bluuebunny/crossref_metadata_2025 huggingface dataset:
Intelsat planning and modelling software in support of IDR
Authors: Duesing Richard W. , Kelinsky Martin J.
Published: July 2007

In order to plan for and integrate intermediate data rate (IDR) carriers into the INTELSAT newtork, while achieving quality service with efficient use of resources, operational planning tools and transmission system models are necessary. These computer software tools and models, which have evolved and grown in parallel with the INTELSAT network, comprise numerous applications on various types of computers, including mainframe, mini and personal computer systems. This paper presents an overview of the major planning and modelling software models used at INTELSAT in support of the use of IDR digital carriers within the INTELSAT system.
IDR digital modem terminal equipment
Authors: Otani S. , Goto Y.
Published: July 2007

This paper describes NEC's latest IDR digital modulator and demodulator equipment, and the IDR digital modem terminal configuration with its associated 1:N redundancy switch‐over and monitor and control units, to comply with the current INTELSAT specification IESS‐308 (Rev. 4).
A supplier's response to IDR
Authors: Entenman A. , Hirschman H.
Published: July 2007

This paper discusses the evolutionary development of the IDR series of modem products from 1986 to the present. User‐friendly features are stressed. Market forces and the availability of complex custom VLSI logic shape the design of the high performance modem products of the future.
A framing unit for all services
Authors: Mills Nigel
Published: July 2007

This article describes the P1300 IDR and IBS framing unit, designed and produced by Paradise Datacom to accompany the new generation of all‐digital satellite modems currently emerging from the modem manufacturers.

The combination of framing unit and all‐digital modem gives a very flexible product, capable of fulfilling the requirements of both the IDR and IBS services, and with the entirely software controlled architecture of the framing unit, it allows for future services as yet undefined.
Understanding signals from glonass navigation satellites
Authors: Dale S. A. , Daly P. , Kitching I. D.
Published: July 2007

In late 1986 details of the radio‐frequency signal structure currently employed by the pre‐operational GLONASS satellite navigation system were revealed by the Satellite Communications Group at Leeds University. Since then further investigation has resulted in a successful interpretation of most of the data message transmitted on the civil code, sufficient to allow the design and construction of a GLONASS receiver capable of the same level of performance as can now be achieved with NAVSTAR GPS. Details of the message content relating to location of GLONASS satellites for the purposes of position‐fixing and time‐referencing are presented for the first time.
Prediction of rain effects on earth‐space communication links operating in the 10 to 35 GHZ frequency range
Authors: Stutzman Warren L.
Published: July 2007

This paper reviews the effects of precipitation on earth‐space communication links operating the 10 to 35 GHz frequency range. Emphasis is on the quantitative prediction of rain attenuation and depolarization. Discussions centre on the models developed at Virginia Tech. Comments on other models are included as well as literature references to key works. Also included is the system level modelling for dual polarized communication systems with techniques for calculating antenna and propagation medium effects. Simple models for the calculation of average annual attenuation and cross‐polarization discrimination (XPD) are presented. Calculation of worst month statistics are also presented.
Some new hybrid ARQ techniques for high error rate conditions
Authors: Benelli G.
Published: July 2007

Some new hybrid ARQ schemes for error control in communication systems are presented in which redundancy, achieved by retransmission of a code word, is exploited to facilitate correct code‐word recovery. In the first two techniques, applicable to cases in which a code word detected in error is retransmitted several times consecutively, an error‐correcting code is used in conjunction with a normal ARQ code to enhance performance even at high error rates. These two techniques have been modified to allow application to protocols in which only one copy is sent each time a code word must be transmitted. Theoretical analysis of the protocols shows that these techniques outperform similar ARQ schemes, particularly for high error rates.
Error correcting codes for fast frequency‐hopped MFSK spread‐spectrum satellite communications under worst case jamming
Authors: Wang Q. , Guliver T. A. , Bhargava V. K. , Felstead E. B.
Published: July 2007

Spread‐spectrum techniques such as frequency hopping (FH) have been used to reduce the vulnerability of satellite communications to jamming. In such a system, error correcting (EC) codes play an essential role. Thus a knowledge of the performance of various EC codes is necessary in order to choose an EC code and related system parameters in the design of an anti‐jam system, this paper examines the performance of various types of error correcting codes under worst case partial band noise jamming and worst case multitone jamming using fast frequency‐hopped, non‐coherent M‐ary frequency‐shift keying (NCMFSK) with optimum diversity. A comprehensive study including convolutional codes, binary and non‐binary block codes and concatenated codes has been conducted. This paper presents bit error rate (BER) performances of various error correcting codes. New candidate codes with superior anti‐jam performance are identified.
An anti‐jam packet data satellite link
Authors: Fairhurst Godred , Spracklen Tim
Published: July 2007

With the advent of the open systems interconnection philosophy, interworking between satellite and ground‐based data networks is rapidly becoming important. X.25 LAPB/HDLC is an important standard in this field. It defines a connection between two data switching nodes. This paper examines how a low capacity (∼kb/s) anti‐jam (A/J) satellite circuit may carry a X.25 LAPB/HDLC data link.

