Self-deployable contracting-cord metamaterials with tunable mechanical properties.

Recent advances in active materials and fabrication techniques have enabled the production of cyclically self-deployable metamaterials with an expanded functionality space. However, designing metamaterials that possess continuously tunable mechanical properties after self-deployment remains a challenge, notwithstanding its importance. Inspired by push puppets, we introduce an efficient design strategy to create reversibly self-deployable metamaterials with continuously tunable post-deployment stiffness and damping. Our metamaterial comprises contracting actuators threaded through beads with matching conical concavo-convex interfaces in networked chains. The slack network conforms to arbitrary shapes, but when actuated, it self-assembles into a preprogrammed configuration with beads gathered together. Further contraction of the actuators can dynamically tune the assembly's mechanical properties through the beads' particle jamming, while maintaining the overall structure with minimal change. We show that, after deployment, such metamaterials exhibit pronounced tunability in bending-dominated configurations: they can become more than 35 times stiffer and change their damping capability by over 50%. Through systematic analysis, we find that the beads' conical angle can introduce geometric nonlinearity, which has a major effect on the self-deployability and tunability of the metamaterial. Our work provides routes towards reversibly self-deployable, lightweight, and tunable metamaterials, with potential applications in soft robotics, reconfigurable architectures, and space engineering.

Origami-based integration of robots that sense, decide, and respond.

Origami-inspired engineering has enabled intelligent materials and structures to process and react to environmental stimuli. However, it is challenging to achieve complete sense-decide-act loops in origami materials for autonomous interaction with environments, mainly due to the lack of information processing units that can interface with sensing and actuation. Here, we introduce an integrated origami-based process to create autonomous robots by embedding sensing, computing, and actuating in compliant, conductive materials. By combining flexible bistable mechanisms and conductive thermal artificial muscles, we realize origami multiplexed switches and configure them to generate digital logic gates, memory bits, and thus integrated autonomous origami robots. We demonstrate with a flytrap-inspired robot that captures 'living prey', an untethered crawler that avoids obstacles, and a wheeled vehicle that locomotes with reprogrammable trajectories. Our method provides routes to achieve autonomy for origami robots through tight functional integration in compliant, conductive materials.

TDMA-based dual-mode communication for mobile wireless sensor networks.

Small highly mobile robots, and in particular micro air vehicles (MAVs), are well suited to the task of exploring unknown indoor environments such as buildings and caves. Such a task imposes a number of requirements on the underlying communication infrastructure, with differing goals during various stages of the mission. This work addresses those requirements with a hybrid communications infrastructure consisting of a stationary mesh network along with the mobile nodes. The combined network operates in two independent modes, coupling a highly efficient, low duty cycle, low throughput mode for routing and persistent sensing with a burst mode for high data rate communication. By strategically distributing available frequency channels between the mobile agents and the stationary nodes, the overall network provides reliable long-term communication paths while maximizing data throughput when needed.

Interrupted inferior vena cava syndrome.

We report a case of interrupted inferior vena cava (IVC) as a rare developmental defect. Inferior vena cava interruption is usually accompanied with azygos and hemiazygos continuation, and is asymptomatic. Consequently, venous blood from the caudal part of the body reaches the heart via the azygous vein and superior vena cava. A 50 year old female who came for routine health check-up was found to have pulmonary hypertension on two dimensional echocardiography. On further investigations she also had restriction on pulmonary function test. When computed tomography pulmonary angiography was done, showed dilated azygous vein without pulmonary embolism. Computed tomography of the abdomen demonstrated interrupted inferior vena cava. Such patients are at increased risk of deep vein thrombosis and pulmonary embolism.

A Cut-and-Fold Self-Sustained Compliant Oscillator for Autonomous Actuation of Origami-Inspired Robots.

