Background: Laparoscopic surgery for colorectal cancer is a novel healthcare technology, for which much research evidence has been published. The objectives of this work were to compare the oncologic outcomes of this technology across different study types, and to define patterns of adoption on the basis of the literature. Methods: A comprehensive systematic review of the literature was conducted using 1) existing systematic reviews, 2) randomized controlled trials (RCTs), and 3) observational studies. Outcomes of interest were overall survival, and total lymph node harvest. Outcomes were compared for congruence. Adoption was evaluated by means of summary expert opinions in the literature. Results: 1) Existing systematic reviews were of low to moderate quality and displayed evidence of overlap and duplication. 2) Laparoscopy was not inferior to open surgery in terms of oncologic outcomes in any study type. 3) Oncologic outcomes from RCTs and observational studies were congruent. 4) Expert opinion in the literature has been supportive of this technology, paralleling the publication of large RCTs. Conclusions: The evaluation of laparoscopic surgery for colorectal cancer in RCTs and observational studies suggests that it is not inferior to open surgery. Adoption of this technology has paralleled RCT evidence.

Sensor networks are innovative wireless networks consisting of a large number of low-cost, resource-constrained sensor nodes that collect, process, and transmit data in a distributed and collaborative way. There are numerous applications for wireless sensor networks, and security is vital for many of them. However, sensor nodes suffer from many constraints, including low computation capability, small memory, limited energy resources, susceptibility to physical capture, and the lack of infrastructure, all of which impose formidable security challenges and call for innovative approaches. In this thesis, we present our research results on three important aspects of securing sensor networks: lightweight entity authentication, distributed node clone detection, and secure data aggregation. As the technical core of our lightweight authentication proposals, a special type of circulant matrix named circulant-P2 matrix is introduced. We prove the linear independence of matrix vectors, present efficient algorithms on matrix operations, and explore other important properties. By combining circulant-P2 matrix with the learning parity with noise problem, we develop two one-way authentication protocols: the innovative LCMQ protocol, which is provably secure against all probabilistic polynomial-time attacks and provides remarkable performance on almost all metrics except one mild requirement for the verifier's computational capacity, and the HB$^C$ protocol, which utilizes the conventional HB-like authentication structure to preserve the bit-operation only computation requirement for both participants and consumes less key storage than previous HB-like protocols without sacrificing other performance. Moreover, two enhancement mechanisms are provided to protect the HB-like protocols from known attacks and to improve performance. For both protocols, practical parameters for different security levels are recommended. In addition, we build a framework to extend enhanced HB-like protocols to mutual authentication in a communication-efficient fashion. Node clone attack, that is, the attempt by adversaries to add one or more nodes to the network by cloning captured nodes, imposes a severe threat to wireless sensor networks. To cope with it, we propose two distributed detection protocols with difference tradeoffs on network conditions and performance. The first one is based on distributed hash table, by which a fully decentralized, key-based caching and checking system is constructed to deterministically catch cloned nodes in general sensor networks. The protocol performance of efficient storage consumption and high security level is theoretically deducted through a probability model, and the resulting equations, with necessary adjustments for real application, are supported by the simulations. The other is the randomly directed exploration protocol, which presents notable communication performance and minimal storage consumption by an elegant probabilistic directed forwarding technique along with random initial direction and border determination. The extensive experimental results uphold the protocol design and show its efficiency on communication overhead and satisfactory detection probability. Data aggregation is an inherent requirement for many sensor network applications, but designing secure mechanisms for data aggregation is very challenging because the aggregation nature that requires intermediate nodes to process and change messages, and the security objective to prevent malicious manipulation, conflict with each other to a great extent. To fulfill different challenges of secure data aggregation, we present two types of approaches. The first is to provide cryptographic integrity mechanisms for general data aggregation. Based on recent developments of homomorphic primitives, we propose three integrity schemes: a concrete homomorphic MAC construction, homomorphic hash plus aggregate MAC, and homomorphic hash with identity-based aggregate signature, which provide different tradeoffs on security assumption, communication payload, and computation cost. The other is a substantial data aggregation scheme that is suitable for a specific and popular class of aggregation applications, embedded with built-in security techniques that effectively defeat outside and inside attacks. Its foundation is a new data structure---secure Bloom filter, which combines HMAC with Bloom filter. The secure Bloom filter is naturally compatible with aggregation and has reliable security properties. We systematically analyze the scheme's performance and run extensive simulations on different network scenarios for evaluation. The simulation results demonstrate that the scheme presents good performance on security, communication cost, and balance.

