Secure transmission in a W-band RoF system based on delta-sigma modulation.

In this Letter, a delta-sigma modulation (DSM) encryption technique in a W-band RoF system is proposed. By performing DSM with different over-sample ratios (OSRs) on the OFDM signal based on the controlled keys generated by the chaotic system at the transmitter and performing constellation masking to disturb the transmitting signal for encryption, a high-order QAM-OFDM-DSM encrypted signal is achieved. In order to further improve the security of the system, bit bidirectional diffusion scrambling is used to resist chosen-plaintext attacks. After experimental verification, under the same transmission power, the encrypted DSM signal can achieve better security than single OSR of DSM signals through a 50-km standard single-mode fiber (SSMF) and a 3-m wireless channel, with the gain of sensitivity increased by ∼1 dBm. From the reliability of the system, the encrypted signal of the proposed scheme can be recovered, which meets a hard decision-forward error correction (HD-FEC) threshold of 3.8 × 10-3.

Nanopore film based enrichment and quantification of low abundance hepcidin from human bodily fluids.

Endogenous peptides that represent biological and pathological information of disease have attracted interest for diagnosis. However, the extraction of those low abundance peptides is still a challenge because of the complexity of human bodily fluids (HBF). Hepcidin, a peptide hormone, has been recognized as a biomarker for iron-related diseases. There is no rapid and reliable way to enrich them from HBF. Here we describe a peptide extraction approach based on nanoporous silica thin films to successfully detect hepcidin from HBF. Cooperative functions of nanopore to biomolecule, including capillary adsorption, size-exclusion and electrostatic interaction, were systematically investigated to immobilize the target peptide. To promote this new approach to clinical practices, we further applied it to successfully assay the hepcidin levels in HBF provided by healthy volunteers and patients suffering from inflammation. Our finding provides a high-throughput, rapid, label-free and cost-effective detection method for capturing and quantifying low abundance peptides from HBF. FROM THE CLINICAL EDITOR: Diagnosing diseases with low concentration peptide biomarkers remains challenging. This team of authors describes a peptide extraction approach based on nanoporous silica thin films to successfully detect low concentrations of hepcidin from human body fluids collected from 119 healthy volunteers and 19 inflammation patients.

Towards a green mining future: A dynamic evolutionary game model for collaborative waste recycling.

In the realm of environmental concerns, the management of mining waste has consistently emerged as a prominent issue. The accumulation of such waste not only results in substantial pollution but also signifies an inefficient use of resources. Rich in heavy metals and an array of toxic substances, mining waste poses a considerable challenge. In China, the situation is exacerbated by mining companies' inadequate and untimely efforts to address the extensive buildup of waste material. The long-term policy of recycling and regulating mining waste can be seen as the result of a long-term game between the government's regulatory decisions and the enterprises' fulfillment of their responsibilities, and the public's ability to participate in monitoring the decisions also changes the pattern of the game. In this study, we develop a tripartite evolutionary game model involving mining enterprises, the public, and local government. System dynamics are used to simulate the dynamic evolution of each stakeholder's strategy, examining the influence of various parameters on the evolution trajectory. Our findings show that: (1) reducing public subsidies, along with increasing enterprise supervision and penalties, effectively encourages public involvement in oversight and promotes proactive waste recycling by enterprises; (2) as enterprises actively engage in recycling efforts, the resulting environmental benefits boost public enthusiasm for participation in monitoring; (3) over time, heightened environmental awareness among the public and advances in recycling technology allow enterprises to improve the profitability of recycling, fostering a sustainable mine waste recycling industry; (4) once a virtuous mine waste recycling industry is established, enterprises autonomously engage in waste recycling, and the public actively participates in supervision, making strict government oversight unnecessary.

A systematic strategy for proteomic analysis of chloroplast protein complexes in wheat.

A systematic strategy was developed for the proteomic analysis of wheat chloroplast protein complexes. First, comprehensive centrifugation methods were utilized for the exhaustive isolation of thylakoid, envelope, and stromal fractions. Second, 1% n-dodecyl-ß-D-maltoside was selected from a series of detergents as the optimal detergent to dissolve protein complexes effectively from membranes. Then, blue native polyacrylamide gel electrophoresis (BN-PAGE) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) were improved to separate and analyze the protein complexes. By this systematic strategy, envelopes, thylakoids, and stromata were enriched effectively from chloroplasts in the same process, and more than 18 complexes were obtained simultaneously by BN-PAGE. Finally, thylakoid protein complexes were further analyzed by BN/SDS-PAGE, and nine complex bands and 40 protein spots were observed on BN-PAGE and SDS-PAGE respectively. Our results indicate that this new strategy can be used efficiently to analyze the proteome of chloroplast protein complexes and can be applied conveniently to the analysis of other subcellular protein complexes.

