To study the fixed parameter undecidability of tiling problem for a set of Wang tiles, Jeandel and Rolin show that the tiling problem for a set of 44 Wang bars is undecidable. In this paper, we improve their result by proving that whether a set of 29 Wang bars can tile the plane is undecidable. As a consequence, the tiling problem for a set of Wang tiles with color deficiency of 25 is also undecidable.

The friends-and-strangers problem is defined on two graphs X and Y of the same order n, where X is the location graph on a set of locations V ( X ) and Y is the friendship graph on a set of people V ( Y ). A configuration is a bijection from V ( X ) to V ( Y ), representing an arrangement of n people at n locations. The friends-and-stranger problem investigates the connectivity of two arbitrary configurations by a sequence of swaps of two people that are neighbors (i.e., adjacent in X) and friends (i.e., adjacent in Y). In this paper, we show that the friends-and-strangers problem with subcubic planar location graphs X is PSPACE-complete by a reduction from the Ncl (non-deterministic constraint logic) problem.

. This paper focuses on the undecidability of translational tiling of n-dimensional space Zn with a set of k tiles. It is known that tiling Z2 with translated copies with a set of 8 tiles is undecidable. Greenfeld and Tao gave strong evidence in a series of works that for sufficiently large dimension n, the translational tiling problem for Zn might be undecidable for just one tile. This paper shows the undecidability of translational tiling of Z3 with a set of 6 tiles.

Is there a fixed dimension $n$ such that translational tiling of $\mathbb{Z}^n$ with a monotile is undecidable? Several recent results support a positive answer to this question. Greenfeld and Tao disprove the periodic tiling conjecture by showing that an aperiodic monotile exists in sufficiently high dimension $n$ [Ann. Math. 200(2024), 301-363]. In another paper [to appear in J. Eur. Math. Soc.], they also show that if the dimension $n$ is part of the input, then the translational tiling for subsets of $\mathbb{Z}^n$ with one tile is undecidable. These two results are very strong pieces of evidence for the conjecture that translational tiling of $\mathbb{Z}^n$ with a monotile is undecidable, for some fixed $n$. This paper gives another supportive result for this conjecture by showing that translational tiling of the $4$-dimensional space with a set of three connected tiles is undecidable.

We give a proof of Ollinger's conjecture that the problem of tiling the plane with translated copies of a set of $8$ polyominoes is undecidable. The techniques employed in our proof include a different orientation for simulating the Wang tiles in polyomino and a new method for encoding the colors of Wang tiles.

The computational complexity of tiling finite simply connected regions with a fixed set of tiles is studied in this paper. We show that the problem of tiling simply connected regions with a fixed set of 23 Wang tiles is NP-complete. As a consequence, the problem of tiling simply connected regions with a fixed set of 111 rectangles is NP-complete. Our results improve that of Igor Pak and Jed Yang by using fewer numbers of tiles. Notably in the case of Wang tiles, the number has decreased by more than one third from 35 to 23.

Burke and Teng introduced a two-player combinatorial game Atropos based on Sperner's lemma, and showed that deciding whether one has a winning strategy for Atropos is PSPACE-complete. In the original Atropos game, the players must color a node adjacent to the last colored node. Burke and Teng also mentioned a variant Atropos-k in which each move is at most of distance k of the previous move, and asked a question on determining the computational complexity of this variant. In this paper, we answer this question by showing that for any fixed integer k (k>=2), Atropos-k is PSPACE-complete by reduction from True Quantified Boolean Formula (TQBF).

We consider the computational complexity of Hearthstone which is a popular online CCG (collectible card game). We reduce a PSPACE-complete problem, the partition game, to perfect information Hearthstone in which there is no hidden information or random elements. In the reduction, each turn in Hearthstone is used to simulate one choice in the partition game. It is proved that determining whether the player has a forced win in perfect information Hearthstone is PSPACE-hard.

