Microwave-Assisted Synthesis and Processing of Al-Doped, Ga-Doped, and Al, Ga Codoped ZnO for the Pursuit of Optimal Conductivity for Transparent Conducting Film Fabrication

This work reports the microwave-assisted fabrication of highly conducting Al-doped ZnO (AZO), Ga-doped ZnO (GZO), and Al, Ga codoped ZnO (AGZO) materials as cheaper earth abundant alternatives to indium tin oxide (ITO) for transparent conducting applications. All three doped ZnO powder samples were compressed into pellets, and their electrical properties were evaluated after the postsynthesis heat treatment. The heat treatment was performed by sintering the pellets at 600 °C in a reducing atmosphere using either conventional radiant annealing for 3 h or microwave annealing for 90 s. The Al and Ga dopant levels were systematically varied from 0.5 to 2.5 at. %, and it was found that the lowest resistivity values for the pelleted singly doped ZnO powders exist when the doping level is adjusted to 1.5 at. % for both AZO and GZO, giving resistivity values of 4.4 × 10–3 and 4.3 × 10–3 Ω·cm, respectively. The lowest resistivity of 5.6 × 10–4 Ω·cm was achieved for the pelleted codoped AGZO powder using the optimized Al and Ga dopant levels. Notably, this value is one magnitude lower than the best literature reported value for conventionally synthesized codoped AGZO powder. The resistivity values obtained for the pellets after radiant and microwave postsynthesis heat treatment are comparable, although the microwave heat treatment was performed only for 90 s, compared to 3 h for conventional radiant heat treatment. Hence, significant gains were made in the postannealing step by reducing time, cost, and energy required, benefiting our thrust for finding sustainable routes toward alternative low-cost transparent conducting oxides. As a proof of concept, transparent conducting thin films were fabricated via a simple aerosol-assisted deposition technique using our best conducting AGZO nanoparticles. The films exhibited a visible transmittance as good as 90% and a resistivity of 5.7 × 10–3 Ω·cm, which can compete with the existing high cost ITO films

Searching for plasticity in dissociated cortical cultures on multi-electrode arrays

We attempted to induce functional plasticity in dense cultures of cortical cells using stimulation through extracellular electrodes embedded in the culture dish substrate (multi-electrode arrays, or MEAs). We looked for plasticity expressed in changes in spontaneous burst patterns, and in array-wide response patterns to electrical stimuli, following several induction protocols related to those used in the literature, as well as some novel ones. Experiments were performed with spontaneous culture-wide bursting suppressed by either distributed electrical stimulation or by elevated extracellular magnesium concentrations as well as with spontaneous bursting untreated. Changes concomitant with induction were no larger in magnitude than changes that occurred spontaneously, except in one novel protocol in which spontaneous bursts were quieted using distributed electrical stimulation

Homologous and heterologous desensitization of guanylyl cyclase-B signaling in GH3 somatolactotropes

The guanylyl cyclases, GC-A and GC-B, are selective receptors for atrial and C-type natriuretic peptides (ANP and CNP, respectively). In the anterior pituitary, CNP and GC-B are major regulators of cGMP production in gonadotropes and yet mouse models of disrupted CNP and GC-B indicate a potential role in growth hormone secretion. In the current study, we investigate the molecular and pharmacological properties of the CNP/GC-B system in somatotrope lineage cells. Primary rat pituitary and GH3 somatolactotropes expressed functional GC-A and GC-B receptors that had similar EC50 properties in terms of cGMP production. Interestingly, GC-B signaling underwent rapid homologous desensitization in a protein phosphatase 2A (PP2A)-dependent manner. Chronic exposure to either CNP or ANP caused a significant down-regulation of both GC-A- and GC-B-dependent cGMP accumulation in a ligand-specific manner. However, this down-regulation was not accompanied by alterations in the sub-cellular localization of these receptors. Heterologous desensitization of GC-B signaling occurred in GH3 cells following exposure to either sphingosine-1-phosphate or thyrotrophin-releasing hormone (TRH). This heterologous desensitization was protein kinase C (PKC)-dependent, as pre-treatment with GF109203X prevented the effect of TRH on CNP/GC-B signaling. Collectively, these data indicate common and distinct properties of particulate guanylyl cyclase receptors in somatotropes and reveal that independent mechanisms of homologous and heterologous desensitization occur involving either PP2A or PKC. Guanylyl cyclase receptors thus represent potential novel therapeutic targets for treating growth-hormone-associated disorders

Net primary productivity of forest stands in New Hampshire estimated from Landsat and MODIS satellite data

© 2007 Potter et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

Immunohistochemical evaluation of human epidermal growth factor receptor 2 and estrogen and progesterone receptors in breast carcinoma in Jordan

