Highly Conductive Networks of Silver Nanosheets Kelly, Adam G.; O'Reilly, Jane; Gabbett, Cian ...
Small (Weinheim an der Bergstrasse, Germany),
04/2022, Letnik:
18, Številka:
14
Journal Article
Recenzirano
Odprti dostop
Although printed networks of semiconducting nanosheets have found success in a range of applications, conductive nanosheet networks are limited by low conductivities (<106 S m−1). Here, dispersions ...of silver nanosheets (AgNS) that can be printed into highly conductive networks are described. Using a commercial thermal inkjet printer, AgNS patterns with unannealed conductivities of up to (6.0 ± 1.1) × 106 S m−1 are printed. These networks can form electromagnetic interference shields with record shielding effectiveness of >60 dB in the microwave region at thicknesses <200 nm. High resolution patterns with line widths down to 10 µm are also printed using an aerosol‐jet printer which, when annealed at 200 °C, display conductivity >107 S m−1. Unlike conventional Ag‐nanoparticle inks, the 2D geometry of AgNS yields smooth, short‐free interfaces between electrode and active layer when used as the top electrode in vertical nanosheet heterostructures. This shows that all‐printed vertical heterostructures of AgNS/WS2/AgNS, where the top electrode is a mesh grid, function as photodetectors demonstrating that such structures can be used in optoelectronic applications that usually require transparent conductors.
This paper describes the printing of silver nanosheets to yield conductive networks. These networks display conductivities of 6 × 106 S m‐1 under ambient processing, two orders of magnitude higher than graphene networks. After annealing, the conductivity surpasses 107 S m‐1, competitive with the best printed conductors. Such networks are exceptional electromagnetic shields and can be utilized as electrodes in printed devices.
Though often perceived as an environmentally-risky practice, biological control of invasive species can restore crop yields, ease land pressure and thus contribute to forest conservation. Here, we ...show how biological control against the mealybug Phenacoccus manihoti (Hemiptera) slows deforestation across Southeast Asia. In Thailand, this newly-arrived mealybug caused an 18% decline in cassava yields over 2009-2010 and an escalation in prices of cassava products. This spurred an expansion of cassava cropping in neighboring countries from 713,000 ha in 2009 to > 1 million ha by 2011: satellite imagery reveals 388%, 330%, 185% and 608% increases in peak deforestation rates in Cambodia, Lao PDR, Myanmar and Vietnam focused in cassava crop expansion areas. Following release of the host-specific parasitoid Anagyrus lopezi (Hymenoptera) in 2010, mealybug outbreaks were reduced, cropping area contracted and deforestation slowed by 31-95% in individual countries. Hence, when judiciously implemented, insect biological control can deliver substantial environmental benefits.
Macroregenerative nodules (MRN) have been detected with increased incidence in explanted livers since orthotopic liver transplantation (OLTx) has become a routine treatment for end-stage liver ...disease. Autopsy series suggest that MRN may be more common than once thought, and several studies point to the malignant potential of these lesions. With increasing waiting times for OLTx, the propensity for these premalignant lesions to arise in cirrhotic livers has important implications for the supervision of patients on OLTx waiting lists. We present here a striking example of a MRN and review a topic that is generating considerable interest.
Liver allografts in many animal models are often spontaneously accepted across a complete histocompatibility barrier without requirement for immunosuppression. In contrast, skin allografts are ...usually rejected, even across minor histocompatibility barriers. To identify the mechanism of liver allograft acceptance we have compared skin rejection with liver acceptance in DA rat strain recipients of PVG donors, a major histocompatibility complex (MHC) class I plus II mismatch. In spite of the established role of draining lymph nodes (LN) in induction of rejection of skin allografts, there was much greater involvement of LN after liver than after skin transplantation. Few donor cells migrated to these organs from transplanted skin but many cells migrated from transplanted liver. There was also a paradoxical increase in interleukin‐2 (IL‐2) and interferon‐γ (IFN‐γ) mRNA in LN and spleen of liver allograft recipients that greatly exceeded their expression in skin allograft recipients. For example, there were 2·7±1·6×104 molecules of IFN‐γ per 106 molecules of β‐actin mRNA in the LN draining liver allografts 1 day after transplantation compared with 2·0±0·3×103 molecules/106β‐actin in LN draining skin allografts and 8·1±1·8×102 molecules/106β‐actin in LN draining skin isografts. Examination of the graft showed that infiltration and cytokine mRNA up‐regulation occurred more slowly in the transplanted skin than in liver but progressed inexorably in skin grafts until rejection. These results show that liver acceptance is associated with a paradoxical marked early activation then subsequent decline of the immune response.
