The divalent Ca2+ metal ion acts as a universal second messenger in virtually all eukaryotic cells from fungi to plants to mammals. In mammals, Ca2+ signaling is vital to a variety of physiological processes including fertilization, cell proliferation, secretion, and muscular contraction. In electrochemically non-excitable tissues, the release of Ca2+ from intracellular stores such as the endoplasmic reticulum is tightly regulated by the inositol 1,4,5-trisphosphate receptor (IP3R). The IP3R Ca2+ release channel is activated by the binding of the small molecule inositol 1,4,5-trisphosphate (IP3) in response to extracellular stimuli such as hormones, growth factors, and neurotransmitters. The conformational changes accompanying IP3 binding were investigated using a biophysical approach. A specific focus of this work is to decipher how signals of ligand binding are transmitted from the N-terminal IP3-binding core to the C-terminal channel domain. To such end, biophysical studies of the ligand-induced conformational changes within the N-terminal domain of IP3R (a.a. 1 – 604) were performed. The results implicated the presence of two flexible linkers which join stably folded domains. This prompted the proposal of a model in which an equilibrium mixture of conformational substrates containing compact and more extended structures co-exist. Determinants within the N- and C-terminal regions of IP3R have previously been reported to be critical to channel function. Employing nuclear magnetic resonance (NMR) as well as biochemical methods, an intermolecular interaction between the S4-S5 linker, the cytoplasmic loop between the fourth and fifth transmembrane helices of IP3R, and the suppressor domain was identified. The determination of the crystal structure of the suppressor domain from isoform type 3 IP3R (IP3R3SUP) allowed us to map the residues involved in this interaction to one face of the molecule. The characterization of this interaction provides insight into the N- and C-terminal determinants essential to the IP3R channel gating mechanism.

The divalent Ca2+ metal ion acts as a universal second messenger in virtually all eukaryotic cells from fungi to plants to mammals. In mammals, Ca2+ signaling is vital to a variety of physiological processes including fertilization, cell proliferation, secretion, and muscular contraction. In electrochemically non-excitable tissues, the release of Ca2+ from intracellular stores such as the endoplasmic reticulum is tightly regulated by the inositol 1,4,5-trisphosphate receptor (IP3R). The IP3R Ca2+ release channel is activated by the binding of the small molecule inositol 1,4,5-trisphosphate (IP3) in response to extracellular stimuli such as hormones, growth factors, and neurotransmitters. The conformational changes accompanying IP3 binding were investigated using a biophysical approach. A specific focus of this work is to decipher how signals of ligand binding are transmitted from the N-terminal IP3-binding core to the C-terminal channel domain. To such end, biophysical studies of the ligand-induced conformational changes within the N-terminal domain of IP3R (a.a. 1 – 604) were performed. The results implicated the presence of two flexible linkers which join stably folded domains. This prompted the proposal of a model in which an equilibrium mixture of conformational substrates containing compact and more extended structures co-exist. Determinants within the N- and C-terminal regions of IP3R have previously been reported to be critical to channel function. Employing nuclear magnetic resonance (NMR) as well as biochemical methods, an intermolecular interaction between the S4-S5 linker, the cytoplasmic loop between the fourth and fifth transmembrane helices of IP3R, and the suppressor domain was identified. The determination of the crystal structure of the suppressor domain from isoform type 3 IP3R (IP3R3SUP) allowed us to map the residues involved in this interaction to one face of the molecule. The characterization of this interaction provides insight into the N- and C-terminal determinants essential to the IP3R channel gating mechanism.

