bluuebunny/crossref_metadata_2025 huggingface dataset:
Opioid receptor subtypes that mediate a microwave‐induced decrease in central cholinergic activity in the rat
Authors: Lai H. , Carino M. A. , Horita A. , Guy A. W.
Published: February 2006

We performed experiments to investigate subtypes of opioid receptors in the brain involved in the effect of acute (45 min) pulsed microwave exposure (2,450‐MHz, 2‐μs pulses, 500 pps, average power density 1 mW/cm2, peak‐power density, 1 W/cm2, average whole body SAR 0.6 W/kg) on cholinergic activity in the rat brain. Rats were pretreated by microinjection of specific antagonists of μ, δ, and κ opioid‐receptors into the lateral cerebroventricle before exposure to microwaves. The data showed that all three subtypes of opioid receptors are involved in the microwave‐induced decrease in cholinergic activity in the hippocampus. However, the microwave‐induced decrease in cholinergic activity in the frontal cortex was not significantly affected by any of the drug treatments, confirming our previous conclusion that the effect of microwaves on the frontal cortex is not mediated by endogenous opioids. © 1992 Wiley‐Liss, Inc.
Modification of acoustic startle by microwave pulses in the rat: A preliminary report
Authors: Seaman Ronald L. , Beblo Dolores A.
Published: February 2006

Single, 1.25‐GHz microwave pulses of 0.8‐ to 1.0‐μs duration were presented to each of four rats 100 ms before presentation of a startle‐inducing acoustic stimulus. This sequential pairing of microwave pulse and acoustic stimulus was found to modify the startle response. At an energy dose to the head of 22–43 mJ/kg per pulse (peak SAR, 23–48 kW/kg), the mean latency to the startle response was longer and the mean amplitude of the response was smaller with respect to control responses that occurred to acoustic stimuli alone. However, at a higher energy dose per microwave pulse in the range of 59–107 mJ/kg (peak SAR, 63–111 kW/kg), the mean latency and amplitude of the startle response were not statistically different from the respective means of control responses. 1992 Wiley‐Liss, Inc.
Research on the neurological effects of nonionizing radiation at the university of washington
Authors: Lai Henry
Published: February 2006

This paper reviews research on neurological effects of low‐level microwave irradiation, which was performed at the University of Washington, during the decade of the 1980s. We studied in the rat the effects of microwave exposure on the actions of various psychoactive drugs, on the activity of cholinergic systems in the brain, and on the neural mechanisms involved. Our results indicate that endogenous opioids play an important mediating role in some of the neurological effects of microwaves, and that parameters of microwave exposure are important determinants of the outcome of the microwave effects. 1992 Wiley‐Liss, Inc.
Effects of magnetic fields on mammary tumor development induced by 7, 12‐dimethylbenz(a)anthracene in rats
Authors: Mevissen Meike , Stamm Andreas , Buntenkötter Siegfried , Zwingelberg Reinhard , Wahnschaffe Ulrich , Löscher Wolfgang
Published: February 2006

A series of epidemiological studies have indicated associations between exposure to magnetic fields (MFs) and a variety of cancers, including breast cancer. In order to test the possibility that MF acts as a cancer promoter or copromoter, four separate experiments have been conducted in rats in which the effects of chronic exposure to MFs on the development of mammary tumors induced by 7,12‐dimethylbenz(a)anthracene (DMBA) were determined. Female rats were exposed in magnetic coils for 91 days (24 h/day) to either alternating current (AC; 50 Hz)‐MF or direct current (DC)‐MF. Magnetic flux density of the DC‐MF was 15 mT. Two AC‐MF exposures used a homogeneous field with a flux density of 30 mT (rms); one used a gradient field with flux density ranging from 0.3–1 μT. DMBA (5 mg) was administered orally at the onset of MF exposure and was repeated thrice at intervals of 1 week. In each experiment, 18–36 animals were exposed in 6 magnetic coils. The same number of rats were used as sham‐exposed control. These control animals were treated with DMBA and were placed in dummy coils in the same room as the MF‐exposed rats. Furthermore, groups of age‐matched rats (reference controls) were treated with DMBA but housed in another room to exclude any MF exposure due to the magnetic stray field from the MF produced by coils. At the end of the exposure or sham‐exposure period, tumor number and weight or size of tumors were determined at necropsy. Results were as follows: In sham‐exposed animals or reference controls, the tumor incidence varied between 50 and 78% in the 4 experiments. The average number of mammary tumors per tumor‐bearing animal varied between 1.6 and 2.9. In none of the experiments did MFs significantly alter tumor incidence, but in one of the experiments with AC‐MF exposure at 30 mT, the number of tumors per tumor‐bearing animal was significantly increased. Furthermore, exposure to a DC‐MF at 15 mT significantly enhanced the tumor weight. Exposure to a gradient AC‐MF at 0.3–1 μT exerted no significant effects. These experiments seem to indicate that MFs at high flux densities may act as a promoter or copromoter of breast cancer. However, this interpretation must be considered only a tentative conclusion because of the limitations of this study, particularly the small sample size used for MF exposure and the lack of repetition of data. © 1993 Wiley‐Liss. Inc.
Effects of 60 Hz electric and magnetic fields on maturation of the rat neopallium
Authors: Yu Mang C. , Gona Amos G. , Gona Ophelia , Al‐Rabiai Suad , Von Hagen Stanley , Cohen Edwin
Published: February 2006