Both Fusobacterium nucleatum (F. nucleatum) and long non-coding RNA (lncRNA) EVADR are associated with colorectal cancer (CRC), but their relationship with CRC metastasis and the mechanisms by which EVADR promotes CRC metastasis are poorly understood. Here, we report that F. nucleatum promotes colorectal cancer cell metastasis to the liver and lung and that it can be detected in CRC-metastasis colonization in mouse models. Furthermore, F. nucleatum upregulates the expression of EVADR, which can increase the metastatic ability of CRC cells in vivo and in vitro. Mechanistically, elevated EVADR serves as a modular scaffold for the Y-box binding protein 1 (YBX1) to directly enhance the translation of epithelial-mesenchymal transition (EMT)-related factors, such as Snail, Slug, and Zeb1. These findings suggest that EVADR induced by F. nucleatum promotes colorectal cancer metastasis through YBX1-dependent translation. The EVADR-YBX1 axis may be useful for the prevention and treatment of patients with F. nucleatum-associated CRC metastasis.

A selfmate is a Chess problem in which White, moving first, needs to force Black to checkmate within a specified number of moves. The reflexmate is a derivative of the selfmate in which White compels Black to checkmate with the added condition that if either player can checkmate, they must do that (when this condition applies only to Black, it is a semi-reflexmate). We slightly modify the reduction of EXPTIME-hardness of Chess and apply the reduction to these Chess problems. It is proved that selfmate, reflexmate, and semi-reflexmate are all EXPTIME-complete.

Early accurate profiling of pathogenic bacteria in patients with nosocomial bloodstream infections (nBSIs) is crucial to optimize antibiotic therapy and patient survival. We present a novel autocatalytic Multi-component DNAzyme (MNAzyme)-integrated surface plasmon resonance (SPR) biosensor assay that rapidly and sensitively detects the DNA of three nBSI pathogenic bacteria. This strategy combines autocatalytic MNAzyme cleavage on magnetic beads, as the molecular recognition and signal amplification element, with hybridization chain reaction (HCR)-mediated nanowire assembly on SPR sensing film, as the signal readout and further amplification. Once the MNAzyme complex was activated as a biocatalyst by co-recognizing the bacterial DNA and initial probes, the MNAzyme substrate was catalytically cleaved into two DNA segments. One hybridized with immobilized probes triggering folded hairpin probes to self-assemble into massive nanowire structures via HCR on the sensing interface, and the other co-recognized the initial probes trigging another cycle of multi turnover cleavage. As a result, the amount of cleaved DNA segments was increasing and greatly enhancing the SPR signal from the analyte. This assay system can provide the fast and quantitative analysis at low concentration (67 cfu/mL of S. aureus, 57 cfu/mL of K. pneumonia and 61 cfu/mL of E. coli, respectively) in a nonenzymatic manner. More importantly, the biosensor was successfully applied to DNA extracted from clinical blood specimens of patients with nBSIs, showing good consistence and practicability. The developed autocatalytic MNAzyme-integrated SPR biosensor provides a sensitive, rapid, reliable and culture-independent approach to efficiently determine multiple pathogenic bacteria for the early diagnosis of nBSIs.

Cystatin C is an important cysteine protease inhibitor in the human body and is proposed as a new indicator of glomerular filtration rate for the detection of kidney damage. In this article, we report an ultra-sensitive, simple, and rapid chemiluminescence immunoassay method for cystatin C detection using functionalized mesoporous silica nanoparticles. After a three step hydrolysis, the amino-functionalized MSN encapsulating dye resulted in a hydrophobic environment for fixing the dye and amino groups for biological modification. The NaIO(4)immobilization method maintained the activity of the antibody notably well. The sandwich immunoassay using two monoclonal antibodies was chosen for its selectivity. The analysis demonstrated that the detection upper was 0.0029 ng/mL and linear relationship within the range of 0.0035-0.5 ng/mL (R-2= 0.9936). The relative standard deviation (RSD) for 11 parallel measurements of 0.25 ng/mL CysC was 4.7%. The automated chemiluminescence analyzer could detect 96 wells continuously. The results demonstrated that this method is ultra-sensitive, simple, and rapid for detecting cystatin C.

The Ebola virus disease (EVD) is a highly contagious disease which is caused by the Ebola virus . Various measures were used to prevent and control the spread of EVD. The aim of this study was to find out the most critical measures to prevent and control the spread of EVD. Both mathematical modeling and comparative analysis were used to explore the development process of EVD outbreak in Guinea, Liberia and Sierra Leone. The results of comparative analysis showed quarantined individuals before infection (R 2 = 0.848, ε = 1.012), safe burial teams (R 2 = 0.772, ε = 0.385), and the Ebola treatment units (ETU) bed (R 2 = 0.690, ε = 0.432) could significantly influence the incidence of EVD which were consistent with the results of mathematical modeling. These findings indicted that a timely and effective quarantine played a significant role in preventing and controlling the spread of EVD, and the findings would help us prevent and control the epidemic outbreak of new infectious disease in the future.

