Determination of natural vitamin A in fish liver by liquid chromatography

In order to accurately determine the content of vitamin A (vitamin A1, vitamin A2) in fish liver, sample pretreatment methods (water bath saponification, room temperature saponification, direct extraction) and detection methods (normal phase chromatography, reversed phase chromatography) were screened and applied to the determination of vitamin A in the liver of nine economic fish species. The results showed that vitamin A1 and vitamin A2 were separated effectively by reversed phase chromatography and showed good linear relationship within their respective linear ranges(R2 > 0.99); the content of vitamin A extracted by water bath saponification was significantly higher than that by room temperature saponification and direct extraction (p <0. 05), and its average recoveries of vitamin A1 and vitamin A2 were 104. 52% and 90. 94%, respectively. Except for the freshwater snakehead and big mouth bass, the total content of vitamin A in the livers of other freshwater fishes and marine fishes was more than 200μg/100 g, and the total content of vitamin A in the liver of marine giant grouper was the highest, reaching 14 413.78μg/100 g. The water bath saponification method combined with reversed phase chromatography has good precision and is suitable for the determination of vitamin A in fish liver

Understanding the digestibility and nutritional functions of rice starch subjected to heat-moisture treatment

In this study, rice starch with well-controlled digestion resistibility achieved by heat-moisture treatment (HMT) was chosen as a supplementary diet for high-fat-diet-fed mice. Then, the nutritional functions of HMT-modified rice starch were evaluated by the physiological and biochemical indices, proliferation and distribution of intestinal microflora, and functional diversity by putative metagenomes analysis. Compared with the native-rice-starch mice (DM) group, the blood glucose, serum lipid, oxidative stress, and liver function metabolic levels/indices of the HMT-rice-starch mice (HMT-DM) group were worse due to the declined level of slowly digestible starch (SDS) in HMT-modified rice starch. Meanwhile, the species diversity index was observed to be higher in the DM group and Bifidobacteria was identified as a type of bacteria related to the relatively higher content of RS in HMT-modified rice starch. Overall, our results provide important information for the rational design of rice starch-based health-promoting foods with nutritional functions

Piano: Extremely Simple, Single-Server PIR with Sublinear Server Computation

We construct a sublinear-time single-server pre-processing Private Information Retrieval (PIR) scheme with optimal client storage and server computation (up to poly-logarithmic factors), only relying on the assumption of the existence of One Way Functions (OWF). Our scheme achieves amortized $\tilde{O}(\sqrt{n})$ online server computation and client computation and $O(\sqrt{n})$ online communication per query, and requires $\widetilde{O}_\lambda(\sqrt{n})$ client storage. Unlike prior single-server PIR schemes that rely on heavy cryptographic machinery such as Homomorphic Encryption, our scheme only utilizes lightweight cryptography such as PRFs, which is easily instantiated in practice. To our knowledge, this is the first practical implementation of a single-server sublinear-time PIR scheme. Compared to existing linear time single-server solutions, our schemes are faster by $10-300\times$ and are comparable to the fastest two-server schemes. In particular, for a 100GB database of 1.6 billion entries, our experiments show that our scheme has less than 40ms online computation time on a single core

Vertical distributions of plutonium isotopes in marine sediment cores off the Fukushima coast after the Fukushima Dai-ichi Nuclear Power Plant accident

The Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident led to the release of large amounts of radionuclides into the atmosphere as well as direct discharges into the sea. In contrast to the intensive studies on the distribution of the released high volatility fission products, such as 131I, 134Cs and 137Cs, similar studies of the actinides, especially the Pu isotopes, are limited. To obtain the vertical distribution of Pu isotopes in marine sediments and to better assess the possible contamination of Pu from the FDNPP accident in the marine environment, we determined the activities of 239+240Pu and 241Pu as well as the atom ratios of 240Pu/239Pu and 241Pu/239Pu in sediment core samples collected in the western North Pacific off Fukushima from July 2011 to July 2012. We also measured surface sediment samples collected from seven Japanese estuaries before the FNDPP accident to establish the comprehensive background baseline data. The observed results of both the Pu activities and the Pu atom ratios for the sediments in the western North Pacific were comparable to the baseline data, suggesting that the FDNPP accident did not cause detectable Pu contamination to the studied regions prior to the sampling time. The Pu isotopes in the western North Pacific 30 km off Fukushima coast originated from global fallout and Pacific Proving Ground close-in fallout