This study was undertaken to determine the effects of extremely low frequency (ELF; 60 Hz) electromagnetic (EM) fields on somatic growth and cortical development, as well as biochemical and morphological maturation, of the rat neopallium. On the fifth day of pregnancy, female rats were put in pairs into plastic cages that were housed in a specially constructed apparatus for irradiation under three separate sets of combination and intensity: 1) 1 kV/m and 10 gauss; 2) 100 kV/m and 1 gauss; and 3) 100 kV/m and 10 gauss. The dams were exposed for 23 h daily, from days 5 through 19 postconception after which they were returned to cages outside the exposure apparatus until they littered. The neonates were culled to eight pups per litter. At 0 (birth), 5, 12, and 19 days postnatally, they were killed for biochemical and morphological studies. Another group of pregnant rats was sham‐exposed in an identical apparatus, which was not energized, and the pups were used as controls. The irradiated rats exhibited no physical abnormalities, nor did they show brain deformities such as swelling or herniation following exposure to ELF‐EM fields. There was no difference in somatic growth between control and exposed rats, but a small reduction in cortical weight was observed in rats exposed at 1 kV/m and 10 gauss, and 100 kV/m and 1 gauss, respectively. Biochemical measurements of DNA. RNA, protein, and cerebroside concentrations indicated that among the three separate exposures, only the neopallium of rats exposed at 1 kV/m and 10 gauss showed a small reduction in DNA level, as well as small reductions in RNA and protein levels. No changes were noticed in cerebroside levels in any exposed animals, and there were no differences in protein/DNA and cerebroside/DNA ratios between control and exposed rats. Morphological observations did not reveal any detectable alterations in the irradiated rats. These results indicate that exposure to ELF‐EM fields caused minimal or no changes in somatic growth and cerebral development of the rat. © 1993 Wiley‐Liss, Inc.
Pain control using high‐intensity pulsed magnetic stimulation
Authors: Ellis Wladislaw V.
Published: February 2006

High‐intensity pulsed magnetic stimulation (HIPMS) non‐invasively depolarizes neurones, which can be deeply embedded in local tissues. Trans‐ or subcutaneous electrical stimulation can produce analgesia. To test the hypothesis that similar analgesia could be obtained using HIPMS, analgesia was determined in ten blinded subjects following HIPMS. Analgesia was consistently produced in all subjects with long‐lasting pain relief occurring in half of the cases. ©1993 Wiley‐Liss. Inc.
Characteristics of microwave evoked body movements in mice
Authors: Brown Dennis O. , Lu Shin‐Tsu , Elson Edward C.
Published: February 2006

Microwave evoked body movements were studied in mice. A resonant cavity was used to provide head and neck exposure of the mouse to pulsed and gated continuous wave (CW) 1.25 GHz microwaves. No difference in response to pulsed and gated CW stimuli of equal average power was found. The incidence of the microwave evoked body movements increased proportionally with specific absorption (dose) when the whole‐body average specific absorption rate was at a constant level (7300 W/kg). Under a constant average specific absorption rate, the response incidence reached a plateau at 0.9 kJ/kg. For doses higher than 0.9 kJ/kg, response incidence was proportional to the specific absorption rate and reached a plateau at 900 W/kg. Body movements could be evoked by a single microwave pulse. The lowest whole‐body specific absorption (SA) tested was 0.18 kJ/kg, and the corresponding brain SA was 0.29 kJ/kg. Bulk heating potentials of these SAs were less than 0.1 °C. For doses higher than 0.9 kJ/kg, the response incidence was also proportional to subcutaneous temperature increment and subcutaneous heating rate. The extrapolated absolute thresholds (0% incidence) were 1.21 °C temperature increment and 0.24 °C/s heating rate. Due to high subcutaneous heating rates, these microwaves must be perceived by the mouse as an intense thermal sensation but not a pain sensation because the temperature increment was well below the threshold for thermal pain. Results of the present study should be considered in promulgation of personnel protection guideline against high peak power but low average power microwaves. © 1994 Wiley‐Liss, Inc.
Sinusoidal 60 Hz electromagnetic fields failed to induce changes in protein synthesis in Escherichia coli
Authors: Kropinski Andrew M. , Morris William C. , Szewczuk Myron R.
Published: February 2006

Escherichia coli JM83 {F− ara Δ(lac‐proAB) rpsL [ϕ80dΔ(lacZ)M15]} in midlog growth phase at 30 °C were exposed to 60 Hz sinusoidal magnetic field of 3 mT of nonuniform diverging flux, inducing a nonuniform electric field with a maximum intensity of 32 μV/cm using an inductor coil. Exposed and unexposed control cells were maintained at 30.8 ± 0.1 °C and 30.5 ± 0.1 °C, respectively. Quadruplicate samples of exposed and unexposed E. coli cells were simultaneously radiolabeled with 35S‐L‐methionine at 10 min intervals over 2 hr. Radiochemical incorporation into proteins was analyzed via liquid scintillation counting and by denaturing 12.5% polyacrylamide gel electrophoresis. The results showed that E. coli exposed to a 60 Hz magnetic field of 3 mT exhibited no qualitative or quantitative changes in protein synthesis compared to unexposed cells. Thus small prokaryotic cells (less than 2 μm × 0.5 μm) under constant‐temperature conditions do not alter their protein synthesis following exposure to 60 Hz magnetic fields at levels at 3 mT. © 1994 Wiley‐Liss, Inc.
Behavioral sensitivity of rats to extremely‐low‐frequency magnetic fields
Authors: Smith Robert F. , Clarke Rex L. , Justesen Don R.
Published: February 2006

