Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Myocardial Effects of Type 2 Diabetes, Co-morbidities, and Changing Loading Conditions : a Clinical Study by Tissue Velocity Echocardiography

Ever since the validation of the tissue velocity echocardiography (TVE) technique more than a decade ago the modality has been used rather successfully in various clinical situations, at rest as well as during stress echocardiography. Hitherto, dobutamine stress echocardiography has been the hallmark of all forms of stress procedures, now with TVE, quantification of the longitudinal motions of the left ventricle shows far superiority, with improved sensitivity and specificity in the functional diagnosis of coronary artery disease. Morever there has been continued interest in this technique for even assessing subclinical myocardial systolic and diastolic function in clinical scenarios like diabetes, hypertension and chronic kidney disease. The aim of the present study was to evaluate left ventricular myocardial functions by applying TVE in human subjects having type 2 diabetes with or without co-morbidities and during changing loading conditions. The effects of changing loading conditions were analyzed during hemodialysis and following oral administration of an AT1 receptor blocker. The studied subjects included individuals with diabetes as well as those with associated hypertension, coronary artery disease, microalbuminuria and end-stage renal disease. All patients with type 2 diabetes and co-morbidities underwent TVE enhanced dobutamine stress echocardiography while load dependant left ventricular functions were analyzed at rest. There were 270 subjects in the study of type 2 diabetes and associated cardiovascular diseases and 101 subjects in the study of changing loading conditions. Patients with type 2 diabetes revealed subclinical left ventricular dysfunction characterized by reduced functional reserve. This influence becomes quantitatively more pronounced in the presence of coexistent coronary artery disease and hypertension. The coexistence of type 2 diabetes and hypertension appears to have additive negative effect on both systolic and diastolic left ventricular function, even in the absence of coronary artery disease. The presence of microalbuminuria in type 2 diabetes patients does not worsen diminished myocardial functional reserve. A single session of hemodialysis improves left ventricular function in patients with end-stage renal disease only in the absence of type 2 diabetes and co-morbidities, while a single dose of an AT1 receptor blocker valsartan results in reduction of afterload and, subsequently, in improvement of left ventricular function. TVE appears to be a sensitive tool for objective assessment of left ventricular function and can be successfully applied for the clinical evaluation of the effect of type 2 diabetes and co-morbidities on myocardial performance.QC 2010070

Left atrial and renal functional status as drivers of adverse outcome in heart failure with reduced ejection fraction : a four-chamber deformation study in a small cohort of northern Sweden

In a small cohort of patients (58 ± 12 years) with heart failure and reduced ejection fraction (HFREF), we have analyzed myocardial mechanics in all the four principal cardiac chambers to investigate the prognostic value of left atrial (LA) remodeling. We have also studied to investigate a possible prognostic role of the biochemical markers, such as estimated glomerular filtration rate (eGFR, mL/min/1.73 m 2) and N-terminal pro-brain natriuretic peptide (NT-proBNP). We used two-dimensional speckle tracking echocardiography to compute cardiac deformation in addition to measuring LA reservoir strain using two algorithms based on the type of electrocardiogram gating protocol chosen. The data have shown that not only four-chamber strain was significantly lower in HFREF compared with the controls but also LA strain predicted an adverse outcome. In addition, in the subgroup analysis, eGFR was significantly lower in patients with adverse outcome (death or cardiac transplantation). Interestingly, the contribution of the renal biomarker was as significant as NT-proBNP in this regard

Achieving of aluminum–aluminum wafer bonding at low temperature and pressure using Surface passivated technique

