How ligands modulate the gastric H,K-ATPase activity and its inhibition by tegoprazan.

The introduction of potassium-competitive acid blockers (P-CABs) has been a major innovation in gastric H,K-ATPase inhibition and many laboratories are actively engaged in the development of novel molecules within this class. This work investigates the interaction between H,K-ATPase and tegoprazan, a representative of the P-CABs group, in terms of K and H binding, through functional and structural analyses. First, by studying the H,K-ATPase activity, we found a model to describe the non-Michaelis-Menten kinetics through a "ping-pong" mechanism that explains a stoichiometry of 1 H, 1 K, and 1 ATP molecule, but also considering the influence of H on the ionization states of the protein.

Bioinformatic Study of Possible Acute Regulation of Acid Secretion in the Stomach.

The gastric H,K-ATPase is an integral membrane protein which derives energy from the hydrolysis of ATP to transport H ions from the parietal cells of the gastric mucosa into the stomach in exchange for K ions. It is responsible for the acidic environment of the stomach, which is essential for digestion. Acid secretion is regulated by the recruitment of the H,K-ATPase from intracellular stores into the plasma membrane on the ingestion of food.

The transported cations impose differences in the thermostability of the gastric H,K-ATPase. A kinetic analysis.

This work analyses the thermostability of a membrane protein, the gastric H,K-ATPase, by means of a detailed kinetic characterization of its inactivation process, which showed to exhibit first-order kinetics. We observed parallel time courses for the decrease of ATPase activity, the decrease of the autophosphorylation capacity and the loss of tertiary structure at 49 °C. Higher temperatures were required to induce a significant change in secondary structure.

Two-boson quantum interference in time.

The celebrated Hong-Ou-Mandel effect is the paradigm of two-particle quantum interference. It has its roots in the symmetry of identical quantum particles, as dictated by the Pauli principle. Two identical bosons impinging on a beam splitter (of transmittance 1/2) cannot be detected in coincidence at both output ports, as confirmed in numerous experiments with light or even matter.

The interaction of Na, K, and phosphate with the gastric H,K-ATPase. Kinetics of E1-E2 conformational changes assessed by eosin fluorescence measurements.

H,K-ATPase and Na,K-ATPase show the highest degree of sequence similarity among all other members of the P-type ATPases family. To explore their common features in terms of ligand binding, we evaluated conformational transitions due to the binding of Na, K and Pi in the H,K-ATPase, and compared the results with those obtained for the Na,K-ATPase. This work shows that eosin fluorescence time courses provide a reasonably precise method to study the kinetics of the E1-E2 conformational changes in the H,K-ATPase.

[Usefulness of frozen section exams during radical cystectomy for urothelial carcinoma].

Aim: To determine the usefulness of the frozen section exams of lymph nodes dissection, ureteral and urethral section during radical cystectomy for urothelial carcinoma and define the impact on the surgical procedure.

Method: A retrospective, single-center study of data collected from 182 patients who underwent radical cystectomy for an cT=3bN0M0 urothelial bladder cancer between 2016 and 2018. Bladder cancer extension was determined by thoracoabdominal CT with contrast enhancement and urography and an 18-FDG PET scanner.

Efficient entanglement distillation without quantum memory.

Entanglement distribution between distant parties is an essential component to most quantum communication protocols. Unfortunately, decoherence effects such as phase noise in optical fibres are known to demolish entanglement. Iterative (multistep) entanglement distillation protocols have long been proposed to overcome decoherence, but their probabilistic nature makes them inefficient since the success probability decays exponentially with the number of steps.

Optimality of Gaussian discord.

In this Letter we exploit the recently solved conjecture on the bosonic minimum output entropy to show the optimality of Gaussian discord, so that the computation of quantum discord for bipartite Gaussian states can be restricted to local Gaussian measurements. We prove such optimality for a large family of Gaussian states, including all two-mode squeezed thermal states, which are the most typical Gaussian states realized in experiments. Our family also includes other types of Gaussian states and spans their entire set in a suitable limit where they become Choi matrices of Gaussian channels.

[Mapping of the key oncology indicators available in France].

Background: Available data in the field of oncology in France are scattered due to the large number of available indicators and their sources. In order to facilitate identification and analysis of these indicators, the French National Cancer Institute (INCa) has mapped the main indicators available in oncology.

Methods: Mapping was based on the needs of various categories of potential users.

Equivalence relations for the classical capacity of single-mode Gaussian quantum channels.

We prove the equivalence of an arbitrary single-mode Gaussian quantum channel and a newly defined fiducial channel preceded by a phase shift and followed by a Gaussian unitary operation. This equivalence implies that the energy-constrained classical capacity of any single-mode Gaussian channel can be calculated based on this fiducial channel, which is furthermore simply realizable with a beam splitter, two identical single-mode squeezers, and a two-mode squeezer. In a large domain of parameters, we also provide an analytical expression for the Gaussian classical capacity, exploiting its additivity, and prove that the classical capacity cannot exceed it by more than 1/ln2 bits.

Security of continuous-variable quantum key distribution against general attacks.

We prove the security of Gaussian continuous-variable quantum key distribution with coherent states against arbitrary attacks in the finite-size regime. In contrast to previously known proofs of principle (based on the de Finetti theorem), our result is applicable in the practically relevant finite-size regime. This is achieved using a novel proof approach, which exploits phase-space symmetries of the protocols as well as the postselection technique introduced by Christandl, Koenig, and Renner [Phys.

