Inhibition of collagen I accumulation reduces glomerulosclerosis by a Hic-5-dependent mechanism in experimental diabetic nephropathy

Glomerulosclerosis of any cause is characterized by loss of functional glomerular cells and deposition of excessive amounts of interstitial collagens including collagen I. We have previously reported that mesangial cell attachment to collagen I leads to upregulation of Hic-5 in vitro, which mediates mesangial cell apoptosis. Furthermore, glomerular Hic-5 expression was increased during the progression of experimental glomerulosclerosis. We hypothesized that reducing collagen I accumulation in glomerulosclerosis would in turn lower Hic-5 expression, reducing mesangial cell apoptosis, and thus maintaining glomerular integrity. We examined archive renal tissue from rats undergoing experimental diabetic glomerulosclerosis, treated with the transglutaminase-2 inhibitor NTU281. Untreated animals exhibited increased glomerular collagen I accumulation, associated with increased glomerular Hic-5 expression, apoptosis, and mesangial myofibroblast transdifferentiation characterized by a-smooth muscle actin (a-SMA) expression. NTU281 treatment reduced glomerular collagen I accumulation, Hic-5 and a-SMA expression, and apoptosis. Proteinurea and serum creatinine levels were significantly reduced in animals with reduced Hic-5 expression. In vitro studies of Hic-5 knockdown or overexpression show that mesangial cell apoptosis and expression of both a-SMA and collagen I are Hic-5 dependent. Together, these data suggest that there exists, in vitro and in vivo, a positive feedback loop whereby increased levels of collagen I lead to increased mesangial Hic-5 expression favoring not only increased apoptosis, but also mesangial myofibroblast transdifferentiation and increased collagen I expression. Prevention of collagen I accumulation interrupts this Hic-5-dependent positive feedback loop, preserving glomerular architecture, cellular phenotype, and function. © 2013 USCAP, Inc All rights reserved.

Statistical mechanics analysis of LDPC coding in MIMO Gaussian channels

Using analytical methods of statistical mechanics, we analyse the typical behaviour of a multiple-input multiple-output (MIMO) Gaussian channel with binary inputs under low-density parity-check (LDPC) network coding and joint decoding. The saddle point equations for the replica symmetric solution are found in particular realizations of this channel, including a small and large number of transmitters and receivers. In particular, we examine the cases of a single transmitter, a single receiver and symmetric and asymmetric interference. Both dynamical and thermodynamical transitions from the ferromagnetic solution of perfect decoding to a non-ferromagnetic solution are identified for the cases considered, marking the practical and theoretical limits of the system under the current coding scheme. Numerical results are provided, showing the typical level of improvement/deterioration achieved with respect to the single transmitter/receiver result, for the various cases. © 2007 IOP Publishing Ltd.

Two sides to attitudinal commitment:the effect of calculative and loyalty commitment on enforcement mechanism in distribution channels

Previous conceptualizations of attitudinal commitment are extended by considering two very different components of a manufacturer’s attachment to an independent channel intermediary. Relying on commitment theory, a model is developed that describes how attitudinal commitment may reside in either the instrumental or the social strain of a manufacturer’s relationship with its distributor. For each strain, the developmental role played by key facets of the channel setting—relative dependence, pledges, and trust—are shown. Furthermore, the nature of the attachment bond is posited to motivate very different governance mechanisms as the distribution agreement is enforced by either social or contractual means. Empirical support for the model demonstrates that an expanded view of attitudinal commitment is important in understanding the complex nature of attachment in channel relationships.

Exploiting sensitivity of nonorthogonal joint diagonalisation as a security mechanism in steganography

We have recently proposed the framework of independent blind source separation as an advantageous approach to steganography. Amongst the several characteristics noted was a sensitivity to message reconstruction due to small perturbations in the sources. This characteristic is not common in most other approaches to steganography. In this paper we discuss how this sensitivity relates the joint diagonalisation inside the independent component approach, and reliance on exact knowledge of secret information, and how it can be used as an additional and inherent security mechanism against malicious attack to discovery of the hidden messages. The paper therefore provides an enhanced mechanism that can be used for e-document forensic analysis and can be applied to different dimensionality digital data media. In this paper we use a low dimensional example of biomedical time series as might occur in the electronic patient health record, where protection of the private patient information is paramount.

An examination of the Prandtl mechanism in large dimension slope failures

An alternative explanation for the modes of failure of large scale failures of open pit walls to those of classical slope stability theory is proposed that makes use of the concept of a transition zone, which is described by a modified Prandtls prism.

A new fast generalized sphere decoding algorithm in MIMO systems

A new generalized sphere decoding algorithm is proposed for underdetermined MIMO systems with fewer receive antennas N than transmit antennas M. The proposed algorithm is significantly faster than the existing generalized sphere decoding algorithms. The basic idea is to partition the transmitted signal vector into two subvectors x and x with N - 1 and M - N + 1 elements respectively. After some simple transformations, an outer layer Sphere Decoder (SD) can be used to choose proper x and then use an inner layer SD to decide x, thus the whole transmitted signal vector is obtained. Simulation results show that Double Layer Sphere Decoding (DLSD) has far less complexity than the existing Generalized Sphere Decoding (GSDs).