Abstract Title: Emerging Markets – A Case Study in Foreign Market Entry toBangladesh Keywords: emerging market, entry strategy, market entry, factors behind entry choice, entry mode, entry node, entry timing Background: Internationalism and international marketing are hot topics among the strategy discussions of the companies and as a result companies continuously look for new, unreached sales potential to their products and services as well as better use of their resources. Purpose: To find the most efficient international market entry strategy for companies moving from developed/transition economy to an emerging market. Theoretical framework: The base for the start of internationalisation process is company’s inner motives and resources. Motives and resources combined with the cultural distance, competition and general external environment of host country form potential company-specific risks for the entry to foreign market. Potential customers in combination with company resources shows how big is the match between market demand and what company can offer and therefore determines the potential reward. Risks and reward are both input to the decision making process where the potential benefits and drawbacks are analysed against each other. The output of this decision making is the entry strategy. Methodology: Internet was mainly used to collect secondary data about company resources, cultural distance and external environment. Interviews with 150 retailers inBangladesh were conducted to collect primary data about the competition and consumer behaviours in the hosiery market ofBangladesh. Then comparative analysis was made based on the model developed by the authors to reach to the decision. Conclusion: The most effective entry strategy for the entry to emerging markets is indirect exporting through an agent in case there is high location risk, moderately high competition risk, medium country risk and moderately low demand risk, the company has no surplus finances for big investments and no prior experience in doing business in an emerging market.

Wireless technology has become an increasingly popular way to gain network access. Wireless networks are expected to provide efficient and reliable service and support a broad range of emerging applications, such as multimedia streaming and video conferencing. However, limited wireless spectrum together with interference and fading pose signi cant challenges for network designers. The novel technique of network coding has a significant potential for improving the throughput and reliability of wireless networks by taking advantage of the broadcast nature of wireless medium. Reverse carpooling is one of the main techniques used to realize the benefits of network coding in wireless networks. With reverse carpooling, two flows are traveling in opposite directions, sharing a common path. The network coding is performed in the intermediate (relay) nodes, which saves up to 50% of transmissions. In this thesis, we focus on the scheduling at the relay nodes in wireless networks with reverse carpooling. When two packets traveling in opposite directions are available at the relay node, the relay node combines them and broadcasts the resulting packet. This event is referred to as a coding opportunity. When only one packet is available, the relay node needs to decide whether to wait for future coding opportunities, or to transmit them without coding. Though the choice of holding packets exploits the positive aspects of network coding, without a proper policy in place that controls how long the packets should wait, it will have an adverse impact on delays and thus the overall network performance. Accordingly, our goal is to find an optimal control strategy that delicately balances the tradeoff between the number of transmissions and delays incurred by the packets. We also address the fundamental question of what local information we should keep track of and use in making the decision of of whether to transmit uncoded packet or wait for the next coding opportunity. The available information consists of queue length and time stamps indicating the arrival time of packets in the queue. We could also store history of all previous states and actions. However, using all this information makes the control very complex and so we try to find if the overhead in collecting waiting times and historical information is worth it. A major contribution of this thesis is a stochastic control framework that uses state information based on what can be observed and prescribes an optimal action. For that, we formulate and solve a stochastic dynamic program with the objective of minimizing the long run average cost per unit time incurred due to transmissions and delays. Subsequently, we show that a stationary policy based on queue lengths is optimal, and the optimal policy is of threshold-type. Then, we describe a non-linear optimization procedure to obtain the optimal thresholds. Further, we substantiate our analytical ndings by performing numerical experiments under varied settings. We compare systems that use only queue length with those where more information is available, and we show that optimal control that uses only the queue length is as good as any optimal control that relies on knowing the entire history.

In this paper, a heuristic backtracking search algorithm is proposed to adjust the phasing arrangement of primary feeders and laterals for phase balancing of distribution systems. The phase unbalance index of distribution feeders is calculated based on the phasing current magnitude of each line segment and branch, which has been solved by a 3-phase load flow program. The database of an automated mapping/facility management (AM/FM) system is used to retrieve the component attributes and topology process is executed to determine the electrical network configuration and to identify the customers served by each distribution transformer. By using the monthly energy consumption of the customers in customer information system (CIS) and the typical daily load patterns of customer classes, the hourly loading profiles of distribution transformers can be derived, which can be integrated to solve the load demand of each service zone. By this manner, the individual phase loadings of each primary feeder and lateral can be determined based on the phasing of distribution transformers and the power consumption served. The optimal phase balancing of distribution systems is performed by heuristic rule-based searching process to minimize the phase unbalance index so that the proper phasings of a primary feeder and its lateral can be assigned. To demonstrate the effectiveness of proposed methodology to enhance three-phase balancing of distribution systems, a practical distribution feeder with 2754 customers are selected for computer simulation. It is concluded that three phase balancing of distribution systems can be obtained by properly phasing design of primary feeders and laterals by considering customer load characteristics.