H5 avian influenza virus (AIV) and velogenic Newcastle disease virus (v-NDV) are pathogens listed in the OIE Terrestrial Animal Health Code and are considered key pathogens to be eliminated in poultry production. Molecular techniques for rapid detection of H5 AIV and v-NDV are required to investigate their transmission characteristics and to guide prevention. Traditional virus isolation, using embryonated chicken eggs, is time-consuming and cannot be used as a rapid diagnostic technology. In this study, a multiplex real-time RT-PCR (RRT-PCR) detection method for six H5 AIV clades, three v-NDV subtypes, and one mesogenic NDV subtype was successfully established. The detection limit of our multiplex NDV and H5 AIV RRT-PCR was five copies per reaction for each pathogen, with good linearity and efficiency (y = −3.194x + 38.427 for H5 AIV and y = −3.32x + 38.042 for NDV). Multiplex PCR showed good intra- and inter-assay reproducibility, with coefficient of variance (CV) less than 1%. Furthermore, using the RRT-PCR method, H5 AIV and NDV detection rates in clinical samples were higher overall than those obtained using the traditional virus isolation method. Therefore, our method provides a promising technique for surveillance of various H5 AIV clades and multiple velogenic and mesogenic NDV subtypes in live-poultry markets.

Kill-all Go is a variant of Go in which Black tries to capture all white stones, while White tries to survive. We consider computational complexity of Kill-all Go with two rulesets, Chinese rules and Japanese rules. We prove that: (i) Kill-all Go with Chinese rules is PSPACE-hard, and (ii) Kill-all Go with Japanese rules is EXPTIME-complete.

We review NP-hardness framework and PSPACE-hardness framework for a type of 2D platform games. We introduce a EXPTIME-hardness framework by defining some new gadgets. We use these hardness frameworks to analyse computational complexity of Xiangqi (Chinese Chess) and Janggi (Korean Chess). We construct all gadgets of the hardness frameworks in Xiangqi and Janggi. In conclusion, we prove that Xiangqi and Janggi are both EXPTIME-complete.

With the deployment of collaborative robots in intelligent manufacturing, object hand-over between humans and robots plays a significant role in human-robot collaborations. In most collaboration studies, human hand-over intentions were usually assumed to be known by the robot, and the research mainly focused on robot motion planning and control during the hand-over process. Several approaches have been developed to control the human-robot hand-over, such as vision-based approach and physical contact-based approach, but their applications in manufacturing environments are limited due to various constraints, such as limited human working ranges and safety concerns. In this paper, we develop a practical approach using a wearable sensory system, which has a natural and simple configuration and can be easily utilized by humans. This approach could make a robot recognize a human's hand-over intentions and enable the human to effectively and naturally control the hand-over process. In addition, the approach could recognize the attribute classes of the objects in the human's hand using the wearable sensing and enable the robot to actively make decisions to ensure that graspable objects are handed over from the human to the robot. Results and evaluations illustrate the effectiveness and advantages of the proposed approach in human-robot hand-over control.

Dou Shou Qi is a Chinese strategy board game for two players. We use a EXPTIME-hardness framework to analyse computational complexity of the game. We construct all gadgets of the hardness framework. In conclusion, we prove that Dou Shou Qi is EXPTIME-complete.