It has been shown that use of an unmodified A/J modem employing convolutional coding gives a particularly poor performance in the presence of jamming. A study of the properties which govern the performance of a packet link has led to some recommendations for a special ‘packet mode’ for anti‐jam modems and to some suggested extensions to the data link protocol. These recommendations have been implemented in a simulator and this has revealed a performance far superior to an unmodified system. The recommendations are being implemented in a trials system, developed at the University of Aberdeen, for RSRE Defford.
An ARQ/FEC coding scheme for land mobile communication
Authors: Ferebee I. C. , Tait D. J. , Taylor D. H.
Published: July 2007

This paper describes the development of a laboratory test unit that implements a new Type I/II ARQ scheme for use on a land mobile forward satellite link. Investigation of channel characteristics showed that it was possible to use convolutional coding to combat random errors, but it was also necessary to employ an ARQ scheme in order to overcome fades due to signal blockage.

The hardware development used commercial 68000‐based VME cards as well as special‐purpose cards to perform the functions of Viterbi decoding and packet synchronization.

Results are presented for the hardware operating with Gaussian noise as time limitations excluded the use of satellite fading simulation. In order to ensure a high degree of data integrity error detection was applied to the data packets such that a residual error rate of less than 10−11 should result. This was not able to be verified due to the limited time. However, long term tests did indicate that an error rate less than 10−8 was achieved.
Algebraic properties of BCH codes useful for decoding
Authors: Da Rocha Valdemar C. , Honary Bahram K. , Bate Steve D.
Published: July 2007

In this paper theorems are presented which allow the simplified decoding of (n, k, δ) BCH codes in certain cases of practical interest. Such results are in a way implicit in the theory of BCH codes, but so far have not appeared explicitly in the literature. It is shown that any t0 errors, 1 ⩽ t0 ⩽ δ‐1, can be detected by using any set of only t0 consecutive coefficients of the syndrome polynomial. The correction of any t0 errors, 1 ⩽ t0 ⩽ [(δ‐1)/2], can be performed by using any set of 2t0 consecutive coefficients of the syndrome polynomial, where [x] means the integer part of x. Similar results are derived for punctured BCH codes. In this case sets of t0 or 2t0 consecutive coefficients, respectively, for detecting or correcting t0 errors, are selected from the δ‐1‐p higher‐order coefficients of the modified syndrome polynomial, where p is the number of digits punctured from a code word. These results hold true even when the punctured digits are not consecutive.
Review of saw devices and their signal processing applications in space communications
Authors: Ananasso Fulvio
Published: July 2007

An increasing number of advanced signal processing techniques are being investigated in satellite communications systems as the ground and space segments require more and more sophisticated, light‐weight, low‐power‐consumption and cost‐effective equipment.

RF signal processing techniques based on surface acoustic wave (SAW) devices can be suitably exploited in these systems, constituting a valid alternative to digital baseband processing.

This paper aims at presenting the most recent applications of SAW devices to RF signal processing in satellite communication systems. They span the frequency range from about 10 MHz to 10 GHz. Interaction of SAWs with laser beams is also illustrated.
Routeing and filtering in the ETS‐V transponder for mobile communication experiments
Authors: Kondo K. , Hashimoto Y. , Ide T.
Published: July 2007

The Japanese spacecraft ETS‐V implemented an experimental mobile satellite communication system via a transponder called AMEX (aeronautical maritime experimental transponder). L‐band was used for the mobile link and C‐band for the feeder link. For the L‐band two‐beam system routeing and filtering were performed through 12 SAW filters and four switches in the IF part. The effective frequency allocation plan was obtained considering the features of the links used and the characteristics of SAW filters. The filtering to prevent EMC problems was also studied for AMEX, which handles high‐ and low‐level signals simultaneously. AMEX shows good performance in orbit and is being used for a variety of mobile communication experiments by many organizations including the Communications Research Laboratory.
Saw devices: Space qualification and reliability issues
Authors: Roush M. , Maynes J.
Published: July 2007

This paper summarizes the current U.S. military space qualification requirements as well as other qualification standards required for SAW components. A new testing procedure is proposed which will significantly cut the qualification costs while still providing a reliable product for space applications.
Signal suppression effects in an ideal hard‐limiter for the many‐carrier case
Authors: Comparetto G. M.
Published: July 2007

An analytical expression, previously derived in a companion paper published in Volume 7, Issue No. 1 of the International Journal of Satellite Communications (pp. 3–6), was used to generate signal suppression data for 3, 5, 10, 20, 40 and 55 input signal scenarios in the presence of Gaussian noise assuming an ideal hard‐limiter for a wide range of input signal ratios. Additionally, the signal suppression effect has been quantified for up to 200 input signals with input SNRs of ∞, 6 dB and 0 dB for the case in which a single higher‐power input signal exists in the presence of lower, equal‐powered signals. The data support the argument that the signal suppression effect is significantly reduced as the number of input signals is increased for the scenarios investigated. Also, the generated data show that the signal suppression effect decreases asymptotically to a value less than 1 dB for the case of a single higher‐power signal in the presence of varying degrees of input Gaussian noise and up to 200 total signals. Finally, a Gaussian approximation of the input signal ensemble was verified for the full range of input signal sets investigated.
A unified statistical rain‐attenuation model for communication link fade predictions and optimal stochastic fade control design using a location‐dependent rain‐statistics database
Authors: Manning Robert M.
Published: July 2007