D-AP5 blocks the increase of intracellular free Ca2+ induced by glutamate in isolated cochlear IHCs.

OBJECTIVE: To investigate the effect of D-AP5 (D-2-amino-5-phosphonopentanoate, a specific NMDA-antagonist) on the increase of intracellular free Ca2+ concentration ([Ca2+]i) induced by glutamate in isolated cochlear inner hair cells (IHCs), and to detect the autoreceptors of the IHC membrane. METHODS: When a laser scanning confocal microscope (LSCM) was used, the exogenous glutamate (Glu)-induced changes in [Ca2+]i of isolated IHCs and OHCs of guinea pig cochlea were observed with fluo-3, a fluorescent probe for [Ca2+]i. After D-AP5 or CNQX (6--cyano--7--nitroguinoxaline--2, 3--dione, a specific AMPA- antagonist) was administered, the exogenous glutamate (Glu)-induced changes in [Ca2+]i of isolated IHCs were recorded. RESULTS: In the presence of a low concentration Glu (3.85 mumol/L), there was an increase of [Ca2+]i in IHCs, whereas there was no change in OHCs. When 50 mumol/L of D-AP5 was administrated in advance, Glu did not induce a corresponding increase in [Ca2+]i in IHCs, and 50 mumol/L of CNQX did not completely block the increase of [Ca2+]i in IHCs. CONCLUSIONS: These results suggest that the autoreceptors existing in the IHC membrane are mainly of NMDA type, while there are relatively few AMPA receptors. Exogenous Glu is capable of increasing [Ca2+]i in IHCs by acting on the NMDA autoreceptor of IHCs in a positive feedback manner.

Comparative peptidome analyses of the profiles of the peptides ranging from 1-10 KD in CSF samples pooled from probable sporadic CJD and non-CJD patients.

The shotgun strategy applying tandem mass spectrometry has been widely used to identify the proteins that are differentially distributed among diseases for its high reliability and efficiency. To find out the potential difference of protein profiles in cerebrospinal fluids (CSF) between Creutzfeldt-Jakob disease (CJD) and non-CJD patients, especially in the fraction ranging from 1-10 KD, the CSF samples of 40 probable sporadic CJD (sCJD) patients, 32 non-CJD cases with dementia and 17 non-CJD cases without dementia were separately pooled and enriched by the magnetic beads based weak cation exchange chromatography (MB-WCX). After trypsin digestion, each enriched CSF was separated and identified by RP-HPLC-ESI-QTOF MS/MS. In total, 42, 53 and 47 signals of proteins were identified in the pooled CSF fraction less than 10 KD of probable sCJD, non-CJD with dementia and non-CJD without dementia, respectively. Compared with that of probable sCJD, the similarity of CSF protein profiles of non-CJD with dementia (76.2%) were higher than that of non-CJD without dementia (57.1%). Nine CSF proteins were found to be specially observed in probable sCJD group. Those data may help to select the potential biomarkers for diagnosis of CJD. Additionally, further studies of the small segments of cellular proteins in CSF of CJD patients may also provide scientific clues for understanding the neuropathogenesis of TSEs.

[Sulfonation modification-assisted enrichment and identification of histidine-containing peptides by strong cation exchange chromatography and mass spectrometry].

By the sulfonation at the N-terminal of peptides, the charge state of histidine-containing peptides is different from that of other peptides in pH < 3.0 solution. Based on this difference, a new method was developed to isolate and identify sulfonated histidine-containing peptides from tryptic digest of proteins by strong cation exchange (SCX) chromatography and matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry (MALDI-TOF MS/MS). Using the standard proteins containing histidines as the model, the methodology was evaluated. The results show that sulfonated histidine-containing peptides were efficiently enriched by SCX, and the N-terminal sulfonation of the peptides simplifies the interpretation of the acquired mass spectra and facilitates the sequencing of histidine-containing peptides by producing consecutive and predominant ions in positive mode MS2 spectra, which is thought to be the result of the charge neutralization of b ions by the N-terminal sulfonic acid group. The discrimination of b ions and y ions can greatly enhance the confidence in peptide and subsequent protein identification. It is feasible to isolate and enrich the histidine-containing peptides by using this method which has the potential applications in proteomics.

A method for rapidly confirming protein N-terminal sequences by matrix-assisted laser desorption/ionization mass spectrometry.

