Recovering the original simplicity: succinct and deterministic quantum algorithm for the welded tree problem

This work revisits quantum algorithms for the well-known welded tree problem, proposing a very succinct quantum algorithm based on the simplest coined quantum walks. It simply iterates the naturally defined coined quantum walk operator for a predetermined time and finally measure, where the predetermined time can be efficiently computed on classical computers. Then, the algorithm returns the correct answer deterministically, and achieves exponential speedups over any classical algorithm. The significance of the results may be seen as follows. (i) Our algorithm is rather simple compared with the one in (Jeffery and Zur, STOC'2023), which not only breaks the stereotype that coined quantum walks can only achieve quadratic speedups over classical algorithms, but also demonstrates the power of the simplest quantum walk model. (ii) Our algorithm theoretically achieves zero-error, which is not possible with existing methods. Thus, it becomes one of the few examples that exhibit exponential separation between deterministic (exact) quantum and randomized query complexities, which may also change people's perception that since quantum mechanics is inherently probabilistic, it impossible to have a deterministic quantum algorithm with exponential speedups for the weled tree problem.Comment: The paper has been revised and been accepted by SODA202

Succinct quantum testers for closeness and kk-wise uniformity of probability distributions

We explore potential quantum speedups for the fundamental problem of testing the properties of closeness and $k$-wise uniformity of probability distributions. \textit{Closeness testing} is the problem of distinguishing whether two $n$-dimensional distributions are identical or at least $\varepsilon$-far in $\ell^1$- or $\ell^2$-distance. We show that the quantum query complexities for $\ell^1$- and $\ell^2$-closeness testing are O\rbra{\sqrt{n}/\varepsilon} and O\rbra{1/\varepsilon}, respectively, both of which achieve optimal dependence on $\varepsilon$, improving the prior best results of \hyperlink{cite.gilyen2019distributional}{Gily{\'e}n and Li~(2019)}. \textit{$k$-wise uniformity testing} is the problem of distinguishing whether a distribution over \cbra{0, 1}^n is uniform when restricted to any $k$ coordinates or $\varepsilon$-far from any such distributions. We propose the first quantum algorithm for this problem with query complexity O\rbra{\sqrt{n^k}/\varepsilon}, achieving a quadratic speedup over the state-of-the-art classical algorithm with sample complexity O\rbra{n^k/\varepsilon^2} by \hyperlink{cite.o2018closeness}{O'Donnell and Zhao (2018)}. Moreover, when $k = 2$ our quantum algorithm outperforms any classical one because of the classical lower bound \Omega\rbra{n/\varepsilon^2}. All our quantum algorithms are fairly simple and time-efficient, using only basic quantum subroutines such as amplitude estimation.Comment: We have added the proof of lower bounds and have polished the languag

Manipulation of the bioactivity of glucose oxidase via raft-controlled surface modification

In this article, poly[poly(ethyleneglycol) acrylate] (polyPEG-A) with mercaptothiazoline ester terminal group was synthesized directly by reversible addition fragmentation chain transfer (RAFT) polymerization using a mercaptothiazoline ester functional RAFT agent. The functional polyPEG-A was then conjugated to glucose oxidase (GOx) via surface-tethered amino groups through covalent amide coupling. Sorensenformaltitration assay revealed that GOx retained ~14 free amino groups available for covalent modification. The conjugation reaction turned out to be efficient and mild. Colorimetric method was applied to evaluate the enzymatic activity of native GOx and its derivatives by introducing another enzyme, horseradish peroxidase. The modified GOx with polymeric chains exhibited reduced enzymatic activity toward the catalytical oxidation of glucose, but with significantly increased thermal stability and elongated lifetime. When GOx was modified with polyPEG-A [molecular weight (MW), 45,000; polydispersity index, 1.12] the enzymatic activity was decreased to 37 U/mg, only 29% left. However, when incubated at 25 ℃ the modified GOx still retained 9.6% of its original bioactivity after 60 days, whereas the native GOx only lived for 29 days. The more polymer chains or the longer polymer chain attached, the more reduction of the enzymatic activity resulted, however, the longer the lifetime of the enzyme obtained.8 page(s

Enhanced Spectral Response of ZnO-Nanorod-Array-Based Ultraviolet Photodetectors by Alloying Non-Isovalent Cu–O with CuAlO₂ P-Type Layer

