Primary percutaneous coronary intervention for acute myocardial infarction: Exploring the experiences of patients, carers and cardiac nurses

A narrative inquiry approach was used to compare and contrast the experiences of ten patients who received Primary Percutaneous Coronary Intervention (PPCI) for Acute Myocardial Infarction. Eight carers and ten cardiac nurses in one Heart Attack Centre were also recruited. The purpose of the study was to understand what mattered to these individuals from their different perspectives. Patients and carers were interviewed within 14 days of hospital discharge. Vignettes were developed from participants’ direct quotations to convey their experiences of different events surrounding the PPCI. Two artificial stories from patients and carers were presented in the nurses’ interviews. Using Labov’s structural analysis, participants’ narratives portrayed the travelling experiences, routes and journeys encountered. The emotional responses depicted how patients felt when they were ill and then suddenly well and of how carers were initially helpless and then able to manage. Different to previous literature on the experience of PPCI was the inclusion of nurses’ experiences. Their narratives revealed a preoccupation with making patients well again. An intriguing finding was the manner in which nurses expected sick patients to respond to their caring actions. When patients were ill, the nurses’ role was clearly defined. When patients felt well, their caring actions were fraught with difficulty. The nurses’ emotional responses provide new understandings about how nurses actively managed the challenges and rewards of working in a Heart Attack Centre. The voices of the patients, carers and nurses heard in this research revealed the compelling and diverse ways in which strategies were taken to protect the self or others from harm and the reasons for these active behaviours. This study has drawn attention to the ways patients, carers and nurses work together and against each other. These experiences will be useful for improving nursing practice

Dual Passivation of Intrinsic Defects at the Compound Semiconductor/Oxide Interface Using an Oxidant and a Reductant

Studies have shown that metal oxide semiconductor field-effect transistors fabricated utilizing compound semiconductors as the channel are limited in their electrical performance. This is attributed to imperfections at the semiconductor/oxide interface which cause electronic trap states, resulting in inefficient modulation of the Fermi level. The physical origin of these states is still debated mainly because of the difficulty in assigning a particular electronic state to a specific physical defect. To gain insight into the exact source of the electronic trap states, density functional theory was employed to model the intrinsic physical defects on the InGaAs (2 × 4) surface and to model the effective passivation of these defects by utilizing both an oxidant and a reductant to eliminate metallic bonds and dangling-bond-induced strain at the interface. Scanning tunneling microscopy and spectroscopy were employed to experimentally determine the physical and electronic defects and to verify the effectiveness of dual passivation with an oxidant and a reductant. While subsurface chemisorption of oxidants on compound semiconductor substrates can be detrimental, it has been shown theoretically and experimentally that oxidants are critical to removing metallic defects at oxide/compound semiconductor interfaces present in nanoscale channels, oxides, and other nanostructures

Passivation of InGaAs(001)-(2 × 4) by Self-Limiting Chemical Vapor Deposition of a Silicon Hydride Control Layer

A saturated Si–H_<i>x</i> seed layer for gate oxide or contact conductor ALD has been deposited via two separate self-limiting and saturating CVD processes on InGaAs(001)-(2 × 4) at substrate temperatures of 250 and 350 °C. For the first self-limiting process, a single silicon precursor, Si₃H₈, was dosed at a substrate temperature of 250 °C, and XPS results show the deposited silicon hydride layer saturated at about 4 monolayers of silicon coverage with hydrogen termination. STS results show the surface Fermi level remains unpinned following the deposition of the saturated silicon hydride layer, indicating the InGaAs surface dangling bonds are electrically passivated by Si–H_<i>x</i>. For the second self-limiting process, Si₂Cl₆ was dosed at a substrate temperature of 350 °C, and XPS results show the deposited silicon chloride layer saturated at about 2.5 monolayers of silicon coverage with chlorine termination. Atomic hydrogen produced by a thermal gas cracker was subsequently dosed at 350 °C to remove the Si–Cl termination by replacing with Si–H termination as confirmed by XPS, and STS results confirm the saturated Si–H_<i>x</i> bilayer leaves the InGaAs(001)-(2 × 4) surface Fermi level unpinned. Density function theory modeling of silicon hydride surface passivation shows an Si–H_<i>x</i> monolayer can remove all the dangling bonds and leave a charge balanced surface on InGaAs

