2,101 research outputs found
Entanglement criterion via general symmetric informationally complete measurements
We study the quantum separability problem by using general symmetric
informationally complete measurements and present a separability criterion for
arbitrary dimensional bipartite systems. We show by detailed examples that our
criterion is more powerful than the existing ones in entanglement detection.Comment: 8 pages, 5 figure
Gold as hydrogen: Structural and electronic properties and chemical bonding in Si3Au3+/0/- and comparisons to Si3H3+/0/-
A single Au atom has been shown to behave like H in its bonding to Si in several mono- and disilicon gold clusters. In the current work, we investigate the AuâH analogy in trisilicon gold clusters, Si3Au+â0ââ3. Photoelectron spectroscopy and density functional calculations are combined to examine the geometric and electronic structure of Si3Auâ3. We find that there are three isomers competing for the ground state of Si3Auâ3 as is the case for Si3Hâ3. Extensive structural searches show that the potential energy surfaces of the trisilicon gold clusters (Si3Auâ3, Si3Au3, and Si3Au+3) are similar to those of the corresponding silicon hydrides. The lowest energy isomers for Si3Auâ3 and Si3Au3 are structurally similar to a Si3Au four-membered ring serving as a common structural motif. For Si3Au+3, the 2Ï aromatic cyclotrisilenylium auride ion, analogous to the aromatic cyclotrisilenylium ion (Si3H+3), is the most stable species. Comparison of the structures and chemical bonding between Si3Au+â0ââ3 and the corresponding silicon hydrides further extends the isolobal analogy between Au and H
Detecting EPR steering via two classes of local measurements
We study the Einstein-Podolsky-Rosen (EPR) steering and present steerability
criteria for arbitrary qubit-qudit (qudit-qubit) systems based on mutually
unbiased measurements (MUMs) and general symmetric informationally complete
measurements (general SIC-POVMs). Avoiding the usual complicated steering
inequalities, these criteria can be more operational than some existing
criteria and implemented experimentally. Detailed examples are given to
illustrate the efficiency of the criteria in both computation and experimental
implementation.Comment: 8 pages, 1 figur
Experimental and theoretical study of the photoelectron spectra of MnOx-(x=1-3) clusters
We report a combined experimental and theoretical investigation of MnOâx and MnOx(x=1â3) clusters. Theoretically, geometrical configurations of various isomers of the clusters were optimized and vertical detachment energies for the anions were evaluated. The ground state of MnOâ was predicted to be 5ÎŁ+, followed by an excited state (7ÎŁ+) 0.14 eV higher in energy. The ground state of MnOâ2 is 5B2, with a 3B1 isomer 0.15 eV higher. MnOâ3 is predicted to be a singlet D3h cluster. Vibrationally resolved photoelectron spectra of MnOâx were measured at several photon energies and under various experimental conditions, and were interpreted based on the theoretical results. The electron affinities of MnO, MnO2,and MnO3 were determined to be 1.375 (0.010), 2.06 (0.03), and 3.335 (0.010), respectively. Five excited states of MnO were observed and assigned using the theoretical results. The 7ÎŁ+ excited state of MnOâ was found to be significantly populated and was distinguished from the ground state of the anion by temperature dependent studies. We observed two isomers for MnOâ2 and the detachment features from both isomers were assigned. Only one vibrationally resolved band was observed for MnOâ3, which corresponds to transitions from the ground state of MnOâ3 to that of MnO3. The combined experimental and theoretical studies allow us to elucidate the complicated electronic and geometricstructures of the various manganese oxide clusters and their anions
Discriminating bipartite mixed states by local operations
Unambiguous state discrimination of two mixed bipartite states via local
operations and classical communications (LOCC) is studied and compared with the
result of a scheme realized via global measurement. We show that the success
probability of a global scheme for mixed-state discrimination can be achieved
perfectly by the local scheme. In addition, we simulate this discrimination via
a pair of pure entangled bipartite states. This simulation is perfect for local
rather than global schemes due to the existence of entanglement and global
coherence in the pure states. We also prove that LOCC protocol and the
sequential state discrimination (SSD) can be interpreted in a unified view. We
then hybridize the LOCC protocol with three protocols (SSD, reproducing and
broadcasting) relying on classical communications. Such hybridizations extend
the gaps between the optimal success probability of global and local schemes,
which can be eliminated only for the SSD rather than the other two protocols
Kinetically Controlled Synthesis of Cefaclor with Immobilized Penicillin Acylase in the Presence of Organic Cosolvents
