Foundational Verification of Stateful P4 Packet Processing

P4 is a standardized programming language for the network data plane. But P4 is not just for routing anymore. As programmable switches support stateful objects, P4 programs move beyond just stateless forwarders into new stateful applications: network telemetry (heavy hitters, DDoS detection, performance monitoring), middleboxes (firewalls, NAT, load balancers, intrusion detection), and distributed services (in-network caching, lock management, conflict detection). The complexity of stateful programs and their richer specifications are beyond what existing P4 program verifiers can handle. Verifiable P4 is a new interactive verification framework for P4 that (1) allows reasoning about multi-packet properties by specifying the per-packet relation between initial and final states; (2) performs modular verification, especially providing a modular description for stateful objects; (3) is foundational, i.e., with a machine-checked soundness proof with respect to a formal operational semantics of P4_{16} (the current specification of P4) in Coq. In addition, our framework includes a proved-correct reference interpreter. We demonstrate the framework with the specification and verification of a stateful firewall that uses a sliding-window Bloom filter on a Tofino switch to block (most) unsolicited traffic

Ethnic disparities in the risk of colorectal adenomas associated with aspirin and statin use: a retrospective multiethnic study

BACKGROUND: Although data on the inverse association between colorectal adenomas (CRA) and daily aspirin or statin therapy exists in white and black patients, scarce data exists on these associations in the Hispanic population. With a rapidly increasing Hispanic population in the United States, defining the association in Hispanics is crucial. METHODS: The study sample included 1,843 consecutive patients who underwent a colonoscopy (screening or diagnostic) from 2009 to 2011 at a community hospital in East Meadow, New York. Data was then extracted from patient charts regarding aspirin and/or statin use. Adjusted odds ratios (OR) and their 95% confidence intervals (CI) were calculated to assess the association between colonoscopy findings and aspirin, statin, or aspirin/statin use. RESULTS: In our total population including all races, aspirin user had an increased risk for having two or more adenomas (OR =1.73, 95% CI: 1.00, 2.99, P=0.05) and presence of an adenoma in the proximal colon (OR =1.66, 95% CI: 1.07, 2.58, P=0.02). In the total study population, those who used both statin and aspirin had an increased risk for having two or more adenomas (OR =2.56, 95% CI: 1.21, 5.39, P=0.01). In the Hispanic population, users of both medications had an increased risk for having two or more adenomas (OR =19.04, 95% CI: 1.30, 280.09, P=0.03), adenoma present in the distal colon (OR =5.75, 95% CI: 1.64, 20.21, P=0.01) and largest adenoma in distal colon (OR =5.75, 95% CI: 1.64, 20.21, P=0.01). CONCLUSIONS: Aspirin use and aspirin/statin use was associated with abnormal colonoscopy findings, particularly in the Hispanic population. These findings may be due to environmental factors such as dietary, colonic flora, or genetic susceptibility. The findings warrant further investigational research, particularly in Hispanics

Long Noncoding RNA Expression Profiles of Lung Adenocarcinoma Ascertained by Microarray Analysis

<div><p>Background</p><p>Long noncoding RNAs (lncRNAs) have been shown to be involved in the development and progression of lung cancer. However, the roles of lncRNAs in lung cancer are not well understood.</p><p>Methodology/Principal Findings</p><p>We used a high-throughput microarray to compare the lncRNA and messenger RNA (mRNA) expression profiles in lung adenocarcinoma and normal tissue (NT) samples. Several candidate adenocarcinoma-associated lncRNAs were verified by real-time quantitative reverse transcription polymerase chain reaction (PCR) analysis. Using abundant and varied probes, we were able to assess 30,586 lncRNAs and 26,109 mRNAs in our microarray. We found that 2,420 lncRNAs and 1,109 mRNAs were differentially expressed (≥2-fold change) in lung adenocarcinoma samples and NT, indicating that many lncRNAs were significantly upregulated or downregulated in lung adenocarcinoma. We also found, via quantitative PCR, that 19 lncRNAs were aberrantly expressed in lung adenocarcinoma compared with matched histologically normal lung tissues. Among these, LOC100132354 and RPLP0P2 were the most aberrantly expressed lncRNAs, as estimated by quantitative PCR in 100 pairs of lung adenocarcinoma and NT samples.</p><p>Conclusions/Significance</p><p>Our study ascertained the expression patterns of lncRNAs in lung adenocarcinoma by microarray. The results revealed that many lncRNAs were differentially expressed in lung adenocarcinoma tissues and NT, suggesting that they may play a key role in tumor development.</p></div

Box plots and Scatter plots showing the variation in lncRNA and mRNA expression between the lung adenocarcinoma and normal lung tissue arrays.

