Personalized Hydrogels for Engineering Diverse Fully Autologous Tissue Implants

Despite incremental improvements in the field of tissue engineering, no technology is currently available for producing completely autologous implants where both the cells and the scaffolding material are generated from the patient, and thus do not provoke an immune response that may lead to implant rejection. Here, a new approach is introduced to efficiently engineer any tissue type, which its differentiation cues are known, from one small tissue biopsy. Pieces of omental tissues are extracted from patients and, while the cells are reprogrammed to become induced pluripotent stem cells, the extracellular matrix is processed into an immunologically matching, thermoresponsive hydrogel. Efficient cell differentiation within a large 3D hydrogel is reported, and, as a proof of concept, the generation of functional cardiac, cortical, spinal cord, and adipogenic tissue implants is demonstrated. This versatile bioengineering approach may assist to regenerate any tissue and organ with a minimal risk for immune rejection.     

On the tractability of hard scheduling problems with generalized due-dates with respect to the number of different due-dates

Journal of Scheduling - We study two $$\mathcal {NP}$$ -hard single-machine scheduling problems with generalized due-dates. In such problems, due-dates are associated with positions in the job...     

On Matrix Rigidity and Locally Self-correctable Codes

We describe a new connection between the problem of finding rigid matrices, as posed by Valiant (MFCS 1977), and the problem of proving lower bounds for linear locally correctable codes. Our result shows that proving linear lower bounds on locally correctable codes with super-logarithmic query complexity will give new constructions of rigid matrices. The interest in constructing rigid matrices is their connection to circuit lower bounds.     

The efficiency range of economical cutting conditions and tool replacement under the age replacement strategy

This paper presents models for calculating the optimal cutting feed rate, spindle speed, and age of preventive tool replacement for a standalone cutting machine. The optimal cutting conditions are determined and analysed for three different objective functions: minimum expected cycle time, minimum expected cost per unit, and maximum expected profit-rate, under the Age Replacement Strategy (ARS) and assuming that the tool-life distribution function is Normal. We show that the first two objective functions are separable, and present an efficient, one-dimensional search procedure for the optimization. A definition of the efficiency ranges of feed rate and standard age of tool replacement is suggested for the ARS, which improves the efficiency range defined in the literature for the Failure Replacement Strategy (FRS).     

Low humidity after harvest changes the abscission site in bunch cherry tomatoes

BACKGROUND: In bunch cherry tomatoes (BCTs) abscission of the fruit from the bunch, rather than deterioration of fruit determines the life‐span of the produce. Two abscission sites have been characterised: the joint (AJ) in the middle of the pedicel, and at the receptacle (AR) at the fruit‐pedicel interphase. The type of abscission is sensitive to growth conditions; joint abscission is typical of winter harvests whereas receptacle abscission is dominant in summer harvests. The aim of the present study was to determine the effect of relative humidity (RH) in terms of water vapour pressure deficit (WVPD) during storage and shelf life on the course and site of abscission of BCTs. RESULTS: The rachis composes only about 2% of the bunch weight, and therefore most of the water loss originated from the fruit. When the bunch lost almost 10% of its weight under low humidity, the relative weight of the rachis was reduced to one‐quarter of its original value. Storage at low WVPD resulted in dominance of AJ whereas storage at high WVPD resulted in dominance of AR. BCTs that exhibited primarily AJ after cold storage was prone to either AJ or AR in high or low shelf‐life RH, respectively. BCTs subjected to elevated temperature and high WVPD after harvest developed receptacle abscission. CONCLUSION: Dehydration of the receptacle abscission zone makes it prone to abscission and this process can be prevented by high‐RH storage. Copyright © 2009 Society of Chemical Industry     

Optical nanomanipulations of malignant cells: controlled cell damage and fusion

Specifically targeting and manipulating living cells is a key challenge in biomedicine and in cancer research in particular. Several studies have shown that nanoparticles irradiated by intense lasers are capable of conveying damage to nearby cells for various therapeutic and biological applications. In this work ultrashort laser pulses and gold nanospheres are used for the generation of localized, nanometric disruptions on the membranes of specifically targeted cells. The high structural stability of the nanospheres and the resonance pulse irradiation allow effective means for controlling the induced nanometric effects. The technique is demonstrated by inducing desired death mechanisms in epidermoid carcinoma and Burkitt lymphoma cells, and initiating efficient cell fusion between various cell types. Main advantages of the presented approach include low toxicity, high specificity, and high flexibility in the regulation of cell damage and cell fusion, which would allow it to play an important role in various future clinical and scientific applications.     

Algorithm optimization using a rule-based system. A case study: The Direct Kinematic Solution in robotics

The computation burden of intensive numerical real-time algorithms is a problem encountered in robotics and many other fields. A cost-effective solution for the implementation of these algorithms requires knowledge of computer architecture, compiler technology and algorithms. A cost-effective numeric processing methodology using a combined hardware-software approach and taking advantage of logic programming tools is presented. The methodology is based on optimizing the numerical calculation process of the algorithm. It also enables the specification of hardware resources. The process uses a rule-based-system (RBS) implemented in the logic programming language Prolog to automatically reduce the number of operations in the numerical execution of the algorithm and optimizes the use of hardware resources. The methodology provides a solution for the problems of handshake overhead and algorithm translation efficiency.The Direct Kinematics Solution (DKS), a robot arm control algorithm, is presented as a case study to illustrate the methodology. The proposed methodology has a general potential which can be extended to the optimization or implementation of different algorithms.