Immunopathology of renal allograft rejection analyzed with monoclonal antibodies to mononuclear cell markers. The composition of the mononuclear cell infiltrate in rejecting renal allografts was ...determined on 96 renal biopsies and 22 nephrectomy specimens by the use of monoclonal antibodies to mononuclear cell surface markers and an indirect immunoperoxidase staining technique. During rejection the composition of the infiltrate was heterogeneous, with T cells (T1l), monocytes (OKM1) and HLA-DR expressing mononuclear cells the most frequent sub-populations. B cells (Bl) and activated T cells, identified by OKT10, were always in the minority. The T cells infiltrate usually included the helper/inducer (T4) and cytotoxic (T8) subclasses, which suggests that both may contribute to the mediation of rejection. Whether T4 or T8 predominated in the graft did not relate to the ratio of T4:T8 in blood, the HLA A, B or DR incompatibilities of the graft, or the immunosuppressive used. The frequency of T1l, T4, T8, HLA-DR positive cells and monocytes, but not B cells, increased with the severity of rejection and was similar in biopsies from patients immuno-suppressed with Cyclosporine (CSA) to those given a combination of azathioprine, prednisone and antilymphocyte globulin (AZA). Severe rejection episodes which did not respond to treatment with corticosteroids were more often characterized by a predominance of T8 over T4 cells and T cells infiltrating the glomeruli. In grafts with evidence of cellular rejection, renal tubular cells were shown to have a marked increase in their expression of HLA-DR antigens compared to normal kidneys or grafts with minimal rejection. The expression of HLA-DR antigens on graft tubular cells correlated with the presence of T cells in the interstitium and the severity of rejection, except for moderate rejection in CSA treated biopsies, in which HLA-DR expression was lower than in AZA biopsies. These immunopathological studies have demonstrated that a variety of potential effector cells exist within the graft, and several features have been identified which may assist in assessing the prognosis of the rejection episode.
We conducted a randomized trial in seven Australian hospitals of the efficacy and safety of three immunosuppressive regimens after first transplantation of a cadaver kidney: long-term cyclosporine, ...short-term (three months) cyclosporine followed by azathioprine and prednisolone, and azathioprine and prednisolone without cyclosporine. Patients assigned to long-term cyclosporine (n = 138) or short-term cyclosporine followed by azathioprine and prednisolone (n = 141) had similar actuarial 12-month survival (98.4 vs. 96.4 percent) and graft survival (83.9 vs. 82.1 percent). Patients assigned to receive only azathioprine and prednisolone (n = 138), with optional use of antithymocyte globulin, had a significantly poorer survival rate (91.3 percent, P = 0.015) because of deaths from cardiac causes and infection, but their graft survival of 76.0 percent (P = 0.31) did not differ significantly from that of either group receiving cyclosporine. After the switch from cyclosporine to azathioprine and prednisolone, 15 percent of patients had reversible rejection episodes, but the frequency of rejection and graft loss did not differ from that in the long-term cyclosporine group. After the change to azathioprine and prednisolone, serum creatinine levels declined in nearly all patients, so that after three months they were comparable to those in the group receiving azathioprine and prednisolone only, and significantly lower than those in the group receiving long-term cyclosporine therapy (P less than 0.003). We conclude that the two cyclosporine regimens result in comparable patient and graft survival, but that changing to azathioprine and prednisolone at three months improves graft function.
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