Maternal exposure to DON during lactation induces testicular toxicity in pubertal and adult offspring mice.

Deoxynivalenol (DON), a type B trichothecene mycotoxin, commonly occurs in cereal grains, and poses significant health risks to humans and animals. Numerous studies reveal its obvious toxic effects on male reproductive performance as well as its ability to transfer from the lactating mother to the suckling offspring through colostrum and milk. The objective of this study was to evaluate the toxic effect of lactational DON exposure on testicular morphology, hormonal levels, inflammation, apoptosis and proliferation of germ cells, tight junction, and sperm quality in male offspring. Sixty-six male offspring mice from lactating dams exposed to DON were euthanized at PND 21 and PND 70 to investigate the reproductive toxicity. Our results indicated that maternal DON exposure had a significant impact on the weight and volume of the testes, caused testicular histopathology, and reduced testosterone levels by downregulating expressions of StAR, CYP11A1, and CYP17A1 in male offspring. We also found that maternal DON exposure led to testicular inflammation in male offspring, which was attributed to increased levels of inflammatory markers, including IL-1ß, IL-6, TNF-α, and IFN-γ. Maternal DON exposure resulted in impaired tight junctions of Sertoli cells in male offspring, as evidenced by decreased expressions of ZO-1, Occludin, and Claudin-3. In addition, maternal DON exposure caused a reduction in the number of Sertoli cells and germ cells, ultimately leading to decreased sperm count and quality in adult male offspring. Collectively, these findings provide compelling evidence that maternal exposure to DON during lactation causes testicular toxicity in both pubertal and adult male offspring.

Visual acuity assessment of central retinal artery occlusion patients with or without paracentral acute middle maculopathy via OCT-A.

PURPOSE: The association between paracentral acute middle maculopathy (PAMM) and visual acuity in patients with central retinal artery occlusion (CRAO) is still unclear. The present study investigated the visual acuity of CRAO patients with and without PAMM. METHODS: CRAO patients with PAMM or without PAMM were included. Optical coherence tomography angiography (OCT-A) was used to record the macular retinal thickness and density of shallow and deep vessels. The Best-corrected visual acuity (BCVA) was converted to a logarithm of the minimum angle of resolution (LogMAR) for statistical analysis. RESULTS: There were 34 CRAO patients with PAMM (43.13%), other 30 CRAO patients without PAMM (46.87%). Compared with the no-PAMM group, PAMM group had better LogMAR BCVA (1.48 (0.49, 1.85) Vs. 1.85 (1.70, 1.96), P < 0.01). There was also a significant difference in retinal thickness of the central macular sulcus (328.00 (304.50-332.25) Vs. 352.50 (311.75-420.50), P = 0.01). A significant correlation between LogMAR BCVA and macular retinal thickness was found (r = 0.42; P < 0.01). CONCLUSION: CRAO patients with PAMM had significantly better visual acuity and less macular edema. OCT-A can be used to distinguish different levels of damage due to CRAO.

Posterior capsular opacification comparison between morphology and objective visual function.

BACKGROUND: To compare the influence of posterior capsule opacification (PCO) morphology and severity on intraocular stray light and visual function with different levels of contrast. METHODS: Forty-five patients diagnosed with PCO were included in this prospective consecutive case series. The Optical Quality Analysis System II (OQAS II) was adopted to assess the objective visual function including objective scatter index (OSI) and optical quality analysis system values (OVs) with 100, 20, and 9% contrast. RTVue-100 OCT was used to evaluate the PCO morphology and severity. Comparisons among visual function, morphology, and severity between pear type and fibrosis PCO were performed. The correlations among the PCO morphology, severity, OSI, and OVs were also determined. RESULTS: There was a significant correlation between increased OSI and decreased visual acuity in PCO patients before laser capsulotomy. The changes of OSI were also correlated with the PCO area for the 3 mm IOL optic region (r = 0.43, p = 0.02). The OSI was significantly higher in pear type PCO when compared with fibrosis PCO (Z = - 4.06, p ≤ 0.001). In addition, the increased OSI in pear type PCO was significantly correlated with the 100% OVs and the 20% OVs but not with the 9% OVs. In fibrosis PCO, OSI was only correlated with the 100% OVs and the 20% OVs pre-YAG. CONCLUSIONS: OSI and OVs could objectively indicate the visual function impairment in PCO patients. Effects of PCO on light scattering and on objective visual function might be explained by the variations of morphology and severity.

