Electrochemical electron beam lithography: Write, read, and erase metallic nanocrystals on demand.

We develop a solution-based nanoscale patterning technique for site-specific deposition and dissolution of metallic nanocrystals. Nanocrystals are grown at desired locations by electron beam-induced reduction of metal ions in solution, with the ions supplied by dissolution of a nearby electrode via an applied potential. The nanocrystals can be "erased" by choice of beam conditions and regrown repeatably. We demonstrate these processes via in situ transmission electron microscopy using Au as the model material and extend to other metals. We anticipate that this approach can be used to deposit multicomponent alloys and core-shell nanostructures with nanoscale spatial and compositional resolutions for a variety of possible applications

Rescue activity of a civilian helicopter emergency medical service in the western cape, South Africa: a five-year retrospective review

Introduction - Helicopter search and rescue in Africa is conducted primarily by military organizations. Since 2002 the Western Cape of South Africa has had a dedicated contracted civilian helicopter emergency medical service (HEMS) conducting air ambulance, terrestrial and aquatic rescue. This is the first description of the operations of an African helicopter rescue service. Objective - To describe the terrestrial and aquatic helicopter rescue activity of a civilian operated HEMS in the Western Cape, South Africa from 1 January 2012 – 31 December 2016. Methods - A five-year retrospective review was conducted using data from the organization's operational database, aviation documents, rescue reports and patient care records. Patient demographics and activity at time of rescue, temporal and geographical distribution, crewing compositions, patient injury, triage, clinical interventions and rescue techniques were analysed. Results – A total of 581 search and rescue missions were conducted, of which 451 were terrestrial and 130 aquatic rescues. The highest volume of rescues was conducted within the urban Cape Peninsula. Hoisting using a rescue harness was the most common rescue technique used. 644 patients were rescued. Uninjured or minorly injured persons represented 79% of the sample. Trauma (33%, 196/644) was the most common medical reason for rescue, with lower limb trauma predominant (15%, 90/644). The most common clinical interventions performed were intravenous access (108, 24%), spinal immobilization (92, 21%), splinting (76, 17%) and analgesia administration (58, 13%). Conclusions - The patient demographics and rescue activity described are similar to those described in high-income settings

Cavity-Backed Slot Antenna Array for the Repeater System of a Satellite Digital Multimedia Broadcasting Service

For the repeater system of the satellite digital multimedia broadcasting (DMB) service (2630~2655 MHz) requiring a high-gain antenna and enough isolation between antennas, a cavity-backed slot antenna array (CBSAA) fed by a single waveguide is proposed to suppress side lobe level (SLL) and to increase front-to-back ratio (FBR). The SLL and FBR are enhanced with an optimized magnitude ratio of the electric field at each slot and an additional vertical reflector. The measured SLLs in the Hand E-planes are under -33.24 and -35.78 dB, respectively. An FBR over 37.84 dB and a peak gain over 17 dBi are measured. The proposed CBSAA consists of 2 X 4 slot elements backed by a single cavity and has the characteristics of high power handling capability, high radiation efficiency, low feed line loss, and simple feed network

IMPLICIT BIAS AND STEM EDUCATION: AN EXPLORATION OF GENDER AND RACIAL DISPARITY

The research study presented in this dissertation was the result of an exploration of the problem of gender enrollment disparities in STEM elective courses at the high school level in an independent school in the western United States, Western Regional School (WRS; a pseudonym). A review of the literature in chapter one revealed several factors contribute to gender, as well as racial/ethnic, disparities in the enrollment of STEM courses at the high school level as well as selection of STEM majors at the university level. Those factors include but are not limited to gender inequalities as displayed in both overt and explicit biases and implicit biases, U.S. gender norms and socialization, as demonstrated by gender stereotyping, and a lack of STEM role models which may affect STEM self-efficacy and STEM self-identities. The needs assessment focused on the investigation of STEM course enrollments during a 10-12 year period along with semi-structured interviews with influential WRS community adults such as teachers, academic advisors, deans, counselors, and administrators. The key findings showed evidence that while there were no significant gender disparities in the enrollment of required STEM courses at WRS, there were significant disparities in the selection of specific STEM electives including physics-based, computer science, and advanced mathematics courses. The needs assessment informed the design of an intervention professional development (PD) program focused on implicit bias as it pertains to gender and race/ethnicity and science performance for educators and academic advisors at WRS. The intervention PD was developed around Bandura’s social cognitive theory of reciprocal determinism. The researcher conducted a mixed methods convergent parallel design study to evaluate the intervention PD program. The eight-session PD program ran for a total of four synchronous and four asynchronous sessions and showed that the participants’ awareness of both what implicit bias meant in general and their own level of individual biases increased. Additionally, with that increased awareness came motivation to change teaching and advising practices in the form of a call to action. These educators and academic advisors shared their plans and priorities to focus on mitigating their own implicit biases, especially as it related to their enrollment discussions with students and classroom practices. Their self-efficacy as academic advisors, on the other hand, did not appear to be significantly improved as a result of the intervention program, but it should be noted that that result may have more to do with the structure and duties of WRS academic advisors and not because of the design of this specific intervention PD program. The findings of this study suggest that the PD program could support the increased awareness of implicit bias around gender and race/ethnicity and a call to action in the broader adult community of WRS, especially all faculty and staff

Internal Antenna for Multiband Mobile Handset Applications

Design of a multiband internal antenna for mobile handset applications is presented. Two antenna elements are formed on top and bottom of the common substrate and connected by metallic pin. Resonant frequency of each element is almost independent. Matching the impedance with the slit, a wide bandwidth is achieved so that the operating frequency bands include GSM (880-960 MHz), GPS (1575 MHz), DCS (1710-1880 MHz), USPCS (1850-1990 MHz), and UMTS (1885-2200 MHz). Radiation patterns are omni-directional for all frequency bands. Details of the proposed antenna as well as the measured results are presented

Point-of-care versus central testing of hemoglobin during large volume blood transfusion.

