Virtual reality as a countermeasure for astronaut motion sickness during simulated post-flight water landings.

Entry motion sickness (EMS) affects crewmembers upon return to Earth following extended adaptation to microgravity. Anticholinergic pharmaceuticals (e.g., Meclizine) are often taken prior to landing; however, they have operationally adverse side effects (e.g., drowsiness). There is a need to develop non-pharmaceutical countermeasures to EMS. We assessed the efficacy of a technological countermeasure providing external visual cues following splashdown, where otherwise only nauseogenic internal cabin visual references are available. Our countermeasure provided motion-congruent visual cues of an Earth-fixed scene in virtual reality, which was compared to a control condition with a head-fixed fixation point in virtual reality in a between-subject design with 15 subjects in each group. We tested the countermeasure's effectiveness at mitigating motion sickness symptoms at the end of a ground-based reentry analog: approximately 1 h of 2Gx centrifugation followed by up to 1 h of wave-like motion. Secondarily, we explored differences in vestibular-mediated balance performance between the two conditions. While Motion Sickness Questionnaire outcomes did not differ detectably between groups, we found significantly better survival rates (with dropout dictated by reporting moderate nausea consecutively over 2 min) in the visual countermeasure group than the control group (79% survival vs. 33%, t(14) = 2.50, p = 0.027). Following the reentry analogs, subjects demonstrated significantly higher sway prior to recovery (p = 0.0004), which did not differ between control and countermeasure groups. These results imply that providing motion-congruent visual cues may be an effective mean for curbing the development of moderate nausea and increasing comfort following future space missions.

Adamantinoma-like Ewing sarcoma of thyroid gland-An unfamiliar mimicker of epithelial and mesenchymal neoplasms of the head and neck.

INTRODUCTION: Adamantinoma-like Ewing Sarcoma (ALES) is a rare variant of the Ewing family of tumours (EFT) harbouring the EWSR1-FLI1 translocation and with complex epithelial differentiation. Very few cases of ALES involving thyroid have been reported in literature. CASE REPORT: We report a case of ALES involving the thyroid in a 61-year-old male who presented with an enlarging nodule in the left lobe of the thyroid and underwent hemithyroidectomy. DISCUSSION: ALES demonstrates morphologic similarity to a multitude of epithelial and mesenchymal tumours, creating a potential diagnostic pitfall in thyroid and head and neck pathology. Given the rarity of this tumour, there is also a lack of accepted guidelines regarding further surgical management of these cases following hemithyroidectomy.

A repeating fast radio burst source in a globular cluster.

Fast radio bursts (FRBs) are flashes of unknown physical origin1. The majority of FRBs have been seen only once, although some are known to generate multiple flashes2,3. Many models invoke magnetically powered neutron stars (magnetars) as the source of the emission4,5. Recently, the discovery6 of another repeater (FRB 20200120E) was announced, in the direction of the nearby galaxy M81, with four potential counterparts at other wavelengths6. Here we report observations that localized the FRB to a globular cluster associated with M81, where it is 2 parsecs away from the optical centre of the cluster. Globular clusters host old stellar populations, challenging FRB models that invoke young magnetars formed in a core-collapse supernova. We propose instead that FRB 20200120E originates from a highly magnetized neutron star formed either through the accretion-induced collapse of a white dwarf, or the merger of compact stars in a binary system7. Compact binaries are efficiently formed inside globular clusters, so a model invoking them could also be responsible for the observed bursts.

Substituent enhanced fluorescence properties of star α-cyanostilbenes and their application in bioimaging.

A series of star α-cyanostilbenes with D-π-A structures comprising triphenylamine as the donor, the cyanovinyl group as the acceptor and different substituents on the terminal phenyl rings were synthesized and characterized. The influence of the substituents on the photophysical, electrochemical and thermal properties of the star molecules was investigated in detail. A strongly electron withdrawing nitro substituent on the phenyl ring (NTBTNPA) increased the absorption and emission maxima, the Stokes shift, and the difference between the ground and excited state dipole moments and decreased the fluorescence quantum yield, fluorescence lifetime and band gap energy between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO). This molecule (i.e., NTBTNPA) also showed aggregation-induced enhanced emission; it showed emission at 608 nm in pure DMF and displayed red-shifted emission at 625 nm and new emission at 706 nm in a DMF/water (50 : 50) binary mixture. Aggregation of this molecule in different DMF/water mixtures was confirmed by the dynamic light scattering method. The HOMO, LUMO and band gap energy values of all the star molecules calculated theoretically using density functional theory (DFT) were in good agreement with the experimentally determined values. The biocompatibility of NTBTNPA was tested with two Gram positive and two Gram negative bacteria and also with a fungus. Based on the photophysical properties, NTBTNPA was used as a fluorophore for bio-imaging application of a fungus, Rhizoctonia solani, as a model and the results obtained were excellent.

