Single step fabrication of nano scale optical devices using binary contact mask deep UV interference lithography.

Interference Lithography (IL) is a powerful and inexpensive tool for large area precision nanoscale patterning of periodic structures. In this work we extend IL's capability to create features in arbitrary shapes and locations through the use of binary contact masks with wavefront division deep-UV interference lithography. Grating couplers for use in a streak measurement system and a focal plane division polarimeter are created to demonstrate the viability and versatility of the technique. Simultaneous fabrication of 90nm and 20µm features proves the potential of this process to simplify and streamline common fabrication processes in research and in industrial applications.

Does continuous positive airway pressure for extubation in congenital tracheoesophageal fistula increase the risk of anastomotic leak? A retrospective cohort study.

AIM: Immediate post-operative care of tracheoesophageal fistula (TEF) and oesophageal atresia (EA) requires mechanical ventilation. Early extubation is preferred, but subsequent respiratory distress may warrant re-intubation. Continuous positive airway pressure (CPAP) is a well-established modality to prevent extubation failures in preterm infants. However, it is not favoured in TEF/EA, because of the theoretical risk of oesophageal anastomotic leak (AL). The aim of this study was to find out if post-extubation CPAP is associated with increased risk of AL. METHODS: Retrospective cohort study (2007-2014). RESULTS: Fifty-one infants underwent primary repair in the newborn period. Median age at surgery was 24 h (interquartile range: 12, 24). In the post-extubation period, 10 received CPAP, whereas 41 did not. The median post-operative day at the commencement of CPAP was 2.5 days (interquartile range: 1, 6 days). Zero out of 10 in the CPAP group and 4/41 in the 'no CPAP' group developed AL on routine post-operative contrast studies (P = 0.57). Zero out of 10 in the CPAP group and 1/41 in the 'no CPAP group' developed recurrence of TEF necessitating re-surgery (P = 1.00). The neonate with recurrent fistula also had coarctation of aorta and needed protracted hospitalisation of 6 months, mainly because of the recurrence of TEF. CONCLUSION: The use of CPAP in the immediate post-extubation period after corrective surgery for TEF/EA appears to be safe and may not be associated with increased risk of AL or recurrence of the fistula. Information from other centres, surveys and large databases is needed to define the benefits and risks of use of CPAP in these infants.

Diagnosing Developmental Dysplasia of Hip in Newborns Using Clinical Screen and Ultrasound of Hips-An Indian Experience.

AIM: To study the cost-effectiveness of clinical screen with ultrasonography (USG) of hip for diagnosing developmental dysplasia of the hip (DDH) in newborns. METHODS: Retrospective study (2006-14). Term newborns had (i) target scan at 6 weeks-family history of DDH or breech presentation-and (ii) early scan-abnormal clinical screen. RESULTS: In all, 736 babies had USG scan. Five early scans (Graf's classification; three Type IIA, one Type IIC and one Type IIIB] and 15 target scans (Type IIA) were reported abnormal. All Type IIA DDH had subsequent 12 weeks' scans normal. Babies with Type IIIB and IIC had hip reduction surgery at 6 and 16 months of age, respectively. At cost 200 INR/scan, total 147 200 INR was incurred against two possible hip replacements prevented. CONCLUSION: Universal clinical screen with USG of hip can aid in early diagnosis of DDH in newborns. Large population-based studies from developing countries need to look in its cost-effectiveness.

Fetal Anemia With Persistent Pulmonary Hypertension: A Report of 3 Cases.

Fetal anemia may cause tissue hypoxia and hence has the potential to predispose to persistent pulmonary hypertension of the newborn (PPHN). Review articles and textbooks do not include severe anemia as a cause of PPHN. We report 3 cases of fetal anemia complicated by severe PPHN.

Photothermal Optical Beam Steering Using Large Deformation Multi-Layer Thin Film Structures.