Enzymatic syntheses of cefaclor with immobilized penicillin acylase in organic cosolvents under kinetic control were carried out. KcPGA from Kluyvera citrophila was selected as the best catalyst among the three species of immobilized penicillin acylase. Ethylene glycol, glycerol, methanol, ethyl estate and polyethyleneglycol (PEG) were selected accordingly and cefaclor syntheses were preformed respectively. Best results in terms of yield were obtained in ethylene glycol, with which further studies were investigated and the maximum yield was Y = 93.5 %. The optimal conditions were pH 6.5, temperature Ξ = 5 °C, 3 mol D-phenylglycine methyl ester (PGME) per mol 7-aminodesacetoxymehtyl-3-chlorocephalosporin acid (7ACCA) and x = 30 % ethylene glycol fraction. Under above mentioned conditions, the yield was Y = 91.1 %
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Glycosylation-dependent opsonophagocytic activity of staphylococcal protein A antibodies
Antibodies may bind to bacterial pathogens or their toxins to control infections, and their effector activity is mediated through the recruitment of complement component C1q or the engagement with Fcγ receptors (FcγRs). For bacterial pathogens that rely on a single toxin to cause disease, immunity correlates with toxin neutralization. Most other bacterial pathogens, including Staphylococcus aureus, secrete numerous toxins and evolved multiple mechanisms to escape opsonization and complement killing. Several vaccine candidates targeting defined surface antigens of S. aureus have failed to meet clinical endpoints. It is unclear that such failures can be solely attributed to the poor selection of antibody targets. Thus far, studies to delineate antibody-mediated uptake and killing of Gram-positive pathogens remain extremely limited. Here, we exploit 3F6-hIgG1, a human monoclonal antibody that binds and neutralizes the abundant surface-exposed Staphylococcal protein A (SpA). We find that galactosylation of 3F6-hIgG1 that favors C1q recruitment is indispensable for opsonophagocytic killing of staphylococci and for protection against bloodstream infection in animals. However, the simple removal of fucosyl residues, which results in reduced C1q binding and increased engagement with FcγR, maintains the opsonophagocytic killing and protective attributes of the antibody. We confirm these results by engineering 3F6-hIgG1 variants with biased binding toward C1q or FcγRs. While the therapeutic benefit of monoclonal antibodies against infectious disease agents may be debatable, the functional characterization of such antibodies represents a powerful tool for the development of correlates of protection that may guide future vaccine trials. © 2020 National Academy of Sciences. All rights reserved
Case report: A rare case of desmoid-type fibromatosis originating in the small intestine
BackgroundDesmoid-type fibromatosis (DF) is characterized by a rare monoclonal fibroblast proliferation that exhibits variable and unpredictable clinical presentation. DF can be classified into sporadic and hereditary types. Despite extensive research efforts, the exact etiology of DF remains elusive.Case descriptionA 31-year-old male patient presented to the hospital with a progressively growing mass in the right lower abdomen, accompanied by abdominal discomfort. Symptoms are discovered 1âweek before admission. Enteroscopy revealed no evidence of colonic abnormalities, and blood tests did not indicate any abnormalities. Due to the indeterminate nature of the mass during surgery, a partial resection of the ileum and cecum was performed, followed by ileocolonic end-to-end anastomosis, with no postoperative complications. The final pathological diagnosis confirmed primary desmoid-type fibromatosis of the distal ileum (invasive fibromatosis). To effectively manage DF, we recommend a follow-up schedule for patients. This includes appointments every 3âmonths in the first year following surgery, followed by appointments every 6âmonths up to the fifth year, and then once a year thereafter. The follow-up examinations should include collection of the patientâs medical history, physical examination, blood tests, ultrasounds, CT scans, and other relevant assessments. During the first year of the follow-up period, no further treatment was administered, and the patient remained disease-free.ConclusionDesmoid-type fibromatosis (DF) originating from the small intestine is an extremely rare condition that exhibits local invasiveness and can be life-threatening. Despite its benign histology, DF has a high local recurrence rate and lacks metastatic potential. Diagnosis of DF remains challenging, especially in cases where surgical intervention is not feasible due to asymptomatic patients or partial organ impairment. In such cases, a âwatchful waitingâ approach is recommended as the initial treatment strategy. However, when preoperative diagnosis is difficult, surgery is typically considered the best option. Given the potential for local recurrence and the uncertain long-term prognosis, regular follow-up is necessary
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