Gecko adhesion based sea star crawler robot.

Over the years, efforts in bioinspired soft robotics have led to mobile systems that emulate features of natural animal locomotion. This includes combining mechanisms from multiple organisms to further improve movement. In this work, we seek to improve locomotion in soft, amphibious robots by combining two independent mechanisms: sea star locomotion gait and gecko adhesion. Specifically, we present a sea star-inspired robot with a gecko-inspired adhesive surface that is able to crawl on a variety of surfaces. It is composed of soft and stretchable elastomer and has five limbs that are powered with pneumatic actuation. The gecko-inspired adhesion provides additional grip on wet and dry surfaces, thus enabling the robot to climb on 25° slopes and hold on statically to 51° slopes.

Battery Charge Curve Prediction via Feature Extraction and Supervised Machine Learning.

Real-time onboard state monitoring and estimation of a battery over its lifetime is indispensable for the safe and durable operation of battery-powered devices. In this study, a methodology to predict the entire constant-current cycling curve with limited input information that can be collected in a short period of time is developed. A total of 10 066 charge curves of LiNiO2 -based batteries at a constant C-rate are collected. With the combination of a feature extraction step and a multiple linear regression step, the method can accurately predict an entire battery charge curve with an error of < 2% using only 10% of the charge curve as the input information. The method is further validated across other battery chemistries (LiCoO2 -based) using open-access datasets. The prediction error of the charge curves for the LiCoO2 -based battery is around 2% with only 5% of the charge curve as the input information, indicating the generalization of the developed methodology for predicting battery cycling curves. The developed method paves the way for fast onboard health status monitoring and estimation for batteries during practical applications.

Designing reliable electrochemical cells for operando lithium-ion battery study.

Operando experiments attract increasing attention in lithium-ion batteries (LIBs) studies for their ability to capture non-equilibrium and fast-transient processes during electrochemical reactions. They provide valuable information and mechanisms that cannot be obtained from ex-situ methods. Designing a suitable and reliable electrochemical cell is the first crucial step for most operando studies. A poorly designed in-situ cell introduces artifacts into the data and might lead to misleading results. Even though many in-situ cells have been designed and applied for operando studies, designing a reliable cell is not trivial, especially for long-term cycling experiments. This study introduces the steps and details of a specific type of in-situ cell, i.e., modified coin cell, that can be applied reliably in various operando experiments. The reliability of the modified coin cell is demonstrated by comparing its electrochemical performance with the standard coin cell. The modified coin cell is then applied in various operando experiments, including operando transmission X-ray microscopy and operando synchrotron X-ray scattering.•Sealing the cell casing window with metal films maintains the overall electrochemical performance of electrodes.•Depending on the operando experiment, the type of the coin cell and the window shape must be selected carefully.

Isolating Specific vs. Non-Specific Binding Responses in Conducting Polymer Biosensors for Bio-Fingerprinting.

A longstanding challenge for accurate sensing of biomolecules such as proteins concerns specifically detecting a target analyte in a complex sample (e.g., food) without suffering from nonspecific binding or interactions from the target itself or other analytes present in the sample. Every sensor suffers from this fundamental drawback, which limits its sensitivity, specificity, and longevity. Existing efforts to improve signal-to-noise ratio involve introducing additional steps to reduce nonspecific binding, which increases the cost of the sensor. Conducting polymer-based chemiresistive biosensors can be mechanically flexible, are inexpensive, label-free, and capable of detecting specific biomolecules in complex samples without purification steps, making them very versatile. In this paper, a poly (3,4-ethylenedioxyphene) (PEDOT) and poly (3-thiopheneethanol) (3TE) interpenetrating network on polypropylene-cellulose fabric is used as a platform for a chemiresistive biosensor, and the specific and nonspecific binding events are studied using the Biotin/Avidin and Gliadin/G12-specific complementary binding pairs. We observed that specific binding between these pairs results in a negative ΔR with the addition of the analyte and this response increases with increasing analyte concentration. Nonspecific binding was found to have the opposite response, a positive ΔR upon the addition of analyte was seen in nonspecific binding cases. We further demonstrate the ability of the sensor to detect a targeted protein in a dual-protein analyte solution. The machine-learning classifier, random forest, predicted the presence of Biotin with 75% accuracy in dual-analyte solutions. This capability of distinguishing between specific and nonspecific binding can be a step towards solving the problem of false positives or false negatives to which all biosensors are susceptible.

Tailoring Electrode-Electrolyte Interfaces in Lithium-Ion Batteries Using Molecularly Engineered Functional Polymers.