Characterization of a novel lipoxygenase-independent senescence mechanism in Alstroemeria peruviana floral tissue

The role of lipoxygenase (lox) in senescence ofAlstroemeria peruviana flowers was investigated using a combination of in vitro assays and chemical profiling of the lipid oxidation products generated. Phospholipids and galactolipids were extensively degraded during senescence in both sepals and petals and the ratio of saturated/unsaturated fatty acids increased. Lox protein levels and enzymatic activity declined markedly after flower opening. Stereochemical analysis of lox products showed that 13-lox was the major activity present in both floral tissues and high levels of 13-keto fatty acids were also synthesized. Lipid hydroperoxides accumulated in sepals, but not in petals, and sepals also had a higher chlorophyll to carotenoid ratio that favors photooxidation of lipids. Loss of membrane semipermeability was coincident for both tissue types and was chronologically separated from lox activity that had declined by over 80% at the onset of electrolyte leakage. Thus, loss of membrane function was not related to lox activity or accumulation of lipid hydroperoxides per se and differs in these respects from other ethylene-insensitive floral tissues representing a novel pattern of flower senescence.

Directed phase separation of PFO:PS blends during spin-coating using feedback controlled in situ stroboscopic fluorescence microscopy

Uniform thin-films of polymer blends can be produced through spin-coating, which is used on an industrial scale for the production of light emitting diodes, and more recently organic photovoltaic devices. Here, we present the results of the direct observation, and control, over the phase separation of polystyrene and poly(9,9′-dioctylfluorene) during spin-coating using high speed stroboscopic fluorescence microscopy. This new approach, imaging the fluorescence, from a blend of fluorescent + non-fluorescent polymers allows for intensity to be directly mapped to composition, providing a direct determination of composition fluctuations during the spin-coating process. We have studied the compositional development and corresponding structural development for a range of compositions, which produce a range of different phase separated morphologies. We initially observe domains formed by spinodal decomposition, coarsening via Ostwald Ripening until an interfacial instability causes break-up of the bicontinuous morphology. Ostwald ripening continues, and depending upon composition a bicontinuous morphology is re-established. By observing compositional and morphological development in real-time, we are able to direct and control morphological structure development through control of the spin coating parameters via in situ feedback. © 2013 The Royal Society of Chemistry.

Raman gain and random distributed feedback generation in nitrogen doped silica core fiber

Recently, the concept of a random distributed feedback (DFB) lasing in optical fibers has been demonstrated [1], A number of different random DFB fiber lasers has been demonstrated so far including tunable, multiwalength, cascaded generation, generation in different spectral bands etc [2-7]. All systems are based on standard low-loss germanium doped silica core fibres having relatively low Rayleigh scattering coefficient. Thus, the typical length of random DFB fiber lasers is in the range from several kilometres to tens of kilometres to accumulate enough random feedback. Here we demonstrate for the first time to our knowledge the random DFB fiber laser based on a nitrogen doped silica core (N-doped) fiber. The fiber has several times higher Rayleigh scattering coefficient compared to standard telecommunication fibres. Thus, the generation is achieved in 500 meters long fiber only. © 2013 IEEE.

‘Let’s talk about feedback’:an exploration of academic feedback practices in pharmacy education

Feedback is considered one of the most effective mechanisms to aid learning and achievement (Hattie and Timperley, 2007). However, in past UK National Student Surveys, perceptions of academic feedback have been consistently rated lower by final year undergraduate students than other aspects of the student experience (Williams and Kane, 2009). For pharmacy students in particular, Hall and colleagues recently reported that almost a third of students surveyed were dissatisfied with feedback and perceived feedback practice to be inconsistent (Hall et al, 2012). Aims of the Workshop: This workshop has been designed to explore current academic feedback practices in pharmacy education across a variety of settings and cultures as well as to create a toolkit for pharmacy academics to guide their approach to feedback. Learning Objectives: 1. Discuss and characterise academic feedback practices provided by pharmacy academics to pharmacy students in a variety of settings and cultures. 2. Develop academic feedback strategies for a variety of scenarios. 3. Evaluate and categorise feedback strategies with use of a feedback matrix. Description of Workshop Activities: Introduction to workshop and feedback on pre-reading exercise (5 minutes). Activity 1: A short presentation on theoretical models of academic feedback. Evidence of feedback in pharmacy education (10 minutes). Activity 2: Discussion of feedback approaches in participants’ organisations for differing educational modalities. Consideration of the following factors will be undertaken: experiential v. theoretical education, formative v. summative assessment, form of assessment and the effect of culture (20 minutes, large group discussion). Activity 3: Introduction of a feedback matrix (5 minutes). Activity 4: Development of an academic feedback toolkit for pharmacy education. Participants will be divided into 4 groups and will discuss how to provide effective feedback for 2 scenarios. Feedback strategies will be categorised with the feedback matrix. Results will be presented back to the workshop group (20 minutes, small group discussion, 20 minutes, large group presentation). Summary (10 minutes). Additional Information: Pre-reading: Participants will be provided with a list of definitions for academic feedback and will be asked to rank the definitions in order of perceived relevance to pharmacy education. References Archer, J. C. (2010). State of the science in health professional education: effective feedback. Medical education, 44(1), 101-108. Hall, M., Hanna, L. A., & Quinn, S. (2012). Pharmacy Students’ Views of Faculty Feedback on Academic Performance. American journal of pharmaceutical education, 76(1). Hattie, J., & Timperley, H. (2007). The power of feedback. Review of educational research, 77(1), 81-112. Medina, M. S. (2007). Providing feedback to enhance pharmacy students’ performance. American Journal of Health-System Pharmacy, 64(24), 2542-2545.