Introduction: Globally, one in four persons infected with the human immunodeficiency virus (HIV) who are living with the acquired immunodeficiency syndrome (AIDS) will die of tuberculosis (TB). The estimated number of HIV-infected children who die of tuberculosis, especially extrapulmonary TB (EPTB), in Haiti, is only loosely based on facts or investigation. This study proposes to describe demographics of children with EPTB in a pediatric TB hospital in Haiti. The objectives are two-fold. The first objective is to describe the population of children discharged from Grace Children's Hospital with a confirmed diagnosis of tuberculosis overall, and broken down by whether or not the child had an extrapulmonary manifestation of the TB disease. Specifically, we describe the demographic characteristics and the prevalence of HIV and other co-morbidities of the children, in-hospital mortality, and the diagnostic tools used to determine TB infection including the sputum test, and th e documentation of family members also infected. As part of the descriptive process, by examining those with only pulmonary TB (PTB) and EPTB separately, we investigate if they appear to be different sub-populations based on demographic characteristics and clinical measures. The second objective of this work is to determine if there is a positive association between HIV infection and the EPTB manifestation in children with a confirmed diagnosis of TB, both crudely and after adjusting for demographic variables and co-morbidities. Methods: A cross-sectional study design was used to review medical charts of clinically diagnosed pediatric TB cases for a five-year period (January 1, 1999 -- December 31, 2003). This included 492 pulmonary TB and 210 extrapulmonary TB cases. Variables measured included clinical measures and demographic characteristics. Results: Data for 615 hospitalized, clinically diagnosed pediatric TB cases were reviewed. There were 315 (51.4%) males and 298 (48.6%) females with a mean age of 5.40 years (range 0.17 - 14 years), with 214 (37.9%) of the patients aged 0-2 years. Percent males were 47.8% and 57.9% in PTB and EPTB groups respectively (p<0.05). One hundred and seven (17.4%) of patients were HIV positive. Three hundred eighty-eight (63%) of the patients had one or more additional co-morbidities: [anemia 299 (48.6%), intestinal parasites 93 (15.1%), malaria 58 (9.4%) and gastroenteritis 19 (3.1%)]. Nearly 85% of the children were undernourished. Eighty-three child patients (13.5%) died in the hospital. Children with EPTB were much more likely to be over the age of two (74% vs. 56% in PTB group), resulting in a highly significant Chi-square stati stic. The overall difference in mean age, however, was only borderline significant with children with EPTB being slightly older [p=0.059] and age was only weakly associated with TB group. They were much less likely to be HIV positive (8.6% vs. 22%, p<0.01). Children in the EPTB group were somewhat less likely to die in the hospital (10.0% vs. 15.4%, p=0.066). The OR was greater than 4 for HIV and was greater than 2 for poor nutrition status [p<0.01 for each]. Conclusion: There was no association in this model between EPTB and mortality. The apparent univariate association between EPTB and reduced mortality can be explained by lower prevalence of HIV and poor nutrition status in this sub-sample. This study has implications for hospital-based pediatric TB diagnosis and epidemiology in resource-poor countries.

