Using Agency Theory in Understanding Switching Behavior in B2B Service Industries “I”

Understanding switching behavior is a cornerstone in sustaining customer led marketing efforts especially in services which depend on long-term relationships with the customers and where the switching process is compound and costly for both the customer and the service provider. The issue of understanding the motives and barriers behind agency-brand switching behavior still needs further conceptual support and empirical investigation in service industries context, where the emphasis placed on investigating the actual switching motives without trying to conceptualize the issue, which if done will result in better understanding for the whole switching process. In this paper, the authors attempt to bridge this gap in the literature by examining the criterion validity of the switching behavior model using the agency theory, as the relation between the business company (principle) and an Advertising agency (the agent) could be described as agency relationship. Furthermore, this approach helps in supporting the efforts for retaining the business-to-business customers, strengthening the relationship with them, developing and adopting globally integrated customer led strategies in different countries, a trend which is expected to dominate the marketing field in the future due to the increasing role of the agency brand selection and switching in today’s world markets.Brand switching, agency theory, business to business marketing, service marketing, international advertising research

Antenna selection and performance analysis of MIMO spatial multiplexing systems

Multiple-input multiple-output spatial multiplexing (MIMO-SM) systems offer an essential benefit referred to as spatial multiplexing gain. Two important signal reception techniques for MIMO-SM systems are the zero-forcing (ZF) and ordered successive interference cancellation (OSIC) as, for example, in the case of the decision-feedback detector (DFD). This thesis studies the communication and signal processing aspects of MIMO-SM. We first investigate the bit error rate (BER) performance of the ZF receiver over transmit correlated Ricean flat-fading channels. In particular, for a MIMO channel with M transmit and N receive antennas, we derive an approximation for the average BER of each sub-stream. A closed-form expression for the optimal transmit correlation coefficient, which achieves the maximum capacity (i.e., uncorrelated case) of two-input two-output spatial multiplexing (TITO-SM) systems, is presented. We further propose an antenna selection (AS) approach for the DFD over independent Rayleigh flat-fading channels. The selected transmit antennas are those that maximize both the post-processing signal-to-noise ratio (SNR) at the receiver end, and the system capacity. An upper bound on the outage probability for the AS approach is derived. It is shown that the AS approach achieves a performance comparable to optimal capacity-based selection based on exhaustive search, but at a lower complexity. Finally, we investigate a cross-layer transmit AS approach for the DFD over spatially correlated Ricean flat-fading channels. The selected transmit antennas are those that maximize the link layer throughput of correlated MIMO channels. A closed-form expression for the system throughput with perfect channel estimation is first derived. We further analyze the system performance with pilot-aided channel estimation. In that, we derive a closed-form expression for the post-detection signal-to-noise-plus-interference ratio (SNIR) of each transmitted substream, conditioned on the estimated channels. The derived SNIR is then used to evaluate the overall system throughput. It is observed that the cross-layer AS approach always assigns the transmission to the antenna combination which sees better channel conditions, resulting in a substantial improvement over the optimal capacity-based AS approach. Considering a training-based channel estimation technique, we compare the performance of the proposed cross-layer AS with that of optimal capacity-based AS when employed with a training-based channel estimation. Our results show that the latter is more robust to imperfect channel estimation. However, in all cases, the cross-layer AS delivers higher throughput gains than the capacity-based A

Preventing Biofilm Formation and Encrustation on Urinary Implants: (Bio)molecular and Physical Research Approaches

Stents and catheters are used to facilitate urine drainage within the urinary system. When such sterile implants are inserted into the urinary tract, ions, macromolecules and bacteria from urine, blood or underlying tissues accumulate on their surface. We presented a brief but comprehensive overview of future research strategies in the prevention of urinary device encrustation with an emphasis on biodegradability, molecular, microbiological and physical research approaches. The large and strongly associated field of stent coatings and tissue engineering is outlined elsewhere in this book. There is still plenty of room for future investigations in the fields of material science, surface science, and biomedical engineering to improve and create the most effective urinary implants. In an era where material science, robotics and artificial intelligence have undergone great progress, futuristic ideas may become a reality. These ideas include the creation of multifunctional programmable intelligent urinary implants (core and surface) capable to adapt to the complex biological and physiological environment through sensing or by algorithms from artificial intelligence included in the implant. Urinary implants are at the crossroads of several scientific disciplines, and progress will only be achieved if scientists and physicians collaborate using basic and applied scientific approaches