Micro-electro-mechanical systems (MEMS) device packaging has proven to be more costly and complex, and it has been a substantial barrier to the commercialization of MEMS. Because of the reason there is a huge requirement of vacuum seal packages for MEMS devices at low cost at low thermal budgets. In this work, we are proposing a method of developing direct aluminum-aluminum (Al-Al) wafer frame bonding using themo-compression bonding method. However, the formation of chemically stable surface oxide, immediately after exposed to ambient conditions, is a major inter-diffusion barrier for grain growth across the interface of bonding. To break this barrier requires high temperature (minimum of ∼450 °C) and pressures, which may cause the some of the MEMS devices may damage or properties of CMOS devise may change. Therefore, we motivated towards the formation of direct Al-Al interconnect at the low temperature and pressures using surface passivation of another noble metal (Palladium (Pd)) for wafer level thigh seal encapsulation for MEMS. Here, we studied the effect of Pd on Al surface and optimization of minimum Pd thickness to protect the surface from oxidation. Based on AFM, XRD, C-SAM, SEM, EDX analysis, the role of Pd on Al Surface for hermetic sealing applications were discussed

High Density metal alloy Interconnections Using Novel Wafer Bonding Approach For 3D IC Packaging Applications

The solder is the one of the most interconnect joining material in the denser electronic interconnects. To follow the paradigm, shift towards the Moor's law, an advanced electronic industry motivated towards the vertical integration of multifunctioning dies. Here the solder is used to connect the dies vertically and also at the packaging level, i.e. Die to PCB (printed circuit board) or silicon interposer. The reliability and electromigration issues of solder, when interconnect dimensions become smaller. This makes the way for involvement of new materials at the die interconnections and at the package level. In this work, the direct bonding of metal alloy (Cu-Cr (0.6 to 1.2% of Cr), which is not only resistive to surface oxidation but also a highly conductive material is proposed. A novel bonding approach which helped in achieving good bonding quality at low temperature and pressure, by creating a density variation in thin film of alloy on silicon substrate. By adjusting the deposition parameters while sputtering, we have created density variation in thin film of Cu-Cr alloy on silicon substrate. Then applied higher temperature to a substrate having high density thin film of Cu-Cr and low temperature to low density varied substrate while performing bonding the used high temperature is 190oC with gradient of 30oC for other substrate and applied pressure is ~0.5 MPa for 40 min. The density variation was verified in terms of bond shear strength analysis. we observed the bonding interfacial quality using cross sectional - FESEM and bonding interfacial strength by manually breaking by diamond cutter and sharp blade insertion. High bonding interfacial strength of ~70MPa, is obtained with proposed bonding method is higher than conventional methodology by ~20MPa. Using these bonding conditions, we achieved the fine pitch bonding of 10 ?m features, inspected using IR imaging. The proposed novel methods maybe useful for achieving high density 3D interconnects both at chip and package level, immaterial of the surface roughness of the thin films

Gold Passivated Cu-Cu Bonding At 140°C For 3D IC Packaging And Heterogeneous Integration Applications

In the present modern era of electronic industry has motivated for high performance integration by vertically stacked three dimensional integrated circuits (3D ICs). Electronic interconnections at packaging and die levels, Pbfree solder micro bumps are intended to replace conventional Pb-containing solder joints due to increasing awareness of an environmental conservation, and processing at low thermal budgets. The better alternative for solder is copper, due to its high electrical and thermal properties. But the surface oxidation was the major bottleneck. In this work, we have demonstrated low temperature and low-pressure copper to copper interconnect bonding using optimized thin gold passivation layer. Here the passivation layer over the copper surface was optimized to a thickness of 3nm there by helps in preventing Cu surface oxidation and makes lower surface RMS roughness. High-density surface plane orientations that have been studied using XRD helped in faster diffusion through an interface. Majorly in this work, we have discussed the time taken for copper atoms to diffuse over the ultra-thin passivation layer of gold using Fick's second law approximation. These conditions have been used while bonding. Bonded samples were subjected to various reliability studies in order to confirm the efficacy of the proposed Au passivation based bonded structure. Also, we have observed the Interface quality using TEM, and C-SAM (mode C-Scanning acoustic microscopy) imaging resulting in good quality of bonding. The diffusion of copper atomic species movement across the interface is confirmed by EDS analysis. Low and stable specific contact resistance ($\sim$1.43 $\times$ 10-8 $\Omega$ cm 2 ) at robust conditions are confirmed to be effective and front runner for low temperature, low pressure Cu-Cu bonding for 3D IC packaging and heterogeneous integration