Electrode-electrolyte interfaces (EEIs) affect the rate capability, cycling stability, and thermal safety of lithium-ion batteries (LIBs). Designing stable EEIs with fast Li+ transport is crucial for developing advanced LIBs. Here, we study Li+ kinetics at EEIs tailored by three nanoscale polymer thin films via chemical vapor deposition (CVD) polymerization. Small binding energy with Li+ and the presence of sufficient binding sites for Li+ allow poly(3,4-ethylenedioxythiophene) (PEDOT) based artificial coatings to enable fast charging of LiCoO2. Operando synchrotron X-ray diffraction experiments suggest that the superior Li+ transport property in PEDOT further improves current homogeneity in the LiCoO2 electrode during cycling. PEDOT also forms chemical bonds with LiCoO2, which reduces Co dissolution and inhibits electrolyte decomposition. As a result, the LiCoO2 4.5 V cycle life tested at C/2 increases over 1700% after PEDOT coating. In comparison, the other two polymer coatings show undesirable effects on LiCoO2 performance. These insights provide us with rules for selecting/designing polymers to engineer EEIs in advanced LIBs.

Quality control in the orthodontic department of a Tertiary Military Dental Centre: A decade clinical audit.

BACKGROUND: The objective of the study was to analyze the quality control of the treatment within the orthodontic department by determining the workload, type of treatment, and quality of outcome. METHOD: Two hundred eighty patients were selected from departmental archives, who underwent orthodontic treatment since January 2010 and assessed using index of complexity, outcome and treatment need. Descriptive statistics was performed by SPSS, version 21 (IBM, USA). Mann-Whitney U test was applied to assess the difference between complexity and improvement grade. RESULT: Orthodontic treatment was provided to 56.43% of female and 43.57% male patients with a mean age of 16.91 years. Angle's class I type malocclusion was the highest with 35.71%. Preadjusted edgewise metal appliance with 95% dominated the mechanics. About 12.14% and 3.57% patients got benefited with myofunctional and orthopedic treatment, respectively. Ten percent of patients were treated with orthognathic surgery. The mean duration of treatment was 31.19 months with a range of minimum of 17 months to a maximum of 46 months. Among 87.14% patients treated by faculty, 47.95% had difficult complexity grading and 22.95% had very difficult complexity grading. Residents had provided treatment with 63.88% difficult and 19.44% very difficult grade. Mann-Whitney U test of overall complexity and improvement grade showed Z score of -9.25715 which was highly significant. CONCLUSION: The present study concludes that fair quality control is being maintained by the department considering the number of patients, its severity, and excellent outcomes. However, being the premier institute of Indian Armed Forces, regular clinical audit should be conducted to fulfill demand and supply ratio in appropriation.

Anisotropy of W-band complex permittivity in Al2O3.

The dielectric anisotropy of Al2O3 is studied here by characterizing W-band (75-110 GHz) complex permittivity of four different orientations of sapphire (Al2O3 single crystals). This was done using free-space, focused beam methods. Dielectric polarizability ([Formula: see text]) of these orientations is then calculated and these values are related to their complex permittivity. Based on this relationship, a framework is developed for rapid and straightforward estimation of dielectric anisotropy using a known crystal structure and a dielectric permittivity measurement performed on one orientation of the material. This framework can be applied to other materials with dielectric anisotropy (e.g. SnO2, LiGaO2) to predict permittivity for different orientations, enabling rapid design of high-frequency systems (e.g. radomes, electromagnetic windows). These permittivity measurements were also used to determine the dominant polarization mechanisms leading to dielectric anisotropy of Al2O3 in the W-band; electronic and ionic polarization orthogonal to the direction of the focused beam.

Surface Engineering of a LiMn2O4 Electrode Using Nanoscale Polymer Thin Films via Chemical Vapor Deposition Polymerization.

