Performance of frequency-modulated differential chaos shift keying (FM-DCSK) communication systems with timing synchronization error is investigated over the additive white Gaussian noise (AWGN) and the multipath channels in this paper.A multi-frame FM-DCSK system is proposed, and compared with the conventional one in terms of the effect of synchronization error on the bit error rate (BER) performance.Simulation results show that the proposed system can tolerate more synchronization error than the conventional one.

Detection, Synchronization, Channel Estimation and Capacity in UWB Sensor Networks using Compressed Sensing by Shao-Yuan Chen Chair: Wayne E. Stark Conventional receivers in ultrawideband (UWB) communication system usually require high sampling rate and thus consume much power. With compressed sensing (CS), the sampling rate can potentially be reduced. In this thesis, the performance of CS used in a UWB receiver is evaluated. Using a compressed sensing approach, the receiver consists of a number of analog correlators that process the received signal by projecting the received signal using random (or pseudo random) vectors. Considering the practical implementation in the receiver, the orthogonal Hadamard vectors in the correlators are adopted. After projection, the matching pursuit or basis pursuit is used to obtain the channel estimate. The recovered channel templates are then correlated with received signal to detect the transmitted information bits. The bit error rate (BER) performance of systems with different number of pilots, projection vectors, and fingers in a rake receiver is also evaluated. Moreover, the performance of different receivers and the effect of the finite bit resolution on channel estimation is investigated. It is shown that the sampling rate can be reduced significantly with only a slight degradation in performance when a compressed projection

The title compound, C18H24O2, was isolated from the leaves extract of Ficus carica L. The cyclo-hexane ring displays a chair conformation whereas the cyclo-hexa-1,4-diene ring adopts a flattened boat conformation with methyl C atoms at the prow and stern. In the crystal, mol-ecules are linked by weak C-H⋯O hydrogen bonds into supra-molecular chains propagated along the b-axis direction.

The asymmetric unit in the crystal of the title compound, C(15)H(22)O(3), contains two independent mol-ecules with similar structures. Each mol-ecule contains two six-membered rings and one five-membered ring. The five-membered ring displays an envelope conformation with the C atom linking the epoxy group as the flap, while the two six-membered rings show half-chair conformations. The two independent mol-ecules are linked by an O-H⋯O hydrogen bond. These dimers are further linked by O-H⋯O hydrogen bonds, forming supra-molecular chains running along the a axis.

Chlorophyll plays an important role in our everyday life.It is used not only as an annexing agent in medicinal and calleidic products but also as an unartificial food coloring agent.Chlorophyll and its ramifications have antioxidant and anti-mutation properties.China has abundant mulberry resources.The mulberry leaf is an excellent Chinese herb from ancient times to the present day and contains many kinds of bioactive components,in which the chlorophyll content is an important physiological index.However,the optimization of chlorophyll extraction from mulberry leaf by response surface methodology(RSM) has not been reported so far.Response surface methodology(RSM) is an effectively statistical technique for optimizing complex processes.The greatest advantage of RSM is that we need fewer experimental trials.It is widely used in optimizing variables of the extraction process,such as polysaccharides,alkaloids,phenolic compounds and protein from various materials.Box-Behnken design(BBD) is one of RSM,which only has three-levels(low,medium and high,coded as ?1,0 and +1),and needs fewer experiments.It's more efficient and easier to arrange and interpret experiments compared with others.This study focused on the optimal conditions of extracting mulberry leaf chlorophyll using RSM.The mixture of acetone and ethanol was used as extraction solvent.The chlorophyll content was calculated by Arnon's method.Extraction time,temperature,ratio of liquor to material and volume ratio of acetone to ethanol in extraction buffer were selected as the experiment factors according to the results of single factor experiments.The extracting parameters were optimized by RSM.Under the optimal extraction conditions described above,the confirmatory experiment was conducted.The single factor experiment results indicated that extraction time of 5 h(Fig.2),extraction temperature of 50 °C(Fig.3),ratio of liquor to material of 100∶1(Fig.4) and volume ratio of acetone to ethanol of 3∶1(Fig.1) were adopted for following experiment.Three independent variables were extraction time(C),extraction temperature(B) and ratio of liquor to material(A),according to the influences of the four factors on the chlorophyll productivity.The statistical analysis indicated that the three variables(Table 4) and the quadratic of extraction time(C) and ratio of liquor to material(A)(Fig.6) had significant effects on the yields,and there had the significant interaction effects between the variables of extraction temperature(B) and extraction time(C)(Fig.7).A high determination co-efficient mathematical model was gained that could be used to optimize chlorophyll extraction.Design Expert 7.1.6 software showed the optimal extraction condition was as follows: extraction time of 5.25 h,extraction temperature of 56.5 °C,ratio of liquor to material of 103∶1.Under the optimal extraction condition,the chlorophyll productivity was 5.376 mg/g,which was in consistent with the predicted value of 5.451 mg/g.In conclusion,the optimization of chlorophyll extraction by RSM is convenient,feasible and highly efficient.