A Randomized Controlled Study Comparing Efficacy of Classical and Gow-Gates Technique for Providing Anesthesia During Surgical Removal of Impacted Mandibular Third Molar: A Split Mouth Design.

INTRODUCTION: Reliable profound mandibular block anesthesia is questionable when depositing the anesthetic solution at the lingula. The Gow-Gates technique is an useful alternative to the classical inferior alveolar nerve block and the incidence of unsuccessful anesthesia may be as high as classical technique. The aim of this study is to compare the clinical efficacy, degree of patient acceptability, advantages, disadvantages and limitations of the classical and Gow-Gates techniques for providing anesthesia in patients undergoing bilateral symmetrical surgical removal of impacted mandibular third molar under local anesthesia. MATERIAL AND METHODS: The split mouth design study was conducted on 100 patients aged between 20 to 40 years undergoing surgical removal of bilateral symmetrical impacted mandibular third molar performed by the same maxillofacial surgeon. 2 ml of 2 % lignocaine hydrochloride with 1:80,000 adrenaline was used as a standard local anesthetic solution in all the cases. By using four-digit numbers from a random number table, either Gow-Gates or classical inferior alveolar nerve block were randomly assigned to either left or right sides in each patient. The injections were administered by another surgeon who was blinded to the experiment. The patient was assessed for Pain experienced during injection, frequency of positive aspirations, Onset and duration of anesthesia and Nerves anesthetized. RESULTS: Results were statistically analyzed by Mann-Whitney and chi square test. A 'P' value of less than 0.05 was considered for statistical significance. Higher mean pain during injection was recorded in classical group, was found to be statistically significant. No significant association was observed between aspiration and the groups. Higher mean onset of anesthesia was recorded in Gow-gates group, was found to be statistically significant. Higher mean duration of anesthesia was recorded in Gow-gates group, was not statistically significant. Higher success rate was recorded in Gow-gates group and was statistically significant. CONCLUSION: If we ignore delayed onset of anesthesia of Gow gates technique, it is found to be more reliable, beneficial and have higher success rate than classical inferior alveolar nerve block technique.

Comparison of 'sutureless' Transconjunctival and Subciliary Approach for Treatment of Infraorbital Rim Fractures: a Clinical Study.

PURPOSE: The aim of the study is to compare subciliary incision and 'sutureless' transconjunctival incision in the treatment of infraorbital rim fractures. MATERIALS AND METHOD: In this prospective study, 40 patients with fractures of the infraorbital rim were selected and divided into 2 groups using random sampling technique. Group A patients were treated using 'sutureless' transconjunctival technique and group B patients were treated using subciliary approach. The following parameters were compared a) time taken, intraoperative ease of access, exposure achieved; b) clinical outcome and postoperative complications; c) Aesthetic outcome at intervals of 15 days, 1 month and 3 months. RESULTS: Total time taken for completion of surgery was lesser in group A patients. The presence of subconjunctival ecchymosis (at 1 month interval) and neurological deficit was found to be statistically significant (P<0.05) in the 'subciliary' group of patients. The transconjunctival approach showed better esthetic results and fewer post-operative complications. CONCLUSION: The subciliary approach gives good exposure of the infra-orbital rim and is better suited to reduce extensively displaced fractures of the infra-orbital rim. The transconjunctival approach is comparatively faster, gives better esthetic results and fewer post-operative complications but is technique sensitive and requires an additional lateral canthotomy in cases where more exposure is needed.

Running and tumbling with E. coli in polymeric solutions.

Run-and-tumble motility is widely used by swimming microorganisms including numerous prokaryotic and eukaryotic organisms. Here, we experimentally investigate the run-and-tumble dynamics of the bacterium E. coli in polymeric solutions. We find that even small amounts of polymer in solution can drastically change E. coli dynamics: cells tumble less and their velocity increases, leading to an enhancement in cell translational diffusion and a sharp decline in rotational diffusion. We show that suppression of tumbling is due to fluid viscosity while the enhancement in swimming speed is mainly due to fluid elasticity. Visualization of single fluorescently labeled DNA polymers reveals that the flow generated by individual E. coli is sufficiently strong to stretch polymer molecules and induce elastic stresses in the fluid, which in turn can act on the cell in such a way to enhance its transport. Our results show that the transport and spread of chemotactic cells can be independently modified and controlled by the fluid material properties.