The simultaneous demand for increased capacity of communication satellite channels and the demand for such systems to be designed and operate within increasingly stringent economic constraints places severe requirements on the ability to predict, achieve and maintain the reliable operation of these satellite links throughout the United States. The operating frequencies of satellite links are such that the occurrence of rain anywhere along the link will induce attenuation of the signal and is the major source of link reliability degradation. A unified model is presented that describes the relevant static and dynamic statistics of attenuation on an arbitrarily specified satellite link for any location for which there is a long‐term data record of rainfall statistics. In addition to providing accurate, location‐dependent statistical predictions of the reliability of satellite links, the generality of the model also establishes a basis for the design of optimal stochastic control algorithms used to mitigate the deleterious effects of attenuation and thus maintain link reliability. The rain statistics that are required to characterize the location of interest are derived from extreme value statistics theory. A rain‐statistics database has been compiled that allows one to apply the model anywhere in the continental United States with the resolution of 0.5° in latitude and longitude. Comparison of the model predictions is made with available experimental observations and agreement is found to be quite good.
Adaptive modulation as a fade countermeasure. An olympus experiment
Authors: Filip M. , Vilar E.
Published: July 2007

With the launch of the European Space Agency's Olympus‐1 satellite, a whole new era of communication experiments in the 20/30 GHz bands will start. Of particular interest will be those experiments concerned with fade countermeasures for the very small aperture terminals (VSATs). Portsmouth Polytechnic's experiment will focus on adaptive modulation as a type of fade countermeasure, and this paper introduces and describes the whole concept. Based on the assumption that the performance of a VSAT operating at 20/30 GHz band will be affected to a major extent by amplitude scintillations and rain fading, the performance of a range of combinations of earth‐station power amplifier and antenna characteristics is presented. An adaptive multi‐phase shift keying technique is then compared with conventional systems in terms of availability and data throughput. It is shown that such a fade countermeasure contributes to increasing both the overall system availability and the total data throughput of a digital communication system, while the inevitable reductions in data rate occur smoothly.
Influence of signal constellation on the performance of 16‐ary deqam transmission through a regenerative satellite link
Authors: Cheung S. W.
Published: July 2007

The paper presents the results of a series of computer‐simulation tests to determine the effects of non‐linear distortion and adjacent channel interference (ACI), on the tolerance to additive white Gaussian noise (AWGN) of a digital satellite modem. The modem transmits a 16‐ary differentially encoded quadrature‐amplitude‐modulated (16‐ary DEQAM) signal over a regenerative satellite link, where the high‐power amplifier (HPA) at the transmitter may introduce AM‐AM and AM‐PM conversion effects into the 16‐ary DEQAM signal. Three signal constellations are used at the transmitter, namely (1) a conventional 16‐ary DEQAM signal constellation, (2) a predistorted 16‐ary DEQAM signal constellation and (3) a prerotated 16‐ary DEQAM signal constellation. An equivalent baseband model of the transmission system is used to determine the performance of the modem under the various conditions studied, and the results are used to select the preferred modem design.
Optimization of satellite orbital positions using an objective function related to aggregate interference levels
Authors: Fortes José Mauro P. , Ribeirete Ericson C.
Published: July 2007

An optimization method to identify satellite orbital positions in an interference environment is proposed. Its objective function is related to the aggregate interference affecting each satellite network and is defined in terms of the isolation concept. The method is applied to two specific situations, and the resulting solutions are compared to those obtained when a minimax technique is used in a tentative manner to equalize interference. Results indicate that the use of the minimax approach may not be adequate.
The measurement of rainfall in Papua New Guinea, and its effect on microwave propagation
Authors: Harris D. J. , Milner E.
Published: July 2007

A programme of measurement on rainfall characteristics has been commenced at Lae, Papua New Guinea, using pluviometers, tipping bucket rain‐gauges and a rapid‐response rain‐gauge. Pluviographs extending over many years have been analysed by computer to give data on general rain conditions and on the probability of rainfall intensity exceeding particular levels. The resultant distribution compares well with the empirical formula of Moupfouma, and corresponding parameters are given. Simultaneous measurements are also being made on the 12 GHz signal level variation from the Aussat television signal, and on the attenuation on a 10 GHz terrestrial link.
Prediction of attenuation due to rain: Characteristics of the 0°C isotherm in temperate and tropical climates
Authors: Ajayi Gabriel Olarere , Barbaliscia Francesco
Published: July 2007

A detailed investigation of the vertical structure of rain and of the characteristics of the 0°C isotherm height in both rainy and non‐rainy conditions has been carried out in connection with the prediction of rain attenuation on Earth‐satellite links. Radiosonde data have been analysed for eight and nine locations in the southern and northern hemispheres, respectively. The temporal, latitudinal variations and the relationship between the 0°C isotherm height and ground meteorological parameters such as rainfall, temperature and relative humidity, are reported. The equivalent rain height measured along the Earth‐satellite link is compared with the heights obtained from meteorological data.
Ku‐band slant‐path radiometric measurements at three locations in Brazil
Authors: Pontes M. S. , Mello L. A. R. Silva , Migliora C. G. S.
Published: July 2007