BACKGROUND: Point-of-care (POC) hemoglobin testing has the potential to revolutionize massive transfusion strategies. No prior studies have compared POC and central laboratory testing of hemoglobin in patients undergoing massive transfusions. METHODS: We retrospectively compared the results of our point-of-care hemoglobin test (EPOC®) to our core laboratory complete blood count (CBC) hemoglobin test (Sysmex XE-5000™) in patients undergoing massive transfusion protocols (MTP) for hemorrhage. One hundred seventy paired samples from 90 patients for whom MTP was activated were collected at a single, tertiary care hospital between 10/2011 and 10/2017. Patients had both an EPOC® and CBC hemoglobin performed within 30 min of each other during the MTP. We assessed the accuracy of EPOC® hemoglobin testing using two variables: interchangeability and clinically significant differences from the CBC. The Clinical Laboratory Improvement Amendments (CLIA) proficiency testing criteria defined interchangeability for measurements. Clinically significant differences between the tests were defined by an expert panel. We examined whether these relationships changed as a function of the hemoglobin measured by the EPOC® and specific patient characteristics. RESULTS: Fifty one percent (86 of 170) of paired samples\u27 hemoglobin results had an absolute difference of ≤7 and 73% (124 of 170) fell within ±1 g/dL of each other. The mean difference between EPOC® and CBC hemoglobin had a bias of - 0.268 g/dL (p = 0.002). When the EPOC® hemoglobin was \u3c 7 g/dL, 30% of the hemoglobin values were within ±7, and 57% were within ±1 g/dL. When the measured EPOC® hemoglobin was ≥7 g/dL, 55% of the EPOC® and CBC hemoglobin values were within ±7, and 76% were within ±1 g/dL. EPOC® and CBC hemoglobin values that were within ±1 g/dL varied by patient population: 77% for cardiac surgery, 58% for general surgery, and 72% for non-surgical patients. CONCLUSIONS: The EPOC® device had minor negative bias, was not interchangeable with the CBC hemoglobin, and was less reliable when the EPOC® value was \u3c 7 g/dL. Clinicians must consider speed versus accuracy, and should check a CBC within 30 min as confirmation when the EPOC® hemoglobin is \u3c 7 g/dL until further prospective trials are performed in this population

Balanced RFID Tag Antenna Mountable on Metallic Plates

A novel balanced tag antenna for radio frequency identification (RFID) system is presented. The radiating elements of two planar inverted-F antennas (PIFAs) are inductively coupled by the feed loop with out of phase. The balanced structure provides smaller degradation of performances when an RFID tag is mounted on the various sizes of metal plates. The HFSS simulator is employed to analyze the proposed antenna in the design process and to compare with measured results

Informing Efforts to Develop Nitroreductase for Amine Production

Nitroreductases (NRs) hold promise for converting nitroaromatics to aromatic amines. Nitroaromatic reduction rate increases with Hammett substituent constant for NRs from two different subgroups, confirming substrate identity as a key determinant of reactivity. Amine yields were low, but compounds yielding amines tend to have a large π system and electron withdrawing substituents. Therefore, we also assessed the prospects of varying the enzyme. Several different subgroups of NRs include members able to produce aromatic amines. Comparison of four NR subgroups shows that they provide contrasting substrate binding cavities with distinct constraints on substrate position relative to the flavin. The unique architecture of the NR dimer produces an enormous contact area which we propose provides the stabilization needed to offset the costs of insertion of the active sites between the monomers. Thus, we propose that the functional diversity included in the NR superfamily stems from the chemical versatility of the flavin cofactor in conjunction with a structure that permits tremendous active site variability. These complementary properties make NRs exceptionally promising enzymes for development for biocatalysis in prodrug activation and conversion of nitroaromatics to valuable aromatic amines. We provide a framework for identifying NRs and substrates with the greatest potential to advance

RFID Tag Antenna Moutable on Metallic Plates

RFID tag antenna which could be mountable on metallic plate is designed and measured for 900MHz band. The proposed antenna consists of ground plane, substrate (εr = 4.7), feed line with shorted circuit and radiating patch with L-shaped slit. The feed line with shorted circuit is designed for the direct impedance matching between the antenna and the RFID microchip. Especially, it is possible to obtain considerably the easy impedance match with the proposed design. Overall dimension of the proposed antenna is 90×54×5mm3. When the antenna is placed in free space and mounted on 125×150mm2, 250×300mm2 metallic plates, the maximum reading distance is 6m, 4.8m and 5.2m, respectively