Surface engineering is a critical technique for improving the performance of lithium-ion batteries (LIBs). Here, we introduce a novel vapor-based technique, namely, chemical vapor deposition polymerization, that can engineer nanoscale polymer thin films with controllable thickness and composition on the surface of battery electrodes. This technique enables us to, for the first time, systematically compare the effects of a conducting poly(3,4-ethylenedioxythiophene) (PEDOT) polymer and an insulating poly(divinylbenzene) (PDVB) polymer on the performance of a LiMn2O4 electrode in LIBs. Our results show that conducting PEDOT coatings improve both the rate and the cycling performance of LiMn2O4 electrodes, whereas insulating PDVB coatings have little effect on these performances. The PEDOT coating increases 10 C rate capacity by 83% at 25 °C (from 23 to 42 mA h/g) and by 30% at 50 °C (from 64 to 83 mA h/g). Furthermore, the PEDOT coating extends the high-temperature (50 °C) cycling life of LiMn2O4 by over 60%. A model is developed, which can precisely describe the capacity degradation exhibited by the different types of cells, based on the aging mechanisms of Mn dissolution and solid-electrolyte interphase growth. Results from X-ray photoelectron spectroscopy suggest that chemical or coordination bonds form between Mn in LiMn2O4 and O and S in the PEDOT film. These bonds stabilize the surface of LiMn2O4 and thus improve the cycling performance. In contrast, no bonds form between Mn and the elements in the PDVB film. We further demonstrate that this vapor-based technique can be extended to other cathodes for advanced LIBs.

Thermal conductivity of poly(3,4-ethylenedioxythiophene) films engineered by oxidative chemical vapor deposition (oCVD).

Oxidative chemical vapor deposition (oCVD) is a versatile technique that can simultaneously tailor properties (e.g., electrical, thermal conductivity) and morphology of polymer films at the nanoscale. In this work, we report the thermal conductivity of nanoscale oCVD grown poly(3,4-ethylenedioxythiophene) (PEDOT) films for the first time. Measurements as low as 0.16 W m-1 K-1 are obtained at room temperature for PEDOT films with thicknesses ranging from 50-100 nm. These values are lower than those for solution processed PEDOT films doped with the solubilizing agent PSS (polystyrene sulfonate). The thermal conductivity of oCVD grown PEDOT films show no clear dependence on electrical conductivity, which ranges from 1 S cm-1 to 30 S cm-1. It is suspected that at these electrical conductivities, the electronic contribution to the thermal conductivity is extremely small and that phonon transport is dominant. Our findings suggest that CVD polymerization is a promising route towards engineering polymer films that combine low thermal conductivity with relatively high electrical conductivity values.

Interdisciplinary Management of Patient with Advanced Periodontal Disease.

This case report describes the interdisciplinary management of an adult patient with advanced periodontal disease. Treatment involved orthodontic and periodontal management. Good esthetic results and dental relationships were achieved by the treatment.

iCVD Cyclic Polysiloxane and Polysilazane as Nanoscale Thin-Film Electrolyte: Synthesis and Properties.

A group of crosslinked cyclic siloxane (Si-O) and silazane (Si-N) polymers are synthesized via solvent-free initiated chemical vapor deposition (iCVD). Notably, this is the first report of cyclic polysilazanes synthesized via the gas-phase iCVD method. The deposited nanoscale thin films are thermally stable and chemically inert. By iCVD, they can uniformly and conformally cover nonplanar surfaces having complex geometry. Although polysiloxanes are traditionally utilized as dielectric materials and insulators, our research shows these cyclic organosilicon polymers can conduct lithium ions (Li(+) ) at room temperature. The conformal coating and the room temperature ionic conductivity make these cyclic organosilicon polymers attractive for use as thin-film electrolytes in solid-state batteries. Also, their synthesis process and properties have been systemically studied and discussed.

Effect of retraction of anterior teeth on pharyngeal airway and hyoid bone position in Class I bimaxillary dentoalveolar protrusion.

BACKGROUND: To test the hypothesis that the retraction of anterior teeth has no effect on the dimensions of pharyngeal airway and to evaluate the retraction of anterior teeth on each parameter of pharyngeal airway. METHODS: Twenty-two adult patients of Class I bimaxillary protrusion requiring first premolar extractions with maximum anchorage requirements were selected. The pharyngeal airway and dentofacial parameters of the patients were compared using pre- and post-treatment lateral cephalograms with the help of Student's paired t-test (P < 0.05). The relationship between airway size and dentofacial parameters was also evaluated using Pearson correlation coefficient. RESULTS: The upper and lower lips were retracted by 2.25 and 5.4 mm after retraction of the incisors. The tips of upper and lower incisors were retracted by 7.75 and 7.15 mm, respectively. There was a statistically significant decrease in SPP-SPPW (P < 0.05), U-MPW (P < 0.001), TB-TPPW (P < 0.001), and change in HRGN (P < 0.01). A significant correlation was observed between the amount of retraction of lower incisor and decrease in the pharyngeal airway posterior to soft palate (r = 0.102), tongue (r = 0.322), and change in HRGN (r = 0.265). CONCLUSIONS: The size of the pharyngeal (velopharyngeal and glossopharyngeal) airway reduced and hyoid bone position changed after retraction of the incisors in extraction space in bimaxillary protrusive adult patients.