This paper presents results of the 12 GHz propagation experiment that is being conducted in Brazil. The data obtained are useful to investigate the impairment due to rain attenuation in satellite links operating in tropical and equatorial climates. Radiometric sky noise temperature and rainfall rate are being measured at three locations. At one location, site diversity measurements are also being conducted. Cumulative distributions of sky‐noise temperature, equivalent attenuation and rainfall rate at each site are presented together with worst‐month statistics. Also, the joint‐probability distribution of equivalent attenuation at the diversity sites is shown. Finally, the measured probability distributions of attenuation are compared to those obtained from the measured rainfall rate distributions, using prediction models.
Operating aspects of new LRE/DSI DCMEs
Authors: Campanella S. Joseph , Reiser Jack H.
Published: July 2007

Digital circuit multiplication equipment (DCME) that uses a combination of talk‐spurt interpolation and low‐rate encoding (32 kb/s ADPCM rather than the traditional 64 kb/s PCM) is about to be introduced in operating satellite systems. These DCMEs possess a number of important features that have been introduced to achieve a suitable balance between high channel multiplication ratios and high quality voice and data transmission. The methods used to accomplish this are generation of overload channels to virtually eliminate talk‐spurt clipping, establishing a limit on the fraction of channels that undergo bit reduction by use of dynamic load control, automatic routeing of trunks carrying in‐band data signals to non‐interpolated bearer channels, use of a bit‐bank approach to provide five‐bits/sample ADPCM coding for in‐band data channels and rotation of the server channels among the talk‐spurts to spread the degradation caused by bit reduction uniformly across all talk‐spurts. This paper analyses the performance of the DCME embodying the above features, and presents results in terms of the input‐to‐output channel multiplication ratio (CMR) as a function of the number of bearer channels (over a range from 4 to 61 bearer channels) and the number of input channels carrying in‐band data. Extending the operation range down to as few as four bearer channels permits evaluation of the effectiveness of multiclique operation. In addition, the influence on CMR of (a) non‐bit‐bank operation, that would be possible if an ADPCM codec capable of supporting in‐band data carriers at four‐bits/sample were used, and (b) a short‐hangover‐time speech detector are examined. Use of hangover times less than 30 ms are shown to achieve a CMR of as great as 3.3: 1.
Intelsat digital circuit multiplication equipment
Authors: Forcina G. , Oei W. S. , Oishi T. , Phiel J. F.
Published: July 2007

This paper illustrates the salient features and the technical structure of the digital circuit multiplication equipment (DCME) specified by INTELSAT. First, an overview of the basic DCME requirements is presented and the network applications of the DCME are discussed. Then a systematic and detailed description of the body of the technical specification is provided. Finally, the complementary activities that followed the completion of the specification are briefly addressed.
New trends in digital circuit multiplication technology
Authors: Piasetzky J.
Published: July 2007

This paper discusses the achievements and the unsolved problems of the first generation of Digital Circuit Multiplication Systems (DCMS)

DCMS is an abbreviation for Digital Circuit Multiplication Systems. DCME is an abbreviation for Digital Channel Multiplication Equipment. Both refer to the same technique of combining digital speech interpolation and low rate encoding.

. The following summarizes proposed improvements in DCMS technology. A major improvement in DCMS gain may be achieved by implementation of facsimile demodulation. The design considerations of this technique are discussed. The CCITT activities on standardization of a 16 kb/s speech coding algorithm are reviewed. In order to adapt this algorithm to implementation in a DCMS, the operation of the algorithm has been modified to enable variable bit rate operation at rates between 12·8 and 24 kb/s. The implementation of such an algorithm in DCMS will further increase the overall compression gain. The first generation of DCMS has been implemented mainly on heavy traffic routes. A DCMS terminal which is optimized for operation on ‘thin’, or smaller, routes, using an IDR link operating at 512 kb/s, is described. Tandem operation of DCMS is becoming an increasingly important consideration on both international and national routes. The accumulation of qdu's (quantization distortion units) when two pairs of DCME/S terminals are operated in tandem can be avoided by an arrangement without ADPCM decoding/encoding in the transit terminals so that the ADPCM decoding is carried out only at the final destination DCMS terminal.
Circuit multiplication equipment
Authors: Bareyt C. , Karas A. , Salomon J. , Aboaf P.
Published: July 2007

This paper discusses the main issues relating to the configuration and equipment which are to be provided in earth‐stations for implementing satellite links with digital circuit multiplication (DCM). Such an implementation is possible using either FDMA/TDM/PSK (continuous) or TDMA/PSK (burst mode) carriers. The main accent will be put in the paper on earth‐stations operating with FMDA/TDM/PSK carriers (called IDR carriers by INTELSAT).

As regards the RF/IF subsystem, it is shown that IDR and TDMA are very effective in terms of earth‐station equipment as compared with conventional FDM/FM operation.