Flagellar kinematics and swimming of algal cells in viscoelastic fluids.

The motility of microorganisms is influenced greatly by their hydrodynamic interactions with the fluidic environment they inhabit. We show by direct experimental observation of the bi-flagellated alga Chlamydomonas reinhardtii that fluid elasticity and viscosity strongly influence the beating pattern - the gait - and thereby control the propulsion speed. The beating frequency and the wave speed characterizing the cyclical bending are both enhanced by fluid elasticity. Despite these enhancements, the net swimming speed of the alga is hindered for fluids that are sufficiently elastic. The origin of this complex response lies in the interplay between the elasticity-induced changes in the spatial and temporal aspects of the flagellar cycle and the buildup and subsequent relaxation of elastic stresses during the power and recovery strokes.

An unusual complication of late onset allergic contact dermatitis to povidone iodine in oral & maxillofacial surgery - a report of 2 cases.

BACKGROUND: Povidone iodine (PVP-I) is a chemical complex of polyvinylpyrrolidone (also known as povidone or PVP) and elemental iodine. Iodine containing compounds are widely and commonly used as antiseptics and disinfectants. They are available in various forms like aqueous solution, tincture, aerosol, ointment, or foam. Skin irritation to them is due to the oxidative effects of iodine. Because of the low free iodine concentration in povidone-iodine, skin irritation is less frequent from short contact (1). CASE: We report two cases, both with no history of allergy to any drugs, who developed an allergic reaction 24 hours after the usage of povidone iodine as a pre-operative antiseptic to prepare (scrub) the lower third of face before surgical removal of third molars. This case report was granted an exemption by the ethical committee of our institution review board. The Helsinki declaration doesn't apply to this case presentation. CONCLUSIONS: PVP-1 is the most commonly used antiseptic scrubbing solution prior to most surgeries. However, allergic contact dermatitis due to PVP-I has not been extensively documented or reported and hence under evaluated, compared to other commonly encountered allergens. There is almost general agreement to the proposition that PVP-I is a very rare sensitizer (2,3) though there are some conflicting reports on the matter. However, sometimes when prolonged skin contact with PVP-I occurs when used as a pre-operative antiseptic agent, it can cause allergic dermatitis (4,5). Does this finding make pre-operative testing for allergies to PVP-1 necessary in all patients? A point to ponder.

Molecular mechanisms of anti-tumor properties of P276-00 in head and neck squamous cell carcinoma.

BACKGROUND: Tumors of the head and neck present aggressive pathological behavior in patients due to high expression of CDK/CCND1 proteins. P276-00, a novel CDK inhibitor currently being tested in clinic, inhibits growth of several cancers in vitro and in vivo. The pre clinical activity of P276-00 in head and neck cancer and its potential mechanisms of action at molecular level are the focus of the current studies. METHOD: We have investigated the anti-cancer activity of P276-00 in head and neck tumors in vitro and in vivo. Candidate gene expression profiling and cell based proteomic approaches were taken to understand the pathways affected by P276-00 treatment. RESULTS: It was observed that P276-00 is cytotoxic across various HNSCC cell lines with an IC50 ranging from 1.0-1.5 µmoles/L and culminated in significant cell-cycle arrest in G1/S phase followed by apoptosis. P276-00 treatment suppressed cell proliferation through inhibition of CCND1 expression, reduced phosphorylation of retinoblastoma protein and abrogative transcription of E2F1 gene targets. Further, we observed that apoptosis was mediated through P53 activation leading to higher BAX/BCL-2 ratio and cleaved caspase-3 levels. It was also seen that P276-00 treatment reduced expression of tumor micro-environment proteins such as IL-6, secreted EGFR and HSPA8. Finally, P276-00 treatment resulted in significant tumor growth inhibition in xenograft tumor models via lowered proliferative activity of E2F1 and aggravated P53 mediated apoptosis. CONCLUSION: In summary, we have observed that P276-00 inhibits cyclin-D/CDK4/P16/pRB/E2F axis and induces apoptosis by increased P53 phosphorylation in HNSCC cells. These results suggest a novel indication for P276-00 in head and neck cancer with a potential role for IL-6 and HSPA8 as candidate serum biomarkers.

Percutaneous Radiofrequency Rhizotomy in Treatment of Trigeminal neuralgia: A Prospective Study.

