Reflected Light Image Research Articles

Rapid detection of turtle cracks in corn seed based on reflected and transmitted images combined with deep learning method

Cracks in corn seeds greatly affect their storage tolerance and germination ability. These cracks are categorized as single, double, and turtle cracks. The vigor experiment showed that turtle cracks lead to the poorest seed vigor, with significantly lower germination rates after artificial aging. Traditional methods to detect turtle cracks, like lightboxes, staining, and colorimetry, are inefficient or costly. Therefore, a detection method for turtle cracks of corn seeds based on reflected light and transmitted light images combined with deep learning was proposed. The transmitted and reflected light images on embryo and endosperm surfaces of 2000 corn seeds with different crack were collected. A Based on Self-Attention Modul Convolutional Neural Support Vector Networks (SACNSVN) model was proposed to detect the turtle cracks seeds, and compared with the model established by LSTM, CNN, BLR, SVM, and MLP. The effects of embryo surface, endosperm surface, varieties and maturity on turtle crack detection were investigated. The results showed that: (1) The transmitted light image had a significant correlation with 62 and 58 indicators of cracks and turtle cracks, respectively, which better reflected the crack and turtle crack seeds than reflected light image; (2) The accuracy of turtle cracks detection model based on embryo endosperm surface combined dataset were higher than embryo surface, endosperm surface, and embryo endosperm surface mixed dataset; (3) The SACNSVN model provides the optimal accuracy with 82.6%; (4) Variety greatly affects turtle crack detection in corn seeds, while maturity level has a minor impact, and SACNSVN exhibits strong generalization ability. This study provides significant technical support for optimizing the seed processing process and improving the seed quality.

Ultra-high-resolution reflected-light imaging for dendrochronology

Dendroclimatic reconstructions play a key role in contextualizing recent climate change by improving our understanding of past climate variability. The Blue Intensity (BI) measurement technique is gaining prominence as a more accessible alternative to X-ray densitometry for producing climatically highly-sensitive tree-ring predictors. Nevertheless, accurately representing low-frequency trends and high-frequency extremes using scanner-based BI remains a challenge due to color biases and resolution limitations. Herein we introduce several methodological advances in sample surfacing, imaging, and image processing which yield measurement series analogous to BI from ultra-high-resolution (UHR; ∼74 700 dpi) images. Such series capture changes in tree-ring anatomical density by representing wood anatomical structure using binary (i.e., black-white) segmentation of sample images. We refer to this novel technique as Binary Surface Intensity (BSI). By utilizing a UHR system and entirely eliminating color and light intensity as variables, the most substantial drawbacks of scanner BI (i.e., discoloration and resolution biases) are bypassed, resulting in more accurate representations of low-frequency climatic trends and high-frequency extremes. Comparisons of several chronologies developed with the BSI and BI techniques, including a multiparameter dataset from Björklund et al. (2019), showed that BSI datasets outperform BI in terms of common signal (r-bar), but also contain strong climatic signals that can exceed those obtained from BI and X-ray density, and even match density datasets based on quantitative wood anatomy. However, measurement software advancements are still required to unlock the full potential of tree-ring parameters produced using the BSI technique. Ongoing development of this new technique will not only aid the attainment of long unbiased chronologies by overcoming color biases and resolution limitations, but also holds promise for unlocking UHR analyses of surface anatomical (sQWA) parameter datasets from reflected-light images. These advances will lead to more accurate tree-ring-based paleoclimatic reconstructions and could also serve a wider range of dendrochronological applications.

Additive manufacturing leveraged microfluidic setup for sample to answer colorimetric detection of pathogens.