As regards the communication subsystem—independently of the DCM equipment proper—a compact terminal, integrating all the signal processing and baseband functions is described.
The effect of channel errors on the performance of a contention‐based tdma protocol
Authors: Liang Lung‐Sing , Chang Jin‐Fu
Published: July 2007

A previously proposed contention‐based TDMA protocol is modified to remain operational for a channel which is not noise free. The protocol is a mixture of random accessing and time division multiplexing and is suitable for data transmission through a channel which is characterized by non‐negligible round‐trip signal propagation delay. The effect of channel errors on the performance of the protocol is studied. Through numerical calculation it is observed that for the bit‐error‐rates encountered in practice the protocol remains stable. When the channel becomes rather noisy, error correcting codes can be imbedded to improve the performance. The validity of analysis has been verified by computer simulation.
Analysis and correction techniques of doppler shift for non‐geosynchronous communication satellites
Authors: Vilar Enric , Austin John
Published: July 2007

A theoretical and experimental study of Doppler correction strategies for elliptical orbit satellite communications is presented. Exact analytical expressions for Doppler shift and elevation angle as a function of perigee time of the ground‐station are also presented. It is shown that for a 63° inclined Molnya orbit and a U.K. observer, the Doppler shift remains below about ± 10 ppm and the Doppler rate below about 6 × 10−4 ppm/s. Various strategies for continuous Doppler correction of the on‐board oscillators are reviewed or proposed. These include a closed loop ground–satellite system and an on‐board programmable correction approach. Two detailed theoretical and experimental studies of on‐board encoded Doppler correction distribution systems are presented in the context of the UK CERS/TSAT mobile communications experiment. A frequency lock system which requires the distribution of only one signal and a phase‐lock system requiring a master reference and the time‐variant code word are described. Numerical values for a 1·5 GHz carrier are presented throughout but can be scaled to other frequencies.
Sperm count as a surrogate endpoint for male fertility control
Authors: Benda Norbert , Gerlinger Christoph
Published: July 2007

When assessing the effectiveness of a hormonal method of fertility control in men, the classical approach used for the assessment of hormonal contraceptives in women, by estimating the pregnancy rate or using a life‐table analysis for the time to pregnancy, is difficult to apply in a clinical development program. The main reasons are the dissociation of the treated unit, i.e. the man, and the observed unit, i.e. his female partner, the high variability in the frequency of male intercourse, the logistical cost and ethical concerns related to the monitoring of the trial. A reasonable surrogate endpoint of the definite endpoint time to pregnancy is sperm count. In addition to the avoidance of the mentioned problems, trials that compare different treatments are possible with reasonable sample sizes, and study duration can be shorter. However, current products do not suppress sperm production to 100 per cent in all men and the sperm count is only observed with measurement error. Complete azoospermia might not be necessary in order to achieve an
acceptable failure rate compared with other forms of male fertility control. Therefore, the use of sperm count as a surrogate endpoint must rely on the results of a previous trial in which both the definitive‐ and surrogate‐endpoint results were assessed. The paper discusses different estimation functions of the mean pregnancy rate (corresponding to the cumulative hazard) that are based on the results of sperm count trial and a previous trial in which both sperm count and time to pregnancy were assessed, as well as the underlying assumptions. Sample size estimations are given for pregnancy rate estimation with a given precision. Copyright © 2007 John Wiley & Sons, Ltd.
Pilot‐plant fractionation of cottonseed: V. A preliminary cost study
Authors: Persell R. M. , Vix H. L. E. , Reuther C. G. , Pollard E. F.
Published: July 2007

A preliminary cost study was made of a combination screw‐press extraction‐fractionation plant. The economic advantage of the combination plant over the screw‐press operation as shown here is small in comparison with the large additional investment required for the combination plant. The present value of the combination process lies in the production of two new products, a purified high‐protein meal and a concentrated pigment gland fraction and in the possibility of producing a high‐grade oil as the removal of the whole pigment gland prevents the pigment material from coming in contact with the oil. Pilot‐plant work under way indicates improvements in the process such as a higher recovery of the meal as purified meal. The development of additional and more profitable uses for the products would increase their value and provide a broader and more stable market for cottonseed.
Comparison of solvent extraction characteristics of rice bran pretreated by hot air drying, steam cooking and extrusion
Authors: Kim C. J. , Byun S. M. , Cheigh H. S. , Kwon T. W.
Published: July 2007

Rice bran was pretreated by hot air drying, steam cooking and extrusion before solvent extraction of oil. The extractions were conducted in a glass column percolator (i.d. 120 mm), packed to a depth of 90 cm and using n‐hexane at 60 C and gravity feed. Fines (defined as<0.5 mm) in raw bran were significantly reduced by steam cooking and extrusion treatments. Extruded rice bran (ERB) was pelletized and had a bulk density 1.5 times higher than the other products. Regardless of the weight of bran loaded in the percolator, extraction time to reach 1% residual oil was decreased in the order of 116, 67 and 10 min for hot air‐dried rice bran (HARB), steam‐cooked rice bran (SRB) and ERB, respectively. This was due to increases in the percolation rate of SRB by 2 times and by 9 times for ERB compared to HARB. The solvent/bran ratio for extraction to 1% residual oil was decreased by nearly half, from 3.18 for HARB and 3.12 for SRB to 1.77 for ERB.
Analysis of milkfat by HPLC
Authors: Frede Ekkehart , Thiele Herbert
Published: July 2007