The asymmetric unit in the crystal of the title compound, C15H22O3, contains two independent molecules with similar structures. Each molecule contains two six-membered rings and one five-membered ring. The five-membered ring displays an envelope conformation with the C atom linking the epoxy group as the flap, while the two six-membered rings show half-chair conformations. The two independent molecules are linked by an O—H...O hydrogen bond. These dimers are further linked by O—H...O hydrogen bonds, forming supramolecular chains running along the a axis.

This paper explores the application of compressive sensing (CS) for ultra wide band (UWB) communication. Channel estimation is an important aspect for any communication system and especially for UWB systems in order to appropriately collect the energy from the multipath channel. UWB generally requires a high sampling rate since the bandwidth is large. Channel estimation using CS is studied along with its impact on reducing the sampling rate for an ADC to reduce power. Practical issues regarding the effect of quantization on channel estimation are addressed and a hardware implementation for CS based on the Walsh-Hadamard transform (WHT) allowing sub-Nyquist sampling is proposed. To separate the effect of channel estimation with CS, the performance of the sub-Nyquist ADC is studied in a noiseless and multipath free channel and design decisions are discussed. Comparison with the Nyquist ADC shows that using the sub-Nyquist ADC reduce power by a factor of about 6×. For the proposed hardware, two receiver architectures based on matched filtering and filtering in the compressed domain (so-called “smashed filtering”) are studied. It is found that with a perfect channel smashed filtering performs better than matched filtering. Finally the effect of channel estimation on the proposed hardware is studied along with two different recovery algorithms namely basis pursuit and matching pursuit.

We consider the problem of channel estimation for ultrawideband communication in a multipath channel using compressed sensing techniques. The receiver when using a compressed sensing approach consists of a number of correlators processing the received signal with random projection vectors. The theory is based on Gaussian distributed vectors. We have compared the performance of using orthogonal Hadamard vectors with that of using a random projection matrix in compressed sensing procedures. We have also compared the performance of systems with different parameters for Gaussian and Hadamard projections vectors such as number of pilots, number of projection vectors and different coding schemes. Moreover, we are investigating different receiver structures resulting in different complexity of the receivers. We show that the sampling rate can be reduced significantly with only a slight degradation in the performance.

Many plants have devised methods of protecting themselves; one of such methods is the use of endophytic fungi. The antagonistic mechanism by endophytic fungi has rarely been revealed. This study investigated Chaetomium cupreum from Macleaya cordata (Willd.) R.Br Herb, which was identified by analysis of morphological characteristics and 28S rDNA sequence. The crystal isolated from culture broth of C. cupreum was identified by X-ray single crystal diffraction as 3,3',6,6'-tetrahydroxy-4,4'- dimethyl-1,1'-bi(cyclohexa-3,6-diene)-2,2',5,5'-tetraone (abbreviated as oosporein). We demonstrated that oosporein had antifungal activity against Rhizoctonia solani, Botrytis cinerea, Pytium ultimum , and antitumor activities against HL-60 and A549. It is toxic to Artemia salina . Keywords: Chaetomium cupreum , toxicity, antifungal activity, oosporein, antitumor African Journal of Biotechnology Vol. 9(36), pp. 5955-5961, 6 September, 2010

Frequency-modulated differential chaos shift keying (FM-DCSK) ultrawideband (UWB) communication systems convey information by transmitting ultrashort chaotic pulses (in the nanosecond scale). Since such pulses are ultrashort, timing offset may severely degrade the bit error rate (BER) performance. In this paper, a fast data-aided timing synchronization algorithm with low complexity is proposed for FM-DCSK UWB systems, which capitalizes on the excellent correlation characteristic of chaotic signals. Simulation results show that the BER performance of such systems is fairly close to that of perfect timing thanks to the proposed new algorithm. Moreover, the new algorithm requires less synchronization searching time and lower computational complexity than the conventional one for transmitted reference UWB systems existing in the current literature.

Eleven strains of endophytic fungi which habitat in an endangered, Chinese endemic medicinal plant, Dysosma pleiantha (Hance) Woodson, were isolated and tested for their cytotoxic activity using the brine shrimp lethality bioassay. Six isolates were found to exhibit some cytotoxic activity. Extracts of F1273, F1276, and F1280, which were identified as Trichoderma citrinoviride, Chaetomium globosum and Ascomycete sp., in particular, showed most potent activity with LC 50 values of 4.86, 7.71, and 14.88 μg/ml, respectively. These results indicate that endophytic fungi of Dysosma pleiantha could be a promising source for antitumour agents.