Colorimetric readout for the detection of infectious diseases is gaining traction at the point of care/need owing to its ease of analysis and interpretation, and integration potential with highly specific loop-mediated amplification (LAMP) assays. However, coupling colorimetric readout with LAMP is rife with challenges including, rapidity, inter-user variability, colorimetric signal quantification, and user involvement in sequential steps of the LAMP assay, hindering its application. To address these challenges, for the first time, we propose a remotely smartphone-operated automated setup consisting of (i) an additively manufactured microfluidic cartridge, (ii) a portable reflected-light imaging setup with controlled epi-illumination (PRICE) module, and (iii) a control and data analysis module. The microfluidic cartridge facilitates sample collection, lysis, mixing of amplification reagents stored on-chip, and subsequent isothermal heating for initiation of amplification in a novel way by employing tunable elastomeric chambers and auxiliary components (heaters and linear actuators). PRICE offers a new imaging setup that captures the colorimetric change of the amplification media over a plasmonic nanostructured substrate in a controlled and noise-free environment for rapid minute-scale nucleic acid detection. The control and data analysis module employs microprocessors to automate cartridge operation in tandem with the imaging module. The different device components were characterized individually and finally, as a proof of concept, SARS-CoV-2 wild-type RNA was detected with a turnaround time of 13 minutes, showing the device's clinical feasibility. The suggested automated device can be adopted in future iterations for other detection and molecular assays that require sequential fluid handling steps.

Automatic identification of semi-tracks on apatite and mica using a deep learning method

Fission track dating is a widely used thermochronological approach to constrain the thermal history of rocks. Conventionally this approach requires manual identification of fission tracks under the microscope which can be time-consuming and labor-intensive. In this study, we proceed with the newly developed approach to identify fission tracks on transmitted light images based on a deep learning method. In this new approach, we use a convolution neural network (CNN) to extract semi-tracks through image semantic segmentation. Considering the boundary ambiguity inherent in the CNN, we also extract the multi-scale boundary of the images in order to refine the semantic segmentation. We then calculate an area threshold of semi-tracks to determine whether semi-tracks are overlapping or not. These non-overlapping tracks are counted directly from the refined semantic segmentation images. For these overlapping tracks, we develop a boundary-superimposed method by using the refined semantic segmentation and the multi-scale boundary images with the help of the reflected-light images to split them before counting. We used 101 images of spontaneous fission tracks and 7 images of induced fission tracks for training with this new approach and tested the resulting convolutional neural networks on 114 spontaneous fission track images and 60 induced fission track images. Most of the test samples show high precision, recall, F1-score, and overall accuracy, highlighting the potential usage of this approach to identify fission tracks automatically.

Research on Biological Detection Based on Reflected Light Images of a Porous Silicon Bragg Mirror

In this paper, based on the gray value change of reflected light image of porous silicon (PSi) Bragg mirror, a fast and simple biological detection method is proposed. In this method, CdSe/ZnS quantum dots (QDs) are used as markers for refractive index amplification, and digital image method is used for detection. The detection light has the same wavelength as the lowest reflectivity of the edge of the Bragg mirror, and the reflected light radiated on the surface of the Bragg mirror is received by the detector. The theoretical simulation results show that the intensity of the reflected light increases with the increase of the refractive index caused by the biological reaction. According to the experimental results, the average gray value variation increases with the increase of the target DNA concentration and becomes a linear relationship in a certain range. Based on this method, the DNA detection limit is 20.74 pM. The method is low-cost, has a short detection time and can be used in the detection of biosensor microarray.

Curcumin nanoparticle doped starch thin film as a green colorimetric sensor for detection of boron

A tapioca starch film doped with curcumin nanoparticles was successfully fabricated and applied as a novel green colorimetric sensor for detection of boron in wastewater. Curcumin nanoparticles (curn, 30-90 nm) extracted from turmeric powder were used as a green probe, while tapioca starch was used as a natural support substrate. A yellow thin film (51 μm thick) fabricated on a used plastic spoon turned red-brown after immersion in boron solution (pH 9) for 15 min with excellent selectivity. The film costs only 0.0007 USD, while the cost of the sensor (curn-film on new plastic spoon) was 0.004 USD. After use the film could be completely washed from the plastic, it being biodegradable, while the used plastic spoon could be re-used to fabricate a new sensor at least 10 times. The good 1.52%RSD precision was obtained across three lots fabricated. When the curn-film was used in conjunction with digital image colorimetry (DIC), a simple and rapid quantification of boron was achieved. The green color layer in reflected light image of the red-brown product (IG) provided the highest sensitivity (64 ± 1 a.u. L mg-1) and the lowest detection limit of 0.052 ± 0.001 mg L-1. The intra-day testing (9 films) had 2.41 to 4.34%RSD, while the inter-day testing had 2.29 to 5.66%RSD (15 films, 5 days). Accuracy in terms of relative error for control samples (0.40 mg L-1) was+3.63%. Wastewater samples from Para-rubber wood processing plant were quantified by curn-film and DIC, giving 4248 ± 391 mg L-1 boron concentration with no significant difference to ICP determination at 95% confidence level. The sensors after storage in a desiccator for a year gave readings changed by only+3.5% and-2.1% relative to freshly prepared sensors.