A routine method for HPLC analysis of milkfat has been developed, which takes into account the specific phenomena of this complex and far‐ranging system of triglycerides. The usual amount of injection of 1 mg has been reduced to 30 or 10 µg of fat. By this the composition of the mobile phase (acetone:acetonitrile, 35/65) and the temperature of the column (Nucleosil C18‐5 µ, 15 cm + Microspher C18‐3µ, 10 cm, in series, T=30–35 C) could be adjusted to a relatively high selectivity without inducing the high‐melting fat components to crystallize on the column. A further advantage resulting from this consisted in permitting the eluent to be recycled over long periods of time. The extremely low amounts of samples necessitated a highly sensitive detection (Δn=5 × 10−7 RI units full scale deflection) which could be realized by an interferential refractometer in connection with a thermostat to keep up a stable temperature of the whole HPLC system (ΔT<0,005 K). By this it was possible to separate milkfat into 45 to 50 different types of triglycerides. By comparing soft and hard milkfats and fractions of milkfats, every fourth peak, starting with C 42, could be attributed to saturated triglycerides; apart from this, easily recognizable qualitative features appearing in the chromatograms permitted conclusions about the feeding regimen and energy supply of the cattle. Furthermore, due to the high stability of separating conditions achieved and due to computer software developed for this purpose it was possible to obtain and compare a large number of chromatograms under the same conditions.
Lipid composition of coconut cake oil
Authors: Gopalakrishnan N. , Narayanan C. S. , Mathew A. G. , Arumughan C.
Published: July 2007

Lipid classes and fatty acids were analyzed in expeller and rotary extracted coconut oils and corresponding solvent extracted cake oils. Triacylglycerols (84.0 to 93.1%); 1,2 diacylglycerols (1.5 to 5.1%); 1,3 diacylglycerols (1.2 to 2.1%); monoacylglycerols (1.0 to 7.0%); free fatty acids (1.0 to 2.6%); phospholipids (0.03 to 0.4%) and glycolipids (0.2 to 0.35%) were present in these oils. Fatty acid composition of triacylglycerols, phospholipids and glycolipids resembled each other and differed from those of 1,2 and 1,3 diacylglycerols which in turn were similar.
Rapid quantitative HPLC analysis of polyethoxylated nonionics
Authors: Yoshimura Haruo , Sugiyama Toyoki , Nagai Toshio
Published: July 2007

A rapid quantitative HPLC method for alkylethoxylate was studied. According to theoretical considerations based on the plate theory, it was expected that alkylethoxylate could be separated to give one chromatographic peak regardless of the carbon number distribution in hydrophobic moiety and adducted number of ethylene oxide by using a back flush technique.

As expected, a single peak with good shape for quantitative use was obtained. Quantitative analytical methods were developed for (i) unconverted alkylethoxylate in alkylethoxysulfate, and (ii) alkylethoxylate nonionics formulated with anionics in detergents.

As anionics generally were retained less than alkylethoxylates under the condition in which ODS‐column and a methanolic aqueous eluent were used, a single peak for alkylethoxylates was obtained by back flushing after anionics were eluted from the column. In the case of a heavy duty detergent, an additional column was needed to remove the interferences owing to co‐existing more retained species.
Time series modelling and trophic interactions: rainfall, vegetation and ungulate dynamics
Authors: Månsson Lena , Ripa Jörgen , Lundberg Per
Published: July 2007

Time series analysis is a tool that is now commonly used when analysing the states of natural populations. This is a particularly complicated task for ungulates, since the data involved usually contain large observation errors and span short periods of time relative to the species’ life expectancies. Here we develop a method that expands on previous analyses, combining statistical state space modelling with biological mechanistic modelling. This enables biological interpretability of the statistical parameters. We used this method to analyse African ungulate census data, and it revealed some clarifying patterns. The dynamics of one group of species were generally independent of density and strongly affected by rainfall, while the other species were governed by a delayed density dependence and were relatively unaffected by rainfall variability. Dry season rainfall was more influential than wet season rainfall, which can be interpreted as indicating that adult survival is more important than recruitment in governing ungulate dynamics.
Determination of the fatty acid composition of canola, flax, and solin by near‐infrared spectroscopy
Authors: Siemens Bert J. , Daun James K.
Published: July 2007

The ability to rapidly measure key FA in oilseed crops would assist in the administration of identity‐preserved systems in the grain‐handling system or in selection systems in plant‐breeding programs. This study shows near‐infrared reflectance (NIR) spectroscopy to be a reliable method of determining FA composition in canola, flax, and solin (low‐linolenic flax), for oleic acid, linoleic acid, linolenic acid, and iodine value, and to a limited extent for saturated fat. Samples from cultivar trials, harvest surveys, and export shipments were scanned on a NIRSystems 6500 spectrometer (Silver Spring, MD), and calibrations were developed and optimized using modified partial least squares. SE of prediction results for prediction sets of canola, flax, and solin, were, respectively: oleic acid (0.77, 1.03, 0.62%); linoleic acid (0.71, 1.20, 0.37%); linolenic acid (0.42, 0.62, 0.08%); saturated FA (0.23, 0.39, 0.31%); and iodine value (0.63, 0.95, 0.43 units).
Temperature‐dependent kinematic viscosity of selected biodiesel fuels and blends with diesel fuel
Authors: Yuan Wenqiao , Hansen Alan C. , Zhang Qin , Tan Zhongchao
Published: July 2007