OCTA characteristics in non-arteritic central retinal artery occlusion and correlation with visual acuity.

AIM: To observe the retinal and choroidal circulations in patients with non-arteritic permanent central retinal artery occlusion (NA-CRAO) via optical coherence tomography angiography (OCTA) and analyze their correlation with visual acuity. METHODS: Sixty-two eyes with clinically confirmed acute NA-CRAO were included in the study and divided into: A type (mild n=29), B type (moderate n=27) and C type (severe n=6) based on the degree of visual loss, retinal edema, and arterial blood flow delay in fundus fluorescence angiography (FFA). Contralateral healthy eyes were used as the control group. Best-corrected visual acuity (BCVA), slit lamp microscopy, indirect ophthalmoscopy, fundus color photography, OCTA, and FFA were performed. Spearman's correlation analysis was used to determine the correlations between retinal and choroidal vessels and visual acuity. RESULTS: There were no statistically significant differences in age, gender, and intraocular pressure among the three types and the control group (P>0.05). Vessel density in deep capillary plexus (VD-DCP) significantly decreased (P<0.05) in all three types of NA-CRAO patients compared to the control group. Vessel density in superficial vascular plexus (VD-SVP) significantly decreased (P<0.05) in type A patients and choriocapillaris flow area significantly decreased (P<0.05) in type B and type C patients compared to the control group; while outer retinal flow areas significantly increased in the type A (P<0.05) and decreased in type C patients (P<0.05). The retinal thickness significantly increased in type C group (P<0.05). The VD-SVP at fovea in the type A was significantly lower than both of type B and C. The VD-SVP at nasal parafovea in type A and B was significantly lower than type C (P<0.05). The logMAR BCVA of type A was significantly better than that of type B and C groups (P<0.05). Spearman's correlation analysis showed that the logMAR BCVA was positively correlated with VD-SVP at fovea (r=0.679, P=0.031) and nasal parafovea (r=0.826, P=0.013). CONCLUSION: OCTA is valuable for assessing retinal ischemia, and evaluating visual impairment. Deep retinal vasculature is commonly affected in all NA-CRAO types. VD-SVPs at fovea and nasal parafovea can serve as reliable markers of visual impairment in NA-CRAO.

Non-arteritic anterior ischemic optic neuropathy combined with branch retinal vein obstruction: A case report.

BACKGROUND: Non-arteritic anterior ischemic optic neuropathy (NAION) is an independent disease characterized by edematous optic discs. In eyes with branch retinal vein occlusion (BRVO), the arteries and veins in the ethmoid plate of the optic disc are relatively crowded; however, a combination of the two is clinically uncommon. Herein, we reported a patient with NAION and concealed BRVO, for which the treatment and prognosis were not similar to those for NAION alone. CASE SUMMARY: Herein, we report a case of NAION with concealed BRVO that did not improve with oral medication. A week later, we switched to intravenous drug administration to improve circulation, and the patient's visual acuity and visual field recovered. Hormonal therapy was not administered throughout the study. This case suggested that: (1) Fundus fluorescein angiography (FFA) can help detect hidden BRVO along with the NAION diagnosis; (2) intravenous infusion of drugs to improve circulation has positive effects in treating such patients; and (3) NAION with concealed BRVO may not require systemic hormonal therapy, in contrast with the known treatment for simple NAION. CONCLUSION: NAION may be associated with hidden BRVO, which can only be observed on FFA; intravenous therapy has proven effectiveness.

High-power ultraviolet 278 nm laser from fourth-harmonic generation of a Nd:YAG laser in CsB3O5.

We demonstrate a high-power UV 278 nm laser by fourth-harmonic generation (FHG) of a 1112 nm Nd:YAG laser in a nonlinear optical (NLO) crystal CsB3O5 (CBO) for the first time, to our best knowledge. A 30 W level diode-pumped Q-switched Nd:YAG laser at 1112 nm with beam quality factor M2=1.2 was used as the fundamental light source at a pulse width of 500 ns. With an LiB3O5 crystal, the 1112 nm laser was first frequency-doubled to 556 nm with an average output power of 13.5 W. It was then frequency doubled again in a CBO crystal to obtain the FHG output at 278 nm. The maximum average output power of the 278 nm laser is up to 1.5 W. The results demonstrated that CBO crystal is a promising NLO material for UV high-power lasers below 300 nm.