Delphi: A Cryptographic Inference Service for Neural Networks

Many companies provide neural network prediction services to users for a wide range of applications. However, current prediction systems compromise one party\u27s privacy: either the user has to send sensitive inputs to the service provider for classification, or the service provider must store its proprietary neural networks on the user\u27s device. The former harms the personal privacy of the user, while the latter reveals the service provider\u27s proprietary model. We design, implement, and evaluate Delphi, a secure prediction system that allows two parties to execute neural network inference without revealing either party\u27s data. Delphi approaches the problem by simultaneously co-designing cryptography and machine learning. We first design a hybrid cryptographic protocol that improves upon the communication and computation costs over prior work. Second, we develop a planner that automatically generates neural network architecture configurations that navigate the performance-accuracy trade-offs of our hybrid protocol. Together, these techniques allow us to achieve a 22x improvement in online prediction latency compared to the state-of-the-art prior work

DIZK: A Distributed Zero Knowledge Proof System

Recently there has been much academic and industrial interest in practical implementations of *zero knowledge proofs*. These techniques allow a party to *prove* to another party that a given statement is true without revealing any additional information. In a Bitcoin-like system, this allows a payer to prove validity of a payment without disclosing the payment\u27s details. Unfortunately, the existing systems for generating such proofs are very expensive, especially in terms of memory overhead. Worse yet, these systems are monolithic , so they are limited by the memory resources of a single machine. This severely limits their practical applicability. We describe DIZK, a system that *distributes* the generation of a zero knowledge proof across machines in a compute cluster. Using a set of new techniques, we show that DIZK scales to computations of up to billions of logical gates (100x larger than prior art) at a cost of 10$\mu$s per gate (100x faster than prior art). We then use DIZK to study various security applications

Galaxy clustering and projected density profiles as traced by satellites in photometric surveys: Methodology and luminosity dependence

We develop a new method which measures the projected density distribution w_p(r_p)n of photometric galaxies surrounding a set of spectroscopically-identified galaxies, and simultaneously the projected correlation function w_p(r_p) between the two populations. In this method we are able to divide the photometric galaxies into subsamples in luminosity intervals when redshift information is unavailable, enabling us to measure w_p(r_p)n and w_p(r_p) as a function of not only the luminosity of the spectroscopic galaxy, but also that of the photometric galaxy. Extensive tests show that our method can measure w_p(r_p) in a statistically unbiased way. The accuracy of the measurement depends on the validity of the assumption in the method that the foreground/background galaxies are randomly distributed and thus uncorrelated with those galaxies of interest. Therefore, our method can be applied to the cases where foreground/background galaxies are distributed in large volumes, which is usually valid in real observations. We applied our method to data from SDSS including a sample of 10^5 LRGs at z~0.4 and a sample of about half a million galaxies at z~0.1, both of which are cross-correlated with a deep photometric sample drawn from the SDSS. On large scales, the relative bias factor of galaxies measured from w_p(r_p) at z~0.4 depends on luminosity in a manner similar to what is found at z~0.1, which are usually probed by autocorrelations of spectroscopic samples. On scales smaller than a few Mpc and at both z~0.4 and z~0.1, the photometric galaxies of different luminosities exhibit similar density profiles around spectroscopic galaxies at fixed luminosity and redshift. This provides clear support for the assumption commonly-adopted in HOD models that satellite galaxies of different luminosities are distributed in a similar way, following the dark matter distribution within their host halos.Comment: 38 pages, 12 figures, published in Ap