INFLUENCE OF MINERAL NITROGEN, COMPOST AND NITROGEN FIXING BACTERIA ON TOMATO PLANTS GROWN IN SANDY SOIL

Pot trials were conducted under plastic house condition during two successive seasons of 2013/2014 and 2014/2015, at the experimental site of Central Laboratory for Agricultural Climate (CLAC), Agricultural Research Center, Giza, Egypt. The present study aims to determine the partial replacement of mineral nitrogen fertilization of tomato by nitrogen fixing bacteria with or without adding compost in sandy soil. Tomato seedlings (Lora F1Hybrid) were transplanted during the first week of October into plastic pots (30 cm diameter) filled with 10 kg of sandy soil. Three rates 25, 50 and 75% of the recommended mineral nitrogen in the nutrient solution for tomato with adding compostat 2% and nitrogen fixing bacteria (Azotobacter chroococcum and Azospirillium brasilense) at 20 ml/plant either individually or in combinationswere investigated on growth, mineral composition and yield of tomato plants compared to 100% of recommended nitrogen only (control). The plants were irrigated daily by drip irrigation and received 200 ml/plant of nutrient solution twice a weekly. The results showed that using 50 or 75% of N-mineral fertilizer + compost + nitrogen fixing bacteria gave the highest values of growth, mineral composition and yield of tomato. It is recommended that 50% of nitrogen mineral fertilizers for tomato plants could be replaced by nitrogen fixing bacteria in presence of compost, which in earn, reduce environment pollution caused by extensive application of mineral nitrogen fertilizers

Evaluation the Effectiveness of CMC and Klucel-E Modified with TiO2 and ZnO Nanoparticles Used for Consolidation the Damaged Paper Maps

The main goal of this work is to study and evaluate the effectiveness of nano titanium dioxide and nano zinc oxide for enhancing the performances of Carboxymethyl cellulose CMC and Klucel-E used as consolidation materials for historical paper maps. Historical map samples dating back to 1817 & 1952 A.D were treated with CMC and Klucel-E loaded with TiO2 nanoparticles and ZnO nanoparticles. Some of the treated samples were submitted to investigation methods and others were submitted to the artificial thermal aging and then to investigation methods to monitor the changes of consolidation materials after accelerated aging test and to evaluate their effect on mechanical, physical and chemical properties of historical  paper samples under effect of  artificial heat  ageing. Visual assessment, pH measurements, Attenuated Total Reflection infrared spectroscopy (FTIR- ATR) study and mechanical properties determination were undertaken, to see if any significant structural or chemical differences could be detected between “untreated”, “treated” and “treated aged” samples. The results showed that no dramatic changes in functional groups on the paper, as monitored by infrared spectroscopy, occurred in the samples before and after treatment; pH values, however, showed that the tested nanocomposites gave good results in decreasing the acidity of the treated paper. The nanocomposites also enhanced optical and mechanical properties of treated samples

Caspase-dependent and -independent suppression of apoptosis by monoHER in Doxorubicin treated cells

Doxorubicin (DOX) is an antitumour agent for different types of cancer, but the dose-related cardiotoxicity limits its clinical use. To prevent this side effect we have developed the flavonoid monohydroxyethylrutoside (monoHER), a promising protective agent, which did not interfere with the antitumour activity of DOX. To obtain more insight in the mechanism underlying the selective protective effects of monoHER, we investigated whether monoHER (1 mM) affects DOX-induced apoptosis in neonatal rat cardiac myocytes (NeRCaMs), human endothelial cells (HUVECs) and the ovarian cancer cell lines A2780 and OVCAR-3. DOX-induced cell death was effectively reduced by monoHER in heart, endothelial and A2780 cells. OVCAR-3 cells were highly resistant to DOX-induced apoptosis. Experiments with the caspase-inhibitor zVAD-fmk showed that DOX-induced apoptosis was caspase-dependent in HUVECs and A2780 cells, whereas caspase-independent mechanisms seem to be important in NeRCaMs. MonoHER suppressed DOX-dependent activation of the mitochondrial apoptotic pathway in normal and A2780 cells as illustrated by p53 accumulation and activation of caspase-9 and -3 cleavage. Thus, monoHER acts by suppressing the activation of molecular mechanisms that mediate either caspase-dependent or -independent cell death. In light of the current work and our previous studies, the use of clinically achievable concentrations of monoHER has no influence on the antitumour activity of DOX whereas higher concentrations as used in the present study could influence the antitumour activity of DOX