Timing synchronization is a crucial issue, especially in the ultra-wideband (UWB) systems, since the information conveying pulses are ultra-short. Frequency-modulated differential chaos shift keying (FM-DCSK) is an outstanding modulation technology that has been proven to have a superior capability of anti-multipath fading over multipath fading channels. In this paper, both theoretical analysis and simulation results are presented with regard to the bit error rate (BER) performance of the FM-DCSK UWB communication systems with timing error. It is shown that the simulation results are in accordance with the theoretical analysis, and the timing error induced by later timing causes much more seriously BER performance degradation than that induced by earlier timing.

An adaptive optics system for the retina imaging is introduced in the paper. It can be applied to the eye with myopia from 0 to 6 diopters without any adjustment of the system. A high-resolution liquid crystal on silicon (LCOS) device is used as the wave-front corrector. The aberration is detected by a Shack–Harmann wave-front sensor (HASO) that has a Root Mean Square (RMS) measurement accuracy of λ/100 (λ=0.633μm). And an equivalent scale model eye is constructed with a short focal length lens (∼18mm) and a diffuse reflection object (paper screen) as the retina. By changing the distance between the paper screen and the lens, we simulate the eye with larger diopters than 5 and the depth of field. The RMS value both before and after correction is obtained by the wave-front sensor. After correction, the system reaches the diffraction-limited resolution approximately 230cycles/mm at the object space. It is proved that if the myopia is smaller than 6 diopters and the depth of field is between −40 and +50mm, the system can correct the aberration very well.

The title compound, C16H16O8, is a potent nonspecific phyto­toxin. The crystal structure is the average of two tauto­mers, 5,6,7,9,10-penta­hydr­oxy-2-meth­oxy-7-methyl-1,4,5,6,7,8-hexa­hydro­anthracene-1,4-dione and 1,4,5,6,7-pentahydr­oxy-2-meth­­oxy-7-methyl-5,6,7,8,9,10-hexa­hydro­anthracene-9,10-di­one. The cyclo­hexene rings in both tautomers display a half-chair conformation. An extensive O—H⋯O hydrogen-bonding network is present in the crystal structure.

Many endophytic fungi are known to protect plants from plant pathogens, but the antagonistic mechanism has rarely been revealed. In this study, we wished to learn whether an endophytic Aspergillus sp., isolated from Taxus mairei, would indeed produce bioactive components, and if so whether (a) they would antagonize plant pathogenic fungi; and (b) whether this Aspergillus sp. would produce the compound also under conditions of confrontation with these fungi. The endophytic fungal strain from T. mairei was identified as Aspergillus clavatonanicus by analysis of morphological characteristics and the sequence of the internal transcribed spacers (ITS rDNA) of rDNA. When grown in surface culture, the fungus produced clavatol (2′,4′-dihydroxy-3′,5′-dimethylacetophenone) and patulin (2-hydroxy-3,7-dioxabicyclo [4.3.0]nona-5,9-dien-8-one), as shown by shown by NMR, MS, X-ray, and EI-MS analysis. Both exhibited inhibitory activity in vitro against several plant pathogenic fungi, i.e., Botrytis cinerea, Didymella bryoniae, Fusarium oxysporum f. sp. cucumerinum, Rhizoctonia solani, and Pythium ultimum. During confrontation with P. ultimum, A. clavatonanicus antagonized its growth of P. ultimum, and both clavatol as well as patulin were formed as the only bioactive components, albeit with different kinetics. We conclude that A. clavatonanicus produces clavatol and patulin, and that these two polyketides may be involved in the protection of T. mairei against attack by plant pathogens by this Aspergillus sp.

In the title natural product, C17H24O4, which is a very potent inhibitor of protein synthesis in mammalian cells, the five-membered ring displays an envelope conformation, whereas the two six-membered rings show different conformations, viz. chair and half-chair.

In the title natural product, C17H24O4, which is a very potent inhibitor of protein synthesis in mammalian cells, the five-membered ring displays an envelope conformation, whereas the two six-membered rings show different conformations, viz. chair and half-chair.

Fermentation broth of endophytic fungus Trichoderma taxi ZJUF0986 has high antifungal activity to the common 15 species of phytopathogenic fungi. Three bioactive metabolites I, II and III were obtained by extracted with petroleum ether, ethyl acetate and n-butanol and subsequent silica gel column chromatography and preparative HPLC. Among them, compound I, the main metabolite, has strong broad-spectrum antifungal activity, especially to Botrytis cinerea, Rhizoctonia solani and Sclerotinia sclerotiorum with IC50 1.06, 1.08 and 1.13 mg/L, respectively.