Work in our laboratory has revealed autonomic and/or behavioral sensitivity of mice, rats, and a domestic fowl to extremely‐low‐frequency (ELF) or nominally static magnetic (B) fields at flux densities between 250 and 1700 μT (rms). To extend our work, an automated exposure and data‐acquisition system was used with the technique of conditional suppression to assess behavioral sensitivity to time‐varying B fields. Each of five rats was exposed aperiodically to a B field during 3 min warning periods that terminated in a brief electric shock. The difference between rates of lever pressing during B‐field warning periods and rates during immediately antecedent, 3 min control periods was analyzed at frequencies of 7, 16, 30, 60, and 65.1 Hz. To produce equivalent induced voltages in the rat at each frequency, graded flux densities were established that ranged from 1900 μT at 7 Hz to 200 μT at 65.1 Hz. Analysis of differences in lever‐pressing rates revealed that in a given session of testing the rats would increasingly suppress responding when exposed to a B field, but this trend was independent of frequency. This experiment provides evidence of behavioral sensitivity by a mammal to an ELF magnetic field. © 1994 Wiley‐Liss, Inc.
Conductivity differences distort probe measurements of magnetically induced electric fields
Authors: Miller Douglas L.
Published: February 2006

Measuring internal induced electric fields in animals with a miniaturized probe involves a potential error related to the difference between the hole conductivity (σh) and the surrounding tissue conductivity (σt). Theory was developed to describe this phenomenon and checked by probe measurements in agar‐filled petri dishes. The value measured in the hole is 2σt/(σh + σt) times the actual field in the tissue. For example, a probe hole in muscle, which is filled with blood, could yield a measurement only about 22% of the true value in the muscle. This potential source of error can be mitigated to some extent by not actually cutting a hole, by using a low‐conductivity (e.g., 0.2 S/m) coupling medium in the hole, or by ensuring contact between the probe's electrodes and the tissue. © 1994 Wiley‐Liss, Inc.
Influence of 50 Hz electric and magnetic fields on the pulse rate of human heart
Authors: Korpinen L. , Partanen J.
Published: February 2006

This investigation studied the effects of 50 Hz electric and magnetic fields on the pulse rate of the human heart. The ECG (electrocardiograms) of 41 male volunteers were recorded with a Holter recorder. Twenty‐six subjects were measured in and outside real fields, and 15 subjects were measured in and outside “sham” fields. The blood pressure and EEG (electroencephalogram) were also measured, but this article presents only the results of ECG recordings. The measurements took 3 h. The subjects were first sitting for 1 h outside the fields, then 1 h in the real or “sham” fields, and then, again, 1 h outside the fields. The electric field strength varied from 3.5 to 4.3 kV/m and the magnetic flux density from 1.4 to 6.6 μT. An analysis of the ECG recordings showed that the subjects' pulse rates were the same in and outside the fields. No response occurred when the subjects were exposed to real or “sham” fields. © 1994 Wiley‐Liss, Inc.
Weak extremely‐low‐frequency magnetic fields and regeneration in the planarianDugesia tigrina
Authors: Jenrow K. A. , Smith C. H. , Liboff A. R.
Published: February 2006

Extremely‐low‐frequency (ELF), low‐intensity magnetic fields have been shown to influence cell signaling processes in a variety of systems, both in vivo and in vitro. Similar effects have been demonstrated for nervous system development and neurite outgrowth. We report that regeneration in planaria, which incorporates many of these processes, is also affected by ELF magnetic fields. The rate of cephalic regeneration, reflected by the mean regeneration time (MRT), for planaria populations regenerating under continuous exposure to combined DC (78.4 μT) and AC (60.0 Hz at 10.0 μTpeak) magnetic fields applied in parallel was found to be significantly delayed (P≪ 0.001) by 48 ± 1 h relative to two different types of control populations (MRT ˜ 140 ± 12 h). One control population was exposed to only the AC component of this field combination, while the other experienced only the ambient geomagnetic field. All measurements were conducted in a low‐gradient, low‐noise magnetics laboratory under well‐maintained temperature conditions. This delay in regeneration was shown to be dependent on the planaria having a fixed orientation with respect to the magnetic field vectors. Results also indicate that this orientation‐dependent transduction process does not result from Faraday induction but is consistent with a Ca2+cyclotron resonance mechanism. Data interpretation also permits the tentative conclusion that the effect results from an inhibition of events at an early stage in the regeneration process before the onset of proliferation and differentiation. © 1995 Wiley‐Liss, Inc.
Effects of static magnetic field on specific adenosine‐5′‐triphosphatase activities and bioelectrical and biomechanical properties in the rat diaphragm muscle
Authors: Iteǧgin Mustafa , Günay Ismail , Loǧoǧlu Gülay , Isbir Turgay
Published: February 2006

In this study, we aimed to clarify the effects of chronically applied static magnetic field (200 Gauss) on specific ATPase activities and bioelectrical and biomechanical responses in the isolated rat diaphragm muscle. The mean activities of Na+‐K+ ATPase and Ca2+ ATPase determined from the diaphragm homogenates were significantly higher in the magnetic field exposed group (n = 20), but that of Mg2+ ATPase was nonsignificantly lower compared to the control group (n = 13). Resting membrane potential, amplitude of muscle action potential, and overshoot values (mean ± SE) in the control group were found to be −76.5 ± 0.6, 100 ± 0.8, and 23.5 ± 0.6 mV, respectively; these values were determined to be −72.8 ± 0.4, 90.3 ± 0.5, and 17.2 ± 0.4 mV in the magnetic field‐exposed group, respectively. The latency was determined to increase in the experimental group, and all the above‐mentioned bioelectrical differences between the groups were significant statistically. Force of muscle twitch was found to decrease significantly in the magnetic field‐exposed group, and this finding was attributed to the augmenting effect of magnetic field on Ca2+ ATPase activity. These results suggest that magnetic field exposure changes specific ATPase activities and, thence, bioelectrical and biomechanical properties in the rat diaphragm muscle. © 1995 Wiley‐Liss, Inc.
Evaluation of whole‐animal data using the ion parametric resonance model
Authors: Blanchard J. P. , House D. E. , Blackman C. F.
Published: February 2006

