Trailing End Research Articles

Effects of dietary reduced glutathione on growth performance, non-specific immunity, antioxidant capacity and expression levels of IGF-I and HSP70 mRNA of grass carp (Ctenopharyngodon idella)

Abstract This study was conducted to evaluate the effects of dietary reduced glutathione (GSH) on growth performance, non-specific immunity, antioxidant capacity and related gene expression of grass carp ( Ctenopharyngodon idella ). Six hundred and thirty juvenile grass carp with initial body weight of 5.10 ± 0.09 g were randomly distributed into six groups with three replicates each, fed six diets containing graded levels of GSH (14.26, 112.41, 210.24, 407.45, 602.85 and 798.32 mg/kg diet) for 60 days. At the end of the feeding trail, ten fish per tank were challenged with Aeromonas hydrophila and the cumulative mortalities were recorded for 7 days. The results showed that the weight gain (WG), specific growth rate (SGR) and survival rate of grass carp, serum total protein (TP), lysozyme, alkaline phosphatase (ALP), and complement 3 (C3) levels, activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) in the liver, and liver total antioxidant capacity (T-AOC) and GSH contents, and expression levels of IGF-I and HSP70 mRNA significantly increased, while feed conversion rate (FCR), liver glutathione reductase (GR) activity and malondialdehyde (MDA) content significantly decreased with dietary GSH levels up to 407.45 mg/kg diet ( P P > 0.05). The challenge experiment showed that the cumulative mortality significantly decreased with dietary GSH contents up to 407.45 mg/kg diet ( P

Flow control of a circular cylinder by using an attached flexible filament

The flow control of a circular cylinder by using a flexible filament has been numerically investigated in this work. The cylinder is either fixed or elastically mounted, and the filament is attached to the base of the cylinder. Its leading end is fixed and its trailing end is free to flap. To execute the numerical simulation and deal with the fluid-structure interaction (FSI) of the filament as well, an improved immersed boundary-lattice Boltzmann method (IB-LBM) is presented. As compared to the conventional IB-LBM for handling the FSI of a filament, the current method can incorporate the mass effect of the filament and no user-defined spring parameter is needed to calculate the interaction force on the filament. After validating the employed method, the effects of the filament on the flow control of the cylinder are systematically examined by varying the bending coefficient (Kb) and length (L) of the filament. The laminar flow with a Reynolds number of 150 is considered in this study. Based on the numerical results obtained, it is found that the fluctuation of lift force and vortex shedding of a fixed cylinder and the vortex-induced vibration of an elastically mounted cylinder can be suppressed efficiently.

Effect of choline on antioxidant defenses and gene expressions of Nrf2 signaling molecule in the spleen and head kidney of juvenile Jian carp (Cyprinus carpio var. Jian)

The present work evaluates the effects of various levels of dietary choline on antioxidant defenses and gene expressions of Nrf2 signaling molecule in spleen and head kidney of juvenile Jian carp (Cyprinus carpio var. Jian). Fish were fed with six different experimental diets containing graded levels of choline at 165 (choline-deficient control), 310, 607, 896, 1167 and 1820 mg kg−1 diet for 65 days. At the end of the feeding trail, fish were challenged with Aeromonas hydrophila and mortalities were recorded over 17 days. Dietary choline significantly decreased malondialdehyde and protein carbonyl contents in spleen and head kidney. However, anti-superoxide anion and anti-hydroxyl radical activities in spleen and head kidney also decreased. Interestingly, activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and glutathione reductase (GR) in spleen, GPx activity in head kidney, and glutathione contents in spleen and head kidney were decreased with increase of dietary choline levels up to a certain point, whereas, activities of SOD, GST and GR in head kidney showed no significantly differences among groups. Similarly, expression levels of CuZnSOD, MnSOD, CAT, GPx1a, GPx1b and GR gene in spleen and head kidney were significantly lower in group with choline level of 607 mg kg−1 diet than those in the choline-deficient group. The relative gene expressions of Nrf2 in head kidney and Keap1a in spleen and head kidney were decreased with increasing of dietary choline up to a certain point. However, the relative gene expression of Nrf2 in spleen were not significantly affected by dietary choline. In conclusion, dietary choline decreased the oxidant damage and regulated the antioxidant system in immune organs of juvenile Jian carp.

