis of bilateral hydronephrosis and Foley catheter placement, presented to the emergency department for fever. Blood cultures grew Aerococcus urinae. Transthoracic echo (TTE) demonstrated thickened aortic valve leaflets with perforation, multiple echo densities, and severe aortic regurgitation. The patient developed decompensated congestive heart failure and cardiogenic shock. En route to surgery for emergent aortic valve replacement, the patient lost pulse and was resuscitated. The patient was subsequently transferred to the ICU where the family decided to initiate comfort care measures. This case highlights the importance and necessity of the prompt diagnosis and treatment of infective endocarditis and makes the reader aware of uncommon and rare organisms, such as Aerococcus urinae, as potential etiologies.

Isolated Tear Of Posterolateral Bundle Of Anterior Cruciate Ligament.

Anterior cruciate ligament injuries are very commonly encountered during routine MRI reporting and various signs have been described for their identification. However, the diagnosis of isolated bundle tears is difficult using MRI, thus can be easily overlooked, especially isolated tear of posterolateral bundle. We present a case of a young male with "Gap" and "Footprint" signs on MRI knee joint, which are considered highly specific of posterolateral ACL bundle tear.

Design and Analysis of a High-Gain and Robust Multi-DOF Electro-thermally Actuated MEMS Gyroscope.

This paper presents the design and analysis of a multi degree of freedom (DOF) electro-thermally actuated non-resonant MEMS gyroscope with a 3-DOF drive mode and 1-DOF sense mode system. The 3-DOF drive mode system consists of three masses coupled together using suspension beams. The 1-DOF system consists of a single mass whose motion is decoupled from the drive mode using a decoupling frame. The gyroscope is designed to be operated in the flat region between the first two resonant peaks in drive mode, thus minimizing the effect of environmental and fabrication process variations on device performance. The high gain in the flat operational region is achieved by tuning the suspension beams stiffness. A detailed analytical model, considering the dynamics of both the electro-thermal actuator and multi-mass system, is developed. A parametric optimization is carried out, considering the microfabrication process constraints of the Metal Multi-User MEMS Processes (MetalMUMPs), to achieve high gain. The stiffness of suspension beams is optimized such that the sense mode resonant frequency lies in the flat region between the first two resonant peaks in the drive mode. The results acquired through the developed analytical model are verified with the help of 3D finite element method (FEM)-based simulations. The first three resonant frequencies in the drive mode are designed to be 2.51 kHz, 3.68 kHz, and 5.77 kHz, respectively. The sense mode resonant frequency is designed to be 3.13 kHz. At an actuation voltage of 0.2 V, the dynamically amplified drive mode gain in the sense mass is obtained to be 18.6 µm. With this gain, a capacitive change of 28.11   f F and 862.13   f F is achieved corresponding to the sense mode amplitude of 0.15   µ m and 4.5   µ m at atmospheric air pressure and in a vacuum, respectively.

Epidermoid cyst of perineum: a rare case in a young female.

Epidermoid cyst is a common, cutaneous, benign lesion that is frequently seen on the face, neck and trunk. It is rarely seen in the perineal region. The differential diagnosis of perineal cystic lesions includes a wide range of lesions, with an epidermoid cyst being a rare entity to be considered, and only a few such cases have been reported in the literature. Our case was a young Asian female who presented with painless perineal swelling for the past 6 months and was diagnosed as having an epidermoid cyst on the basis of diffusion-weighted MRI and contrast enhancement pattern, which was later confirmed by histopathological findings.

Large hiatal hernia in infancy with right intrathoracic stomach along with left sided morgagni hernia.

Congenital diaphragmatic hernia is a very common intrathoracic fetal anomaly with Morgagni hernia typically seen on right side anteriorly and Bochdalek hernia on left side posteriorly, because of the protective effects of liver and heart on either side respectively. Hiatal hernias range from herniation of a small portion of stomach into thoracic cavity to herniation of entire stomach into the left thoracic cavity. Very rarely the herniated stomach has been reported in the right thoracic cavity. Early diagnosis and treatment of all diaphragmatic hernias is essential to reduce the associated morbidity and mortality. We present a very rare and interesting case of an 18 months old baby girl with reverse scenarios. She had a large hiatal hernia with right intrathoracic stomach along with a left sided Morgagni hernia in combination.