Multiwavelength green-yellow laser based on a Nd:YAG laser with nonlinear frequency conversion in a LBO crystal.

We demonstrate a multiwavelength laser in the green-yellow region by means of a diode-pumped neodymium-doped yttrium aluminum garnet laser. This laser system combines a homemade 1074 nm and 1112 nm dual-wavelength laser with extracavity second harmonic generation (SHG) or sum-frequency generation in a lithium triborate crystal to generate visible output at any one of three wavelengths, 537 nm, 546 nm, and 556 nm, by simple temperature tuning, which has an important application in detecting carbon monoxide. The maximum average output power at the three wavelengths (537 nm, 546 nm, and 556 nm) was obtained to be 10.5 W, 0.5 W, and 8.5 W, respectively. The maximum SHG conversion efficiency from the infrared to the visible spectral region was about 51%.

High-power narrow-linewidth quasi-CW diode-pumped TEM00 1064 nm Nd:YAG ring laser.

We demonstrated a high average power, narrow-linewidth, quasi-CW diode-pumped Nd:YAG 1064 nm laser with near-diffraction-limited beam quality. A symmetrical three-mirror ring cavity with unidirectional operation elements and an etalon was employed to realize the narrow-linewidth laser output. Two highly efficient laser modules and a 90° quartz rotator for birefringence compensation were used for the high output power. The maximum average output power of 62.5 W with the beam quality factor M(2) of 1.15 was achieved under a pump power of 216 W at a repetition rate of 500 Hz, corresponding to the optical-to-optical conversion efficiency of 28.9%. The linewidth of the laser at the maximum output power was measured to be less than 0.2 GHz.

Loratadine-associated cystoid macular edema: A case report.

Purpose: To report the first known case of bilateral cystoid macular edema in a patient undergoing long-term loratadine treatment. Observations: A 49-year-old Chinese woman who had been undergoing treatment with loratadine for the past 6 years presented with decreased visual acuity and bilateral cystoid macular edema (CME). Upon cessation of loratadine, macular edema partially resolved, and visual acuity markedly improved. Fundus autofluorescence (FAF), optical coherence tomography (OCT), and fluorescence fundus angiography (FFA) were used to document the severity of CME and its subsequent resolution after cessation of loratadine therapy. Conclusions and Importance: Long-term use of loratadine might cause CME that partially resolves with discontinuation of the drug. The pathophysiology of drug-induced CME without leakage remains unclear. Dysfunction of histamine receptor1-expressed retinal neurons and the associated signal transduction, toxicity to Müller cells or RPE cells with subsequent intracellular fluid accumulation, and subclinical damage to the blood-retina barrier leading to leakage of extracellular fluid, have been proposed.

Effect of amblyopia treatment on macular microvasculature in children with anisometropic amblyopia using optical coherence tomographic angiography.

To measure the retinal microvascular density in patients with anisometropic amblyopia using optical coherence tomographic angiography (OCTA) and to evaluate the effects of successful amblyopia treatment on microvasculature in retina. 59 children (5-12 years old) including 22 newly diagnosed unilateral anisometropic amblyopia, 16 recovered unilateral anisometropic amblyopia, and 21 control children were imaged with OCTA using 6 × 6-mm macular scan pattern. Vessel densities of the superficial capillary plexus (SCP), the deep capillary plexus (DCP), and the overall macular thickness were acquired and compared among the three groups. After adjustment for axial length, the amblyopia group showed lower macular vessel density in the SCP (P = 0.005) and in the DCP (P = 0.004) compared with that of the control group. However, for the recovered amblyopia group, no difference of vessel density was found when compared with the control group in both the SCP (P = 0.548) and the DCP (P = 0.124). No difference of the mean macular thickness was found among three groups (P ≥ 0.15). Children with anisometropic amblyopia have reduced macular vessel density in OCTA, while no difference of macular vessel density was found between the recovered amblyopic and control eyes. Macular thickness showed no difference in anisometropic amblyopia and remained unchanged after amblyopic treatment.

Characteristics of fixation patterns and their relationship with visual function of patients with idiopathic macular holes after vitrectomy.