Percutaneous In Utero Thoracoamniotic Shunt Creation for Fetal Thoracic Abnormalities Leading to Nonimmune Hydrops

PurposeTo describe a transabdominal, transuterine Seldinger-based percutaneous approach to create a shunt for treatment of fetal thoracic abnormalities. Materials and MethodsFive fetuses presented with nonimmune fetal hydrops secondary to fetal thoracic abnormalities causing severe mass effect. Under direct ultrasound guidance, an 18-gauge needle was used to access the malformation. Through a peel-away sheath, a customized pediatric transplant 4.5-F double J ureteral stent was advanced; the leading loop was placed in the fetal thorax, and the trailing end was left outside the fetal thorax within the amniotic cavity. ResultsSeven thoracoamniotic shunts were successfully placed in five fetuses; one shunt was immediately replaced because of displacement during the procedure, and another shunt was not functioning at follow-up requiring insertion of a second shunt. All fetuses had successful decompression of the thoracic malformation, allowing lung reexpansion and resolution of hydrops. Three of five mothers had meaningful (> 7 d) prolongation of their pregnancies. All pregnancies were maintained to > 30 weeks (range, 30 weeks 1 d–37 weeks 2 d). There were no maternal complications. ConclusionsA Seldinger-based percutaneous approach to draining fetal thoracic abnormalities is feasible and can allow for prolongation of pregnancy and antenatal lung development and ultimately result in fetal survival.

Thermal structure of a major crustal shear zone, the basal thrust in the Scandinavian Caledonides

Crustal-scale thrust zones accommodate most of the horizontal shortening at the front of orogenic wedges. Their thermal state is a key feature of collision zones, depending on critical parameters such as thrust rate or initial thermal properties of involved lithosphere units. We present here the first direct imaging of the thermal envelope of such a thrust zone: the Jotun Basal Thrust (JBT) in the Scandinavian Caledonides, through Raman Spectroscopy of Carbonaceous Material in the alum shales, an organic carbon-rich unit of Cambro-Ordovician age along which the basal decollement of the JBT developed. Maximum temperature mapping within this unit shows isotherms grading from ∼320 °C in the south–east to ∼500 °C in the north–west in the trailing end of the nappe stack. Based on bt + chl + grt + ph equilibrium, we estimate that the trailing end reached a temperature of 500 °C at 1.2±0.1 GPa pressure. 2-D thermo-kinematic modelling constrained with these new natural data and timing considerations for the Scandian collision indicates that (1) peak temperature mainly reflects maximum burial stage, (2) thrust rate and dip angle must have been low for the JBT and (3) the Scandinavian Caledonides represent a relatively cold orogenic wedge compared to other orogens.

Modelling flow and work hardening behaviour of cold worked Zr–2.5Nb pressure tube material in the temperature range of 30–600 ̊C

Under a postulated accident scenario of loss of cooling medium in an Indian Pressurised Heavy Water Reactor (IPHWR), temperature of the pressure tubes can rise and lead to large deformations. In order to investigate the modes of deformation of pressure tube – calandria tube assembly, material property data defining the flow behaviour over a temperature range from room temperature (RT) to 800̊C are needed. It is of practical importance to formulate mathematical equations to describe the stress–strain relationships of a material for a variety of reasons, such as the analysis of forming operations and the assessment of component's performance in service. A number of constitutive relations of empirical nature have been proposed and they have been found very suitable to describe the behaviour of a material. Although these relations are of empirical nature, various metallurgical factors appear to decide applicability of each of these relations. For example, grain size influences mainly the friction stress while the strain hardening is governed by dislocation density. In a recent work, tensile deformation behaviour of pressure tube material of IPHWR has been carried out over a range of temperature and strain rates (Dureja et al., 2011). It has been found that the strength parameters (yield and ultimate tensile strength) vary along the length of the tube with higher strength at the trailing end as compared to the leading end. This stems from cooling of the billet during the extrusion process which results in the variation of microstructure, texture and dislocation density from the leading to the trailing end. In addition, the variation in metallurgical parameters is also expected to influence the work hardening behaviour, which is known to control the plastic instability (related to uniform strain).In the present investigation, the tensile flow and work-hardening behaviour of a cold worked Zr–2.5Nb pressure tube material of IPHWRs has been studied over the temperature range of 30–600̊C. The stress strain data have been analysed in terms of stress–strain relations proposed by Hollomon (1945), Voce (1948) and Ramberg–Osgood (RO) (Ramberg and Osgood, 1943). The relative efficacies of these relations has been examined by fitting the appropriate equation to the experimentally obtained true stress–true strain data. The quality of fit of these empirical relations is quantified using square root of co-efficient of determination, i.e. R value (in %). The results have been discussed in terms of the correlation coefficient and in error in the estimation of UTS and uniform strain. Of the various relations employed, the Voce's relation has been found to describe the stress–strain behaviour most precisely up to 300̊C. Hollomon's relation describes the strain–stress behaviour of the material over the entire temperature range but with over-estimation of UTS. RO relation does not fit well in the initial stage but satisfactorily models the uniform elongation regime till UTS for temperatures up to 500̊C.