A radiographic study of external apical root resorption in patients treated with single-phase fixed orthodontic therapy.

BACKGROUND: External apical root resorption (EARR) is one of the most common iatrogenic consequences of orthodontic tooth movement. Many factors like gender, duration, orthodontic force and duration of orthodontic treatment have been implicated to cause EARR. METHODS: Pre- and post-treatment OPGs of 60 orthodontic patients (30 males and 30 females) who had undergone treatment with a single phase of fixed orthodontic therapy were randomly selected from institutional archives. The root apices were evaluated for EARR by a single operator on an radiograph viewing box at a standardized source of light using a four-grade ordinal scale. Anterior EARR was measured on the maxillary and mandibular canines. Posterior EARR was measured on premolars, mesiobuccal and distobuccal roots of maxillary first molars and mesial and distal roots of mandibular first molars. The results were compiled and subjected to statistical analysis. RESULTS: The cases in which the patients underwent therapeutic extraction had a relatively higher amount of EARR compared to the cases in which the patients were treated by non-extraction therapy (P < 0.001). Odds ratio indicated that extraction cases had two-fold increased risk of EARR than non-extraction cases (P < 0.001). No statistically significant difference was observed in the distribution of EARR based on gender or duration of orthodontic treatment (P > 0.05). CONCLUSION: Therapeutic extraction is an important determinant of post-treatment EARR. Gender and duration of orthodontic treatment may not be important variables in the causation of EARR according to the findings of this study. However, longitudinal studies with larger sample size are required to validate the results of this study.

Effect of surgical mandibular advancement on pharyngeal airway dimensions: a three-dimensional computed tomography study.

The aim of this study was to quantify the changes in pharyngeal airway space (PAS) in patients with a skeletal class II malocclusion managed by bilateral sagittal split ramus osteotomy for mandibular advancement, using three-dimensional (3D) registration. The sample comprised 16 patients (mean age 21.69±2.80 years). Preoperative (T0) and postoperative (T1) computed tomography scans were recorded. Linear, cross-sectional area (CSA), and volumetric parameters of the velopharynx, oropharynx, and hypopharynx were evaluated. Parameters were compared with paired samples t-tests. Highly significant changes in dimension were measured in both sagittal and transverse planes (P<0.001). CSA measurements increased significantly between T0 and T1 (P<0.001). A significant increase in PAS volume was found at T1 compared with T0 (P<0.001). The changes in PAS were quantified using 3D reconstruction. Along the sagittal and transverse planes, the greatest increase was seen in the oropharynx (12.16% and 11.50%, respectively), followed by hypopharynx (11.00% and 9.07%) and velopharynx (8.97% and 6.73%). CSA increased by 41.69%, 34.56%, and 28.81% in the oropharynx, hypopharynx, and velopharynx, respectively. The volumetric increase was greatest in the oropharynx (49.79%) and least in the velopharynx (38.92%). These established quantifications may act as a useful guide for clinicians in the field of dental sleep medicine.

Management of Tooth Size Arch Size Discrepancy (TSASD) in Patients with Sleep Disorder Breathing.

This case report describes the interdisciplinary management of an adult patient with sleep disorder breathing i.e. snoring. Treatment involved combined ortho-surgical management. Marked improvement in general health, good esthetic results, and dental relationships were achieved by the treatment.

Therapeutic efficacy of a hybrid mandibular advancement device in the management of obstructive sleep apnea assessed with acoustic reflection technique.

Obstructive sleep apnea (OSA) is one of the most common forms of sleep-disordered breathing. Various treatment modalities include behavior modification therapy, nasal continuous positive airway pressure (CPAP), oral appliance therapy, and various surgical modalities. Oral appliances are noninvasive and recommended treatment modality for snoring, mild to moderate OSA cases and severe OSA cases when patient is not compliant to CPAP therapy and unwilling for surgery. Acoustic reflection technique (ART) is a relatively new modality for three-dimensional assessment of airway caliber in various clinical situations. The accuracy and reproducibility of acoustic rhinometry and acoustic pharyngometry assessment are comparable to computerized tomography and magnetic resonance imaging. This case report highlights the therapeutic efficacy of an innovative customized acrylic hybrid mandibular advancement device in the management of polysomnography diagnosed OSA cases, and the treatment results were assessed by ART.

Oligomeric interface modifiers in hybrid polymer solar cell prototypes investigated by fluorescence voltage spectroscopy.

