Enabling Fine-Grain Restricted Coset Coding Through Word-Level Compression for PCM

Phase change memory (PCM) has recently emerged as a promising technology to meet the fast growing demand for large capacity memory in computer systems, replacing DRAM that is impeded by physical limitations. Multi-level cell (MLC) PCM offers high density with low per-byte fabrication cost. However, despite many advantages, such as scalability and low leakage, the energy for programming intermediate states is considerably larger than programing single-level cell PCM. In this paper, we study encoding techniques to reduce write energy for MLC PCM when the encoding granularity is lowered below the typical cache line size. We observe that encoding data blocks at small granularity to reduce write energy actually increases the write energy because of the auxiliary encoding bits. We mitigate this adverse effect by 1) designing suitable codeword mappings that use fewer auxiliary bits and 2) proposing a new Word-Level Compression (WLC) which compresses more than 91% of the memory lines and provides enough room to store the auxiliary data using a novel restricted coset encoding applied at small data block granularities. Experimental results show that the proposed encoding at 16-bit data granularity reduces the write energy by 39%, on average, versus the leading encoding approach for write energy reduction. Furthermore, it improves endurance by 20% and is more reliable than the leading approach. Hardware synthesis evaluation shows that the proposed encoding can be implemented on-chip with only a nominal area overhead.Comment: 12 page

Automated transition state theory calculations for high-throughput kinetics

A scarcity of known chemical kinetic parameters leads to the use of many reaction rate estimates, which are not always sufficiently accurate, in the construction of detailed kinetic models. To reduce the reliance on these estimates and improve the accuracy of predictive kinetic models, we have developed a high-throughput, fully automated, reaction rate calculation method, AutoTST. The algorithm integrates automated saddle-point geometry search methods and a canonical transition state theory kinetics calculator. The automatically calculated reaction rates compare favorably to existing estimated rates. Comparison against high level theoretical calculations show the new automated method performs better than rate estimates when the estimate is made by a poor analogy. The method will improve by accounting for internal rotor contributions and by improving methods to determine molecular symmetry.Comment: 29 pages, 8 figure

Using real occupancy in retrofit decision-making: Reducing the performance gap in low utilisation higher education buildings

Retrofit analysis relies on intuition and faith in the simulations used to justify strategy selection. However, intuition is built upon belief systems which become increasing unjustifiable as building operation deviates from design whether in utilisation, occupant behaviours or climate models. Higher education facilities are known for persistently low but well recorded occupant presence and density, and therefore are susceptible to counterintuitive behaviours related to utilisation. When operation has little correlation with design it is possible for performance issues to appear to be symptoms of design considerations rather than direct root of the issue. Using an EnergyPlus and SBEM virtual case study based on a floor of a university building and class registration data this paper describes how lighting retrofit simulation alludes to intuitive thermal property and HVAC efficiency concerns where heating management is the primary cause for concern. In doing so, it demonstrates a new approach to scheduling utilisation in higher education facilities and a method of meaningfully modelling BMS systems in EnergyPlus as replacement for the efficiency credits method. Results are discussed in terms of relevance to legislative compliance, cost-benefit analysis and how the scheduling methods contribute to intuitive analysis of low utilisation buildings

Periodic Fever, Aphthous Stomatitis, Pharyngitis, and Cervical Adenitis (PFAPA) Misdiagnosed as Recurrent Urinary Tract Infection

Recurrent fever is common in children and specific infections account for the fever in most cases. PFAPA is not an uncommon cause of periodic fever during childhood. On the other hand, in patients with vesicoureteral reflux (VUR), urinary tract infection usually presents with fever.Here, we report two PFAPA cases in patients with VUR in whom recurrent episodes of fever were misdiagnosed as UTI. Keywords: PFAPA Syndrome; Periodic Fever Syndrome; Vesico-Ureteral Reflux; Urinary Tract Infections; Child

Optical code division multiple access codes comparison in free space optics and optical fiber transmission medium

Performance of three different Optical Code Division Multiple Access codes namely Prime Code (PC), Quadratic Congruence (QC), and Khazani-Syed (KS) code are compared in Free Space Optic (FSO) and optical fiber transmission. The simulation results show that efficiency of a code family is medium-dependent. While one code family performs the best in fiber medium, it is not necessary that it acts the same in FSO. For instance, KS with code weight of 6 provides BER 10-12 at 600 m distance, while other codes cannot even reach to the threshold 10-9 at this point. However this code shows vulnerability against fiber dispersion. At 5 km fiber, it provides BER of 10-7, even less then PC with 10-8. In that point KS code with weight 6 attains the best performance with BER of 10-11

Investigating how cell extrinsic and intrinsic factors affect cytotoxic T lymphocyte function