Changes observed in the behavioral response of land snails from exposure to parallel ac and dc magnetic fields demonstrate limited agreement with the predictions of an interaction model proposed by Lednev and the predictions of a recently proposed ion parametric resonance (IPR) model. However, the inadequate number of reported data points, particularly in a critical exposure range, prevents unambiguous application of either the Lednev or the IPR model. © 1995 Wiley‐Liss, Inc.
Fetal loss in mice exposed to magnetic fields during early pregnancy
Authors: Svedenstål Britt‐Marie , Johanson Karl‐Johan
Published: February 2006

The effects of low‐frequency magnetic fields (MFs) on early pregnancy were studied in CBA/S mice. The magnetic field was a 20 kHz, 15 μT sawtooth. Pregnant females were divided into four groups, two control groups and two exposed groups. One group was exposed to MFs continuously from day 1 postconception (pc) until day 5.5 pc, and the other group was exposed continuously until day 7 pc. All animals were sacrificed on day 19 pc, the day before partus, and their uterine contents were analyzed. No significant increase in the resorption (early fetal death) rate was found in the exposed animals compared to the sham controls. In the group exposed during days 1.0–5.5 pc, the body weight and length of the living fetuses were significantly decreased. Except on day 3 pc (progesterone) and day 13 pc (calcium) in the treated groups, there were no significant differences in progesterone and calcium levels in peripheral blood. Implantation occurred on the same day in MF‐treated and control animals. © 1995 Wiley‐Liss, Inc.
Absence of radiofrequency heating from auditory implants during magnetic resonance imaging
Authors: Chou C. K. , McDougall J. A. , Chan K. W.
Published: February 2006

The possibility of tissue heating due to an auditory brainstem implant (ABI) or a modified cochlear implant (CI) during magnetic resonance imaging (MRI) of the head was tested on a full‐sized human phantom using a realistic phantom head consisting of simulated skull, brain, and muscle. Dielectric properties of the brain, muscle, and bone materials were similar to those of human tissues at 64 MHz. The body consisted of homogeneous phantom muscle enclosed in a human‐shaped fiberglass shell. Thermographic and fiber‐optic temperature measurements were conducted to reveal any heating. Thermograms of sagittal, frontal, and horizontal planes of the head with the ABI and CI electrodes were taken immediately before and after a 26 min MRI scan. The MRI sequence was set at 94 excitations and 25 ms echo time to induce maximum radiofrequency heating, as suggested by the General Electric Company. The difference of these two thermograms gives the heating results. In two uncut phantom heads, Teflon tubes were placed along the implanted ABI and CI, and temperature data were recorded via fiber‐optic probes before, during, and after the MRI. Results showed no observable heating associated with the ABI and the modified CI during worst‐case MRI of the head. © 1995 Wiley‐Liss, Inc.
Zur Dauerhaftigkeit externer Spannglieder bei wechselnden Beanspruchungen
Authors: Hegger Josef , Neuser Jens U. , Peters Sonja , Schmitz Martin
Published: February 2006

Externe Spannglieder sind an Umlenkstellen wechselnden Beanspruchungen aus Temperatur und geringen Relativverschiebungen ausgesetzt. In einem vom Deutschen Institut für Bautechnik (DIBt) geförderten Forschungsvorhaben wurden die Auswirkungen dieser wechselnden Beanspruchungen untersucht, um den Korrosionsschutz von im Bauwerk eingesetzten externen Spanngliedern besser beurteilen zu können.
Zur Querkraftbemessung bei Kreisquerschnitten. Teil 1: Bauteile ohne Querkraftbewehrung
Authors: Bender Michél , Mark Peter
Published: February 2006

Die Querkraftwiderstände nach DIN 1045‐1 schließen Träger mit Kreisquerschnitt zunächst nicht ein. Nach Auslegung des Normenausschusses Bauwesen (NABau) kann ein rechteckiger Ersatzquerschnitt angenommen werden. Dies erweist sich für Träger aus Normalbeton ohne Bügelbewehrung im Vergleich zu experimentellen Daten als konservativ, ist allerdings mit erheblichen Streuungen verbunden. Basierend auf dem Konzept der DIN 1045‐1 wird ein praxisorientierter Ansatz für den Widerstand VRd,ctfür nicht bügelbewehrte Träger mit Kreisquerschnitt vorgestellt, welcher die bekannten Einflußgrößen von Geometrie, Längsbewehrungsgrad und Betonfestigkeit – speziell auf die Verhältnisse bei Kreisquerschnitten zugeschärft – einschließt. Die positiven Wirkungen drückender Normalkräfte sind darin über einen additiven Sprengwerkansatz einbezogen. Der Ansatz wird statistisch beurteilt und an Experimenten verifiziert.
Verbundstützen der Bügelbauten über dem Berliner Hauptbahnhof
Authors: Petersen Lasse , Naujoks Bernd
Published: February 2006