HEAVY METAL BIOSORPTION BY SOME BACTERIAL SPECIES ISOLATED FROM DRINKING WATER AT DIFFERENT SITES IN SHARQIA GOVERNORATE

The nine most frequent bacterial strains out of 127 were isolated form ten drinking water samples collected from tap water and bottled water in sharqia governorate. The nine isolates were purified and examined for their resistance to increasing concentrations of two heavy metal ions, lead (Pb+2) and iron (Fe+3). Four stains out of the nine isolates encoded I, II, IV, and VIII showed the highest efficiency of both Pb+2 and Fe +3 uptake from nutrient broth media containing 100 ppm of the heavy metal ions. The four bacteria were preliminary identified and then confirmed by the Biolog examination as Corynebacterium jeikeium, Pseudomonas putida biotype A, Acinetobacter calcoaceticus and Acidovorax delafieldii. The increased concentrations of Pb+2 ions (from 100 to 500 ppm) in nutrient broth media had deleterious effect on the process of heavy metal uptake (biosorption) by all the four selected isolates. Whereas percentage of Pb+2 uptake decreased from 42.9 to 24%; from 72.6 to 42%, from 78.9 to 37% and from 68.8 to 45%, for the four selected isolates, respectively. Meanwhile there was slight decrease change in Fe+3 uptakes percentage accompanying the increase in heavy metal ion concentration. Optimization of the cultural conditions releaved maximum uptake op pb+2 and Fe+3 by the four tested strains in presence of 100 ppm heavy metal concentration when incubated at 25oC except for Acinetobacter calcoaceticus at 35oC in case of Pb+2 uptake, when pH, was adjusted at 5 under static conditions. Upon addition of 50 ppm Cu+2 ions to broth media supplemented with 100 ppm Pb+2 ions, the percentage of metal biosorption by the four tested isolated decreased between 41.11% and 48.45% according to type of strain. Similarly presence of Cu+2 ions caused decrease in Fe+2 uptake by the four isolates ranging between 29.14-45.1%. Percentage of Pb+2 ions uptake by the tested bacteria sharply decreased when a sterile tap water sample was used as natural medium for cell-metal contact. The percentage of uptake inhibition of Pb+2 ranged between 57-65.23% and between 75.1-84.27% for Fe+3 ions. Cell hydrolysate of three tested bacteria appeared to be free from plasmid DNA proving that the genetic character of heavy metal resistance is plasmidless and related to chromosmal DNA in case of Cory. jeikeium, P. putida and A. delafieldii. On the other hand, Acinet. Calcoaceticus contained plasmid of size 23.130 kb. Examining Acientobacter calcoaceticus using transmission electron microscope revealed the accumulation of Pb+2 ions on bacterial cell surface and the intracellular absorption of Fe+3 ions

Novi steroidni derivati sintetizirani iz 3betha-hidroksiandrosten-17-ona

In this study, we synthesized some new substituted steroidal derivatives using 3betha-hydroxyandrosten-17-one (dehydroepiandrosterone) as starting material. The synthesized steroidal derivatives 1-11 were evaluated for their androgenic-anabolic activities compared to testosterone as positive control. Details of the synthesis, spectroscopic data and toxicity (LD50) of synthesized compounds are reported.U radu je opisana sinteza novih steroidnih derivata 1-11 koristeći 3betha-hidroksiandrosten-17-on (dehidroepiandrosteron) kao početnu supstanciju. Androgeno-anaboličko djelovanje tih spojeva uspoređivano je s djelovanjem testosterona kao pozitivnom kontrolom. Navode se detaljni sintetski postupci, spektroskopska karakterizacija i podaci o toksičnosti (LD50)

Controlling of Mycobacterium by Natural Degradant-Combination Models for Sequestering Mycolic Acids in Karish Cheese

Degradation of the mycobacterial complex containing mycolic acids (MAs) by natural bioactive compounds is essential for producing safe and value-added foods with therapeutic activities. This study aimed to determine the degradation efficiency of natural organic acid extracts (i.e., citric, malic, tartaric, and lactic), quadri-mix extract from fruits and probiotics (i.e., lemon, apple, grape, and cell-free supernatant of Lactobacillus acidophilus), and synthetic pure organic acids (i.e., citric, malic, tartaric, and lactic), against MA in vitro in phosphate buffer solution (PBS) and Karish cheese models. The degradation effect was evaluated both individually and in combinations at different concentrations of degradants (1, 1.5, and 2%) and at various time intervals (0, 6, 12, 24, and 48 h). The results show that MA degradation percentage recorded its highest value at 2% of mixed fruit extract quadri-mix with L. acidophilus and reached 99.2% after 48 h both in PBS and Karish cheese, unlike other treatments (i.e., citric + malic + tartaric + lactic), individual acids, and sole extracts at all concentrations. Conversely, organic acid quadri-mix revealed the greatest MA degradation% of 95.9, 96.8, and 97.3% at 1, 1.5, and 2%, respectively, after 48 h. Citric acid was more effective in MA degradation than other acids. The fruit extract quadri-mix combined with L. acidophilus-fortified Karish cheese showed the highest sensorial characteristics; hence, it can be considered a novel food-grade degradant for MA and could be a promising biocontrol candidate against Mycobacterium tuberculosis (Mtb) in food matrices