Carboxylated oligothiophenes were evaluated as interfacial modifiers between the organic poly(3-hexylthiophene) (P3HT) and inorganic TiO2 layers in bilayer hybrid polymer solar cells. Carboxylated oligothiophenes can be isolated using conventional purification techniques resulting in pure, monodisperse molecules with 100% carboxylation. Device prototypes using carboxylated oligothiophenes as interfacial modifiers showed improved performance in the open-circuit voltage and fill factor over devices using unmodified oligothiophenes as interfacial modifiers. X-ray photoelectron spectroscopy (XPS) studies supported the idea that interface layer adhesion was improved by functionalizing oligothiophenes with a carboxyl moiety. Wide-field fluorescence images revealed that devices made using carboxylated oligothiophenes had fewer aggregates in the P3HT layers atop the modified TiO2 surface. Hysteresis seen in the fluorescence intensity as a function of applied bias, obtained from In-Device Fluorescence Voltage Spectroscopy (ID-FVS), was found to be a diagnostic criterion of the quality of the hybrid interface modification. The best interfaces were found using oligothiophenes functionalized with carboxylates, which created smooth layers on TiO2, and showed no hysteresis, suggesting elimination of interfacial charge traps. However, this hysteresis could be re-introduced by increasing the scan rate of the applied bias, suggesting that smooth P3HT layers created by carboxylated oligothiophene interface modifiers were necessary but not sufficient for sustaining improved photovoltaic properties especially during long-term device operation.

Evaluation of the hard and soft tissue changes after maxillary advancement with rigid external distractor in unilateral cleft lip and palate induced maxillary hypoplasia.

BACKGROUND: Midfacial growth retardation in cleft lip and palate (CLP) cases, is seen in all the three dimensions. Conventionally these cases are managed by orthographic surgery which has a high rate of relapse. The application of the distraction osteogenesis (DO) has revolutionized the management protocol. The aim of the study was to evaluate the efficacy of rigid external distractor (RED) in management of cleft induced maxillary hypoplasia. METHODS: Ten cases of unilateral CLP between 11 and 20 years of age having gross midfacial deficiency and those who have undergone presurgical orthodontic treatment were included in the study. The cases were operated for Le Fort 1 osteotomy and application of RED. DO was carried out through transnasal traction wires. Clinico-radiological evaluation of presurgical and 1, 6 and 12 months post distraction parameters were statistically analysed by application of paired 't'-test. RESULT: There were 4 males and 6 females with a mean age of 15.1 years. The mean distraction carried out was 14.95 mm. There was a significant improvement in all the hard and soft tissue parameters except SNB. Facial profile improvement and stable occlusion was achieved in all the cases. CONCLUSION: Midfacial DO using RED is a versatile procedure where the maxilla can be moved in multiple planes to achieve a functional, aesthetic and occlusal balance. Keeping in view of the significant relapse rate the clinicians are required to plan 15-20% excess amount of distraction.

Pharyngeal airway analysis in obese and non-obese patients with obstructive sleep apnea syndrome.

BACKGROUND: Sleep disorders are a group of disorders characterized by abnormalities of respiration during sleep. OSA (Obstructive Sleep Apnea) is characterized by the repetitive episodes of complete or partial collapse of the upper airway during sleep, causing a cessation or a significant reduction of airflow. METHOD: The study population consisted of 30 control patients (AHI ≤ 5) events per hour, 74 patients with OSAS, including 34 Obese (BMI ≥ 27) and 40 non-obese (BMI ≤ 27). Polysomnography and measurements of 21 cephalometric variables were carried out for all patients with OSAS. RESULTS: Obese patient with OSAS showed significant difference in following cephalometric parameters: (1) PAS (2) MPT (3) MPH (4) PNS-P (5) SAS. In addition, obese patient had longer tongue (TGL), more anteriorly displaced hyoid bones (H-VL) and more anterior displacement of mandible (G-VL) when compared with control groups. The findings of non-obese patients when compared to controls showed all the findings of obese patients and in addition to that narrow bony oropharynx were significant. Step wise regression analysis showed the significant predictors for all patients were MPH, PNS-P, bony nasopharynx (PNSBa), MPT, and palatal length (ANS-PNS) for AHI. The significant predictors for obese OSA (obstructive sleep apnea) group were MAS while for non-obese OSA group ANS-PNS was significant predictor for AHI (apnea-hypopnea index). CONCLUSION: Craniofacial landmarks such as increase in hyoid distance, longer tongue and soft palate with increased thickness and narrowing of superior pharyngeal, oropharyngeal and hypopharyngeal airway space may be important risk factors for development of OSAS.