En els sistemes de comunicacions on el transmissor disposa de certa informació sobre l'estat del canal (CSI), es possible dissenyar esquemes lineals de precodificació que assignin la potència de manera òptima induint guanys considerables, sigui en termes de capacitat, sigui en termes de la fiabilitat de l'enllaç de comunicacions. A la pràctica, aquest coneixement del canal mai és perfecte i, per tant, el senyal transmès es veurà degradat degut al desajust entre la informació que el transmissor disposi del canal i el seu estat real.En aquest context, aquesta tesi estudia dos problemes diferents però alhora estretament relacionats: el disseny d'un esquema pràctic de seguiment del canal en transmissió per canals variants en temps, i el disseny d'esquemes lineals de precodificació que siguin robustos a la incertesa del canal. La primera part de la tesi proposa el disseny d'un esquema de seguiment de canal que, mitjançant un enllaç de retorn de baixa capacitat, proporcioni al transmissor una informació acurada sobre el seu estat. Històricament, aquest tipus d'esquemes han rebut fortes crítiques degut a la gran quantitat d'informació que és necessari transmetre des del receptor cap el transmissor. Aquesta tesi, doncs, posa especial èmfasi en el disseny d'aquest canal de retorn. La solució que es proposa, basada en el filtre de Kalman, utilitza un esquema que recorda al transmissor DPCM. Les variacions del canal són tractades mitjançant dos predictors lineals idèntics situats en el transmissor i en el receptor, i un canal de retorn que assisteix el transmissor amb l'error de predicció. L'interès d'aquest esquema diferencial és que permet seguir les variacions del canal amb només dos o quatre bits per coeficient complex, fins i tot en canals ràpidament variants.La resta de la tesi cobreix el segon objectiu, l'estudi de diferents esquemes d'assignació de potències quan el coneixement del canal en transmissió no és perfecte. El problema es planteja per a un sistema MIMO OFDM com a formulació més general, incloent els casos d'una sola antena, de l'esquema beamforming i del canal multiplicatiu com a casos particulars.Primerament s'ha plantejat l'optimització dels criteris de mínim error quadràtic mig (MMSE) i mínima BER sense codificar. La innovació en el treball presentat a la tesi, respecte a altres treballs que segueixen els mateixos criteris de disseny, ha estat la formulació Bayesiana del problema per al disseny dels algoritmes robustos.La tesi continua amb el plantejament d'estratègies robustes d'assignació de potència destinades a minimitzar la BER codificada. Per aquesta tasca s'han utilitzat criteris de teoria de la informació. Possiblement una de les principals contribucions d'aquesta tesi ha estat el plantejament del cut-off rate com a paràmetre de disseny. Aquest criteri s'introdueix com alternativa a la capacitat de canal o a la informació mutual per al disseny del transmissor quan s'inclou codificació de canal. La ultima part de la tesi proposa un interleaver adaptatiu de baixa complexitat que, utilitzant el coneixement del canal disponible en el transmissor, assigna estratègicament els bits no només per combatre les ràfegues d'errors, sinó també per lluitar contra els esvaïments que puguin presentar les diferents portadores del canal per a una realització concreta. El disseny d'aquest interleaver, anomenat "interleaver RCPC" està basat en els codis Rate-Compatible Punctured Convolutional Codes. Com s'il·lustra a partir del resultats numèrics, l'ús d'aquest interleaver millora les prestacions dels algoritmes quan es comparen amb les que s'obtindrien si s'utilitzes un interleaver de bloc o un interleaver pseudo-aleatori. / When the transmitter of a communication system disposes of some Channel State Information (CSI), it is possible to design linear precoders that optimally allocate the power inducing high gains either in terms of capacity or in terms of reliable communications. In practical scenarios, this channel knowledge is not perfect and thus the transmitted signal suffers from the mismatch between the CSI at the transmitter and the real channel.In that context, this thesis deals with two different, but related, topics: the design of a feasible transmitter channel tracker for time varying channels, and the design of optimal linear precoders robust to imperfect channel estimates.The first part of the thesis proposes the design of a channel tracker that provides an accurate CSI at the transmitter by means of a low capacity feedback link. Historically, those schemes have been criticized because of the large amount of information to be transmitted from the receiver to the transmitter. This thesis focuses, thus, the attention in an accurate design of the return link. The proposed solution is based on the Kalman filter and follows a scheme that reminds the well known DPCM transmitter. The channel variability is processed by two identical linear predictors located at the transmitter and at the receiver, and a feedback link that assists the transmitter with the prediction error. The interest of this differential scheme is that allows to track the channel variations with only two or four bits per complex channel coefficient even in fast time-varying channels.The rest of the thesis covers the second topic, studying different robust power allocation algorithms when the CSI is not perfectly known at the transmitter. For the sake of generality, the problem is formulated for the general MIMO OFDM case, encompassing the single antenna transmission, the beamforming schemes and the frequency-flat fading channels as particular cases. First, the minimum MSE and the minimum uncoded BER parameters are chosen to be optimized, evaluating the performance of the algorithms in terms of uncoded BER. The basic novelty with respect to previous works that considers the same strategies of design is the proposal of a Bayesian approach for the design of the robust algorithms.Next the study is extended by proposing robust power allocation strategies focused on the minimization of the coded BER. For this purpose, information-theoretic criteria are used. Probably, one of the main contributions in the thesis is the proposal of the cut-off rate as a parameter of design whose maximization is directly related to the coded BER. This criterion is introduced as an alternative to the channel capacity and the mutual information for the design of optimal transceivers in the presence of any channel coding stage. The last part of the thesis proposes a low complexity adaptive interleaver that, making use of the CSI available at the transmitter, reallocates the bits not only to combat the bursty channel errors but also to combat the specific distribution of the faded subcarriers as a function of the channel response. The design of this interleaver, named as "RCPC interleaver", is based on the Rate-Compatible Punctured Convolutional Codes. As shown by numerical results, the use of this interleaver improves the performance of the algorithms when they are compared with the classical block interleavers and pseudo-random interleavers.