Performance optimisation of the MAC protocol with multiple contention slots in MIMO ad hoc networks

The multiple-input multiple-output (MIMO) technique can be used to improve the performance of ad hoc networks. Various medium access control (MAC) protocols with multiple contention slots have been proposed to exploit spatial multiplexing for increasing the transport throughput of MIMO ad hoc networks. However, the existence of multiple request-to-send/clear-to-send (RTS/CTS) contention slots represents a severe overhead that limits the improvement on transport throughput achieved by spatial multiplexing. In addition, when the number of contention slots is fixed, the efficiency of RTS/CTS contention is affected by the transmitting power of network nodes. In this study, a joint optimisation scheme on both transmitting power and contention slots number for maximising the transport throughput is presented. This includes the establishment of an analytical model of a simplified MAC protocol with multiple contention slots, the derivation of transport throughput as a function of both transmitting power and the number of contention slots, and the optimisation process based on the transport throughput formula derived. The analytical results obtained, verified by simulation, show that much higher transport throughput can be achieved using the joint optimisation scheme proposed, compared with the non-optimised cases and the results previously reported.

Causes of tension in post-observation feedback in pre-service teacher training: an alternative view

A central component in pre-service teacher training is teaching practice and feedback. In some cases, feedback results in disquiet and tension (Brandt, 2008). Many researchers attribute this tension to the incompatibility of the assessment and development roles that the trainer must perform. The research reported on here, however, suggests that tension may also be rooted in a difference in expectation amongst trainers and trainees about the purpose and performance of feedback. This can result in trainees not playing by the rules of the game (Roberts & Sarangi, 2001) either because they do not understand them or because they wish to challenge them.

Packet switching in wide area broadband private networks

B-ISDN is a universal network which supports diverse mixes of service, applications and traffic. ATM has been accepted world-wide as the transport technique for future use in B-ISDN. ATM, being a simple packet oriented transfer technique, provides a flexible means for supporting a continuum of transport rates and is efficient due to possible statistical sharing of network resources by multiple users. In order to fully exploit the potential statistical gain, while at the same time provide diverse service and traffic mixes, an efficient traffic control must be designed. Traffic controls which include congestion and flow control are a fundamental necessity to the success and viability of future B-ISDN. Congestion and flow control is difficult in the broadband environment due to the high speed link, the wide area distance, diverse service requirements and diverse traffic characteristics. Most congestion and flow control approaches in conventional packet switched networks are reactive in nature and are not applicable in the B-ISDN environment. In this research, traffic control procedures mainly based on preventive measures for a private ATM-based network are proposed and their performance evaluated. The various traffic controls include CAC, traffic flow enforcement, priority control and an explicit feedback mechanism. These functions operate at call level and cell level. They are carried out distributively by the end terminals, the network access points and the internal elements of the network. During the connection set-up phase, the CAC decides the acceptance or denial of a connection request and allocates bandwidth to the new connection according to three schemes; peak bit rate, statistical rate and average bit rate. The statistical multiplexing rate is based on a `bufferless fluid flow model' which is simple and robust. The allocation of an average bit rate to data traffic at the expense of delay obviously improves the network bandwidth utilisation.

Legitimate talk in feedback conferences

Feedback on performance is a feature of professional training. Much feedback is delivered in post-observation conferences where a ‘trainer’ will discuss the ‘trainee's’ performance with him/her. What transpires in these conferences, however, is ‘hidden from view’ (Heritage and Sefi 1992: 362) and the norms of interaction are largely unexamined in the literature. Even less is known about feedback conducted in groups, yet many teachers training to teach English experience feedback in this way. This article provides a discourse analysis of four extracts from group feedback conferences on a pre-service programme for teachers of English language. Drawing on the concept of ‘legitimate talk’, the analysis shows how topics and speaking rights are established and negotiated and how participants orientate to and contest both the forms of knowledge that emerge and the speaking rights. While the study was not initially designed to support trainers in their professional development, the argument is made that data from linguistic ethnographic studies can be used by research participants and others for these purposes, thus enhancing the relationship between the researcher and the researched.