CuAlO2 was synthesized by a hydrothermal method, in which the Cu–O dimers were incorporated by simply altering the ratio of the reactants and the temperature. The incorporation process increases the grain size in CuAlO2, and modulates the work function and binding energies for CuAlO2 due to the partial substitution of Cu+ 3d10 with Cu2+ 3d9 orbitals in the valence band maximum by alloying non-isovalent Cu–O with a CuAlO2 host. Based on the ZnO nanorod arrays (NRs) ultraviolet photodetector, CuAlO2/Cu–O fabricated by the low-cost drop-coating method was used as the p-type hole transport layer. The incorporation of the Cu–O clusters into CuAlO2 lattice to enhance the conductivity of CuAlO2 is an effective way for improving ZnO NRs/CuAlO2 device performance. The photodetectors exhibit significant diode behavior, with a rectification ratio approaching 30 at ±1 V, and a dark saturation current density 0.81 mA cm−2. The responsivity of the ZnO-NRs-based UV photodetector increases from 13.2 to 91.3 mA/W at 0 V bias, with an increase in the detectivity from 2.35 × 1010 to 1.71 × 1011 Jones. Furthermore, the ZnO NRs/[CuAlO2/Cu–O] photodetector exhibits a maximum responsivity of 5002 mA/W at 1.5 V bias under 375 nm UV illumination

Characterization of Cu1.4Te Thin Films for CdTe Solar Cells

The copper telluride thin films were prepared by a coevaporation technique. The single-phase Cu1.4Te thin films could be obtained after annealing, and annealing temperature higher than 220°C could induce the presence of cuprous telluride coexisting phase. Cu1.4Te thin films also demonstrate the high carrier concentration and high reflectance for potential photovoltaic applications from the UV-visible-IR transmittance and reflectance spectra, and Hall measurements. With contacts such as Cu1.4Te and Cu1.4Te/CuTe, cell efficiencies comparable to those with conventional back contacts have been achieved. Temperature cycle tests show that the Cu1.4Te contact buffer has also improved cell stability

MHC class I chain-related gene A-A5·1 allele is associated with ulcerative colitis in Chinese population

The human MHC class I chain-related gene A (MICA) plays a role in regulating protective responses by intestinal epithelial Vδ1 γδ T cells and the polymorphism of MICA were reported to be related to several autoimmune diseases. The present study aimed to investigate the association of the microsatellite polymorphisms of TM region of MICA gene with the susceptibility to ulcerative colitis (UC) in Chinese population. The microsatellite polymorphisms of the MICA were genotyped in unrelated 86 Chinese patients with UC and 172 ethnically matched healthy controls by a semiautomatic fluorenscently labelled PCR method. All the subjects were the Chinese with Han nationality. The frequency of MICA-A5·1 homozygous genotype and A5·1 allele were significantly increased in UC patients compared with healthy controls (22·1%versus 7%, P = 0·0009, Pc = 0·0126, OR = 3·781, 95%CI: 1·738–8·225 and 30·2%versus 17·4%, P = 0·0014, Pc = 0·007, OR = 2·051, 95%CI: 1·336–3·148, respectively). Adjusted the effects of gender and age at onset, MICA-A5·1 homozygous genotype and A5·1 allele were also increased in the UC patients. Moreover MICA-A5·1 allele was significantly increased in frequency in the female UC patients (38·2% versus 21·0%, P = 0·0095, Pc = 0·0475, OR = 2·326, 95%CI: 1·234–4·382). Logistic regression analysis also revealed that gender was independently associated with UC patients carried MICA-A5·1 allele (P = 0·046, OR (male) = 0·511, 95% CI: 0·264–0·987). Although the UC patients with extensive colitis (32·5% versus 17·4% in the healthy controls, P = 0·005, Pc = 0·025) and the UC patients with extraintestinal manifestations (36% versus 17·4% in the healthy controls, P = 0·0039, Pc = 0·0195) were more likely to carry the MICA-A5·1 allele, EIMs was associated with extent of disease (P < 0·0001, OR (with EIMs) = 3·511, 95% CI 1·747–7·056) and MICA-A5·1 allele was not associated with UC patients with extensive colitis or with EIMs in the logistic regression analysis. Therefore, the MICA-A5·1 homozygous genotype and A5·1 allele were closely associated with UC and the MICA-A5·1 allele was positively associated with the female UC patients in Chinese population

Exploiting Polyphenol-Mediated Redox Reorientation in Cancer Therapy

Polyphenol, one of the major components that exert the therapeutic effect of Chinese herbal medicine (CHM), comprises several categories, including flavonoids, phenolic acids, lignans and stilbenes, and has long been studied in oncology due to its significant efficacy against cancers in vitro and in vivo. Recent evidence has linked this antitumor activity to the role of polyphenols in the modulation of redox homeostasis (e.g., pro/antioxidative effect) in cancer cells. Dysregulation of redox homeostasis could lead to the overproduction of reactive oxygen species (ROS), resulting in oxidative stress, which is essential for many aspects of tumors, such as tumorigenesis, progression, and drug resistance. Thus, investigating the ROS-mediated anticancer properties of polyphenols is beneficial for the discovery and development of novel pharmacologic agents. In this review, we summarized these extensively studied polyphenols and discussed the regulatory mechanisms related to the modulation of redox homeostasis that are involved in their antitumor property. In addition, we discussed novel technologies and strategies that could promote the development of CHM-derived polyphenols to improve their versatile anticancer properties, including the development of novel delivery systems, chemical modification, and combination with other agents