FLOW PHYSICS OF 3-BLADED STRAIGHT CHORD H-DARRIEUS WIND TURBINE

Steady-state two-dimensional Computational Fluid Dynamics (CFD) simulations were performed using Fluent 6.0 software to analyze the flow physics of 3-bladed straight chord H-Darrieus wind turbine having blade twist of 300 for 10% of its chord at the trailing ends. The flow was simulated using finite volume method coupled with moving mesh technique to solve mass and momentum conservation equations. The standard k-ε turbulence model with enhanced wall condition was used. Second-order upwind discretization scheme was adopted for pressure-velocity coupling of the flow. Flow physics of the turbine was analyzed with the help of pressure and velocity contours. It was found that velocity magnitude decreases from upstream to downstream side across the turbine, which will cause overall lift for the turbine. Further, blade twist at the trailing ends creates circulations that interact with the blades in a direction opposite to the direction of rotation of the turbine which would enhance power production for the three bladed turbine.

FLOW PHYSICS OF 3-BLADED STRAIGHT CHORD H-DARRIEUS WIND TURBINE

Steady-state two-dimensional Computational Fluid Dynamics (CFD) simulations were performed using Fluent 6.0 software to analyze the flow physics of 3-bladed straight chord H-Darrieus wind turbine having blade twist of 300 for 10% of its chord at the trailing ends. The flow was simulated using finite volume method coupled with moving mesh technique to solve mass and momentum conservation equations. The standard k-ε turbulence model with enhanced wall condition was used. Second-order upwind discretization scheme was adopted for pressure-velocity coupling of the flow. Flow physics of the turbine was analyzed with the help of pressure and velocity contours. It was found that velocity magnitude decreases from upstream to downstream side across the turbine, which will cause overall lift for the turbine. Further, blade twist at the trailing ends creates circulations that interact with the blades in a direction opposite to the direction of rotation of the turbine which would enhance power production for the three bladed turbine.

Large-scale molecular dynamics simulations of wear in diamond-like carbon at the nanoscale

We perform large-scale molecular dynamics simulations on diamond-like carbon to study wear mechanism and law at the nanoscale. Our simulations show that material loss during sliding varies linearly with normal load and sliding distance, consistent with Archard's law. Our simulations also show that the number of chemical bonds across the contact interface during sliding correlates well with friction force, but not with material loss, indicating that friction and wear follow different mechanisms. Our analysis reveals the following wear mechanism: the shear traction causes mass accumulation at the trailing end of contact, which is then lost by a cluster detachment process.

Dietary choline modulates immune responses, and gene expressions of TOR and eIF4E-binding protein2 in immune organs of juvenile Jian carp (Cyprinus carpio var. Jian)

The present work evaluates the effects of various levels of dietary choline on immune parameters, immune-related gene expression and protection against Aeromonas hydrophila (AH) in juvenile Jian carp (Cyprinus carpio var. Jian). Fish were fed with six different experimental diets containing graded levels of choline at 165 (choline-deficient control), 310, 607, 896, 1167 and 1820 mg kg−1 diet for 65 days. At the end of the feeding trail, Fish were challenged with AH and mortalities were recorded over 17 days. Dietary choline significantly enhanced spleen and head kidney weights, spleen index, red blood cell and white blood cell counts, and intestinal Lactobacillus counts of juvenile Jian carp; whereas, intestinal Escherichia coli and A. hydrophila counts decreased. Moreover, the post-challenge survival rate, leucocyte phagocytic capacity, serum lysozyme and acid phosphatase activities, hemagglutination titer, complement 3 and 4 contents, immunoglobulin M content, and anti-AH antibody titer were significantly enhanced by choline and the lowest in choline-deficient group, while serum total iron-binding capacity was the highest in choline-deficient group. The relative gene expressions of interleukin 10 in spleen and head kidney, target of rapamycin (TOR) in spleen and eIF4E-binding protein2 (4E-BP2) in head kidney significantly increased with increasing of dietary choline up to a certain point. However, the relative gene expressions of interleukin 1β, tumor necrosis factor α and transforming growth factor β2 in spleen and head kidney, TOR in head kidney and 4E-BP2 in spleen significantly decreased. In conclusion, dietary choline improved disease resistance, enhanced the immune function, and regulated immune-related gene expression of juvenile Jian carp.