Permian (Kungurian) Foraminifera from Western Australia described by Walter Parr in 1942: reassessment and additions

Haig, D.W., October 2017. Permian (Kungurian) Foraminifera from Western Australia described by Walter Parr in 1942: reassessment and additions. Alcheringa 42, 37–66. ISSN 0311-5518.Exceptionally well-preserved siliceous agglutinated Foraminifera originally recorded by Walter Parr in 1942 are redescribed and illustrated by rendered multifocal reflected-light images. Significant new observations are made on wall texture and apertural morphology. The specimens are from the Quinnanie Shale and lower Wandagee Formation in the Merlinleigh Sub-basin of the Southern Carnarvon Basin, a marginal rift that splayed from the East Gondwana interior rift. During the Early Permian, a restricted shallow sea inundated the rift. The formations are part of sequence III of the Byro Group and belong within the Kungurian Stage (Cisuralian, Lower Permian). Of the 14 agglutinated species described by Parr, six are retained under their original names, viz., Hyperammina coleyi Parr, 1942, H. rudis Parr, 1942, Ammodiscus nitidus Parr, 1942, A. wandageeensis Parr, 1942, Tolypammina undulata Parr, 1942 and Reophax tricameratus Parr, 1942; one is transferred to a different species, viz., Thurammina texana Cushman & Waters, 1928a; six are placed with other genera, viz., Thuramminoides pusilla (Parr, 1942), Teichertina teicherti (Parr, 1942), Sansabaina acicula (Parr, 1942), Tolypammina? adhaerens (Parr, 1942), Kunklerina subasper (Parr, 1942), Trochamminopsis subobtusa (Parr, 1942); and a species of Ammobaculites Cushman, 1910 identified by Parr is now left in open nomenclature. From Parr's material, eight additional species are described: two new species, viz., Hyperammina parri sp. nov. and Gaudryinopsis raggatti sp. nov.; rare representatives of Aaptotoichus quinnaniensis Haig, 2003; and very rare species of Lagenammina Rhumbler, 1911, Giraliarella Crespin, 1958, Glomospira Rzehak, 1885, Hormosinella Shchedrina, 1969, and Reophax Denys de Montfort, 1808, all of which are left in open nomenclature. Hyperammina rudis is the type species of Hyperamminita Crespin, 1958, a genus now considered a junior subjective synonym of Hyperammina Brady, 1878. Thuramminoides pusilla is considered a senior subjective synonym of T. sphaeroidalis Plummer, 1945, the type species of Thuramminoides Plummer, 1945. Imagery is presented confirming that the simple cylindrical canals through the wall of Teichertia teicherti differ from the branching canals in Crithionina rotundata Cushman, 1910, type species of Oryctoderma Loeblich & Tappan, 1961. The collection contains some of the earliest representatives of the revised family Verneuilinoididae Suleymanov, 1973, herein elevated from subfamily rank, and considered to include Pennsylvanian–Cisuralian representatives of Mooreinella Cushman & Waters, 1928a, Aaptotoichus Loeblich & Tappan, 1982, Digitina Crespin & Parr, 1941, Gaudryinopsis Podobina, 1975, Caronia Brönnimann, Whittaker & Zaninetti, 1992 (=Palustrella Brönnimann, Whittaker & Zaninetti, 1992) and Verneuilinoides Loeblich & Tappan, 1949.David W. Haig [david.haig@uwa.edu.au] Centre for Energy Geoscience, School of Earth Sciences, University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia.

Image Processing of Porous Silicon Microarray in Refractive Index Change Detection.