Photothermal actuation of microstructures remains an active area of research for microsystems that demand electrically isolated, remote, on-chip manipulation. In this study, large-deformation structures constructed from thin films traditional to microsystems were explored through both simulation and experiment as a rudimentary means to both steer and shape an incident light beam through photothermal actuation. A series of unit step infrared laser exposures were applied at increasing power levels to both uniformly symmetric and deliberately asymmetric absorptive structures with the intent of characterizing the photothermal tilt response. The results indicate that a small angle (<4° at ~74 W/cm2) mechanical tilt can be instantiated through central placement of an infrared beam, although directional control appears highly sensitive to initial beam placement. Greater responsivity (up to ~9° mechanical tilt at ~54 W/cm2) and gross directional control was demonstrated with an asymmetrical absorptive design, although this response was accompanied by a large amount (~5-10°) of mechanical tilt burn-in and drift. Rigorous device cycling remains to be explored, but the results suggest that these structures, and those similar in construction, can be further matured to achieve controllable photoactuation suitable for optical beam control or other applications.

A comparative evaluation of portable Doppler ultrasound versus electrocardiogram in heart-rate accuracy and acquisition time immediately after delivery: a multicenter observational study.

BACKGROUND: The assessment of newborns' heart rate (HR) in the delivery room is one of the important steps to ascertain the need for initiation and continuation of resuscitation. At present, ECG is the "gold standard" to monitor neonatal HR in the delivery room. However, various limitations with the use of ECG exist. Furthermore, in developing countries, ECG may not be universally available in delivery rooms. OBJECTIVE: To compare the accuracy and HR acquisition time of portable Doppler ultrasound (PDU) versus electrocardiogram (ECG) in newborns. METHODS: This multicenter, prospective, observational study across five centers in India between January and September 2017 included neonates more than 34 weeks of gestation (n = 131) delivered by cesarean section. The accuracy of HR recorded by PDU (HRPDU) versus that by ECG (HRECG) was the primary outcome. Secondary outcomes included time to acquisition of an audible and/or visible signal and device application. RESULTS: Mean (±SD) gestational age and birthweight were 37.7 (±1.2) weeks and 2954 (±457) g, respectively. The mean (±SD) visible HRPDU was 158 (±21) bpm versus HRECG of 161.3 (±20) bpm (p = .07) which were comparable. The median (1st, third quartile) time to acquisition of audible HRPDU (76 [51, 91] s), was significantly shorter than that of HRECG (96.5 [74.2, 118] s; p < .001). CONCLUSION: Portable Doppler has similar accuracy to ECG and is faster in acquiring the signal.

Giant nonreciprocity of surface acoustic waves enabled by the magnetoelastic interaction.

Nonreciprocity, the defining characteristic of isolators, circulators, and a wealth of other applications in radio/microwave communications technologies, is generally difficult to achieve as most physical systems incorporate symmetries that prevent the effect. In particular, acoustic waves are an important medium for information transport, but they are inherently symmetric in time. In this work, we report giant nonreciprocity in the transmission of surface acoustic waves (SAWs) on lithium niobate substrate coated with ferromagnet/insulator/ferromagnet (FeGaB/Al2O3/FeGaB) multilayer structure. We exploit this structure with a unique asymmetric band diagram and expand on magnetoelastic coupling theory to show how the magnetic bands couple with acoustic waves only in a single direction. We measure 48.4-dB (power ratio of 1:69,200) isolation that outperforms current state-of-the-art microwave isolator devices in a previously unidentified acoustic wave system that facilitates unprecedented size, weight, and power reduction. In addition, these results offer a promising platform to study nonreciprocal SAW devices.

Converse magneto-electric effects in a core-shell multiferroic nanofiber by electric field tuning of ferromagnetic resonance.

This report is on studies directed at the nature of magneto-electric (ME) coupling by ferromagnetic resonance (FMR) under an electric field in a coaxial nanofiber of nickel ferrite (NFO) and lead zirconate titanate (PZT). Fibers with ferrite cores and PZT shells were prepared by electrospinning. The core-shell structure of annealed fibers was confirmed by electron- and scanning probe microscopy. For studies on converse ME effects, i.e., the magnetic response of the fibers to an applied electric field, FMR measurements were done on a single fiber with a near-field scanning microwave microscope (NSMM) at 5-10 GHz by obtaining profiles of both amplitude and phase of the complex scattering parameter S11 as a function of bias magnetic field. The strength of the voltage-ME coupling Av was determined from the shift in the resonance field Hr for bias voltage of V = 0-7 V applied to the fiber. The coefficient Av for the NFO core/PZT shell structure was estimated to be - 1.92 kA/Vm (- 24 Oe/V). A model was developed for the converse ME effects in the fibers and the theoretical estimates are in good agreement with the data.