To analyze the relationships between the fixation location and the visual function of idiopathic macular hole (IMH) patients with macular integrity assessment (MAIA) examination preoperatively and 3 months postoperatively. This was a retrospective case analysis. Forty-three eyes of 43 patients diagnosed with IMH were included in this study. The best corrected visual acuity (BCVA) assessments, optical coherence tomography (OCT) and MAIA examinations were performed before surgery and 1 week, 1 month and 3 months after surgery. The relationships between MAIA parameters and visual acuity were assessed by correlation analysis. Grouping by fixation location with the foveola (2°) as the centre, the locations could be divided into five groups, including foveolar, temporal, nasal, inferior and superior fixation. The mean macular sensitivity (MMS) of the macular area was correlated with the BCVA in the IMH patients before and 3 months after surgery (before surgery P = 0.00, after surgery P = 0.00). The MMS could be used as a good indicator for evaluating visual function in IMH patients. There was a significant difference in fixation location before and after the operation (P = 0.01). The preoperative fixation location of IMH patients was mainly in the superior area, while postoperatively moved to the foveola and nasal areas. Paying attention to the changes of fixation locations in IMH patients may provide new clues for further improving postoperative visual function.

A homeobox gene is essential for conidiogenesis of the rice blast fungus Magnaporthe oryzae.

Magnaporthe oryzae starts its infection by the attachment of pyriform conidia on rice tissues, and severity of the disease epidemic is proportional to the quantity of conidia produced in the rice blast lesions. However, the mechanism of conidial production is not well understood. Homeodomain proteins play critical roles in regulating various growth and developmental processes in fungi and other eukaryotes. Through targeted gene replacement, we find that deletion of HTF1, one of seven homeobox genes in the fungal genome, does not affect mycelial growth but causes total defect of conidial production. Further observation revealed that the Deltahtf1 mutant produces significantly more conidiophores, which curve slightly near the tip but could not develop sterigmata-like structures. Although the Deltahtf1 mutant fails to form conidia, it could still develop melanized appressoria from hyphal tips and infect plants. The expression level of HTF1 is significantly reduced in the Deltamgb1 G-beta and DeltacpkA deletion mutant, and the ACR1 but not CON7 gene that encodes transcription factor required for normal conidiogenesis is significantly downregulated in the Deltahtf1 mutant. These data suggest that the HTF1 gene is essential for conidiogenesis, and may be functionally related to the trimeric G-protein signaling and other transcriptional regulators that are known to be important for conidiation in M. oryzae.

Compact high-efficiency 100-W-level diode-side-pumped Nd:YAG laser with linearly polarized TEM00 mode output.

We present a compact high-efficiency and high-average-power diode-side-pumped Nd:YAG rod laser oscillator operated with a linearly polarized fundamental mode. The oscillator resonator is based on an L-shaped convex-convex cavity with an improved module and a dual-rod configuration for birefringence compensation. Under a pump power of 344 W, a linearly polarized average output power of 101.4 W at 1064 nm is obtained, which corresponds to an optical-to-optical conversion efficiency of 29.4%. The laser is operated at a repetition rate of 400 Hz with a beam quality factor of M(2)=1.14. To the best of our knowledge, this is the highest optical-to-optical efficiency for a side-pumped TEM(00) Nd:YAG rod laser oscillator with a 100-W-level output ever reported.

Yellow-green 52.3W laser at 556nm based on frequency doubling of a diode side-pumped Q-switched Nd:YAG laser.

We demonstrate a high-power 556nm yellow-green laser generated by intracavity frequency doubling of a diode side-pumped Nd:YAG laser at 1112nm. A symmetrical L-shaped flat-flat cavity was employed to implement efficient operation of the low-gain 1112nm transition and to achieve good power scalability. The coatings of the cavity mirrors were carefully designed to optimize the performance of the laser, and a 92W continuous wave laser output at 1112nm was achieved when the pumping power of the laser diodes reached 960W. By intracavity frequency doubling of the fundamental laser in a lithium triborate crystal, the maximum power of the frequency-doubled output at 556nm was found to be as high as 52.3W with a pulse repetition frequency of 10kHz. This corresponds to an optical-to-optical conversion efficiency of about 5.4%.

Rice PcG gene OsEMF2b controls seed dormancy and seedling growth by regulating the expression of OsVP1.

