Deciphering a novel image cipher based on mixed transformed Logistic maps

Since John von Neumann suggested utilizing Logistic map as a random number generator in 1947, a great number of encryption schemes based on Logistic map and/or its variants have been proposed. This paper re-evaluates the security of an image cipher based on transformed logistic maps and proves that the image cipher can be deciphered efficiently under two different conditions: 1) two pairs of known plain-images and the corresponding cipher-images with computational complexity of $O(2^{18}+L)$; 2) two pairs of chosen plain-images and the corresponding cipher-images with computational complexity of $O(L)$, where $L$ is the number of pixels in the plain-image. In contrast, the required condition in the previous deciphering method is eighty-seven pairs of chosen plain-images and the corresponding cipher-images with computational complexity of $O(2^{7}+L)$. In addition, three other security flaws existing in most Logistic-map-based ciphers are also reported.Comment: 10 pages, 2 figure

A necessary and sufficient condition for lower bounds on crossing numbers of generalized periodic graphs in an arbitrary surface

Let $H$, $T$ and $C_n$ be a graph, a tree and a cycle of order $n$, respectively. Let $H^{(i)}$ be the complete join of $H$ and an empty graph on $i$ vertices. Then the Cartesian product $H\Box T$ of $H$ and $T$ can be obtained by applying zip product on $H^{(i)}$ and the graph produced by zip product repeatedly. Let $\textrm{cr}_{\Sigma}(H)$ denote the crossing number of $H$ in an arbitrary surface $\Sigma$. If $H$ satisfies certain connectivity condition, then $\textrm{cr}_{\Sigma}(H\Box T)$ is not less than the sum of the crossing numbers of its ``subgraphs". In this paper, we introduced a new concept of generalized periodic graphs, which contains $H\Box C_n$. For a generalized periodic graph $G$ and a function $f(t)$, where $t$ is the number of subgraphs in a decomposition of $G$, we gave a necessary and sufficient condition for $\textrm{cr}_{\Sigma}(G)\geq f(t)$. As an application, we confirmed a conjecture of Lin et al. on the crossing number of the generalized Petersen graph $P(4h+2,2h)$ in the plane. Based on the condition, algorithms are constructed to compute lower bounds on the crossing number of generalized periodic graphs in $\Sigma$. In special cases, it is possible to determine lower bounds on an infinite family of generalized periodic graphs, by determining a lower bound on the crossing number of a finite generalized periodic graph.Comment: 26 pages, 20 figure

Effect of recombinant human brain natriuretic peptide on myocardial enzymes and cardiac function after percutaneous coronary intervention in patients with acute myocardial infarction

Purpose: To study the effect of recombinant human brain natriuretic peptide rhBNP on myocardial enzymes and cardiac function following percutaneous coronary intervention (PCI) in acute myocardial infarction (AMI) subjects.Methods: Patients with AMI (124 cases) subjected to PCI for 2 years were used as subjects in this investigation. Two groups of patients were used (62 patients per group). One group received rhBNP while the other group served as control. The patients consisted of 76 males and 48 females (mean age, 63.54 ± 12.31 years). The two groups of patients received 75 mg/kg body weight of clopidogrel orally and aspirin (300 mg/kg) 2 h before PCI. The peaks of creatine kinase (CK), creatine kinase MB (CKMB), and the levels of troponin I (cTnI) were assayed at pre-determined intervals with an automated biochemical analyzer, and changes in the enzyme levels were recorded. Echocardiography (ECG) parameters were also measured.Results: Lower peaks of CK, CK-MB and levels of cTnI were seen in rhBNP-treated patients, when compared with controls (p < 0.05). Total effectiveness was markedly higher in rhBNP-treated group than in control group (p < 0.05). Moreover, myocardial infarct size was significantly lower in rhBNP treatment group than in control group (p < 0.05).Conclusion: Treatment with rhBNP before PCI in patients with AMI increases coronary blood flow, ameliorates perfusion injury, inhibits left ventricular remodeling, reduces myocardial cell necrosis, and improves cardiac function and prognosis.Keywords: Recombinant human brain natriuretic peptide (rhBNP), Acute myocardial infarction, percutaneous coronary intervention, Myocardial enzymes, Cardiac functio

Leveraging the UAV to support Chinese Antarctic expeditions: a new perspective

Recent developments in Unmanned Aerial Vehicles (UAVs) and their applications in various subjects are of interest to polar communities. Due to the harsh climate and dangerous environment, these regions pose challenges for the expedition teams. Several countries have tested the UAV technology to support Antarctic research and logistics. In this trend paper, we provide insightful reviews and discussions on such a prospective topic. Based on a comprehensive literature survey, we firstly summarize the key research progress of UAV in Antarctic studies. Then the examples of risk scenarios during the field exploration are given, after which several promising applications of the UAVs in safety guarantee are illustrated. In particular, we present a case of site-selection for the Chinese first ice sheet airfield, using the data collected in the 34th Chinese National Antarctic Research Expedition (CHINARE). In the end, we highlight the unique value of the UAVs in the popularization of polar science before concluding the advantages and limitations. Considering their excellent performance, we expect more innovations for UAV’s applications in the following Antarctic expeditions