In excitable tissues, voltage-gated calcium channel activity is critical in the linkage of electrical stimuli to physiological responses, and so modulation of calcium channels therefore has significant implications. The exact mechanisms of calcium channel modulation and membrane expression, however, remain elusive. Previous work suggests that the calcium channel β subunit (Cavβ) modulates the expression and biophysical properties of the pore-forming α1 subunit. Previous research has shown that the core domains of Cavβ subunits are highly conserved, although alternative splicing in the highly variable N-terminus and HOOK regions is commonly observed in invertebrates, teleost fish and mammals. Splicing in these regions can produce unique isoforms that differentially modulate the membrane trafficking and gating properties of high voltage-activated calcium channels. With this in mind, two novel isoforms of an invertebrate Cavβ subunit have been identified and cloned from the pond snail Lymnaea stagnalis, which contain a novel N-terminus not previously identified. In addition, one of these novel isoforms excludes an optional, short exon in the HOOK region of LCavβ. Intron sequencing and amino acid alignments of the variable N-terminal and HOOK regions with mammalian and fish homologs have revealed that the genomic structure of Cavβ subuinits is conserved, despite the divergence in sequence and function between genes and splice isoforms. It was determined that the previously characterized LCavβ isoform, as well as the two new isoforms, can act to fine-tune calcium channel activity by modulating the membrane expression, voltage-dependencies of activation and inactivation and gating kinetics of invertebrate homologs of L-type (LCav1) and neuronal (LCav2) calcium channels. It is hoped that broadening our knowledge of simplified invertebrate calcium channels, like those found in Lymnaea, may advance our understanding the workings of our own highly elaborate and dynamic calcium channel complexes, and the nervous system as a whole.

In excitable tissues, voltage-gated calcium channel activity is critical in the linkage of electrical stimuli to physiological responses, and so modulation of calcium channels therefore has significant implications. The exact mechanisms of calcium channel modulation and membrane expression, however, remain elusive. Previous work suggests that the calcium channel β subunit (Cavβ) modulates the expression and biophysical properties of the pore-forming α1 subunit. Previous research has shown that the core domains of Cavβ subunits are highly conserved, although alternative splicing in the highly variable N-terminus and HOOK regions is commonly observed in invertebrates, teleost fish and mammals. Splicing in these regions can produce unique isoforms that differentially modulate the membrane trafficking and gating properties of high voltage-activated calcium channels. With this in mind, two novel isoforms of an invertebrate Cavβ subunit have been identified and cloned from the pond snail Lymnaea stagnalis, which contain a novel N-terminus not previously identified. In addition, one of these novel isoforms excludes an optional, short exon in the HOOK region of LCavβ. Intron sequencing and amino acid alignments of the variable N-terminal and HOOK regions with mammalian and fish homologs have revealed that the genomic structure of Cavβ subuinits is conserved, despite the divergence in sequence and function between genes and splice isoforms. It was determined that the previously characterized LCavβ isoform, as well as the two new isoforms, can act to fine-tune calcium channel activity by modulating the membrane expression, voltage-dependencies of activation and inactivation and gating kinetics of invertebrate homologs of L-type (LCav1) and neuronal (LCav2) calcium channels. It is hoped that broadening our knowledge of simplified invertebrate calcium channels, like those found in Lymnaea, may advance our understanding the workings of our own highly elaborate and dynamic calcium channel complexes, and the nervous system as a whole.