The actin-based machinery ofTrichomonas vaginalismediates flagellate-amoeboid transition and migration across host tissue

Trichomonas vaginalis is the most widespread non-viral pathogen of the human urogenital tract, infecting ∼ 3% of the world's population annually. At the onset of infection the protist changes morphology within minutes: the flagellated free-swimming cell converts into the amoeboid-adherent stage. The molecular machinery of this process is not well studied, but is thought to involve actin reorganization. We have characterized amoeboid transition, focusing in particular on TvFim1, the only expressed protein of the fimbrin family in Trichomonas. Addition of TvFim1 to actin polymerization assays increases the speed of actin filament assembly and results in bundling of F-actin in a parallel and anti-parallel manner. Upon contact with vaginal epithelial cells, the otherwise diffuse localization of actin and TvFim1 changes dramatically. In the amoeboid TvFim1 associates with fibrous actin bundles and concentrates at protrusive structures opposing the trailing ends of the gliding amoeboid form and rapidly redistributes together with actin to form distinct clusters. Live cell imaging demonstrates that Trichomonas amoeboid stages do not just adhere to host tissue, rather they actively migrate across human epithelial cells. They do so in a concerted manner, with an average speed of 20 μm min(-1) and often using their flagella and apical tip as the leading edge.

Jet Propulsion Model of Cell Motility in Confined Spaces

Recent experiment showed that cells without integrin can still migrate in confined environments, but they are immobile on a flat surface. However, the mechanism of cell migration in confined spaces is still unclear. Here we propose a jet propulsion model of the cell motility when cells migrate through heterogeneous structures in tissues, such as lymphatic vessels, vasculature and nerves. We show that as long as the cell is polarized so that an ion concentration gradient along the elongated cell body can be maintained, water molecules can be ingested into the cell at the leading end and emitted at the trailing end of the cell. Therefore, cells can migrate forward at a high speed. Our model also predicts that an osmotic shock can reverse the direction of cell migration in microchannels. These predictions were verified by our microfluidic experiments. The effects of actin, mysoin, microtubules and ion transporters were studied theoretically and experimentally.

Stability of the shape of a translating viscoelastic drop at low Reynolds number

We examine the stability of the shape of a viscoelastic drop translating in an immiscible, otherwise quiescent Newtonian fluid at low Reynolds number. Non-Newtonian stresses in the drop phase are characterized by the finitely extensible nonlinear elastic-Chilcott-Rallison model. A boundary integral method is used to numerically examine the time-evolution of initially perturbed drop shapes over a range of dimensionless parameters. For sufficiently small capillary numbers, the drop achieves an oblate spheroidal steady shape. For large initial deformations or capillary numbers, however, the drop deforms continuously and eventually breaks up through either the formation of an elongated tail or the development of a re-entrant cavity at its trailing end. These mechanisms of drop breakup are qualitatively similar to those reported earlier for Newtonian drops [C. J. Koh and L. G. Leal, Phys. Fluids A 1, 1309 (1989)10.1063/1.857359; C. Pozrikidis, J. Fluid Mech. 210, 1 (1990)10.1017/S0022112090001203; H. A. Stone, Annu. Rev. Fluid Mech. 26, 65 (1994)10.1146/annurev.fl.26.010194.000433]. Compared to the case of a Newtonian drop, drop phase elasticity is found to have a stabilizing (destabilizing) effect for initially oblate (prolate) shape perturbations, due to the development of polymeric stresses caused by deformation of polymer chains in alignment with streamlines of the flow. Polymer viscosity has a strong influence on the stability of the shape of drops, whereas polymer relaxation time and extensibility have relatively weak influences.