Mit den heute zur Verfügung stehenden Betonzusatzmitteln können Betonrezepturen entwickelt werden, die ein sehr effizientes Vorgehen beim Verfüllen von Verbundstützen ermöglichen. Dabei werden Stahlprofile über tiefliegende Einfüllstutzen mit Beton zuverlässig und entmischungsfrei auch über große Höhen ohne zusätzliche Verdichtungsenergie vollständig verfüllt. Der vorliegende Beitrag berichtet über die Errichtung der tragenden Verbundkonstruktion der Bügelbauten des Berliner Hauptbahnhofs, bei der diverse Stahlhohlprofile zu Verbundstützen ausbetoniert wurden. Die Stahlprofile, in denen teilweise sehr hohe Bewehrungsgehalte und aufwendige Einbauteile vorhanden waren, wurden bis zu Höhen von ca. 25 m in einem Arbeitsgang mit einem speziell dafür entwickelten Beton der Festigkeitsklasse C45/55 verfüllt.
Phosphorylated and nonphosphorylated epitopes of the La/SSB autoantigen: Comparison of their antigenic and conformational characteristics
Authors: Coudevylle Nicolas , Rokas Dimitrios , Sakarellos‐Daitsiotis Maria , Krikorian Dimitrios , Panou‐Pomonis Eugenia , Sakarellos Constantinos , Boussard Guy , Cung Manh Thong
Published: February 2006

La/SSB phosphoprotein is the target antigen of autoantibodies in sera of patients with Sjögren's syndrome (SS) and systemic lupus erythematosus (SLE). Among other structural and function motifs, four phosphorylation sites are encompassed in the primary sequence of La/SSB. Two of them (Thr‐362 and Ser‐366) are located within GSGKGKVQFQGKKTKFASDD (346–368) and one (Thr‐302) within VTWEVLEGEVEKEALKKI (301–318), which are main B‐cell epitopes of La/SSB. With the aim to investigate how phosphorylation, one of the most common posttranslational protein modifications, affects the antigenic and conformational characteristics of the La/SSB epitopes, we synthesized and studied the phosphorylated epitopes La/SSB(346–368)‐P, La/SSB(359–368)‐P, and La/SSB(301–318)‐P with respect to their nonphosphorylated counterparts. Anti‐La/SSB positive sera from SS and SLE patients are better recognized by the phosphorylated epitopes compared to their nonphosphorylated counterparts. Conformational analysis by1H nuclear magnetic resonance spectroscopy and molecular dynamics showed that the phosphorylated epitopes adopt different structural characteristics from those of the corresponding nonphosphorylated epitopes. It is concluded that phosphorylation can create neoepitopes with altered functions, compared to the nonphosphorylated epitopes, which might be seen from the immune system as “foreign.” © 2006 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 84: 368–382, 2006

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Plate height determination for gradient elution chromatography of proteins
Authors: Yamamoto Shuichi
Published: February 2006

A method for determining the plate height HETP from the elution curve obtained by the linear gradient elution (LGE) ion‐exchange chromatography (IEC) of proteins is presented. The method was developed on the basis of the numerical solutions of a chromatography model which considers the zone sharpening and the distribution coefficient as a function of the salt concentration. The plate height HETP is determined from the peak width and the salt concentration at which the peak is eluted in LGE. The method was applied to the experimental results with various ion‐exchange chromatography media. A calculation example based onthe present method is presented to show how the chromatographic and operating parameters should be tuned to obtain a desired resolution. A simplified calculation procedure for the peak profile is also described. © 1995 John Wiley & Sons, Inc.
Countercurrent gradient chromatography: A continuous focusing technique
Authors: Evans Lisa L. , Burns Mark A.
Published: February 2006

The continuous separation of proteins was performed in a countercurrent gradient chromatography (CGC) system. A magnetically stabilized fluidized bed (MSFB) was used to establish true countercurrent contact of a solid resin with a liquid buffer. STable pH gradients were formed in the system in less than 10 min and remained stable throughout the course of the separation experiment (>2 h). The shape of the pH gradient, which ultimately controls the resolution and purity of the separation, can be controlled by making simple adjustments in the interstitial velocities of the liquid and solid phases. We have performed the separation of myoglobin and human serum albumin (HSA) using this device and achieved concentration factors of 1.75 for myoglobin and 1.2 for HSA. A mathematical model that has no adjustable parameters has been developed that predicts the focusing behaviour and capabilities of the CGC system. Using the model, we have estimated the optimum phase velocities, particle diameters, and equilibrium parameters necessary for achieving high purity and high concentrations. © 1995 John Wiley & Sons, Inc.
Review: Protein refolding and inactivation during bioseparation: Bioprocessing implications
Authors: Sadana Ajit
Published: February 2006

The recombinant production of proteins leads to inclusion bodies which contain aggregated proteins in active, partially active, and inactive conformational states. These aggregated proteins must be extracted from the inclusion bodies, unfolded, and carefully refolded to the active and the stable conformational state. Mechanistic models for protein refolding are briefly presented. Different strategies and protocols are presented that lead to the active and stable protein conformational state. The techniques presented include chaperonin‐assisted refolding, amino acid substitution, polyethylene glycolassisted refolding, protein refolding in reverse micelles, and antibody‐assisted refolding of proteins. The techniques presented together provide a reasonable framework of the state‐of‐the‐art and may be carefully applied to the bioseparation of other proteins and biological macromolecules of interest. © 1995 John Wiley & Sons, Inc.
Chemical instability of protein pharmaceuticals: Mechanisms of oxidation and strategies for stabilization
Authors: Li Shihong , Schöneich Christian , Borchardt Ronald T.
Published: February 2006