The kinematic viscosities of four biodiesel fuels—two natural soybean oil methyl esters, one genetically modified soybean oil methyl ester, and one yellow grease methyl ester—and their 75, 50, and 25% blends with No. 2 diesel fuel were measured in the temperature range from 20 to 100°C in steps of 20°C. The measurements indicated that all these fuels had viscosity‐temperature relationships similar to No. 2 diesel fuel, which followed the Vogel equation as expected. A weighted semilog blending equation was developed in which the mass‐based kinematic viscosity of the individual components was used to compute the mixture viscosity. A weight factor of 1.08 was applied to biodiesel fuel to account for its effect on the mixture viscosity. The average absolute deviation achieved with this method was 2.1%, which was better than the uncorrected mass average blending equation that had an average absolute deviation of 4.5%. The relationship between the viscosity and the specific gravity of biodiesel fuels was studied. A method that could estimate the viscosity from the specific gravity of biodiesel fuel was developed. The average absolute deviation for all the samples using this method was 2.7%. The accuracy of this method was comparable to the weighted mass‐based semilog blending equation.
Physical properties of oleochemical carbonates
Authors: Kenar James A. , Knothe Gerhard , Dunn Robert O. , Ryan Thomas W. , Matheaus Andrew
Published: July 2007

Carbonates are a class of compounds that have recently found increasing interest in commercial applications owing to their physical properties and relatively straightforward synthesis. In this work, physical and fuel properties of five straight‐chain C17–39 and three branched C17–33 oleochemical carbonates were investigated. These properties included cetane number (CN), low‐temperature properties, (kinematic) viscosity, lubricity, and surface tension. The carbonates studied had CN ranging from 47 to 107 depending on carbon chain length and branching. For the same number of carbons, the CN of carbonates were lower than those of FA alkyl esters owing to interruption of the CH2 chain by the carbonate moiety. Kinematic viscosities at 40°C ranged from 4.9 to 22.6 mm2/s whereas m.p. ranged from +3 to below −50°C depending on the carbonate structure. High‐frequency reciprocating rig testing showed the neat carbonates to have acceptable lubricity that improved as chain length increased. Finally, the carbonate's ability to influence cold‐flow properties in biodiesel (methyl soyate) and lubricity in low‐lubricity ultra‐low sulfur diesel were examined. The carbonates studied did not significantly affect cold flow or lubricity properties at concentrations up to 10,000 ppm (1 wt%). The properties of the carbonates resemble those of fatty alkyl esters with similar trends resulting from compound structure.
Nociceptor sensitization to mechanical and thermal stimuli in pig skin in vivo
Authors: Rukwied Roman , Dusch Martin , Schley Marcus , Forsch Elmar , Schmelz Martin
Published: July 2007

Primary hyperalgesia to mechanical and thermal stimuli are major clinical symptoms of inflammatory pain and can be induced experimentally by ultraviolet‐B (UV‐B) irradiation in humans. We set‐up a pig model in order to have more options for pharmacological intervention on primary hyperalgesia.

Pig skin was irradiated with a dose one‐ to threefold higher than the minimum erythema dose (MED) and investigated for mechanical and heat responsiveness 24 and 48h post UV‐B treatment. C‐fiber activation upon mechanical and thermal stimulation was assessed indirectly by extent of the axon reflex erythema (flare) measured by laser Doppler imaging. Mechanical stimulation with von Frey filaments (100mN) induced flare responses in UV‐B treated skin at 24 and 48h, but no effect was measured in normal untreated skin. Increased mechanical stimulation (600mN) elicited a small flare response in normal skin in an area of 1.8cm2 on average that was extending about 2.5cm2 in the UV‐B irradiated sites. Thermal stimuli provoked in normal pig skin flare areas of approximately 2cm2 (45°C, 10s) and 4.5cm2 (47°C, 10s) which increased to about 3.5cm2 (45°C) and 5.5cm2 (47°C) following UV‐B irradiation at 24 and 48h. No significant differences of mechanically or thermally induced hypersensitivity were seen between 24 and 48h after irradiation.

We conclude that UV‐B induced mechanical and heat sensitization of primary afferent nociceptors can be assessed in pig skin, providing a new human‐like model of primary hyperalgesia. Sensitization of primarily mechano‐insensitive (silent) nociceptors, which are underlying the flare response in humans, most probably contributes to the observation presented here.
The CER3 wax biosynthetic gene from Arabidopsis thaliana is allelic to WAX2/YRE/FLP1
Authors: Rowland Owen , Lee Robert , Franke Rochus , Schreiber Lukas , Kunst Ljerka
Published: July 2007