Interface and reliability analysis of Au passivated Cu-Cu fine pitch thermocompression bonding for 3D IC applications

Optimally engineered ultra-thin gold (Au) layer as an effective surface passivation for low temperature, low pressure fine pitch Cu-Cu bonding is demonstrated in this work. The Au passivation layer not only performs the role of protecting the underlying Cu surface from unwanted oxidation but it also helps in reducing the effective surface roughness, which are two major requirements for thermocompression bonding. Additionally, Au, being a noble metal, ensures efficient surface passivation of Cu even at elevated temperatures. Furthermore, Au passivated Cu surfaces show significantly high 111 oriented surface planes with random grain structures at the bonding interface, which account for enhanced diffusion ability. Herein, an optimized Au passivation layer of 3 nm has resulted in high quality fine pitch Cu-Cu thermocompression bonding at 140 °C and 0.3MPa pressure. The bonded samples have further been subjected to various reliability studies in order to confirm the efficacy of the proposed bonding scheme, along with mathematical modeling to cross check using Fick’s second law of approximation. The bonded samples have attributed to a high bond strength (>200MPa) and a very low and stable specific contact resistance (~1.43 × 10-8 Ω-cm2) at robust conditions, which is significantly better than the values previously reported in literature

Fabrication of On-Silicon Aperture Coupled Patch Antenna Through Micromachining and Cu-Cu Thermocompression Bonding

This paper, for the first time, reports the fabrication of an on-Silicon aperture-coupled 3D Patch antenna using micromachining and low-temperature, low-pressure Copper(Cu)-Copper(Cu) thermo-compression bonding. Micromachining technique was used to reduce the effective dielectric constant of Silicon (Si), thereby increasing the radiation efficiency. One of the main challenges in fabricating the aperture coupled patch antenna on Si is the realization of its 3D structure. The top and bottom substrates of the 3D antenna have to be bonded together without disturbing the micromachined thin membrane. This was achieved using thermo-compression bonding under optimized temperature and pressure conditions with a 3 nm Gold (Au) passivation layer, which prevents the oxidation of the Cu layer underneath and thereby reducing the inter-diffusion barrier across the interface. The proposed fabrication process flow introduces the novelty of using bonding/stacking metal inter-layer as the common ground of the antenna. The device was fabricated on high resistivity Si wafers to minimize the conduction losses. Herein, we have fabricated an aperture coupled 3D patch antenna with a cavity depth of 200± 10μm, and the device characteristics were compared with the HFSS simulation results. The reliability of the fabricated antenna was assessed by bond strength analysis, cross sectional FESEM and TEM imaging. The on-chip antenna yielded a resonance frequency of 13.4 GHz, with VSWR 1.16. The radiation pattern of the antenna was also analyzed experimentally. This technology is the way forward to fabricating miniaturized high performance on-chip antennas. IEE

Silicide Based Low Temperature and Low Pressure Bonding of TI/SI for Microfludic and Hermetic Selaling Application

In this work, we have shown and validated bonding of titanium (Ti) coated glass with (100) silicon wafer at lower thermocompression cycle of 377 °C temperature and a nominal contact pressure of 0.15 MPa. Excellent bond strength > 100 MPa and void free interface have been observed using scanning acoustic tomography (SAT), which clearly suggest that optimized temperature-pressure together can provide a superior quality bonding. Furthermore, post-bond dicing was performed in order to validate further the bonding strength which was confirmed by successfully dicing the Glass-Silicon pair without any damage to the bonding interface. This noble, low cost and low temperature simple bonding approach must be useful in hermetic sealing of microfluidic channels for on-chip compatible applications