The induction and release of seed dormancy are a precisely regulated process that influences seed germination. ABA promotes seed dormancy but suppresses seed germination and seedling growth. However, how chromatin and epigenetic mechanisms regulate the expression of ABA related genes during these processes remains unclear. Polycomb gene OsEMF2b was required for regulation of seed dormancy and seedling growth by dynamically activating and repressing ABA signal response genes. Downregulation of OsEMF2b led to vivipary and decreased expression level of OsVP1, which was involved in ABA signal pathway in seed dormancy. While, the seedlings with downregulation of OsEMF2b exhibited hyper-sensitive response to ABA and the expression of OsVP1 is upregulated. Yeast one-hybrid assay and ChIP analyses proved that OsEMF2b could bind to the promoter of OsVP1 directly and affected H3K27me3 enrichments of OsVP1 in seedling. Interestingly, both H3K27me3 and H3K4me3 enrichments of OsVP1 were changed with OsEMF2b mis-expression in seed and seedling. We proposed that OsEMF2b may play a pivotal role in seed dormancy and seedling growth by regulating the expression of OsVP1 indirectly or directly.

Change of Retinal Nerve Layer Thickness in Non-Arteritic Anterior Ischemic Optic Neuropathy Revealed by Fourier Domain Optical Coherence Tomography.

PURPOSE: To examine the changes of non-arteritic anterior ischemic optic neuropathy (NAION) by serial morphometry using Fourier domain optical coherence tomography (FD-OCT). MATERIALS AND METHODS: Retrospective study in patients with newly diagnosed NAION (n=33, all unilateral) and controls (n=75 unilateral NAION patients with full contralateral eye vision) who underwent FD-OCT of the optic disk, optic nerve head (ONH), and macula within 1 week of onset and again 1, 3, 6, and 12 months later. The patients showed no improvement in vision during follow-up. RESULTS: Within 1 week of onset, all NAION eyes exhibited severe ONH fiber crowding and peripapillary retinal nerve fiber layer (RNFL) edema. Four had subretinal fluid accumulation and 12 had posterior vitreous detachment (PVD) at the optic disc surface. Ganglion cell complex (GCC) and RNFL thicknesses were reduced at 1 and 3 months (p < 0.05), with no deterioration thereafter. Initial RNFL/GCC contraction magnitude in the superior hemisphere correlated with the severity of inferior visual field deficits. CONCLUSIONS: NAION progression is characterized by an initial phase of accelerated RNFL and GCC deterioration. These results reveal that the kinetic change of neural retina in NAION and may have implication on the time window for treatment of NAION. FD-OCT is useful in the evaluation of NAION.

Aqueous Levels of Pigment Epithelium-Derived Factor and Macular Choroidal Thickness in High Myopia.

Purpose. To investigate the correlation between aqueous and serum levels of pigment epithelium-derived factor (PEDF) and macular choroidal thickness in high myopia patients, both with and without choroidal neovascularization (CNV). Methods. Serum and aqueous levels of PEDF were measured by enzyme-linked immunosorbent assay in 36 high myopia patients (36 eyes) with no CNV (non-CNV group), 14 high myopia patients (14 eyes) with CNV (CNV group), and 42 nonmyopia patients (42 eyes) (control group). Macular choroidal thickness was measured by enhanced-depth imaging optical coherence tomography. Results. Aqueous levels of PEDF were significantly higher in CNV group compared with non-CNV (P < 0.001) and control (P < 0.001) groups. Macular choroidal thicknesses were significantly decreased in the non-CNV and CNV groups compared with the control (P < 0.001) group. A statistically significant difference (P = 0.012) was found between the CNV and non-CNV groups. There was a positive correlation between aqueous PEDF and macular choroidal thickness in the non-CNV group (P = 0.005), but no correlation with the CNV group. No correlation between serum PEDF and macular choroidal thickness was detected in the three groups. Conclusion. Variations in aqueous PEDF levels coincide with changes in macular choroidal thickness in high myopia patients with no CNV, while no such relationship exists in high myopia patients with CNV.

Correlation of macular choroidal thickness with concentrations of aqueous vascular endothelial growth factor in high myopia.