INTRODUCTION: Trigeminal neuralgia (TN) often called as "Tic douloureux" is a syndrome characterized by paroxysmal facial pain, is one of the most painful and debilitating craniofacial pain disorders. The controversy regarding the etiology and treatment of TN still exists. OBJECTIVE: To evaluate the effectiveness of percutaneous radiofrequency rhizotomy (PRR) for TN, after failure of pharmacological management. METHOD: A nonrandomized, non comparative, descriptive, in vivo study of 15 patients with TN of maxillary and mandibular divisions of trigeminal nerve and patients with pain refractory to pharmacological management were done. It was performed as an O.P.D procedure. A routine follow up was done in all cases for 1 year. RESULTS: In a total of 15 patients, 8 female and 7 male patients were enrolled for the study. Early pain relief (immediately, postoperatively to 6 month) classified as excellent or good (successful), occurred in 12 of 15 patients (80 %). Fair or poor pain relief (unsuccessful) occurred in three patients (20 %).There was no mortalities and no major morbidity. SUMMARY: It was found that surgical treatment with PRR is a safe and effective way to manage patients with TN in whom pharmacologic therapy is either ineffective or not tolerated, with low side effects which are well tolerated.

"Transport distraction osteogenesis for reconstruction of mandibular defects": our experience.

INTRODUCTION: Mandibular defects usually involve a combination of osseous and soft tissue deficiency and are among the most challenging problems in maxillofacial surgery, many options are available for mandibular reconstruction. One of the options discussed in literature recently being distraction osteogenesis. AIM AND OBJECTIVE: The aims and objectives of the study were to evaluate clinically the technique of distraction osteogenesis to reconstruct mandibular defects, using indigenous transport distractors, and to evaluate the efficacy of Indigenous transport distraction osteogenesis device. MATERIALS AND METHODS: A prospective, experimental study was designed to examine the use of transport distraction osteogenesis in the treatment of defects of the mandible. Four patients with defects of the mandible were subjected to distraction osteogenesis with indigenously manufactured distraction device. The regenerate was assessed clinically and radiographically. RESULTS: The results showed that the regenerate was clinically as hard as the adjacent unaffected mandible and radiologic evidence of bone regeneration was observed. The major advantage being regeneration of hard tissue and soft tissue components without the morbidity of donor site, so that functional rehabilitation of the patient is possible. CONCLUSION: Thus from our study it is shown that transport distraction osteogenesis using indigenous distractors is a reliable yet affordable option for reconstruction of mandibular defects.

A comparative study of temporary splints: bonded polyethylene fiber reinforcement ribbon and stainless steel wire + composite resin splint in the treatment of chronic periodontitis.

UNLABELLED: The present clinical study was undertaken to determine the effects of splinting overunsplinted mobile teeth following periodontal surgery and compared the efficacy of two splinting materials, i.e. Ribbond ribbon + Composite with Stainless steel wire + Composite. MATERIALS AND METHODS: Total of 30 patients (20 experimental and 10 control) formed the study group. Entire study was extended over a period of 12 weeks for each patient and treatment plan was divided into 8 phases. Healing response was monitored and application, durability, biocompatibility of splint material was assessed. RESULTS: Splint had a promising and beneficial effects on anterior teeth exhibiting Grade I to Grade II degrees of mobility. Experimental group showed a greater reduction in tooth mobility compared to control group. There was no significant difference in plaque index and Ribbond Ribbon reinforced with composite resin was an excellent material for application, patient comfort, resistance to fracture, biocompatable and esthetic acceptability. CLINICAL SIGNIFICANCE: Splinting is recommended as an adjunct to periodontal surgery in the treatment of hypermobile teeth, especially in cases where patient discomfort is a prominent factor.

Gastric emptying of hexose sugars: role of osmolality, molecular structure and the CCK1 receptor.

BACKGROUND: It is widely reported that hexose sugars slow gastric emptying (GE) via osmoreceptor stimulation but this remains uncertain. We evaluated the effects of a panel of hexoses of differing molecular structure, assessing the effects of osmolality, intra-individual reproducibility and the role of the CCK(1) receptor, in the regulation of GE by hexoses. METHODS: Thirty one healthy non-obese male and female subjects were studied in a series of protocols, using a (13) C-acetate breath test to evaluate GE of varying concentrations of glucose, galactose, fructose and tagatose, with water, NaCl and lactulose as controls. GE was further evaluated following the administration of a CCK(1) receptor antagonist. Three subjects underwent repeated studies to evaluate intra-individual reproducibility. KEY RESULTS: At 250 mOsmol, a hexose-specific effect was apparent: tagatose slowed GE more potently than water, glucose and fructose (P < 0.05). Fructose (P < 0.05) also slowed GE, but with substantial inter-, but not intra-, individual differences. As osmolality increased further the hexose-specific differences were lost. At 500 mOsmol, all hexoses slowed GE compared with water (P < 0.05), whereas lactulose and saline did not. The slowing of GE by hexose sugars appeared to be CCK(1) receptor-dependent. CONCLUSIONS & INFERENCES: The effects of hexose sugars on GE appear related to their molecular structure rather than osmolality per se, and are, at least in part, CCK(1) receptor-dependent.