Laser additive nano-manufacturing under ambient conditions.

Additive manufacturing at the macroscale has become a hot topic of research in recent years. It has been used by engineers for rapid prototyping and low-volume production. The development of such technologies at the nanoscale, or additive nanomanufacturing, will provide a future path for new nanotechnology applications. In this review article, we introduce several available toolboxes that can be potentially used for additive nanomanufacturing. We especially focus on laser-based additive nanomanufacturing under ambient conditions.

High frequency jet ventilation in preterm infants: experience from Western Australia.

Objective: To assess if high frequency jet ventilation (HFJV) is associated with reduced odds of death or discharge home on oxygen in preterm infants. Methods: A case control study (1 February 2010 - 1 June 2014) comparing the primary outcome as "death or discharge home on oxygen" in preterm infants who needed HFJV (Cases) versus those who did not (Controls). Controls were matched to cases (1:1) on gestation, birthweight, gender, place of birth, growth status, antenatal glucocorticoids, and dexamethasone as treatment for severe bronchopulmonary dysplasia (BPD). Logistic regression analysis was used to control for confounders. Results: Data on all preterm infants who needed HFJV (Cases: n = 50) and 50 controls during the study period were analysed. Primary outcome was more frequent in cases versus controls, but not significant after adjusting for mean airway pressure and adjuvant therapy (e.g. diuretics) [aOR: 1.46 (0.23-9.14), p = .687]. Death before discharge [odds ratios (OR): 6.00 (1.34-55.2), p = .013] was more frequent in cases; discharge on home oxygen [OR: 0.88 (0.27-2.76), p = 1.000] was comparable between groups. Duration of oxygen [adjusted hazard ratios (aHR): 1.23 (0.69-2.17), p = .475] and incidence of treatment warranting retinopathy of prematurity [aOR: 0.10 (0.01-1.96), p = .127] was not significant between cases versus controls. Conclusions: HFJV was not associated with reduced odds of death or discharge home on oxygen in preterm infants in our study. Adequately powered randomized trials are required to assess the efficacy and safety of HFJV in preterm infants.

Outcomes of infants with Apgar score of zero at 10†min: the West Australian experience.

BACKGROUND: Infants who have an Apgar score of zero at 10 min of age are known to have poor long-term prognosis. Expert committee guidelines suggest that it is reasonable to cease resuscitation efforts if the asphyxiated infant does not demonstrate a heart beat by 10 min of life. These guidelines are based on data from the era when therapeutic hypothermia was not the standard of care for hypoxic ischaemic encephalopathy (HIE). Hence, we aimed to review our unit data from the era of therapeutic hypothermia to evaluate the outcomes of infants who had an Apgar score of zero at 10 min and had survived to reach the neonatal intensive care unit. METHODS: Retrospective chart review. STUDY PERIOD: 2007-2013. RESULTS: 13 infants (gestational age ≥35 weeks) with Apgar scores of zero at 10 min were admitted to the neonatal intensive care unit. All were born outside the tertiary perinatal centre. Of them, eight died before discharge. The type and duration of follow-up varied. Of the five survivors, three had normal cognitive scores (100, 100 and 110) on Bayley III assessment at 2 years of age and one had normal Griffiths score (general quotient (GQ) 103) at 1 year. Only one infant developed severe spastic quadriplegia. CONCLUSIONS: 4 out of 13 (30.7%) infants with 10 min Apgar scores of zero who survived to reach the neonatal intensive care unit had normal scores on formal developmental assessments. Information from large databases (preferably population based) is necessary to review recommendations regarding stopping delivery room resuscitation in term infants.