Oxidation is one of the major chemical degradation pathways for protein pharmaceuticals. Methionine, cysteine, histidine, tryptophan, and tyrosine are the amino acid residues most susceptible to oxidation due to their high reactivity with various reactive oxygen species. Oxidation during protein processing and storage can be induced by contaminating oxidants, catalyzed by the presence of transition metal ions and induced by light. Oxidative modification depends on the structural features of the proteins as well as the particular oxidation mechanisms inherent in various oxidative species, and may also be influenced by pH, temperature, and buffer composition. Protein oxidation may result in loss of biological activity and other undesirable pharmaceutical consequences. Strategies to stabilize proteins against oxidation can be classified into intrinsic methods (site‐directed mutagenesis and chemical modification), physical methods (solid vs. liquid formulations) and use of chemical additives. The optimum choice of chemical additives needs to be evaluated on the basis of the specific oxidation mechanism. Oxidation induced by the presence of oxidants in the system is referred to as a non‐site‐specific mechanism. Under such conditions, oxidation can be effectively inhibited by the appropriate addition of antioxidants or free radical scavengers. metal‐catalyzed oxidation is a site‐specific process, in which the addition of antioxidants may accelerate the oxidation reaction. Careful screening of chelating agents has been shown to be an alternative method for preventing metal‐catalyzed oxidation. © 1995 John Wiley & Sons, Inc.
The Use of RP‐HPLC for measuring activation and cleavage of rFVIIa during purification
Authors: Mollerup Inger , Bayne Stephen , Halkjaer Erik , Jørgensen Tony , Mandrup Gitte , Nicolaisen Else Marie , Thim Lars
Published: February 2006

A reverse phase HPLC (RP‐HPLC) method for analysis of recombinant factor VIIa (rFVIIa) has been developed. The method discriminates between different forms of recombinant FVII (rFVII). To obtain separation of these closely related molecules the method has been optimized with respect to gradient profile and temperature. The method has been used for optimization of purification processes and for kinetic studies. EVidence for autolytic cleavage was obtained. © 1995 John Wiley & Sons, Inc.
Development of surface swabbing procedures for a cleaning validation program in a biopharmaceutical manufacturing facility
Authors: Lombardo Silvia , Inampudi Prasad , Scotton Anthony , Ruezinsky Gary , Rupp Randall , Nigam Somesh
Published: February 2006

Validation of direct surface swabbing procedure in conjuction with total organic carbon (TOC) analysis is described for a biopharmaceutical product manufacturing operation. The swabbing technique was found to be very effective in reliably detecting very low levels of residuals for diverse process streams (limit of detection of approximately 0.5µg/cm2). However, contaminant recovery was significantly dependent on both the type of contaminant and the processing surface. This study serves as a guide for designing effective cleaning validation protocols based on direct surface swabbing techniques. © 1995 John Wiley & Sons, Inc.
Purification of a pyrogen‐free human growth hormone antagonist
Authors: Gu Tingyue , Zheng Yizhou , Gu Yesong , Haldankar Raj , Bhalerao Nihar , Ridgway Darin , Wiehl Paul E. , Chen Wen Y. , Kopchick John J.
Published: February 2006

Human growth hormone (hGH) is a polypeptide with 191 amino acids and a molecular mass of 22 kilodaltons. With the aid of computer molecular simulation, an hGH analog was created by altering an hGH gene to reflect the change of one amino acid (glycine [G] 120 to arginine [R]) within the third α‐helix of the hGH molecule. This hGH analog, named hGHG120R, was found to be an hGH antagonist. It may have important implications in treating human conditions in which hGH levels are abnormally high, as found in type I diabetics. Several hundred milligrams of purified hGHG120R were needed to determine the biological activity of the antagonist in animal models. A multistep downstream process was developed to purify hGHG120R from cultured mouse L cells transfected with the hGHG120R gene. The process consisted of cell clarification, salt precipitation, membrane ultrafiltration, reversed phase high performance liquid chromatography, phase separation, and lyophiliation. This work discusses the rationale for the design of the process and experimental results on the purification of hGHG120R using the process. © 1995 John Wiley & Sons, Inc.
Large scale purification of myo‐inositol monophosphate phosphatase from porcine brains
Authors: Kwok Francis , Wang Xing Hua , Cheng Christopher H. K. , Lo Samuel C. L.
Published: February 2006

myo‐Inositol monophosphate phosphatase (IMPase) has been purified 888‐fold to apparent homogeneity from procine brains. The purification procedure involves: homogenization, ammonium sulfate fractionation, and a number of ion‐exchange and gel‐filtration chromatography steps. The purified enzyme exhibited a final specific activity of 932 nmol · min−1 · mg−1. The molecular mass of the enzyme was estimated to be 29kDa by SDS poly‐acrylamide gel electrophoresis and 58 ± 5 kDa by HPLC gel filtration in 10mM Tris‐HCI, pH 7.4. Kinetic measurements have shown that the apparent Km value of the phosphatase for the utilization of inositol‐1‐phosphate and β‐glycerol phosphate are 3.20 × 10−4 and 8 × 10−3 M, respectively. Similar to the same enzyme isolated from bovine brains, the porcine brain enzyme has been shown to be inhibited by lithium. The K1 was determined to be 6.38 × 10−4 M and the inhibition is uncompetitive. © 1995 John Wiley & Sons, Inc.
Fermentation and isolation of C10‐deacetylase for the production of 10‐deacetylbaccatin III from baccatin III
Authors: Nanduri Venkata B. , Hanson Ronald L. , LaPorte Thomas L. , Ko Raphael Y. , Patel Ramesh N. , Szarka Laszlo J.
Published: February 2006