A new method for extracting the dots is proposed by the reflected light image of porous silicon (PSi) microarray utilization in this paper. The method consists of three parts: pretreatment, tilt correction and spot segmentation. First, based on the characteristics of different components in HSV (Hue, Saturation, Value) space, a special pretreatment is proposed for the reflected light image to obtain the contour edges of the array cells in the image. Second, through the geometric relationship of the target object between the initial external rectangle and the minimum bounding rectangle (MBR), a new tilt correction algorithm based on the MBR is proposed to adjust the image. Third, based on the specific requirements of the reflected light image segmentation, the array cells are segmented into dots as large as possible and the distance between the dots is equal in the corrected image. Experimental results show that the pretreatment part of this method can effectively avoid the influence of complex background and complete the binarization processing of the image. The tilt correction algorithm has a shorter computation time, which makes it highly suitable for tilt correction of reflected light images. The segmentation algorithm makes the dots in a regular arrangement, excludes the edges and the bright spots. This method could be utilized in the fast, accurate and automatic dots extraction of the PSi microarray reflected light image.

High-temperature magnetic fabric development from plastically deformed magnetite in experimental shear zones

Magnetic fabric development has been studied in synthetic magnetite-silicate aggregates in a series of high-temperature simple shear deformation experiments. Samples composed of magnetite grains with a nominal size of 20-40 µm dispersed at 3 wt % in a matrix of plagioclase were deformed between 1000 and 1200 °C with a confining pressure of 300 MPa, shear stresses in the range 10-130 MPa, and shear strains up to γ = 3. We determined that both magnetite and plagioclase were deformed plastically at these conditions. An oblate magnetic fabric ellipsoid develops subparallel to the shear plane and the degree of AMS rapidly increases with strain up to a value of 2.5. Theoretical strain response models of magnetic fabric development were applied to the data to obtain estimated magnetite strains. The shape-preferred orientation of magnetite grains after deformation, determined from reflected light image analysis, was used to calculate independent magnetite strain estimates. These results were then compared with strains estimated from theoretical magnetic anisotropy development. Both strain estimation methods indicate strain partitioning between magnetite and the plagioclase matrix and the results are used to determine approximate viscosity ratios between the two phases at the experimental conditions.

How Do Craftspeople Distinguish The Appearance of Natural-Lacquerware?-Approach by Optical Image Analysis-

The light reflective images of natural Japanese lacquer paints applied on a board were analysed in addition to their colour and gloss measurements, in order to clarify the optical characteristics of the paint, which craftspeople can distinguish. The distribution of luminance on sample images was obtained at two angles under visible light irradiation and the envelope intensity curve was taken from the luminance histogram for black natural-lacquer-painted and chemically coated boards. There are no distinguishing differences in the spectroreflectance and gloss characteristics for the three kinds of black sample boards. It was found by the Gaussian curve fitting for the reflected light profile in the vicinity of the edge of reflected light image on the samples that the glossy natural-lacquer-painted sample shows the smallest area and standard deviation value of the reflected light profile. The results show that the glossy natural-lacquer-painted board reflects light most regularly and the diffusion of the light is smallest. Further, the area and standard deviation values for only the glossy natural-lacquer-painted sample decrease with an increase in the angle between the directions of the normal to the plane of the sample and the reflected sample image.

A new method for measurement of annual growth rings in cork by means of autofluorescence

A new method for measuring annual growth rings in cork has been developed. It is based on the fact that excitation of Quercus suber L. cork cross-sectional planes with UV light and also with blue light results in enhanced autofluorescence at the growth ring borders. This distinct autofluorescence band is located in the cork produced at the end of the vegetation period, with its smaller cells and thicker cell walls. The enhanced autofluorescence of polyphenolics mainly results from a very thick suberin layer in the walls of the small late cork cells. The gradient in autofluorescence from late cork to first early cork is steep. The best visibility of cork annual rings was found under the epifluorescence microscope in 60 μm thick microtome cork cross sections. For fast screening of high sample numbers scanning the blue-excited (473 nm) fluorescence of water wetted polished cross-sectional surfaces of cork pieces with a laser-equipped fluorescence image analyzer was most suitable. Evaluation of visibility of cork rings showed a clear improvement in comparison with reflected light image analysis; thus data obtained with this new autofluorescence scanning method are excellent for modeling the yearly growth increment of cork.