Origami-inspired robots are of particular interest due to their potential for rapid and accessible design and fabrication of elegant designs and complex functionalities through cutting and folding of flexible two-dimensional sheets or even strings, that is, printable manufacturing. Yet, origami robots still require bulky rigid components or electronics for actuation and control to accomplish tasks with reliability, programmability, ability to output substantial force, and durability, restricting their full potential. In this study, we present a printable self-sustained compliant oscillator that generates periodic actuation using only constant electrical power, without discrete components or electronic control hardware. This oscillator is robust (9 out of 10 prototypes worked successfully on the first try), configurable (with tunable periods from 3 to 12 s), powerful (can overcome hydrodynamic resistance to consistently propel a swimmer at ∼1.6 body lengths/min or 3.66 mm/s), and long lasting (∼103 cycles); it enables driving macroscale devices with prescribed autonomous behaviors, for example, locomotion and sequencing. This oscillator is also fully functional underwater and in high magnetic fields. Our analytical model characterizes essential parameters of the oscillation period, enabling programmable design of the oscillator. The printable oscillator can be integrated into origami-inspired systems seamlessly and monolithically, allowing rapid design and prototyping; the resulting integrated devices are lightweight, low cost, compliant, electronic free, and nonmagnetic, enabling practical applications in extreme areas. We demonstrate the functionalities of the oscillator with: (1) autonomous gliding of a printable swimmer, (2) LED flashing, and (3) fluid stirring. This work paves the way for realizing fully printable autonomous robots with high integration of actuation and control.

Combined Central Retinal Vein and Branch Retinal Artery Occlusion Post Intense Physical Activity.

We report a case of combined central retinal vein occlusion and branch retinal artery occlusion. A previously healthy 47-year-old male presented with decreased vision in the right eye after completing a half marathon. A fundus exam and retinal imaging revealed a combined central retinal vein and branch retinal artery occlusion. In the present report, we review the literature and discuss the possible mechanisms behind combined retinal vessel occlusions. To our knowledge, this is the first reported case of combined central retinal vein occlusion and branch retinal artery occlusion following intense exercise.

Delayed relapse in pseudotumor cerebri due to new stenosis after transverse sinus stenting.

A patient presented with recurrent severe pseudotumor cerebri (PTC). Transverse sinus stenting is a very effective treatment option, however stenosis and intracranial hypertension can recur. In our patient, stenting initially resulted in resolution of papilloedema. However, after 5 years, a new stenosis developed which required further stenting. This case highlights the fact that, in patients with PTC who undergo transverse sinus stenting, a small proportion require repeat treatment due to formation of a new stenosis, usually adjacent to the existing stent. Patients with severe disease, such as ours, may be at higher risk of recurrence. Regardless of the severity, all patients who undergo stenting should have regular ocular follow-up.

Delayed relapse in pseudotumor cerebri due to new stenosis after transverse sinus stenting.

A patient presented with recurrent severe pseudotumor cerebri (PTC). Transverse sinus stenting is a very effective treatment option, however stenosis and intracranial hypertension can recur. In our patient, stenting initially resulted in resolution of papilloedema. However, after 5 years, a new stenosis developed which required further stenting. This case highlights the fact that, in patients with PTC who undergo transverse sinus stenting, a small proportion require repeat treatment due to formation of a new stenosis, usually adjacent to the existing stent. Patients with severe disease, such as ours, may be at higher risk of recurrence. Regardless of the severity, all patients who undergo stenting should have regular ocular follow-up.

Head and neck multidisciplinary team meetings: Effect on patient management.

BACKGROUND: The purpose of this study was for us to present our findings on the prospectively audited impact of head and neck multidisciplinary team meetings on patient management. METHODS: We collected clinical data, the pre-multidisciplinary team meeting treatment plan, the post-multidisciplinary team meeting treatment plans, and follow-up data from all patients discussed at a weekly multidisciplinary team meeting and we recorded the changes in management. RESULTS: One hundred seventy-two patients were discussed in 39 meetings. In 52 patients (30%), changes in management were documented of which 20 (67%) were major. Changes were statistically more likely when the referring physician was a medical or radiation oncologist, when the initial treatment plan did not include surgery, and when the histology was neither mucosal squamous cell cancer nor a skin malignancy. Compliance to the multidisciplinary team meeting treatment recommendation was 84% for all patients and 70% for patients with changes in their treatment recommendation. CONCLUSION: Head and neck multidisciplinary team meetings changed management in almost a third of the cases.

Bilateral panuveitis in a patient on vemurafenib BRAF inhibitor therapy for stage IV melanoma.

PURPOSE: To describe a case of recurrent, bilateral panuveitis caused by the BRAF proto-oncogene inhibitor vemurafenib. METHODS: Case report. RESULTS: A 25-year-old woman developed bilateral panuveitis and macular edema after initiating treatment with the BRAF enzyme inhibitor vemurafenib for stage IV cutaneous melanoma. The patient was successfully treated with sub-Tenon triamcinolone injections along with cessation of the medication. CONCLUSIONS: Panuveitis is a potential adverse effect of vemurafenib. Good communication with oncology is necessary, in case the medication needs to be discontinued.

