Wide-field Magnetic Field and Temperature Imaging using Nanoscale Quantum Sensors

The simultaneous imaging of magnetic fields and temperature (MT) is important in a range of applications, including studies of carrier transport, solid-state material dynamics, and semiconductor device characterization. Techniques exist for separately measuring temperature (e.g., infrared (IR) microscopy, micro-Raman spectroscopy, and thermo-reflectance microscopy) and magnetic fields (e.g., scanning probe magnetic force microscopy and superconducting quantum interference devices). However, these techniques cannot measure magnetic fields and temperature simultaneously. Here, we use the exceptional temperature and magnetic field sensitivity of nitrogen vacancy (NV) spins in conformally-coated nanodiamonds to realize simultaneous wide-field MT imaging. Our "quantum conformally-attached thermo-magnetic" (Q-CAT) imaging enables (i) wide-field, high-frame-rate imaging (100 - 1000 Hz); (ii) high sensitivity; and (iii) compatibility with standard microscopes. We apply this technique to study the industrially important problem of characterizing multifinger gallium nitride high-electron-mobility transistors (GaN HEMTs). We spatially and temporally resolve the electric current distribution and resulting temperature rise, elucidating functional device behavior at the microscopic level. The general applicability of Q-CAT imaging serves as an important tool for understanding complex MT phenomena in material science, device physics, and related fields

Inversion produces opposite size illusions for faces and bodies

Faces are complex, multidimensional, and meaningful visual stimuli. Recently, Araragi and colleagues (Araragi, Aotani, & Kitaoka, 2012) demonstrated an intriguing face size illusion whereby an inverted face is perceived as larger than a physically identical upright face. Like the face, the human body is a highly familiar and important stimulus in our lives. Here, we investigated the specificity of the size underestimation of upright faces illusion, testing whether similar effects also hold for bodies, hands, and everyday objects. Experiments 1a and 1b replicated the face-size illusion. No size illusion was observed for hands or objects. Unexpectedly, a reverse size illusion was observed for bodies, so that upright bodies were perceived as larger than their inverted counterparts. Experiment 2 showed that the face and reverse body size illusions were maintained even when the photographic contrast polarity of the stimuli was reversed, indicating that the visual system driving the illusions relies on geometric featural information rather than image contrast. Our findings show that size illusions caused by inversion show a high level of category specificity, with opposite illusions for faces and bodies

Natural history of asymptomatic pancreatic cystic neoplasms

AbstractBackgroundThe management of asymptomatic pancreatic cysts is controversial and indications for excision are based on pathology and natural history.ObjectivesThis study aimed to examine outcomes of asymptomatic lesions using a protocol based on size and cyst fluid analysis.MethodsAsymptomatic cysts were identified from a prospectively maintained database. Sequential cross‐sectional imaging studies were assessed, and results of endoscopic ultrasound‐guided aspiration were co‐analysed.ResultsA total of 338 asymptomatic patients underwent evaluation. Overall, 84 cysts were <1.5 cm and 254 were ≥1.5 cm in diameter. Median patient follow‐up was 5.1 years [interquartile range (IQR): 4.1–6.9 years]. In the group in which cysts measured <1.5 cm in diameter, median cyst size was 1.0 cm (IQR: 0.6–1.2 cm) at presentation and increased to 1.2 cm (IQR: 0.7–1.6 cm) during follow‐up. Five (6.0%) patients underwent resection, all within 2 months of presentation. In the group in which cysts measured ≥1.5 cm in diameter, median cyst size was 2.5 cm (IQR: 2.0–3.4 cm) at presentation and increased to 2.7 cm (IQR: 3.0–4.2 cm). A total of 63 (24.8%) patients underwent resection. Surgery was performed with 2 months in 53 (84.1%) patients, within 12 months in four (6.3%) patients and at >12 months post‐presentation in six (9.5%) patients. A total of 70.6% of resected specimens were identified as malignancies or mucinous lesions.conclusionsAsymptomatic cysts of <1.5 cm in diameter can safely be followed by imaging and are expected to undergo little change. A quarter of all asymptomatic cysts measuring ≥1.5 cm are appropriately resected based on imaging and cyst fluid analysis

Biomechanical evaluation of shape-memory alloy staples for internal fixation—an in vitro study

Background: The field of orthopaedics is a constantly evolving discipline. Despite the historical success of plates, pins and screws in fracture reduction and stabilisation, there is a continuing search for more efficient and improved methods of fracture fixation. The aim of this study was to evaluate shape-memory staples and to compare them to a currently used implant for internal fracture fixation. Multi-plane bending stability and interfragmentary compression were assessed across a simulated osteotomy using single and double-staple fixation and compared to a bridging plate. Methods: Transverse osteotomies were made in polyurethane blocks (20 × 20 × 120 mm) and repairs were performed with one (n = 6), or two (n = 6) 20 mm nitinol staples, or an eight-hole 2.7 mm quarter-tubular plate (n = 6). A pressure film was placed between fragments to determine contact area and compressive forces before and after loading. Loading consisted of multi-planar four-point bending with an actuator displacement of 3 mm. Gapping between segments was recorded to determine loads corresponding to a 2 mm gap and residual post-load gap. Results: Staple fixations showed statistically significant higher mean compressive loads and contact areas across the osteotomy compared to plate fixations. Double-staple constructs were superior to single-staple constructs for both parameters (p < 0.001). Double-staple constructs were significantly stiffer and endured significantly larger loads before 2 mm gap formation compared to other constructs in the dorsoventral plane (p < 0.001). However, both staple constructs were significantly less stiff and tolerated considerably lower loads before 2 mm gap formation when compared to plate constructs in the ventrodorsal and right-to-left lateral loading planes. Loading of staple constructs showed significantly reduced permanent gap formation in all planes except ventrodorsally when compared to plate constructs. Conclusions: Although staple fixations were not as stable as plate fixations in particular loading planes, double-staple constructs demonstrated the most consistent bending stiffness in all planes. Placing two perpendicular staples is suggested instead of single-staples whenever possible, with at least one staple applied on the compression side of the anticipated loading to improve construct stability