Effects of artemisinin on ventricular arrhythmias in response to left ventricular afterload increase and microRNA expression profiles in Wistar rats

Background Patients with dilated cardiomyopathy, increased ventricular volume, pressure overload or dysynergistic ventricular contraction and relaxation are susceptible to develop serious ventricular arrhythmias (VA). These phenomena are primarily based on a theory of mechanoelectric feedback, which reflects mechanical changes that produce alterations in electrical activity. However, very few systematic studies have provided evidence of the preventive effects of artemisinin (ART) on VA in response to left ventricle (LV) afterload increases. MicroRNAs (miRNAs) are endogenous small non-coding RNAs that regulate expression of multiple genes by suppressing mRNAs post-transcriptionally. Aims The aims of this study were to investigate preventive effects of ART on mechanical VA and the underling molecular mechanisms of differentially expressed miRNAs (DEMs). Methods For the study, 70 male Wistar rats were randomly divided into seven groups: group 1 was a control group (sham surgery); group 2 was a model group that underwent transverse aortic constriction (TAC) surgery; groups 3, 4, 5 and 6 were administered ART 75, 150, 300 and 600 mg/kg before TAC surgery, respectively; and group 7 was administered verapamil (VER) 1 mg/kg before TAC surgery. A ventricular arrhythmia score (VAS) was calculated to evaluate preventive effects of ART and VER on mechanical VA. The high throughput sequencing-based approach provided DEMs that were altered by ART pretreatment between group 2 and group 4. All predicted mRNAs of DEMs were enriched by gene ontology (GO) and Kyoto Encyclopedia annotation of Genes and Genomes (KEGG) databases. These DEMs were validated by a real time quantitative polymerase chain reaction (RT-qPCR). Results The average VASs of groups 3, 4, 5, 6 and 7 were significantly reduced compared with those of group 2 (2.70 ± 0.48, 1.70 ± 0.95, 2.80 ± 0.79, 2.60 ± 0.97, 1.40 ± 0.52, vs 3.70 ± 0.67, p < 0.01, respectively). The three top GO terms were neuron projection, organ morphogenesis and protein domain specific binding. KEGG enrichment of the 16 DEMs revealed that MAPK, Wnt and Hippo signaling pathways were likely to play a substantial role in the preventive effects of ART on mechanical VA in response to LV afterload increases. All candidate DEMs with the exception of rno-miR-370-3p, rno-miR-6319, rno-miR-21-3p and rno-miR-204-5p showed high expression levels validated by RT-qPCR. Conclusions Artemisinin could prevent mechanical VA in response to LV afterload increases. Validated DEMs could be biomarkers and therapeutic targets of ART regarding its prevention of VA induced by pressure overload. The KEGG pathway and GO annotation analyses of the target mRNAs could indicate the potential functions of candidate DEMs. These results will help to elucidate the functional and regulatory roles of candidate DEMs associated with antiarrhythmic effects of ART

Chemotherapy-induced nausea and vomiting among cancer patients in Shanghai: a cross-sectional study

Background and purpose: Chemotherapy-induced nausea and vomiting (CINV) can cause severe damage to body functions and even lead to death. The prevention of CINV is critically important in patients receiving emetogenic chemotherapy regimen. This study aimed to investigate the prevalence and treatment of CINV in Grade-A tertiary hospitals in Shanghai and explore risk factors of CINV to improve its management. Methods: The clinical data of 376 cancer patients in Grade-A tertiary hospitals in Shanghai from October 2022 to December 2022 were collected retrospectively. The questionnaire was used to conduct a cross-sectional study. The univariate and multivariable logistic regression models were used to evaluate the influencing factors of CINV. Results: The management and coincidence of the guideline in 2022 significantly improved compared to five years ago. For patients receiving high-emetic-risk chemotherapy regimen, the coincidence of the guideline increased from 21.6% to 67.0%. For patients receiving moderate-emetic-risk chemotherapy regimen, the neurokinin-1 (NK-1) receptor antagonist was not significantly associated with CINV. Multivariable analysis showed that the chemotherapy regimen was the only risk factor for CINV during the whole period (P&lt;0.05). Conclusion: The chemotherapy regimen is the main risk factor for CINV. To control CINV better, clinical practitioners should focus on the intrinsic risk of chemotherapy regimens preferentially, estimate the risk and adhere better to guidelines

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals &lt;1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data