Involvement of human decidual cell-expressed tissue factor in uterine hemostasis and abruption.

Vascular injury increases access and binding of plasma-derived factor VII to perivascular cell membrane-bound tissue factor (TF). The resulting TF/VIIa complex promotes hemostasis by cleaving pro-thrombin to thrombin leading to the fibrin clot. In human pregnancy, decidual cell-expressed TF prevents decidual hemorrhage (abruption). During placentation, trophoblasts remodel decidual spiral arteries into high conductance vessels. Shallow trophoblast invasion impedes decidual vascular conversion, producing an inadequate uteroplacental blood flow that elicits abruption-related placental ischemia. Thrombin induces several biological effects via cell surface protease activated receptors. In first trimester human DCs thrombin increases synthesis of sFlt-1, which elicits placental ischemia by impeding angiogenesis-related decidual vascular remodeling. During pregnacy, the fibrillar collagen-rich amnion and choriodecidua extracellular matrix (ECM) provides greater than additive tensile strength and structural integrity. Thrombin acts as an autocrine/paracrine mediator that degrades these ECMs by augmenting decidual cell expression of: 1) matrix metalloproteinases and 2) interleukin-8, a key mediator of abruption-associated decidual infiltration of neutrophils, which express several ECM degrading proteases. Among the cell types at the maternal fetal interface at term, TF expression is highest in decidual cells indicating that this TF meets the hemostatic demands of labor and delivery. TF expression in cultured term decidual cells is enhanced by progestin and thrombin suggesting that the maintenance of elevated circulating progesterone provides hemostatic protection and that abruption-generated thrombin acts in an autocrine/paracrine fashion on decidual cells to promote hemostasis via enhanced TF expression.

Compressibility effects on steady streaming from a noncompact rigid sphere.

The problem of steady streaming around a rigid isolated sphere in a plane standing acoustic field is considered. Existing results in the literature have been generalized to allow for noncompactness of the sphere, and the influence of fluid compressibility on the streaming behavior has been included. It is found that in the high-frequency limit of interest for which the streaming is strongest, the effective steady slip velocity at the edge of the inner boundary layer region that is responsible for driving the steady streaming in the bulk of the fluid in the outer region, has a complex variation over the surface of the sphere that depends on (i) the sphere position (with respect to the node/antinode of the acoustic field), (ii) the extent of sphere compactness, and (iii) on a well-defined function (representing compressibility effects) of the fluid Prandtl number and its ratio of specific heats. Not surprisingly, the contribution from this function is negligible when the host fluid is a liquid. The steady streaming behavior around the sphere is demonstrated with the help of flow streamlines for various cases in the diffusive limit of weak outer flow for low streaming Reynolds numbers.

Spatial-mode control of vertical-cavity lasers with micromirrors fabricated and replicated in semiconductor materials.

Micromirrors were fabricated in gallium phosphide by mass transport to provide spatial-mode control of vertical-cavity surface-emitting lasers (VCSEL's). The concave mirrors were used in an external-cavity configuration to provide spatial filtering in the far field. Single-mode cw lasing was demonstrated in 15-microm-diameter VCSEL's with currents as high as 6 times threshold. The fabrication process was extended to micromirrors in gallium arsenide by use of a replication and dry-etch transfer process.

Is the incidence of deep vein thrombosis following myocardial infarction decreasing?

A trial was undertaken to compare the effectiveness of the antiplatelet drug, flurbiprofen, and subcutaneous heparin in the prevention of deep vein thrombosis following acute myocardial infarction. The original aim of the study could not be fulfilled as the incidence of isotopically-determined venous thrombosis in the group of control patients was only 9.5%. The incidence in all three groups was too low to assess the effectiveness of flurbiprofen prophylaxis. It is suggested that the low incidence may be related to the recent practice of early physiotherapy and ambulation in coronary care units. The patients who developed venous thrombosis were, on average, a little older than those who did not. No differences were observed in blood viscosity, plasma antithrombin III concentration or mean coronary prognostic index. The low incidence of venous thrombosis following acute myocardial infarction suggests a need to reassess the practice of prophylactic anticoagulant therapy in this condition.