PURPOSE: To investigate the association of both aqueous and serum vascular endothelial growth factor (VEGF) levels and macular choroidal thickness in high myopia. MATERIALS AND METHODS: VEGF concentrations were measured in aqueous and serum samples via enzyme-linked immunosorbent assay (ELISA) and compared between high myopia (n = 36 eyes, 36 patients) and normal control (n = 42 eyes, 42 patients) eyes. Macular choroidal thickness, the distance from the retinal pigment epithelium (RPE) to the scleral interface, was determined via enhanced depth-imaging optical coherence tomography (EDI-OCT). Axial length was measured using the intraocular (IOL) lens Master. RESULTS: Aqueous levels of VEGF from high myopia patients were significantly lower compared with those from control persons (61.4 ± 27.6 versus 122.6 ± 52.4 pg/ml; p < 0.001), respectively. Macular choroidal thickness of high myopia patients was significantly lower compared with that of control persons (111.1 ± 45.0 versus 230.6 ± 81.8 µm; p < 0.001), respectively. Aqueous levels of VEGF were significantly associated with both macular choroidal thickness (R(2)= 0.641; p < 0.001) and axial length (R(2)= 0.679; p < 0.001) in high myopia patients. In addition, there was a significantly negative correlation between macular choroidal thickness and axial length (R(2)= 0.69; p < 0.001). However, no correlation between serum VEGF and either macular choroidal thickness or axial length was detected in high myopia patients (R(2)= 0.009; p = 0.59; R(2)= 0.00002; p = 0.981). CONCLUSIONS: Macular choroidal thickness was significantly correlated with aqueous, but not serum, levels of VEGF in highly myopic eyes. Macular choroidal thickness may be of predictive value for identifying aqueous VEGF levels in high myopia patients and may, thus, be a useful prognostic modality.

Short-term and long-term effects of small incision lenticule extraction (SMILE) on corneal endothelial cells.

PURPOSE: Small incision lenticule extraction (SMILE) is being used increasingly as a novel approach to correct refractive errors with femtosecond laser. The study was aimed to investigate the corneal endothelial changes 1 day (short term) and 1 year (long term) after SMILE procedure. METHODS: In this prospective study, a total of 56 eyes of 30 patients with myopia ranging from -3.25 to -8.25 diopters (D) and cylinder up to -3.50D were treated by SMILE. Postoperative uncorrected distance visual acuity (UDVA) and complications were assessed. Endothelial cell density (ECD), the coefficient of variation (CV), and the percentage of hexagonal cells were measured using a noncontact specular microscope preoperatively and at 1 day and 1 year postoperatively. The estimated residual stromal thickness (RST) of each patient was recorded. RESULTS: The median UDVA improved significantly from 1.00logMAR preoperatively to -0.10logMAR both at 1 day and 1 year (p<0.001). No eyes developed corneal edema or other complications during the follow-up period. There were no significant changes in the ECD, CV or the percentage of hexagonal cells at any visit point (all p>0.05). The mean estimated RST was 355.1±32.2µm (range 290-429µm). Endothelial cell changes in terms of ECD, CV or the percentage of hexagonal cells were not correlated with the estimated RST (p>0.05). CONCLUSIONS: SMILE yielded improvement in visual acuity and no adverse effects to corneal endothelial cells were found. However, further studies with a lower preoperative ECD and deeper lenticule extraction are needed to conduct.

Study of dynamic sorption and desorption of polycyclic aromatic hydrocarbons in silty-clay soil.

This study reported a well controlled laboratory experiment of high concentration PAHs solute, containing fluorene, phenanthrene, fluoranthene and pyrene, through a nearly homogeneous soil column to reveal sorption and desorption behavior of these four PAHs in soil. The duration of the experiment was 64 days and the flow rate through the soil column was a constant which equals to 2000 mL d(-1). The result showed that the mechanism of isothermal sorption and desorption of fluorene can be perfectly described by the Langmuir model, and the correlation coefficients were greater than 0.997. The first-order Lagergren and the Bangham equation can precisely describe the rate of sorption of PAHs, while the rate of desorption can be represented by the second-order kinetics model. The results of the desorption experiment indicated that the desorption hysteresis of fluorene was evident. Few phenanthrene, fluoranthene and pyrene were desorpted to the aqueous phase for the chemical bond with the clay minerals. The most important process determining the behavior of PAHs in soils and their availability to further transformations was the sorption to soil solids with further sequestration and desorption to the aqueous phase.