Colorectal cancer (CRC) is a common and highly lethal form of cancer. Although the etiologic role of Fusobacterium nucleatum (F. nucleatum) in the development of CRC has been elucidated, the specific tumor molecules involved in the progression of CRC induced by F. nucleatum have not been identified. This study investigated several miRNAs and genes involved in the progression of F. nucleatum-induced CRC by Affymetrix miRNA microarray technology and GeneChip Human Transcriptome Array 2.0. The results suggest that miR-4474 and miR-4717 are up-regulated in CRC tissues in response to F. nucleatum infection, compared with the control group (paracancerous tissues), while other genes associated with signaling pathways in cancer, including CREB-binding protein (CREBBP), STAT1, PRKACB, CAMK2B, JUN, TP53 and EWSR1, were dysregulated. Bioinformatic analysis identified CREBBP as the primary aberrantly expressed gene in F. nucleatum-induced CRC. Consistent with the microarray analysis results, real-time RT-PCR analysis demonstrated that the expression of miR-4474/4717 was upregulated while that of CREBBP mRNA was downregulated in CRC patients infected with F. nucleatum. Additionally, CREBBP was identified as a novel target of miR-4474/4717. The results of this study suggest that miR-4474 and miR-4717 are involved in the progression of F. nucleatum-induced CRC by posttranscriptionally regulating the target gene CREBBP.

Recently, Fuchun Zhang and Yue Feng with colleagues successively described three human infection cases with the emerging H7N9 influenza virus possessing different motifs of multiple basic amino acids at the hemagglutinin (HA) cleavage site in this journal. 1 Zhang F. Bi Y. Wang J. Wong G. Shi W. Hu F. et al. Human infections with recently-emerging highly pathogenic H7N9 avian influenza virus in China. J Infect. July 2017; 75: 71-75 Abstract Full Text Full Text PDF PubMed Scopus (119) Google Scholar , 2 Feng Y. Gao L. Miao J. Zhang M. Zhang C. Wang X. et al. Human infection with a novel H7N9 avian influenza virus in Yunnan, China. J Infect. 8 August 2017; ([in Press] [Epub ahead of print]) Abstract Full Text Full Text PDF Scopus (6) Google Scholar Since the first human case of H7N9 influenza virus infection in February 2013 in Eastern China, 3 Gao R. Cao B. Hu Y. Feng Z. Wang D. Hu W. et al. Human infection with a novel avian-origin influenza A (H7N9) virus. N Engl J Med. 2013; 368: 1888-1897 Crossref PubMed Scopus (1921) Google Scholar a total of 1557 laboratory-confirmed cases with an approximate 40% fatality have been reported to WHO so far. 4 World Health Organization. Influenza at the human-animal interface. http://www.who.int/entity/influenza/human_animal_interface/Influenza_Summary_IRA_HA_interface_07_25_2017.pdf?ua=1. Google Scholar Previous studies showed that the human-origin H7N9 virus with monobasic amino acids in the HA cleavage site was low pathogenic or avirulent to chickens but was highly virulent in mice. 5 Kalthoff D. Bogs J. Grund C. Tauscher K. Teifke J.P. Starick E. et al. Avian influenza H7N9/13 and H7N7/13: a comparative virulence study in chickens, pigeons, and ferrets. J Virol. 2014; 88: 9153-9165 Crossref PubMed Scopus (37) Google Scholar , 6 Spackman E. Pantin-Jackwood M. Swayne D.E. Suarez D.L. Kapczynski D.R. Impact of route of exposure and challenge dose on the pathogenesis of H7N9 low pathogenicity avian influenza virus in chickens. Virology. 2015; 477: 72-81 Crossref PubMed Scopus (27) Google Scholar , 7 Belser J.A. Creager H.M. Sun X. Gustin K.M. Jones T. Shieh W.J. et al. Mammalian pathogenesis and transmission of H7N9 influenza viruses from three waves, 2013–2015. J Virol. 2016; 90: 4647-4657 Crossref PubMed Scopus (20) Google Scholar , 8 Belser J.A. Gustin K.M. Pearce M.B. Maines T.R. Zeng H. Pappas C. et al. Pathogenesis and transmission of avian influenza A (H7N9) virus in ferrets and mice. Nature. 2013; 501: 556-559 Crossref PubMed Scopus (261) Google Scholar , 9 Su S. Gu M. Liu D. Cui J. Gao G.F. Zhou J. et al. Epidemiology, evolution, and pathogenesis of H7N9 influenza viruses in five epidemic waves since 2013 in China. Trends Microbiol. September 2017; 25: 713-728 Abstract Full Text Full Text PDF PubMed Scopus (164) Google Scholar Although having caused an unexpected loss, the pathogenicity of the highly pathogenic (HP) H7N9 viruses in animal models remains unclear. In this study, we have presented a brief assessment on the characteristics and pathogenicity of two chicken-origin HP H7N9 viruses in chickens and mice.