Noiseless loss suppression in quantum optical communication.

We propose a protocol for conditional suppression of losses in direct quantum state transmission over a lossy quantum channel. The method works by noiselessly attenuating the input state prior to transmission through a lossy channel followed by noiseless amplification of the output state. The procedure does not add any noise; hence, it keeps quantum coherence.

Majorization theory approach to the Gaussian channel minimum entropy conjecture.

A long-standing open problem in quantum information theory is to find the classical capacity of an optical communication link, modeled as a Gaussian bosonic channel. It has been conjectured that this capacity is achieved by a random coding of coherent states using an isotropic Gaussian distribution in phase space. We show that proving a Gaussian minimum entropy conjecture for a quantum-limited amplifier is actually sufficient to confirm this capacity conjecture, and we provide a strong argument towards this proof by exploiting a connection between quantum entanglement and majorization theory.

Continuous-variable quantum key distribution protocols over noisy channels.

A continuous-variable quantum key distribution protocol based on squeezed states and heterodyne detection is introduced and shown to attain higher secret key rates over a noisy line than any other one-way Gaussian protocol. This increased resistance to channel noise can be understood as resulting from purposely adding noise to the signal that is converted into the secret key. This notion of noise-enhanced tolerance to noise also provides a better physical insight into the poorly understood discrepancies between the previously defined families of Gaussian protocols.

No-go theorem for gaussian quantum error correction.

We prove that Gaussian operations are of no use for protecting Gaussian states against Gaussian errors in quantum communication protocols. Specifically, we introduce a new quantity characterizing any single-mode Gaussian channel, called entanglement degradation, and show that it cannot decrease via Gaussian encoding and decoding operations only. The strength of this no-go theorem is illustrated with some examples of Gaussian channels.

Experimentally feasible quantum erasure-correcting code for continuous variables.

We devise a scheme that protects quantum coherent states of light from probabilistic losses, thus achieving the first continuous-variable quantum erasure-correcting code. If the occurrence of erasures can be probed, then the decoder enables, in principle, a perfect recovery of the original light states. Otherwise, if supplemented with postselection based on homodyne detection, this code can be turned into an efficient erasure-filtration scheme.

Superiority of entangled measurements over all local strategies for the estimation of product coherent states.

It is shown that the ensemble {P(alpha),|alpha|alpha;{*}}, where P(alpha) is a Gaussian distribution of finite variance and |alpha is a coherent state, can be better discriminated with an entangled measurement than with any local strategy supplemented by classical communication. Although this ensemble consists of products of quasiclassical states without any squeezing, it thus exhibits a purely quantum feature. This remarkable effect is demonstrated experimentally by implementing the optimal local strategy on coherent states of light together with a global strategy that yields a higher fidelity.

Temporal trends and epidemiological aspects of ciguatera in French Polynesia: a 10-year analysis.

Objectives: The purpose of this study was to report the temporal trends of the incidence of ciguatera poisoning from 1992 to 2001 in French Polynesia.

Methods: This retrospective study analysed 7842 cases of ciguatera disease recorded over a period of 10 years.

Results: The annual incidence varied from 26.

Experimental implementation of non-Gaussian attacks on a continuous-variable quantum-key-distribution system.

An intercept-resend attack on a continuous-variable quantum-key-distribution protocol is investigated experimentally. By varying the interception fraction, one can implement a family of attacks where the eavesdropper totally controls the channel parameters. In general, such attacks add excess noise in the channel, and may also result in non-Gaussian output distributions.

Unconditional optimality of Gaussian attacks against continuous-variable quantum key distribution.

A fully general approach to the security analysis of continuous-variable quantum key distribution (CV-QKD) is presented. Provided that the quantum channel is estimated via the covariance matrix of the quadratures, Gaussian attacks are shown to be optimal against all collective eavesdropping strategies. The proof is made strikingly simple by combining a physical model of measurement, an entanglement-based description of CV-QKD, and a recent powerful result on the extremality of Gaussian states [M.

Universal optical amplification without nonlinearity.

We propose and experimentally realize a new scheme for universal phase-insensitive optical amplification. The presented scheme relies only on linear optics and homodyne detection, thus circumventing the need for nonlinear interaction between a pump field and the signal field. The amplifier demonstrates near optimal quantum noise limited performance for a wide range of amplification factors.

Separating the classical and quantum information via quantum cloning.

An application of quantum cloning to optimally interface a quantum system with a classical observer is presented; in particular, we describe a procedure to perform a minimal disturbance measurement on a single qubit by adopting a 1-->2 cloning machine followed by a generalized measurement on a single clone and the anticlone or on the two clones. Such a scheme can be applied to enhance the transmission fidelity over a lossy quantum channel.

Non-Gaussian cloning of quantum coherent states is optimal.

We consider the optimal cloning of quantum coherent states with single-clone and joint fidelity as figures of merit. While the latter is maximized by a Gaussian cloner, the former is not: the optimal single-clone fidelity for a symmetric 1-to-2 cloner is 0.6826, compared to 2/3 in a Gaussian setting.

Experimental error filtration for quantum communication over highly noisy channels.

Error filtration is a method for encoding the quantum state of a single particle into a higher dimensional Hilbert space in such a way that it becomes less sensitive to noise. We have realized a fiber optics demonstration of this method and illustrated its potentialities by carrying out the optical part of a quantum key distribution scheme over a line whose phase noise is too high for a standard implementation of BB84 to be secure. By filtering out the noise, a bit error rate of 15.