Coincidence mapping - a key strategy for the automatic counting of fission tracks in natural minerals

Abstract We report on new image-analysis techniques that, for the first time, provide a practical solution to the problem of fully automated counting of fission tracks in natural minerals, a long-desired goal in fission-track dating. Specific challenges to be overcome have been the discrimination of fission tracks from non-track defects, polishing scratches, etc.; resolving multiple track overlaps; and reliable identification of small tracks amongst a similarly sized background of surface defects, fluid inclusions, etc. Most previous attempts at automated image analysis have failed in one or more of these tasks. The central component of our system is called ‘coincidence mapping’ and utilizes two images of the same tracks obtained in transmitted and reflected light. The complementary nature of the information in these two images allows a powerful discrimination of true fission tracks from most non-track features. The much smaller average track size in the reflected light image allows the resolution of most track overlaps apparent in transmitted light. The discrimination is achieved by segmenting the two images using a custom-developed thresholding routine and extracting the coincidence of features in the two binary images. The analysis is computationally efficient and takes only a few seconds to complete the processing of images that may contain up to many hundreds of tracks. Preliminary indications are that error rates are about the same as, or better than, those achieved by a human operator using normal counting conditions in transmitted light. The performance is even better at high track densities (>10 7 cm −2 ) giving the potential for measuring track densities up to an order of magnitude greater than a human operator can count. Automated counting should significantly increase the speed and consistency of analysis and improve data quality in fission-track dating through better counting statistics, increased objectivity and measurement of additional track description parameters that are not currently determined.

Solving the "Magnification Irony" in Microscope-Based Reflected Light Image Analysis of Conifer Tree Rings

This paper describes a technique for allowing the magnification of a microscope to be changed and still obtain quantitative reflectance values for low-magnification reflected light image analysis of conifer tree rings. A remotely controllable digital camera is used to capture images, and a multireflectance gray standard is used to calibrate the luminance response of the camera across a range of reflectances. The imaging system was tested by measuring two conifer rings of differing widths and densities at several different levels of magnification. Upon adjusting the camera and converting gray values to true reflectances, the earlywood maximum and latewood minimum reflectances of each ring were essentially identical across all magnification settings. Total ring widths were also equal across all magnification settings. The "magnification irony" is solved for microscope-based reflected light image analysis of conifer tree rings, and reflected light image analysis of conifer tree rings should become more prominent in future dendrochronological investigations.

A105 水面反射光を用いた波面計測法

The reflected light image method has been developed to measure unsteady wave height distributions. In this method, the gradient vector distribution of water surface height can be obtained through image analysis. And the wave height distribution can be reconstructed from the measured gradient distribution and a known height at one point. In this paper, we made the following modifications to measure the waves around a model ship :(i) Formulation errors in calculating gradient are modified, (ii) Random pattern and grid pattern are used as the reference images, (iii) A new technique to reconstruct height from gradient is applied. Direct cross correlation method is applied to image tracking. But in the case of a wave having large surface curvature, a point in the reference pattern corresponds to several points in the deformed surface image, therefore we used grid pattern as a reference image and tracked the grid points manually.

C104 反射光による非定常波高計測法の開発

C104 反射光による非定常波高計測法の開発

Digital thin-film color optical memory

A promising optical memory device called digital thin-film (DTF) color optical memory is presented. The DTF optical memory utilizes localized regions of varying thickness to adjust the spectral characteristic of reflected light from a broad band source. The DTF structure has been fabricated by Ga+ focused ion beam milling on thermally grown silicon dioxide on Si to prove the concept. A charge-coupled device array is used as the optical detector for the readout of the stored data. The reflected light image of the DTF memory reveals easily discriminated color levels and proves the suitability of using optical means to extract the stored data. DTF optical memory structures with 16 physical levels or 4 bits/pixel have been fabricated providing an equivalent storage density in excess of 5 Gb/in.2

Measuring Surface Roughness on Stone: Back to Basics

Stylus profilometry, reflected-light image analysis and visual/tactile evaluation were tested as techniques for assessing roughness of abrasive-blasted stone. Measurement of microdrop water absorption time was also tested as a complementary technique. Instrumental techniques showed significant shortcomings when measuring surfaces of roughness similar to most weathered stone, as well as flame-finished surfaces comparable to tooled stone. Tactile comparison of surfaces wasfound to be a more practical and cost-effective technique. On historic masonry structures, however, soiling and uneven weathering limit the usefulness of roughness as a property to be measured in evaluating cleaning techniques.

The Circumstellar Disk of HD 141569 Imaged with NICMOS.

