Sequential Relay Research Articles

Distinct and sequential re-replication barriers ensure precise genome duplication.

Achieving complete and precise genome duplication requires that each genomic segment be replicated only once per cell division cycle. Protecting large eukaryotic genomes from re-replication requires an overlapping set of molecular mechanisms that prevent the first DNA replication step, the DNA loading of MCM helicase complexes to license replication origins, after S phase begins. Previous reports have defined many such origin licensing inhibition mechanisms, but the temporal relationships among them are not clear, particularly with respect to preventing re-replication in G2 and M phases. Using a combination of mutagenesis, biochemistry, and single cell analyses in human cells, we define a new mechanism that prevents re-replication through hyperphosphorylation of the essential MCM loading protein, Cdt1. We demonstrate that Cyclin A/CDK1 can hyperphosphorylate Cdt1 to inhibit MCM re-loading in G2 phase. The mechanism of inhibition is to block Cdt1 binding to MCM independently of other known Cdt1 inactivation mechanisms such as Cdt1 degradation during S phase or Geminin binding. Moreover, our findings suggest that Cdt1 dephosphorylation at the mitosis-to-G1 phase transition re-activates Cdt1. We propose that multiple distinct, non-redundant licensing inhibition mechanisms act in a series of sequential relays through each cell cycle phase to ensure precise genome duplication.

Enantioselective Conjugate Addition of Aryl Halides and Triflates to Electron-Deficient Olefins via Nickel- and Rhodium-Catalyzed Sequential Relay Reactions.

Asymmetric conjugate addition of aryl halides or aryl triflates to electron-deficient olefins was realized by sequential Miyaura borylation and Hayashi-Miyaura conjugate addition in one pot. A nickel-catalyzed borylation of aryl halides or triflates and a rhodium-chiral diene complex catalyzed enantioselective conjugate addition was executed as a pair of relay reactions as a more efficient and greener protocol.

Copper-Catalyzed N-H/C-H Sequential Relay Oxidative Radical Carboannulation: Construction of Diversely Substituted [60]Fullerene-Fused Tetrahydrocyclopenta[b]indoles.

Reported herein is a new copper-catalyzed N-H/C-H sequential relay oxidative radical carboannulation of [60]fullerene with C2-functionalized free indoles for the direct construction of novel [60]fullerene-fused tetrahydrocyclopenta[b]indoles. The transformation shows high regioselectivity and atom economy, broad substrate scope, and good functional group tolerance, providing an efficient and practical approach to access diversely substituted fullerene-fused polycyclic derivatives from simple hydrocarbons.

Sequential Relay Selection in D2D-Enabled Cellular Networks With Outdated CSI Over Mixed Fading Channels

The impact of outdated channel state information on two sequential relay selection schemes for device-to-device underlaid cellular networks over mixed fading channels is investigated. To this end, the mutual outage probability (MOP) is analyzed in which an easy-to-evaluate analytical expression for the MOP is derived. Moreover, an asymptotic analysis of the MOP at high signal-to-noise ratio is provided, and the diversity order is evaluated.

Asynchronous Stochastic Approximation Based Learning Algorithms for As-You-Go Deployment of Wireless Relay Networks Along a Line

We are motivated by the need, in emergency situations, for impromptu (or “as-you-go”) deployment of multihop wireless networks, by human agents or robots (e.g., unmanned aerial vehicles (UAVs)); the agent moves along a line, makes wireless link quality measurements at regular intervals, and makes on-line placement decisions using these measurements. As a first step, we have formulated such deployment along a line as a sequential decision problem. In our earlier work, reported in [1] , we proposed two possible deployment approaches: (i) the pure as-you-go approach where the deployment agent can only move forward, and (ii) the explore-forward approach where the deployment agent explores a few successive steps and then selects the best relay placement location among them. The latter was shown to provide better performance (in terms of network cost, network performance, and power expenditure), but at the expense of more measurements and deployment time, which makes explore-forward impractical for quick deployment by an energy constrained agent such as a UAV. Further, since in emergency situations the terrain would be unknown, the deployment algorithm should not require a-priori knowledge of the parameters of the wireless propagation model. In [1] , we, therefore, developed learning algorithms for the explore-forward approach. The current paper fills in an important gap by providing deploy-and-learn algorithms for the pure as-you-go approach. We formulate the sequential relay deployment problem as an average cost Markov decision process (MDP), which trades off among power consumption, link outage probabilities, and the number of relay nodes in the deployed network. While the pure as-you-go deployment problem was previously formulated as a discounted cost MDP (see [1] ), the discounted cost MDP formulation was not amenable for learning algorithms that are proposed in this paper. In this paper, first we show structural results for the optimal policy corresponding to the average cost MDP, and provide new insights into the optimal policy. Next, by exploiting the special structure of the average cost optimality equation and by using the theory of asynchronous stochastic approximation (in single and two timescale), we develop two learning algorithms that asymptotically converge to the set of optimal policies as deployment progresses. Numerical results show reasonably fast speed of convergence, and hence the model-free algorithms can be useful for practical, fast deployment of emergency wireless networks.

UTILIZATION OF PLC PROGRAMMING FOR GRAVITY DIE CASTING AUTOMATION

Under the present regime of globalization and liberalization, quality enhancement and cost reduction are two major steps to enhance productivity in major Industries. We focused on the very practical, safe, economical and rewarding strategies i.e. the application of LOW COST AUTOMATION. In Industry which uses of automation, a sequence is followed in the manufacturing of number of products of the same kind and thus chance for Automation. In our research we have achieved low cost automation through a Programmable Logic Controller (SIEMENS SIMANTIC S7300PLC with STEP7 software). It is used to replace the necessary sequential relay circuits for the control on the devices. In automated system, PLC is usually the central part of the control system. With execution of a program stored in program memory, PLC continuously monitors status of the system through signals from input devices (sensors). Based on the logic implemented in the program PLC determines which action is to be executed with output instruments Actuators). Depending on our requirement Pneumatic actuators, Solenoid valves and sensors are used to run the sequence. Flow control valves are used to regulate the flow of air pressure where ever necessary.