The N-terminal sequence is important for the identification of a protein and the confirmation of its N-terminal processing. Although mass spectrometry (MS) is a sensitive and high-throughput method to sequence and identify peptides and proteins, N-terminal peptides, diluted among most of the peptides that do not originate at the N-termini, are not easy to identify directly with MS. To develop a simple and rapid method to identify and sequence the N-terminal peptide of a protein, a new strategy based on specific sulfonation of terminal amino groups and selective monitoring of the sulfonated peptide was introduced. After a protein had been guanidinated, 2-sulfobenzoylated, and reduced, it was digested with trypsin and analyzed by MS. Because of the strong acidity of sulfonic groups and the specific sulfonation of alpha-amino groups, the sulfonated N-terminal peptide dominated as base peak in the negative mode peptide mass fingerprint (PMF) and was easy to identify. The N-terminal peptide was then selected as precursor ion for tandem mass spectrometric (MS/MS) analysis. Four proteins were tested with this method and their N-terminal peptides were successfully recognized and sequenced. The results suggest that the addition of a sulfonic acid group facilitates the identification and de novo sequencing of N-terminal peptides.

Method for quantitative proteomics research by using metal element chelated tags coupled with mass spectrometry.

The mass spectrometry-based methods with a stable isotope as the internal standard in quantitative proteomics have been developed quickly in recent years. But the use of some stable isotope reagents is limited by the relative high price and synthetic difficulties. We have developed a new method for quantitative proteomics research by using metal element chelated tags (MECT) coupled with mass spectrometry. The bicyclic anhydride diethylenetriamine-N,N,N',N' ',N' '-pentaacetic acid (DTPA) is covalently coupled to primary amines of peptides, and the ligand is then chelated to the rare earth metals Y and Tb. The tagged peptides are mixed and analyzed by LC-ESI-MS/MS. Peptides are quantified by measuring the relative signal intensities for the Y and Tb tag pairs in MS, which permits the quantitation of the original proteins generating the corresponding peptides. The protein is then identified by the corresponding peptide sequence from its MS/MS spectrum. The MECT method was evaluated by using standard proteins as model sample. The experimental results showed that metal chelate-tagged peptides chromatographically coeluted successfully during the reversed-phase LC analysis. The relative quantitation results were accurate for proteins using MECT. DTPA modification of the N-terminal of peptides promoted cleaner fragmentation (only y-series ions) in mass spectrometry and improved the confidence level of protein identification. The MECT strategy provides a simple, rapid, and economical alternative to current mass tagging technologies available.

[Research on the separation of caffeine and its nine analogues by micellar electrokinetic capillary chromatography].

The separation of caffeine and its nine analogues by micellar electrokinetic capillary chromatography (MECC) using sodium dodecyl sulphate (SDS) as the micellar phase was investigated. The effects of pH and concentration of phosphate buffer solution, SDS micelle concentration, methanol volume fraction, applied voltage and temperature on the separation were studied. It was found that the migration of these compounds was affected by these factors, especially by pH of the solution. The order of elution, as well as the migration time and separation efficiency of these compounds changes with the acidity of the solution, which suggests the disassociation of the hydrogen on the secondary amino group in these compounds. The optimized separation conditions consisted of a running buffer of 20 mmol/L sodium phosphate buffer, at pH 11.0, containing 20 mmol/L SDS, with an applied voltage of 25 kV and a temperature of 25 degrees C. All of the compounds were resolved within 9 min with the detection limits of 0.70 mg/L and the linearity in the range of 1.40 mg/L-45.5 mg/L with the correlation coefficients of 0.998-0.999.

[Synergistic Induction of Apoptosis by Chemotherapeutic Drugs and Cytokines in Mouse T-Lymphoma Cell Line]

The objective of the study is to find out the synergistic effect on apoptosis resulting from the combination of chemotherapeutic drugs and some cytokines. Dexamethasone (DEX), etoposide (VP16), arsenic trioxide (As(2)O(3)) and alltrans-retinoic acid (ATRA) were added to the murine T lymphoma cell line RMA as well as to the cells preincubated with IL-2, IL-6 or GM-CSF, respectively. The effect on apoptosis was observed. All four chemotherapeutic drugs inhibited the cell proliferation. DEX, VP16 or As(2)O(3), except ATRA, singly induced apoptosis of RMA cells. The DEX concentration of inducing apoptosis was reduced when it was added together with ATRA. IL-2, IL-6 and GM-CSF did not induce apoptosis when the cytokines were added to RMA separately, however, apoptosis could be induced by combination of IL-2 and IL-6. The cytokines facilitated the apoptotic action of chemotherapeutic drugs, the drug concentration for inducing apoptosis decreased and the time period of starting apoptosis shortened. The results demonstrated that there was synergistic effect of chemotherapeutic drugs and some cytokines for induction of apoptosis. It raised an experimental basis for combination of chemotherapeutic drugs and some cytokines, especially IL-2, in the treatment of malignant lymphoma.