Coronagraphic imaging with the Near-Infrared Camera and Multiobject Spectrometer on the Hubble Space Telescope reveals a large, approximately 400 AU (4&arcsec;) radius, circumstellar disk around the Herbig Ae/Be star HD 141569. A reflected light image at 1.1 µm shows the disk oriented at a position angle of 356&j0;+/-5&j0; and inclined to our line of sight by 51&j0;+/-3&j0;; the intrinsic scattering function of the dust in the disk makes the side inclined toward us, the eastern side, brighter. The disk flux density peaks 185 AU (1&farcs;85) from the star and falls off to both larger and smaller radii. A region of depleted material, or a gap, in the disk is centered 250 AU from the star. The dynamical effect of one or more planets may be necessary to explain this morphology.

Protective role for proteoglycans against cationic lipid cytotoxicity allowing optimal transfection efficiency in vitro

A dependence on proteoglycans for cationic lipid-mediated gene transfer has been suggested in previous studies [Mislick and Baldeschwieler (1996) Proc. Natl. Acad. Sci. U.S.A. 93, 12349-12354; Mounkes, Zhong, Cipres-Palacin, Heath and Debs (1998) J. Biol. Chem. 273, 26164-26170]. We have evaluated the mechanism of proteoglycan involvement in cationic lipid-mediated gene transfer. DNA plasmid uptake and gene expression were studied in wild-type Chinese hamster ovary (CHO) cells (CHO-K1), heparan sulphate-deficient CHO cells (pgsD-677) and proteoglycan-deficient CHO cells (pgsB-618). At an optimal ratio of cationic lipid to DNA, a substantial decrease in reporter gene expression was observed in proteoglycan-deficient cells compared with that in heparan sulphate-deficient and wild-type cells. However, there were no differences in reporter gene expression between the cell lines when transfected by electroporation. Moreover, all cell lines exhibited equal cationic-lipid-DNA complex uptake activities, as assessed by the measurement of intracellular 32P-labelled and rhodamine-labelled DNA plasmid. An analysis of reflected-light images of wild-type and proteoglycan-deficient cells suggested that cationic lipids were preferentially toxic to proteoglycan-deficient cells. Cell-growth assays confirmed this, showing that cationic lipids exhibited a greater anti-proliferative activity in proteoglycan-deficient cells and in chlorate-treated wild-type cells than in the other cell lines. The growth-inhibitory effect of cationic lipids was abrogated by the addition of exogenous sulphated glycosaminoglycans. We conclude that the glycosaminoglycan part of proteoglycans serves a protective role against cationic lipid cytotoxicity, allowing optimal transfection efficiency in vitro.

Protective role for proteoglycans against cationic lipid cytotoxicity allowing optimal transfection efficiency in vitro

A dependence on proteoglycans for cationic lipid-mediated gene transfer has been suggested in previous studies [Mislick and Baldeschwieler (1996) Proc. Natl. Acad. Sci. U.S.A. 93, 12349-12354; Mounkes, Zhong, Cipres-Palacin, Heath and Debs (1998) J. Biol. Chem. 273, 26164-26170]. We have evaluated the mechanism of proteoglycan involvement in cationic lipid-mediated gene transfer. DNA plasmid uptake and gene expression were studied in wild-type Chinese hamster ovary (CHO) cells (CHO-K1), heparan sulphate-deficient CHO cells (pgsD-677) and proteoglycan-deficient CHO cells (pgsB-618). At an optimal ratio of cationic lipid to DNA, a substantial decrease in reporter gene expression was observed in proteoglycan-deficient cells compared with that in heparan sulphate-deficient and wild-type cells. However, there were no differences in reporter gene expression between the cell lines when transfected by electroporation. Moreover, all cell lines exhibited equal cationic-lipid-DNA complex uptake activities, as assessed by the measurement of intracellular (32)P-labelled and rhodamine-labelled DNA plasmid. An analysis of reflected-light images of wild-type and proteoglycan-deficient cells suggested that cationic lipids were preferentially toxic to proteoglycan-deficient cells. Cell-growth assays confirmed this, showing that cationic lipids exhibited a greater anti-proliferative activity in proteoglycan-deficient cells and in chlorate-treated wild-type cells than in the other cell lines. The growth-inhibitory effect of cationic lipids was abrogated by the addition of exogenous sulphated glycosaminoglycans. We conclude that the glycosaminoglycan part of proteoglycans serves a protective role against cationic lipid cytotoxicity, allowing optimal transfection efficiency in vitro.