Atomic Imaging of the Irreversible Sensing Mechanism of NO₂ Adsorption on Copper Phthalocyanine

Ambient NO₂ adsorption onto copper­(II) phthalocyanine (CuPc) monolayers is observed using ultrahigh vacuum (UHV) scanning tunneling microscopy (STM) to elucidate the molecular sensing mechanism in CuPc chemical vapor sensors. For low doses (1 ppm for 5 min) of NO₂ at ambient temperatures, isolated chemisorption sites on the CuPc metal centers are observed in STM images. These chemisorbates almost completely desorb from the CuPc monolayer after annealing at 100 °C for 30 min. Conversely, for high NO₂ doses (10 ppm for 5 min), the NO₂ induces a fracture of the CuPc domains. This domain fracture can only be reversed by annealing above 150 °C, which is consistent with dissociative chemisorption into NO and atomic O accompanied by surface restructuring. This high stability implies that the domain fracture results from tightly bound adsorbates, such as atomic O. Existence of atomic O on or under the CuPc layer, which results in domain fracture, is revealed by XPS analysis and ozone-dosing experiments. The observed CuPc domain fracturing is consistent with a mechanism for the dosimetric sensing of NO₂ and other reactive gases by CuPc organic thin film transistors (OTFTs)

Selective Chemical Response of Transition Metal Dichalcogenides and Metal Dichalcogenides in Ambient Conditions

To fabricate practical devices based on semiconducting two-dimensional (2D) materials, the source, channel, and drain materials are exposed to ambient air. However, the response of layered 2D materials to air has not been fully elucidated at the molecular level. In the present report, the effects of air exposure on transition metal dichalcogenides (TMD) and metal dichalcogenides (MD) are studied using ultrahigh-vacuum scanning tunneling microscopy (STM). The effects of a 1-day ambient air exposure on MBE-grown WSe₂, chemical vapor deposition (CVD)-grown MoS₂, and MBE SnSe₂ are compared. Both MBE-grown WSe₂ and CVD-grown MoS₂ display a selective air exposure response at the step edges, consistent with oxidation on WSe₂ and adsorption of hydrocarbon on MoS₂, while the terraces and domain/grain boundaries of both TMDs are nearly inert to ambient air. Conversely, MBE-grown SnSe₂, an MD, is not stable in ambient air. After exposure in ambient air for 1 day, the entire surface of SnSe₂ is decomposed to SnO_<i>x</i> and SeO_<i>x</i>, as seen with X-ray photoelectron spectroscopy. Since the oxidation enthalpy of all three materials is similar, the data is consistent with greater oxidation of SnSe₂ being driven by the weak bonding of SnSe₂

Atomic Layer Deposition of Al₂O₃ on WSe₂ Functionalized by Titanyl Phthalocyanine

To deposit an ultrathin dielectric onto WSe₂, monolayer titanyl phthalocyanine (TiOPc) is deposited by molecular beam epitaxy as a seed layer for atomic layer deposition (ALD) of Al₂O₃ on WSe₂. TiOPc molecules are arranged in a flat monolayer with 4-fold symmetry as measured by scanning tunneling microscopy. ALD pulses of trimethyl aluminum and H₂O nucleate on the TiOPc, resulting in a uniform deposition of Al₂O₃, as confirmed by atomic force microscopy and cross-sectional transmission electron microscopy. The field-effect transistors (FETs) formed using this process have a leakage current of 0.046 pA/μm² at 1 V gate bias with 3.0 nm equivalent oxide thickness, which is a lower leakage current than prior reports. The n-branch of the FET yielded a subthreshold swing of 80 mV/decade