10‐Deacetylabaccatin III (10 DAB), an important precursor for paclitaxel semisynthesis, is enhanced in yew extracts using C10‐deacetylase and C13‐deacylase enzymes.4 C10‐deacetylase is an intracellular enzyme produced by the fermentation of a soil microorganism, Nocardioides luteus (SC 13912). During the fermentation of Nocardioides luteus, the growth of cells reaches a maximum growth at 28 h. C10‐deacetylase enzyme activity starts at 26 h and peaks at 38 h of the fermentation. The cells are recovered by centrifugation. The C10‐deacetylase enzyme was purified from the Nocardioides luteus cells. The enzyme was purified 190‐fold to near homogeneity. The purified enzyme appeared as a single band on 12.5% SDS‐PAGE analysis with a molecular weight of 40,000 daltons. © 1995 John Wiley & Sons, Inc.
Fermentation and recovery of glutamic acid from palm waste hydrolysate by Ion‐exchange resin column
Authors: Das K. , Anis M. , Azemi B. M. N. Mohd. , Ismail N.
Published: February 2006

Glutamic acid produced from palm waste hydrolysate by fermentation with Brevibacterium lactofermentum ATCC 13869 is produced with a remarkably high yield compared with that produced from pure glucose as a carbon source. The produce yield is 70 g/L with glucose, wherease, when palm waste hydrolysate is the fermentation medium in the same bioreactor under same conditions, it is 88 g/L. The higher yield may be attributed to the fact that this organism has the ability to convert sugars other than only glucose present in the hydrolysate. Bioreactor conditions most conducive for maximum production are pH 7.5, temperature of 30°rmentation period of 48 h, inoculum size 6%, substrate concentration of 10 g per 100 mL, yeast extract 0.5 g per 100 mL as a suitable N source, and biotin at a concentration of 10 pg/L. Palm waste hydrolysate used in this study was prepared by enzymic saccharification of treated palm press fiber under conditions that yielded a maximum of 30 g/L total reducing sugars. Glutamic acid from fermentation broth was recovered by using a chromatographic column (5cm × 60 cm) packed with a strong ion‐exchange resin. The filtered broth containing glutamic acid and other inorganic ions was fed to the fully charged column. The broth was continuously recycled at a flow rate of 50 mL/min (retention time of 55 min) until glutamic acid was fully adsorbed on the column leaving other ions in the effluent. Recovery was done by eluting with urea and sodium hydroxide for total displacement of glutamic acid from the resin. The eluent containing 88 g/L of glutamic acid was concentrated by evaporation to obtain solid crystals of the product. © 1995 John Wiley & Sons, Inc.
Preparation of a Nanowire‐Structured Polyaniline Composite and Gas Sensitivity Studies
Authors: Ma Xingfa , Li Guang , Wang Mang , Cheng Yunan , Bai Ru , Chen Hongzheng
Published: February 2006

To obtain organic nanowire sensors with high sensitivity and rapid response times, based on the inducement effect of surfactants during in situ polymerization, nanostructured polyaniline composites are obtained by using a chemical oxidation method by adding a small amount of surfactant. A casting method is employed on interdigitated carbon electrodes. The gas sensitivity to a series of chemical vapors is examined at room temperature. The results indicate that polyaniline with regular nanowire structure is obtained when succinic acid is added. The gas sensitivity and response rates of a film with nanowire structure are much better than those of conventional polyaniline films produced by means of organic solution spin coating methods. The film described in this work shows good selectivity to trimethylamine and other related gases and, the reaction being reversible with the ues of high‐purity nitrogen.
Polyelectrolyte Templated Polymerization in Langmuir Films: Nanoscopic Control of Polymer Chain Organization
Authors: Chandra M. Sharath , Radhakrishnan T. P.
Published: February 2006

Polyelectrolytes introduced in the aqueous subphase are shown to have a profound impact on the kinetics of polymerization of N‐octadecylaniline at the air/water interface. This can be attributed to changes effected in molecular organization and reorientation behavior in the Langmuir film. The polyelectrolyte templates lead to considerable modification of the morphology of the monomer and polymer Langmuir films. Polyelectrolyte complexation is found to be an elegant and efficient methodology to achieve enhanced alignment of the polyaniline chains in the transferred Langmuir–Blodgett (Langmuir–Schafer) film.
Selective Oxidation of Alkanes with Molecular Oxygen and Acetaldehyde in Compressed (Supercritical) Carbon Dioxide as Reaction Medium
Authors: Theyssen Nils , Hou Zhenshan , Leitner Walter
Published: February 2006

The oxidation of cycloalkanes or alkylarenes with molecular oxygen and acetaldehyde as sacrificial co‐reductant occurs efficiently in compressed (supercritical) carbon dioxide (scCO2) under mild multiphase conditions. No catalyst is required and high‐pressure ATR‐FTIR online measurements show that a radical reaction pathway is heterogeneously initiated by the stainless steel of the reactor walls. For secondary carbon atoms, high ketone to alcohol ratios are observed (3.5–7.9), most probably due to fast consecutive oxidation of alcoholic intermediates. Since CC scission reactions are detected only to a very small extent, tertiary carbon atoms are transformed into the corresponding alcohols with high selectivity. Detailed analysis of the product distributions and other mechanistic evidence suggest that acetaldehyde acts not only as the sacrificial oxygen acceptor, but also as an efficient H‐atom donor for peroxo and oxo radicals and as a crucial reductant for hydroperoxo intermediates. In comparison to other inert gases such as compressed N2 or Ar, the use of carbon dioxide was shown to increase the yields of alkane oxygenates under identical reaction conditions.
Supramolecular Template‐Directed Synthesis of Perfect Phenelenediimino‐Bridged Ladderlike Polyphenylsiloxanes
Authors: Zhang Taoyi , Deng Kuilin , Zhang Pingping , Xie Ping , Zhang Rongben
Published: February 2006