Οι φυλετικές ορμόνες επηρεάζουν τη βιολογική συμπεριφορά του μελανώματος. Μετά την ανακάλυψη των οιστρογονικών υποδοχέων (ER) και ιδίως του υποδοχέα βήτα, η άποψη πως τα μελανώματα εκφράζουν χαμηλές συγκεντρώσεις ER αναθεωρήθηκε. Ο σκοπός της παρούσας μελέτης ήταν να διερευνήσει το βαθμό έκφρασης των ER στο πρωτοπαθές μελάνωμα αλλά και στο λεμφαδένα φρουρό αυτού που παριστά ένα σημαντικό σταθμό στη μεταστατική διαδικασία και να εκτιμήσει πιθανή συσχέτιση με την πρόγνωση και τη συνολική επιβίωση. Πραγματοποιήθηκε ανάλυση δεδομένων 60 ασθενών, μέσης ηλικίας 54,4 ± 14,5 ετών, με διάγνωση μελανώματος κατά την περίοδο 2001-2012. Όλοι οι ασθενείς υποβλήθηκαν σε βιοψία λεμφαδένα φρουρού, μετά την αναγνώρισή του με ραδιοϊσοτοπική λεμφαγγειογραφία. Εάν η ιστοπαθολογική εξέταση αναδείκνυε διήθηση του λεμφαδένα από το νεόπλασμα, διενεργείτο συμπληρωματικός λεμφαδενικός καθαρισμός, σε δεύτερο χρόνο. Με ανοσοϊστοχημική μέθοδο εκτιμήθηκε η έκφραση των οιστρογονικών υποδοχέων (ERα και ERβ) σε όλες τις δυνατές περιπτώσεις. Η έκφραση του ERα ήταν εξαιρετικά ασθενής, αναδεικνύοντας τον ERβ σαν τον επικρατούντα οιστρογονικό υποδοχέα, τόσο στον πρωτοπαθή όγκο, όσο και στο λεμφαδένα φρουρό. H εντονότερη ανοσοέκφραση του ERβ καταδείχθηκε σε λεπτά, λιγότερο διηθητικά μελανώματα με αρνητικούς λεμφαδένες φρουρούς. Επιπρόσθετα, η έκφραση του ERβ στον πρωτοπαθή όγκο σχετιζόταν σαφώς με το κυτταρικό μικροπεριβάλλον του, πιθανά επηρεάζοντας τη λεμφογενή διασπορά. Τα επίπεδα έκφρασης του ERβ είναι ελαττωμένα σταθερά σε επιθετικά μελανώματα, μεγάλου πάχους με μεταστατική νόσο στο λεμφαδένα φρουρό. Η αξιολόγησή τους υποδεικνύει έναν πιθανό δείκτη του μεταστατικού δυναμικού των μελανωμάτων και κατ’ επέκταση της πρόγνωσης της νόσου. / Steroid hormones seem to affect the biological behavior of melanoma. Prior to the discovery of estrogen receptor beta (ERb), melanomas were considered to contain low estrogen receptor concentrations. Furthermore, no studies have examined the role of estrogen receptor expression in sentinel lymph nodes (SLNs) of melanomas. The purpose of this study was to investigate the immunoexpression of estrogen receptors in malignant melanomas and SLNs and to examine any possible association with prognosis and overall survival. A retrospective analysis of prospectively collected data was conducted during a 12-year period (2001-2012). Sixty patients with mean age of 54.4 ± 14.5 years old diagnosed with melanomas after excision biopsy of pre-existing melanocytic lesions, were included in the study. All patients underwent wide excision of the primary tumor and SLN identification. Therapeutic lymph node dissection was conducted in cases where the final pathological report was indicative of SLN tumor invasion. Determination of estrogen receptor alpha (ERa) and beta (ERb) status by immunohistochemistry on tumor and nodal paraffin blocks was performed in all feasible cases. ERb but not ERa was the predominant estrogen receptor found in all primary tumors and SLNs examined. The most intense ERb immunostaining was seen in negative SLNs associated with thinner, less invading melanomas. ERb expression in the primary tumor seems to correlate with the cellular microenvironment, possibly altering the process of SLN invasion. ERb expression is down-regulated in aggressive melanomas with sentinel nodal disease, suggesting its possible usefulness as a surrogate marker for metastatic potential and prognosis in malignant melanoma.

No description available.

No description available.

Objective: In this study, 22 cases of locally recurrent urological malignant fibrous histiocytoma were reviewed considering therapeutic options, follow-up and prognosis. Patients and Methods: In the available literature on this topic we identified 19 cases of locally recurrent genitourinary malignant fibrous histiocytoma. Three additional cases are discussed, primarily arising from the kidney, the bladder and the paratesticular region. Results: The prognosis of locally recurrent urological malignant fibrous histiocytoma was found to be extraordinarily poor. Only 2 of 22 patients have survived for longer than 3.5 years. One of them reported herein is still alive 10 years after extensive lymphatic spread accompanying the first local recurrence. In this case, late local recurrence occurred after an 8-year interval free of disease. Conclusion: Malignant fibrous histiocytoma is an unusual urological malignancy with a high rate of local recurrence. The latter is frequently accompanied by metastatic disease and unrelenting progression. Despite the poor prognosis early detection of local failure and aggressive salvage therapy might offer the chance of long-term survival in selected cases. Close and life-long follow-up is advisable for patients once treated for recurrent urological malignant fibrous histiocytoma. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.