<p>(A–B) Box plots showing the distribution of the lncRNA (A) and mRNA (B) profiles. After normalization, the distributions of the log2-ratios among the tested samples were nearly the same. (C–D) Scatter plots showing the variation in lncRNA (C) and mRNA (D) expression between the lung adenocarcinoma and normal lung tissue arrays. The values of the X and Y axes in the scatter plot are averaged normalized values in each group (log2-scaled). The lncRNAs above the top green line and below the bottom green line are those with a >3-fold change in expression between tissues.</p

Pathway analysis of downregulated mRNAs in lung adenocarcinoma.

<p>Twenty-four downregulated pathways were identified, including propionate metabolism and fatty acid metabolism pathways.</p

Heat map and hierarchical clustering of lncRNA and mRNA profile comparison between the lung adenocarcinoma and normal lung samples.

<p>(A) lncRNA (B) mRNA.</p

The expression level of RPLPOP2 and LOC100132354 between one hundred lung adenocarcinoma sample and the normal lung sample.

<p>LOC100132354 expression of lung adenocarcinoma was significantly higher than the adjacent tissues (Mann-Whitney U = 126.00, P = 0.01), while RPLP0P2 expression of lung adenocarcinoma was significantly lower than the adjacent tissues (Mann-Whitney U = 178.78, P = 0.002).</p

A Study of the Mechanism and Separation of Structurally Similar Phenolic Acids by Commercial Polymeric Ultrafiltration Membranes

This study examined the behavior and penetration mechanisms of typical phenolic (benzoic) acids, which determine their observed penetration rates during membrane separation, focusing on the influence of electrostatic and hydrophobic solute/membrane interactions. To understand the effects of hydrophobicity and electrostatic interaction on membrane filtration, the observed penetration of five structurally similar phenolic acids was compared with regenerated cellulose (RC) and polyamide (PA) membranes at different solute concentrations and solution pHs. Variation partitioning analysis (VPA) was performed to calculate the relative contributions of electrostatic and hydrophobic effects. The penetration of phenolic acids was mainly influenced by the electrostatic interaction, with salicylic acid having the highest penetration. Penetration of phenolic acids through the PA membrane decreased from 98% at pH 3.0 to 30&ndash;50% at pH 7.4, indicating the dominance of the electrostatic interaction. Moreover, based on its hydrophobicity and greater surface charge, the PA membrane could separate binary mixtures of protocatechuic/salicylic acid and 4-hydroxybenzoic/salicylic acid at pH 9.0, with separation factors of 1.81 and 1.78, respectively. These results provide a greater understanding of solute/membrane interactions and their effect on the penetration of phenolic acids through polymeric ultrafiltration membranes

Pathway analysis of upregulated mRNAs in lung adenocarcinoma.

<p>Seven upregulated pathways were identified, including ethanol metabolism, viral carcinogenesis, RNA transduction, and cell cycle pathways.</p

Comparison between gene chip data and qPCR result.

<p>RP11-1C1.7, RP4-575N6.5, RP11-473M20.11, XLOC_003286, CTA-363E6.2, RP5-826L7.1, ZNF295-AS1, RPLP0P2, AC079776.2, RP13-514E23.1, LOC100499405, RP1-90D4.3, XLOC_012255, RP11-445K13.2, LOC100132354, AC004166.7, XLOC_003405, RP11-893F2.6, RP11-909N17.3 determined to be differentially expressed in lung adenocarcinoma samples compared with NT samples in six patients by microarray were validated by qPCR. The heights of the columns in the chart represent the log-transformed median fold changes (T/N) in expression across the six patients for each of the four lncRNAs validated; the bars represent standard errors. The validation results of the 19 lncRNAs indicated that the microarray data correlated well with the qPCR results.</p