INTRODUCTION: Although breast carcinoma (BC) is the most common malignancy affecting Jordanian females and the affected population in Jordan is younger than that in the West, no information is available on its biological characteristics. Our aims in this study are to evaluate the expression of estrogen receptor (ER) and progesterone receptor (PR) and Her-2/neu overexpression in BC in Jordan, and to compare the expression of these with other prognostic parameters for BC such as histological type, histological grade, tumor size, patients' age, and number of lymph node metastases. METHOD: This is a retrospective study conducted in the Department of Pathology at Jordan University of Science and Technology. A confirmed 91 cases of BC diagnosed in the period 1995 to 1998 were reviewed and graded. We used immunohistochemistry to evaluate the expression of ER, PR, and Her-2. Immunohistochemical findings were correlated with age, tumor size, grade and axillary lymph node status. RESULTS: Her-2 was overexpressed in 24% of the cases. The mean age of Her-2 positive cases was 42 years as opposed to 53 years among Her-2 negative cases (p = 0.0001). Her-2 expression was inversely related to ER and PR expression. Her-2 positive tumors tended to be larger than Her-2 negative tumors with 35% overexpression among T3 tumors as opposed to 22% among T2 tumors (p = 0.13). Her-2 positive cases tended to have higher rates of axillary metastases, but this did not reach statistical significance. ER and PR positive cases were seen in older patients with smaller tumor sizes. CONCLUSION: Her-2 overexpression was seen in 24% of BC affecting Jordanian females. Her-2 overexpression was associated with young age at presentation, larger tumor size, and was inversely related to ER and PR expression. One-fifth of the carcinomas were Her-2 positive and ER negative. This group appears to represent an aggressive form of BC presenting at a young age with large primary tumors and a high rate of four or more axillary lymph node metastases

Structural and biochemical characterization of the exopolysaccharide deacetylase Agd3 required for Aspergillus fumigatus biofilm formation

The exopolysaccharide galactosaminogalactan (GAG) is an important virulence factor of the fungal pathogen Aspergillus fumigatus. Deletion of a gene encoding a putative deacetylase, Agd3, leads to defects in GAG deacetylation, biofilm formation, and virulence. Here, we show that Agd3 deacetylates GAG in a metal-dependent manner, and is the founding member of carbohydrate esterase family CE18. The active site is formed by four catalytic motifs that are essential for activity. The structure of Agd3 includes an elongated substrate-binding cleft formed by a carbohydrate binding module (CBM) that is the founding member of CBM family 87. Agd3 homologues are encoded in previously unidentified putative bacterial exopolysaccharide biosynthetic operons and in other fungal genomes. The exopolysaccharide galactosaminogalactan (GAG) is an important virulence factor of the fungal pathogen Aspergillus fumigatus. Here, the authors study an A. fumigatus enzyme that deacetylates GAG in a metal-dependent manner and constitutes a founding member of a new carbohydrate esterase family.Bio-organic Synthesi

Simple synthesis of 32P-labelled inositol hexakisphosphates for study of phosphate transformations

In many soils inositol hexakisphosphate in its various forms is as abundant as inorganic phosphate. The organismal and geochemical processes that exchange phosphate between inositol hexakisphosphate and other pools of soil phosphate are poorly defined, as are the organisms and enzymes involved. We rationalized that simple enzymic synthesis of inositol hexakisphosphate labeled with 32P would greatly enable study of transformation of soil inositol phosphates when combined with robust HPLC separations of different inositol phosphates

Constructing osteoarthritis through discourse – a qualitative analysis of six patient information leaflets on osteoarthritis

BACKGROUND: Health service policy in the United Kingdom emphasises the importance of self-care by patients with chronic conditions. Written information for patients about their condition is seen as an important aid to help patients look after themselves. From a discourse analysis perspective written texts such as patient information leaflets do not simply describe the reality of a medical condition and its management but by drawing on some sorts of knowledge and evidence rather than others help construct the reality of that condition. This study explored patient information leaflets on osteoarthritis (OA) to see how OA was constructed and to consider the implications for self-care. METHODS: Systematic and repeated readings of six patient information leaflets on osteoarthritis to look for similarities and differences across leaflets, contradictions within leaflets and the resources called on to make claims about the nature of OA and its management. RESULTS: Biomedical discourse of OA as a joint disease dominated. Only one leaflet included an illness discourse albeit limited, and was also the only one to feature patient experiences of living with OA. The leaflets had different views on the causes of OA including the role of lifestyle and ageing. Most emphasised patient responsibility for preventing the progression of OA. Advice about changing behaviour such as diet and exercise was not grounded in lived experience. There were inconsistent messages about using painkillers, exercise and the need to involve professionals when making changes to lifestyle. CONCLUSION: The nature of the discourse impacted on how OA and the respective roles of patients and professionals were depicted. Limited discourse on illness meant that the complexity of living with OA and its consequences was underestimated. Written information needs to shift from joint biology to helping patients live with osteoarthritis. Written information should incorporate patient experience and value it alongside biomedical knowledge

Exploring participatory visions of smart transport in Milton Keynes

This paper explores citizen concerns emerging in the design stage of MotionMap, a smart transport initiative developed in the context of a £16 million smart city programme. A city-wide sensing system integrated with other databases will provide real-time information about vehicular and pedestrian movement. The experience of a series of smart transport workshops in Milton Keynes suggests that citizens feel that they bear the cost of smart cities through potentially intrusive surveillance producing sacrifices in convenience and privacy, while the gains are captured by industrial and governmental actors. This distrust of surveillance through urban sensing systems is not inflexible. Such systems can gain legitimacy through a participatory approach where users legitimize the sensing system by taking an active role in providing transport data, as opposed to having it ‘harvested’ from them through passive or opportunistic mechanisms. Participatory approaches are challenging because users will engage only if the system can provide compelling benefits. A key contribution of this research comes from identifying that the benefits important to citizens are not necessarily measured in economic terms nor in terms of increased efficiency