A template synthesis of the soluble, high molecular weight (Mw), and perfect p‐phenylenediimino (p‐PDA)‐bridged ladderlike polyphenylsiloxane (PLPS) is reported. First, N,N′‐bis(phenyldichlorosilyl)‐p‐PDA monomers were self‐assembled into a perfect ladder superstructure (LS) by concerted interaction of aromatic π–π stacking and hydrogen bonding. Then the LS underwent a novel stoichiometric hydrolysis/dehydrochlorination–condensation reaction instead of the usual hydrolysis/dehydration–condensation reaction, leading to the PLPS. The perfect ladder structures of both the PLPS and, in particular, the unstable supramolecular LS were confirmed as follows. 1) There are two Bragg peaks in solid and/or solution X‐ray diffraction (XRD) spectra representing the ladder width (w) and ladder thickness (t); these peaks were consistent with those calculated by molecular simulation. 2) Both the PLPS and LS have extremely sharp absorption peaks with small half‐peak widths (Δ1/2<0.3 ppm) in 29Si NMR spectra, suggesting the presence of the perfect ladder structure for PLPS and LS. 3) Moreover, no noticeable absorption peaks for the SiOH and NH2 groups were observed in FT‐IR and 29Si NMR spectra, indicating that the SiN bond of the Si‐NH‐C6H4‐NH‐Si ladder rung of PLPS and LS is not cleaved. 4) Both PLPS and LS show similar emission peaks (in fluorescence spectroscopy) attributed to the excimer formed by face‐to face π–π stacking of phenyl groups along the ladder chain rather than a branched direction. 5) Differential scanning calorimetry (DSC) measurements indicate a high glass temperature (Tg=176.4 °C) for PLPS. As circumstantial evidence, this result further indicates very high stiffness of PLPSs ladder backbone as compared with flexible single‐chain polyphenylmethylsiloxane with a low Tg=−69.4 °C.
Direct Observation of Size Dependent Activation of NO on Gold Clusters.
Authors: Fielicke Andre , von Helden Gert , Meijer Gerard , Simard Benoit , Rayner David M.
Published: February 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
First Experimental Evidence of Potassium Ordering in Layered K4Co7O14.
Authors: Blangero Maxime , Decourt Rodolphe , Carlier Dany , Ceder Gerbrand , Pollet Michael , Doumerc Jean‐Pierre , Darriet Jacques , Delmas Claude
Published: February 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
(Nb2W4O19), TMA2, Na4(OH2)14(SO4): A New Layered Structure with Lindqvist Heteropolyanions, XAS Characterization of the HPAs.
Authors: Kaezer Franca Marcia Cristina , Eon Jean‐Guillaume , Fournier Michel , Payen Edmond , Mentre Olivier
Published: February 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Studies of P—C Isotherms in LnNi5—H (Ln: La, Pr, Nd, Sm, Gd, Tb and Dy) Systems.
Authors: Senoh H. , Takeichi N. , Kiyobayashi T. , Tanaka H. , Takeshita H. T. , Oishi T. , Kuriyama N.
Published: February 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Photocatalytic Activity of the RuO2‐Dispersed Composite p‐Block Metal Oxide LiInGeO4 with d10—d10 Configuration of Water Decomposition.
Authors: Kadowaki H. , Sato J. , Kobayashi H. , Saito N. , Nishiyama H. , Simodaira Y. , Inoue Y.
Published: February 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Montmorillonite K10 Catalyzed Nucleophilic Addition Reaction to Aldimines in Water.
Authors: Akiyama Takahiko , Matsuda Keiichiro , Fuchibe Kohei
Published: February 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Oxalylation of the 3‐Oxo‐N‐phenyl‐3‐R‐propanethioamides.
Authors: Britsun V. N. , Borisevich A. N. , Samoylenko L. S. , Chernega A. N. , Lozynskii M. O.
Published: February 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Synthesis, Structure, and Chemoselective Reactivity of N‐(2‐Iodylphenyl)acylamides: Hypervalent Iodine Reagents Bearing a Pseudo‐Six‐Membered Ring Scaffold.
Authors: Ladziata Uladzimir , Koposov Alexey Y. , Lo Ka Y. , Willging Jeff , Nemykin Victor N. , Zhdankin Viktor V.
Published: February 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
A Mild Radical Procedure for the Reduction of B‐Alkylcatecholboranes to Alkanes.
Authors: Pozzi Davide , Scanlan Eoin M. , Renaud Philippe
Published: February 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Flavin‐Catalyzed Generation of Diimide: An Environmentally Friendly Method for the Aerobic Hydrogenation of Olefins.
Authors: Imada Yasushi , Iida Hiroki , Naota Takeshi
Published: February 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
P(RNCH2CH2)N: Efficient Catalysts for the Cyanosilylation of Aldehydes and Ketones.
Authors: Fetterly Brandon M. , Verkade John G.
Published: February 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Silver‐Catalyzed Asymmetric Sakurai—Hosomi Allylation of Ketones.
Authors: Wadamoto Manabu , Yamamoto Hisashi
Published: February 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Conversion of N‐Acyl‐4‐phenyl/benzyl‐oxazolidine‐2‐thiones (I) into Thiol Esters (III) in the Presence of EtSH‐K2CO3.
Authors: Hu Qi , Sun Ya‐Ping , Wu Yi‐Kang
Published: February 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.