Effects of targeting pod modification on F/A-18C Hornet weapons release

AbstractThis paper describes a study that investigated the efficacy of modifications to the trailing end of the externally mounted advanced targeting forward looking infrared pod (ATFLIR) on the store separation characteristics of the F/A-18C aircraft. Prior work by Godiksen suggests that the trailing end of the geometrically similar targeting forward looking infrared pod (TFLIR) is the likely source of shock waves that can adversely impact the trajectory of a recently released store. In our study five different modifications to the aft end of the ATFLIR were analysed using computational fluid dynamics (CFD). The two most promising designs, an ogive shape such as that used in artillery shells and rockets, and a simpler extended but truncated cone shape were then further investigated. The moments that these trailing shapes produced on an adjacent released store were compared. CFD analysis revealed that the simpler cone shape resulted in weaker shocks from the aft end of the pod with a resultant smaller adverse moment on the store. While there is an extensive history of using CFD to predict store separation behavior, results from our study should be compared with wind tunnel data in order to validate the CFD simulations.

Large Proton Anisotropies in the 18 August 2010 Solar Particle Event

The solar particle event observed at STEREO Ahead on 18 August 2010 displayed a rich variety of behavior in the particle anisotropies. Sectored rates measured by the Low Energy Telescope (LET) on STEREO showed very large bidirectional anisotropies in 4 – 6 MeV protons for the first ∼ 17 hours of the event while inside a magnetic cloud, with intensities along the field direction several hundred to nearly 1000 times greater than those perpendicular to the field. At the trailing end of the cloud, the protons became isotropic and their spectrum hardened slightly, while the He/H abundance ratio plunged by a factor of approximately four for about four hours. Associated with the arrival of a shock on 20 August was a series of brief (< 10 minute duration) intensity increases (commonly called “shock spikes”) with relatively narrow angular distributions (∼ 45∘ FWHM), followed by an abrupt decrease in particle intensities at the shock itself and a reversal of the proton flow to a direction toward the Sun and away from the receding shock. We discuss the STEREO/LET observations of this interesting event in the context of other observations reported in the literature.

P65 Truncation Impacts P30 Dynamics during Mycoplasma pneumoniae Gliding

The cell wall-less prokaryote Mycoplasma pneumoniae is a major cause of community-acquired bronchitis and pneumonia in humans. Colonization is mediated largely by a differentiated terminal organelle, which is also the leading end in gliding motility. Cytadherence-associated proteins P30 and P65 appear to traffic concurrently to the distal end of developing terminal organelles. Here, truncation of P65 due to transposon insertion in the corresponding gene resulted in lower gliding velocity, reduced cytadherence, and decreased steady-state levels of several terminal organelle proteins, including P30. Utilizing fluorescent protein fusions, we followed terminal organelle development over time. New P30 foci appeared at nascent terminal organelles in P65 mutants, as in the wild type. However, with forward cell motility, P30 in the P65 mutants appeared to drag toward the trailing cell pole, where it was released, yielding a fluorescent trail to which truncated P65 colocalized. In contrast, P30 was only rarely observed at the trailing end of gliding wild-type cells. Complementation with the recombinant wild-type P65 allele by transposon delivery restored P65 levels and stabilized P30 localization to the terminal organelle.

Wagons Ho! (review)

Reviewed by: Wagons Ho! Elizabeth Bush Hallowell, George . Wagons Ho!; by George Hallowell and Joan Holub; illus. by Lynne Avril. Whitman, 2011. [32p]. ISBN 978-0-8075-8612-9 $16.99 Reviewed from galleys R Gr. 2-4. Pulling up roots and transplanting a family clear across country never is and never has been easy. In this lively picture-book account of westward migration, Jenny Johnson and her family's covered-wagon trek from Independence, Missouri to Oregon City, Oregon is portrayed alongside that of Katie Miller, whose family is now following the same route by car, trailer, and moving van. The Johnsons' five-month journey is marked by regret over friends and items left behind, the needling antics of a younger brother, worries about whether they can find their way, friends briefly made and lost, and long periods of boredom. Not much different, actually, from the scenes that play out among the Millers. On the whole, most kids will agree Katie has the sweeter deal, with hotel pools, plenty of snacks, paved roads, bridges, and a ready-made house waiting for her at trail's end. Still, there are moments over the five interminable days in which Katie might envy Jenny's campfires, easy access to "bathrooms" (behind just about any bush), and the sheer joy of hopping off the vehicle and walking alongside to stretch the legs. Parallel layouts of the breezy cartoon-styled jaunt make comparisons easy, and the overlap of the stories at Independence Rock, where the Johnsons inscribe their names and Millers read them, invites the past into the present for a young audience. The final panels realistically situate the families in their new surroundings, with Jenny far from school and the nearest friend, and Katie pretty close to just about everything, including the mall. And, happily, both gals can envision good times ahead in their new Home Sweet Homes. [End Page 147] Copyright © 2011 The Board of Trustees of the University of Illinois