Cytotoxic T lymphocytes (CTLs) can target and induce apoptosis in cancer cells during the anti-tumour immune response. However, the cytotoxicity (or killing) function of CTLs can be perturbed directly by cancer cells or via the tumour microenvironment (TME). Among the various factors in TME that can influence T cell function, the effect that mechanical properties of the extracellular matrix (ECM) have on CTL responses is unclear. Research into CTL-mediated cytotoxicity is typically performed in either two-dimensional (2D) matrix-free culture or in complex in vivo animal models. In vitro, 2D studies are limited in recapitulating the CTL response in vivo, whereas it is very difficult to manipulate the TME and perform high-throughput experiments using in vivo models. Recently 3D culture models have been introduced to fill the gap between 2D and in vivo studies. In this study, we used an automated 3D bioprinter to incorporate OT-I T cells and cognate and non-cognate target cells in a polyethylene glycol (PEG)-based hydrogel and studied the killing efficiency in comparison with 2D culture and manually-prepared gels. Here, we showed that the 3D bioprinter embeds both CTLs and target cells in the hydrogel and enables control over the dimensions of the embedding matrix as well as the number and spatial organisation of cells. Moreover, the ability to digest the gel and release the cells allowed us to perform killing efficiency comparisons and downstream high-throughput CTL functional analyses using flow cytometry. This novel 3D cell culture system allowed us to investigate the effects of tunable ECM mechanical properties in a reproducible cytotoxicity model of matrix-embedded CTL and target cells. Our results demonstrate that in matrices with higher density, CTL killing efficacy was compromised. This demonstrates that matrix stiffness, independent of matrix porosity or other variable characteristics, has a large impact on CTL function. From another perspective, cancer cells can directly induce dysfunctional programming in CTLs. Repeated stimulation of the T cell receptor (TCR) on CTLs with the tumour-associated antigen leads to overexpression of inhibitory receptors such as programmed cell death (PD)-1 on the surface of T cells, leading to aberrant response and eventually tumour escape. TCR signalling machinery can be affected by the expression of inhibitory receptors, but it is not clear whether inhibitory receptors alone are responsible for the dysfunction of exhausted T cells or to what degree other mechanisms contribute. To address this, we used a mouse model of T cell dysfunction, finding that T cells could exhibit a dysfunctional phenotype with minimal upregulation of inhibitory receptors and without downregulation of TCR. Instead, we found a decrease in the proximal signalling kinases Lck and ZAP70, specifically in dysfunctional cells. To confirm these results, we developed a human primary in vitro CD8+ T cell dysfunction model, which allowed us to study the effect of repeated antigen stimulation on the inhibitory receptors expression and expression of Lck and ZAP70 in human T cells. In this model, we again found that dysfunctional T cells had lower expression of Lck and ZAP70, confirming the results from the mouse model. Future experiments could be performed in which Lck and/or ZAP70 expression is enhanced in dysfunctional T cells. If this restores the functional phenotype, it may confirm that a low level of Lck and ZAP70 protein expression is a cause of T cell dysfunction. This research sheds light on how the external (matrix stiffness) and internal factors (TCR stimulation) affect the CTL response

Variable - weight optical code division multiple access system using different detection schemes

In this paper a Variable Weight OCDMA (VWOCDMA) system using KS code with Direct Decoding (DD), Complementary Subtraction (CS) and AND subtraction detections is proposed. System performance is analyzed using mathematical approximation and software simulation. In mathematical analysis, the effects of Phase-Induced Intensity Noise, shot noise and thermal noise are taken into account. Bit Error Rate of different users is plotted as a function of received optical power per chip with varying the bit rates and number of active users. It has been shown that for different bit rates and number of users, system using DD has better performance than the system applying CS and AND detection. Using DD scheme, the number of active users are 100 while this value is 27 and 25 in case of using CS and AND detection, respectively, when the received optical power per chip is –10 dBm

A 40 Gb/s duty-cycle/polarization division multiplexing system

Ever increasing demand for higher bandwidth and capacity requests more efficient multiplexing techniques. To increase supportable subscribers in networks, hybrid fiber optic systems have been proposed lately. In this research work a combination of polarization division multiplexing (PDM) and duty-cycle division multiplexing (DCDM) system is proposed for long haul communication. In the proposed system each PDM channel carries 2-channel DCDM where each user is operating at data rate of 10 Gb/s which forms 2 × 2 × 10 Gb/s optical system. Results show that the bit error rate of 10-9 for worst user is achieved at received power per chip of 21.12 dBm and optical signal to noise ratio of 22.08. Furthermore, system analysis demonstrates that the proposed system can tolerate the ±10 ps/nm dispersion without any need for compensation