Are you suggesting that’s my hand? The relation between hypnotic suggestibility and the rubber hand illusion

Hypnotic suggestibility (HS) is the ability to respond automatically to suggestions and to experience alterations in perception and behaviour. Hypnotically suggestible participants are also better able to focus and sustain their attention on an experimental stimulus. The present study explores the relation between HS and susceptibility to the rubber hand illusion (RHI). Based on previous research with visual illusions, it was predicted that higher HS would lead to a stronger RHI illusion. Two behavioural output measures of the RHI, an implicit (proprioceptive drift) and an explicit (RHI questionnaire) measure were correlated against HS scores. Hypnotic suggestibility correlated positively with the implicit RHI measure contributing to 30% of the variation. However, there was no relation between HS and the explicit RHI questionnaire measure, or with compliance control items. High hypnotic suggestibility may facilitate, via attentional mechanisms, the multisensory integration of visuoproprioceptive inputs that leads to greater perceptual mislocalisation of a participant’s hand. These results may provide insight into the multisensory brain mechanisms involved in our sense of embodiment

A comparison of the effects of manual hyperinflation and ventilator hyperinflation on restoring end-expiratory lung volume after endotracheal suctioning: a pilot physiologic study

Purpose: Endotracheal suctioning (ES) of mechanically ventilated patients decreases end-expiratory lung volume (EELV). Manual hyperinflation (MHI) and ventilator hyperinflation (VHI) may restore EELV post-ES but it remains unknown which method is most effective. The primary aim was to compare the efficacy of MHI and VHI in restoring EELV post-ES. Materials and methods: ES was performed on mechanically ventilated intensive care patients, followed by MHI or VHI, in a randomised crossover design. The washout period between interventions was 1 h. End-expiratory lung impedance (EELI), measured by electrical impedance tomography, was recorded at baseline, during ES, during hyperinflation and 1, 5, 15 and 30 min post-hyperinflation. Results: Nine participants were studied. ES decreased EELI by 1672z (95% CI, 1204 to 2140) from baseline. From baseline, MHI increased EELI by 1154z (95% CI, 977 to 1330) while VHI increased EELI by 769z (95% CI, 457 to 1080). Five minutes post-VHI, EELI remained 528z (95% CI, 4 to 1053) above baseline. Fifteen minutes post-MHI, EELI remained 351z (95% CI, 111 to 592) above baseline. At subsequent time-points, EELI returned to baseline. Conclusions: MHI and VHI effectively restore EELV above baseline post-ES and should be considered post suctioning

Associations of Objectively Measured Light-Intensity Activity on Metabolic Risk Factors in Female Adults

Metabolic syndrome (MetSy) has been defined as a collection of metabolic irregularities that increase the risk of cardiovascular disease, type 2 diabetes, and all-cause mortality. Women are at an even greater risk for developing MetSy when compared to men with prevalence increasing with age. Moderate to vigorous physical activity (MVPA) has shown consistent association with decreases in risk of MetSy; however, light physical activity (LPA) has been studied less often in comparison. PURPOSE: The purpose of this study was to examine relationships between accelerometer-determined LPA and MetSy risk factors (waist circumference (WC), glucose, high density lipoprotein (HDL), triglycerides, systolic blood pressure (SBP), and diastolic blood pressure (DPB)) across women of different age groups. METHODS: A cross-sectional study design was used to examine 68 female participants, ages 20-65, employed in sedentary careers working in an urban area in the south central United States. Venous blood samples were taken from the antecubital area of the arm from all participants who had fasted at least eight hours prior to their scheduled appointment times. Physical activity data was collected for seven days via hip-worn accelerometers with LPA being measured based on Freedson cut-points (100-1951 counts per minute). MetSy was diagnosed based on the criteria set forth by the National Cholesterol Education Program in 2002. Data were analyzed using regression analysis with SPSS version 20.0. Between-subject analysis was conducted for four age groups (group1=20-35; group2=36-45; group3=46-55; group4=55 and older) using LPA, WC, glucose, HDL, triglycerides, SBP, and DPB. RESULTS: Between-subject regression analysis showed HDL as a significant MetSy risk factor in a full model (p=0.02) and a model with age groups as the only independent variable (p=0.00). Post-hoc Tukey tests showed significance differences in HDL among groups 4 and 2 (confidence interval (CI): 4.03, 35.92; p=0.00), and groups 4 and 3 (CI: 6.06, 39.63; p=0.00). Significance dropped below the apriori level of 0.05 in a model based on LPA. Post-hoc Tukey tests revealed non-significant (α\u3e0.05) associations between LPA levels (high, medium, low) and all MetSy values. CONCLUSION: The relationship between LPA and MetSy risk factors has been studied less frequently than MVPA in relation to MetSy risk factors. Based on these findings LPA is not significantly related with these risk factors. Future studies should continue to explore the relationship between LPA and MetSy risk factors among both men and woman, and in different settings