The cuticle coats the aerial organs of land plants and is composed of a cutin matrix embedded and overlayed with waxes. The Arabidopsis CER3 gene is important for cuticular wax biosynthesis and was reported to correspond to At5g02310 encoding an E3 ubiquitin ligase. Here, we demonstrate that CER3 is not At5g02310 and instead corresponds to WAX2/YRE/FLP1 (At5g57800), a gene of unknown function required for wax biosynthesis. CER3 protein has also been implicated in cutin production because strong cer3 alleles display organ fusions. Leaf cutin analysis of two cer3 alleles did not reveal significant differences in cutin load or composition, indicating that CER3 has no major role in leaf cutin formation.
An apoptosis‐related gene network induced by novel compound‐cRGD in human breast cancer cells
Authors: Huang Tsui-Chin , Huang Hsuan-Cheng , Chang Chih-Chin , Chang Hsin-Yi , Ou Chern-Han , Hsu Chun-Hua , Chen Shui-Tein , Juan Hsueh-Fen
Published: July 2007

Synthetic peptides with the arginine‐glycine‐aspartate (RGD) motif have been used widely as inhibitors of integrin–ligand interactions to study cell growth, adhesion, migration and differentiation. We designed cyclic‐RGD peptide (Tpa‐RGDWPC‐, cRGD) which could cause cell death in MCF‐7 cell line. In order to understand the mechanism involved in cRGD‐induced apoptosis, we used microarray, real‐time quantitative PCR (Q‐PCR) and bioinformatics to study the effects of cRGD on breast cancer cell line MCF‐7. By time‐series gene expression measurements and our developed software BSIP and GeneNetwork, we reconstructed an apoptosis‐related gene network. In the network, caspase‐9, located at the upstream, activates downstream effector caspases such as caspase‐7, leading to the induction of caspase‐4. Combined our previous proteomics data with newly performed docking simulation, it indicated that the cell death induced by cRGD may be triggered through blocking integrin signaling to the extracellular matrix and activation of caspase pathway. This study provides a molecular explanation of cRGD treatment in breast cancer cells and set forth a constructive far‐reaching impact on breast cancer therapy.
Cruentaren A, a highly cytotoxic benzolactone fromMyxobacteriais a novel selective inhibitor of mitochondrial F1‐ATPases
Authors: Kunze Brigitte , Sasse Florenz , Wieczorek Helmut , Huss Markus
Published: July 2007

Cruentaren A, a new antifungal benzolactone produced by the myxobacteriumByssovorax cruenta, proved to be highly cytotoxic against various human cell lines. It inhibited the proliferation of different cancer cell lines including a multidrug‐resistant KB line at low nanomolar levels. It arrested human histocytic lymphoma cells (U‐937) in G0/1phase, but did not trigger an apoptotic process. Studies to uncover the molecular target of cruentaren A showed that the novel compound, despite its structural similarity to the benzolactone enamides apicularen and salicylihalamide, was no V‐ATPase inhibitor. In contrast, cruentaren specifically inhibited mitochondrial FOF1‐ATPases with IC50 values of 15–30 nM. Although the exact binding site of cruentaren remains undefined, inhibition was shown to occur by interaction with the catalytic F1domain. Since mitochondrial ATPases play a crucial role in the pathophysiology of several human disorders including cancer, cruentaren or synthetic derivatives thereof could form the basis of future therapeutic strategies.
Comparison of misoprostol and manual vacuum aspiration for the treatment of incomplete abortion
Authors: Bique C. , Ustá M. , Debora B. , Chong E. , Westheimer E. , Winikoff B.
Published: July 2007

Objective: To compare the safety, efficacy, and acceptability of misoprostol versus manual vacuum aspiration (MVA) for treatment of incomplete abortion in Maputo, Mozambique. Methods: A total of 270 women with clinically diagnosed incomplete abortions of up to 12 weeks of gestation were randomized to either 600 μg oral misoprostol or MVA. Women were followed‐up seven days later to evaluate whether the abortion was complete. Results: Success was high for both MVA and misoprostol groups (100% vs 91%, P = 0.002). Women in the MVA arm reported fewer side effects but higher pain scores. Women who received misoprostol were significantly more likely to be “very satisfied” with the treatment and willing to choose the method again. Conclusion: Although oral misoprostol was less effective than MVA in this study, it was more acceptable to women. Misoprostol is well‐suited for use in low‐resource settings, and should be promoted as an option for the treatment of incomplete abortion.
Inventing needs: expertise and water supply in late eighteenth- and early nineteenth-century Paris
Authors: GRABER FRÉDÉRIC
Published: July 2007

The aim of this paper is to investigate the notion of need, in this case an entire city's global need for water. This was a notion invented by Paris technicians between 1760 and 1804 in the context of several water supply projects, notably two river diversion schemes, those of the Yvette and the Ourcq, where the concept was much discussed. Different ways of considering the question of need – such as water resources, consumption and use, whether present or future – were strongly related to engineers' or scientists' conceptions of their own work. State engineers claimed they could make objective estimates of future needs with no reference to either value judgements or political intentions, a position which made it possible to keep strong control over the decision in the name of the state. In contrast, a practically trained engineer working outside the state corps claimed that in the case of expertise about the future, estimates would depend strongly on political intentions, norms and ideals, so the government should first give an outline of its intended actions. The paper studies the differences between these two approaches to the concept of need, especially how they articulated knowledge about what is and knowledge about what ought to be, present and future. The paper ends by linking these differences to conceptions of what was supposed to be technical or political in such projects and of what role engineers intended to play in the decision-making process.