Sequential relay autotuning method for the temperature control of multizone heated rollers

This heated rollers are used to give tactility and gloss to papers, fabrics, non-woven fabrics, films and so on. The surface temperature of the heated roller and its uniformity are especially important. Existing heated rollers have surface temperature profiles up to 10oC deviations, causing listing in fabrics. In order to suppress the surface temperature deviation, a heated roller system having multizone electric heaters and heating oil within the steel roller is proposed. The temperature control of the heated roller is a multivariable system with interactions. To identify the heated roller dynamics and design a control system systematically, a recent sequential relay autotuning method is applied. Experimental results are given.

Immunosuppressants Used in a Steroid-Sparing Strategy for Childhood Uveitis

To review, with respect to etiology, the efficacy and complications of different immunosuppressants used in a steroid-sparing strategy for children with uveitis. Forty children with uveitis were observed during a 5-year period, from 1997 to 2002. After complete ocular and physical assessment, routine and specific laboratory investigations were conducted along with radiologic examination. All cases underwent local therapy. Systemic corticosteroids were necessary in 75% of cases. Pediatric staff determined the need for initial association or sequential relay with immunosuppressants, depending on the severity of the uveitis. A steroid-sparing strategy was developed. The average age was 6.5 years (range, 3 months to 14 years), with a male-to-female ratio of 23 to 17. Uveitis was anterior in 55% of cases, intermediate in 2.5%, posterior in 42.5%, and bilateral in 62.5%. A positive etiology was found in 47.5% of cases, and articular symptoms were present in 25%. Overall, the improvement in visual acuity was 62.2%. Where corticotherapy was associated with azathioprine, a 61% improvement was achieved. Corticosteroid therapy associated with mycophenolate mofetil resulted in a 94% improvement. No complications were present in 42.5% of cases. Ocular complications were present in 57.5% of cases and systemic complications were present in 12.5% of cases, none being directly related to the use of steroids. The association of systemic corticotherapy and immunosuppressants in pediatric relapsing or steroid-dependent uveitis allows good recovery of visual acuity, fewer complications, and a minimization of side effects, especially those related to systemic corticosteroids. It requires close collaboration between the ophthalmologist and a fully involved pediatrician.

SUBJECTIVE EVALUATION OF A PROTOTYPE EARMUFF EXHIBITING FLAT AND NONLINEAR ATTENUATION CHARACTERISTICS

Subjective user responses were obtained for a test earmuff exhibiting approximately flat (uniform) attenuation of about 25 dB from 500 to 8000 Hz for sound pressure levels (SPLs) less than 120 dB. At SPLs above 120 dB, the test earmuff exhibited nonlinear (level-dependent) attenuation characteristics such that noise reduction increased with increasing sound level. The study population consisted of police officers from the Raleigh, North Carolina, Police Department as they were performing arms requalification by executing a series of firing programs during two sequential and identical relays. The study subjects wore either the test earmuff or a comparable conventional earmuff during the first relay, then the alternate protector for the second relay with the order counterbalanced. Results indicated a significant preference for the test earmuff in three comparison areas: comfort, perceived hearing protection, and speech understanding. The study demonstrates that ammunition type and level of noise exposure contributed significantly to a preference in favor of the test earmuff. The subjects who used the quietest of the ammunition types rated the test earmuff significantly better than the remaining subjects with respect to speech understanding.

Analysis of electrical potentials evoked in the cerebellar anterior lobe by stimulation of hindlimb and forelimb nerves.

Responses were evoked in the anterior lobe of the cerebellum by volleys in group I and II fibers of forelimb and hindlimb nerves — cutaneous, muscular, joint and fascial. These responses have been observed along microelectrode tracks that traverse the whole depth of the anterior lobe. These tracks have been identified in histological sections, and the recording sites along these tracks have been determined. It has been shown that there are many distinguishing features for the responses produced by the two types of afferent input to the cerebellum: climbing fibers and mossy fibers. The depth profiles are of particular importance in the differentiation of the CF and MF responses, and they correspond to those already determined for the exposed surface areas of the cerebellar cortex. As would be expected from the distribution of synapses by the CF fibers to the Purkinje cell dendrites, there is a maximum extracellular negativity deep in the molecular layer with sources superficial and deep thereto. In contrast, the mossy fiber input produces a powerful synaptic excitation in the granular layer, which is recorded there as a negative wave (N2). The mossy fiber input by sequential relay also produces a negative wave (N3) in the molecular layer. This wave is distinguished from the CF-evoked negative wave because it is not reversed in the fissura and the adjacent superficial molecular layer. An important distinguishing feature of the MF- and CF-evoked responses is that the latencies of the former are shorter by 6–12 msec for forelimb nerves and by 9–15 msec for hindlimb nerves. It is thus possible to measure the sizes of the MF and CF responses in the same traces. Another distinguishing feature is the failure of the CF responses with stimulus frequencies of 5–15/sec, whereas the MF-evoked potentials are well maintained above 15/sec. Also CF-evoked responses show much more size and latency variance than the MF-evoked responses, and often the facilitation of two or three volleys is required in order to evoke a stable CF response. By utilizing these various tests it is always possible to distinguish between the CF- and the MF-evoked responses recorded along the microelectrode tracks in the anterior lobe.