Experimental investigation of flow and heat transfer in a rectangular channel with 45° angled ribs on one/two walls

The flow and heat transfer characteristics in a rectangular channel (aspect ratio AR = 5) with angled rib turbulators, inclined at 45°, have been investigated. The angled ribs were attached, with parallel orientations, on one or two surfaces of the channel. The ratio of rib height to hydraulic diameter ( e/ D) was 0.09, while the rib pitch-to-height ratio ( P/ e) was 10. Experiments were carried out using air as the convective fluid, with the Reynolds number Re = 29,000 and periodic fully developed conditions. The flow patterns were investigated by using laser-Doppler velocimetry (LDV), while the local heat transfer coefficients were provided by liquid crystal (LC) thermography. Inclined ribs are responsible for two-cell secondary flow when installed on two opposite walls of the channel and for one-cell secondary flow when placed on one wall only. The secondary flow brings relatively cold core fluid towards the rib leading end regions and warm fluid towards the opposite rib trailing end regions, causing marked spanwise variations in the local heat transfer coefficient.

Radiofrequency Guide Wire Recanalization of Venous Occlusions in Patients with Malignant Superior Vena Cava Syndrome

Fibrotic central venous occlusions in patients with thoracic malignancy and prior radiotherapy can be impassable with standard catheters and wires, including the trailing or stiff end of a hydrophilic wire. We report two patients with superior vena cava syndrome in whom we successfully utilized a radiofrequency guide wire (PowerWire, Baylis Medical, Montreal, Quebec, Canada) to perforate through the occlusion and recanalize the occluded segment to alleviate symptoms.

The effects of hitchhiker antigens co-eluting with affinity-purified research antibodies

The popularity of Protein G for the purification of antibodies has given rise to an entire industry that supplies scientists with research grade immunoreagents; however, many times the supplied product is contaminated with antigens bound to the antibody's complementarity-determining regions (CDRs). These “hitchhikers” are a category of host cell proteins that are elusive to detect due to their interaction with the antibody in the final product and yet their impact on an experiment or an entire field of study can be far reaching. In an earlier work, the role of hitchhikers on a human anti-histone antibody destined for clinical usage was explored and a stringent purification scheme developed. Here we use a murine monoclonal, which reflects the type of commercial antibody usually purchased for research. We evaluate three purification schemes: a traditional approach using a one-step, low pH elution buffer (pH 2.5); a gentler approach using a pH gradient elution scheme (pH 7 down to pH 2.5); and finally, a more stringent purification patterned on our earlier published method that uses a quaternary amine guard column and a high salt wash during antibody immobilization on the Protein G. We stress that the stringent purification incorporates the pH gradient scheme and is gentler than the low-pH approach. The resulting product from all three purifications is directly compared for binding potency, histone content (using an ELISA based assay) and residual DNA (using quantitative PCR). The results demonstrate that the first two methods are inadequate for hitchhiker removal. The traditional one-step, low pH approach produces a single elution peak containing histone contaminated antibody with picogram quantities of residual DNA, however, the trailing end of the same peak is loaded with antibody complexed to nanogram amounts of DNA, in some cases, over 100 ng. The pH gradient approach provided antibodies accompanied by only picograms of residual DNA and, on average, 1 out of every 10–20 CDRs occupied by a histone antigen. The more stringent approach, using the salt wash prior to elution with the pH gradient, has an average of 1 out of every 75 CDRs contaminated with a histone while the majority of the residual DNA is captured by the quaternary amine column placed in front of the Protein G. The consequences of these contaminants is illustrated by showing how they manifest themselves in unusual antibody potency values ranging from 558% for antibody bound to histone hitchhikers down to 15% for antibody contaminated with DNA hitchhikers. Those samples purified by the recommended stringent approach show potency values between 90 and 101%. Most importantly, we repeatedly demonstrate in a simulated chromatin immunoprecipitation (ChIP) assay the ability to precipitate clean plasmid DNA with histone contaminated antibody that had been purified using the traditional one-step, low pH elution approach. Expectedly, those antibodies stringently purified and showing 100% binding potency were unable to precipitate DNA in the absence of histone hitchhikers.