Bronchoscopic needle aspiration in the diagnosis of mediastinal lymphadenopathy and staging of lung cancer.

Transbronchial needle aspiration (TBNA) has the potential to allow adequate mediastinal staging of non-small cell lung cancer with enlarged lymph nodes in most patients without the need for mediastinoscopy. Metastasis to the mediastinal lymph nodes is one of the most important factors in determining resectability and prognosis in non-small cell lung cancer. The importance of TBNA as a tool for diagnosing intrathoracic lymphadenopathy as well as in the staging of lung cancer has been reported in various studies. We performed a literature search in PubMed and Journal of Bronchology using the keyword transbronchial needle aspiration. TBNA is a safe and effective procedure to diagnose mediastinal lymphadenopathy. Real-time bronchoscopic ultrasound-guided TBNA is the new kid on the block, which can further enhance the sensitivity of bronchoscopy in the diagnosis of mediastinal lesions.

Therapeutic bronchoscopy for malignant airway stenoses: choice of modality and survival.

BACKGROUND: There are no data regarding the factors influencing the choice of therapeutic bronchoscopic modality in the management of malignant airway stenoses. OBJECTIVES: To assess the choice of therapeutic bronchoscopy modality and analyze factors influencing survival in patients with malignant central airway obstruction. MATERIALS AND METHODS: We performed 167 procedures in 130 consecutive patients, for malignant central airway obstruction, over six years. RESULTS: Laser was used either alone or in combination with stent insertion in 76% procedures. Laser only was used in 53% procedures for lesions below the main bronchi. Stents alone were used for extrinsic compression or stump insufficiency. Combined laser and stent insertion was most frequently used for lesions involving the trachea plus both main bronchi or only the main bronchi. The Dumon stent was preferred in lesions of the trachea and the right bronchial tree, the Ultraflex stent for lesions on the left side and stenoses below the main bronchi. Survival was better in patients with lung cancer, lesions restricted to one lung and when laser alone was used compared to esophageal cancer, metastases and tracheal involvement. CONCLUSION: The choice of different airway stents can be made based on the nature and site of the lesion. Dumon stents are suited for lesions in trachea and right main bronchus and the Ultraflex stents on the left side and stenoses beyond the main bronchi. Survival can be estimated based on the diagnosis, site of the lesion and treatment modality used.

Idiopathic pulmonary fibrosis with bronchogenic carcinoma.

Idiopathic pulmonary fibrosis is essentially a benign disease. We present a case of 65-year-old female patient who presented with left-sided chest pain and breathlessness. Her CT thorax revealed idiopathic pulmonary fibrosis along with a left-sided pleural-based mass. Biopsy of the mass revealed a squamous cell carcinoma. She was exposed to home wood smoke while cooking on the chulla for many years, which was possibly responsible for both the diseases.

Acute lung injury following exposure to nitric acid.

We present a series of three cases of survival following inhalation of nitric acid fumes, which resulted in acute respiratory distress. Inhalation of nitric acid fumes and its decomposition gases such as nitrogen dioxide results in delayed onset of acute respiratory distress syndrome. Intensive respiratory management, ventilatory support, and steroids can help in survival.

Beta-alanine suppresses heat inactivation of lactate dehydrogenase.

Beta-Alanine exhibits neurotransmitter activity and is a component of the anti-glycation agent carnosine. We propose that beta-alanine may have additional properties which may be of physiological significance. Interestingly, stress modulates the level of beta-alanine, which regulates excitotoxicity responses and prevents neuronal cell death. We hypothesize that beta-alanine's protective role may involve preservation of enzyme structure and function, suggesting that beta-alanine may act as a chemical chaperone. We used light scattering, enzyme activity and intrinsic fluorescence to monitor heat-induced changes in lactate dehydrogenase (LDH) in the presence and absence of beta-alanine. We observed that beta-alanine suppressed heat-induced LDH inactivation, prevented LDH aggregation, ameliorated the decrease in intrinsic fluorescence and reactivated thermally denatured LDH. These observations support the hypothesis that beta-alanine has chaperone-like activity and may play a cellular role in the preservation of enzyme function.