Since Taiwan implemented national health insurance, the advanced medical equipment companies began to enter the Taiwan market, driven by the rise of medical equipment industry. But with the degree of national health insurance payment system limitations and changes, such as: Global Budget, DRG (Diagnosis-Related Group), resulting in market competition. How to be successful business development, the medical equipment suppliers have to think about it and find the solutions. Medical device marketing channel is a very important part , especially , under the environmental situation of the development of innovative products is not easy, as well as NHI price reduction , so the channel strategy to optimize all the more were necessary up. The purpose of this study is to explore the medical equipment business channel business development decision-making factors and decision-making method. In this study, using the literatures of medical equipment industrial property, business model, channel management, relationship Marketing and the key factors ¡K.etc, to construct a number of dimensions of "the critical factor of medical equipment operation and development ". In addition to conduct expert interviews with some executives of the medical equipment suppliers, access decision factors and decision-making methods into the questionnaire of interview, as well as analyze the correlation between decision factors and decision-making . The results could be a reference of decision making for medical equipment industry. The findings are as follows: 1. Supplies will based on Company size, financial capacity and lack of core parts to select distributors, the selection of channel pattern will consider the complementary of each other. Some core advantages, as the channel management of resources, can improve market penetration and market share. 2. Financial strategy usually results in considering the growth of the financial strategy or cost control, will affect the choice of channel type. Growth strategy will be direct , cost-control strategies will be authorized . 3. Product professional level will be considered together with the ability of distributors, and distributors of professional competence will affect the extent of authorization from suppliers. 4. Brand awareness and product profitability are channel management resources for suppliers. 5. Distributor professional ability and risk-taking ability have to match product attributes and customer attributes. 6. Suppliers¡¦ resources have to integrate a good channel relationship models to improve efficiency and benefits.

A Rayleigh/Rician fading channel based on Jakes¡¦ model is implemented by FPGA hardware in this thesis. Parameters, including vehicular speed, carrier frequency, quantization bits and internal clock rate, are carefully chosen according to the fading statistics. Verification of this fading channel hardware is carried out on Altera FPGA board with functional and time sequential test. Finally, performance of a differential PSK modem via fading and noisy channel is simulated and emulated in both software and hardware methods.

The fourth generation cellular mobile communication system in the future needs to provide high data rate transmissions. Multi-Tone CDMA (MT-CDMA) system combines the advantages of CDMA and OFDM, and it is one of the promising choices for the fourth cellular mobile communication system. In order to raise the performance, we amend MT-CDMA named Modified MT-CDMA. We use different pilot arrangement in different channel to enhance the channel estimation of system. The receiver architecture includes a baseband signal detection and a channel estimation. We use a pilot symbol to estimation the channel. In this thesis, we make a study of pilot arrangement on different channel estimation performance of system. We use Least Square estimation(LS)¡Blinear interpolation¡Bspline interpolation¡BFFT/IFFT interpolation and spline interpolation combine FFT/IFFT algorithm to estimate the system performance.

Nowadays, the components are made more and more small, the flow import or exports through the components are required frequently, so a set of micro-channel is need. The main aim of this paper is to study the effect of different inlet pressure and inlet flow velocity of micro-channel. By using the proposed numerical simulation, the pressure, velocity and equivalent stress inside the micro-channel corresponding to different inlet pressure and inlet velocity can be obtained. Also, the life of micro-channel was discussed also. Due to the size effect of the micro-channel, the boundary condition is set as . The error between the simulated and experiment results in less than 15%.

Kv channel interacting proteins (KChIPs) are Ca2+-binding proteins with four EF-hands and well-known to modulate Kv4.2 channel gating. The present study is carried out to investigate the molecular mechanism related to regulate the interaction of KChIP2.2 and KChIP4a with Kv channel. In comparison with KChIP4a, the interaction of KChIP2.2 with Kv4.2 was more obvious in the absence of Ca2+ or Mg2+. However the binding of KChIP2.2 and KChIP4a toward Kv4.2 increased with increasing Ca2+ and Mg2+ concentration. Nevertheless, no individual regions within KChIP2.2 and KChIP4a could exclusively fulfill the interaction between KChIPs mutants and Kv channel. Fluorescence measurement showed that KChIP2.2 possessed both high affinity and low affinity Ca2+-binding sites, but only low affinity Ca2+-binding site was observed with KChIP4a. However, both of them have only one Mg2+-binding site. Studies on the truncated mutants revealed that the EF-hand 4 of KChIP2.2 was related to high affinity binding with Ca2+, and the integrity of molecular structure of KChIP2.2 and KChIP4a was important for Ca2+ -and Mg2+-binding. The thermal stability of KChIP2.2 and KChIP4 was found to be differentiately affected by Ca2+ and Mg2+. Proteolytic digestion and thiol reactivity assays also supported that Ca2+ and Mg2+-induced conformational change of KChIP2.2 was differed from KChIP4a. Moreover, in cells co-transfected with Kv4.2 cDNA, it was formed that KChIP2.2 trafficking to the cell surface was increased by elevating intracellular Ca2+ concentration, but no noticeable change was observed for KChIP4a. Taken together, these results suggest that the conformational changes of KChIP2.2 and KChIP4a differently induced by Ca2+ and Mg2+ affect their binding with Kv channel and/or cellular distribution.