Filtration Zone Research Articles

A young man with a sudden 'white out' of right hemithorax on chest radiograph

In May 2011, a 27-year-old man presented with acute onset of dyspnoea associated with localized pleuritic pain over the right upper chest wall. There was no radiation of the pain and he did not have cough, haemoptysis nor leg swelling. Six months ago, he was diagnosed to have pulmonary tuberculosis with sputum positive for Mycobacterium tuberculosis on microscopy and culture. His presenting symptoms at that time were cough with blood-stained sputum with occasional dyspnoea and wheezing. Physical examination was unremarkable then and chest radiograph showed a mild right upper zone infiltrate. Sensitivity testing of the M. tuberculosis strain revealed no drug resistance. He complied to a 6-month course of anti-tuberculous treatment with satisfactory clinical and radiological response upon completion of treatment. …

Ethambutol and pyrazinamide-induced toxic epidermal necrolysis in an immunocompetent adult with tuberculosis

Ethambutol and pyrazinamide-induced toxic epidermal necrolysis in an immunocompetent adult with tuberculosis

Groundwater recharge to a sedimentary aquifer in the topographically closed Uley South Basin, South Australia

The chloride mass balance (CMB) and water-table fluctuation (WTF) analysis methods were used to estimate recharge rates in the Uley South Basin, South Australia. Groundwater hydrochemistry and isotope data were used to infer the nature of recharge pathways and evapotranspiration processes. These data indicate that some combination of two plausible processes is occurring: (1) complete evaporation of rainfall occurs, and the precipitated salts are washed down and redissolved when recharge occurs, and (2) transpiration dominates over evaporation. It is surmised that sinkholes predominantly serve to by-pass the shallow soil zone and redistribute infiltration into the deeper unsaturated zone, rather than transferring rainfall directly to the water table. Chlorofluorocarbon measurements were used in approximating recharge origins to account for coastal proximity effects in the CMB method and pumping seasonality was accounted for in the WTF-based recharge estimates. Best estimates of spatially and temporally averaged recharge rates for the basin are 52–63 and 47–129 mm/year from the CMB and WTF analyses, respectively. Adaptations of both the CMB and WTF analyses to account for nuances of the system were necessary, demonstrating the need for careful application of these methods.

Evolution of fouling deposition and removal on hollow fibre membrane during filtration with periodical backwash

Fouling deposition and removal during filtration with short periodical backwash was investigated by direct observation coupled with hydraulic resistance measurement. Using a model mixture of bentonite and alginate, it was found that short periodical backwash only (i.e. without air scouring) expanded the foulant cake, which is subsequently recompressed back to membrane surface when the filtration resumes. With air-scouring aided backwash, the fouling material is convected away from the effective filtration zone, thus limiting re-deposition. However, due to the potential fractionation of foulant species at high air scouring rate, the deposition of more highly resistant components was observed over multiple filtration and backwash cycles. The results indicated that the changes in cake height, composition and structure were affected not only by the initial composition of the feed, but also by the hydrodynamics of the backwash and air scouring present.

Non-penetrating intracanalicular partial trabeculectomy via the ostia of Schlemm's canal

In order to distinguish a more pronounced and sustained hypotensive effect of non-penetrating glaucoma surgery, a modified surgical procedure is proposed, which provides enlargement of the filtration membrane area with maximal maintenance of natural aqueous outflow pathways. In 21 eyes of 17 patients with open-angle glaucoma (intraocular pressure: 32.4 ± 4.7 mmHg; age: 69.2 ± 4.4 years) the following non-penetrating surgery was performed. After the excision of the outer wall of Schlemm's canal, outer layers of the trabecular meshwork were removed with a trabecular spatula (Geuder AG, G-16240) at the site of the open area of Schlemm's canal. A cannula-harpoon (Geuder AG, G-S02199) was introduced through both Schlemm's canal ostia, between the less permeable and well-permeable trabecular layers and separating them. Due to the harpoon configuration of the cannula, the superficial less permeable trabecular layers were removed within Schlemm's canal adjacent to its ostia during the retracting movement of the cannula. Thus, the filtration zone became extended using the outflow pathways into Schlemm's canal. A postoperative intraocular pressure of 13.4 ± 2.3 mmHg after 2 years of follow-up was measured. In all 21 eyes the hypotensive effect was absolute (without medications). In seven cases (33%) a hyphema had occurred during surgery, which dissolved in all cases within 2-3 days postoperatively. The results of the study demonstrate a pronounced and sustained effect of the modified surgery technique, and show that this surgery can be applied successfully in patients with therapy-resistant open-angle glaucoma. Further randomized prospective studies with larger case numbers are needed for generalized conclusions for a large population.

CFD simulations of membrane filtration zone in a submerged hollow fibre membrane bioreactor using a porous media approach

The current membrane bioreactor (MBR) design methods and the popular bio-kinetic models rely on the assumption that membrane bioreactor is completely mixed, neglecting the real hydrodynamic condition within the reactor. MBRs differ from conventional reactors in so far as the spatial distribution of reactor discharge points is very broad for an MBR compared with a conventional bioreactor. Computational Fluid Dynamics (CFD) provides a possibility to investigate the hydrodynamic behaviour of large scale MBRs. The CFD modelling of whole MBR plant requires a macro-scale approximation which can keep the mesh size and computation effort within the reasonable limit. However, the simulation of the flow behaviour surrounding the membranes requires high mesh resolutions and hence large element numbers. Therefore, it is impossible to model each individual hollow fibre using the Navier–Stokes equations as it is too computationally costly. In this paper, the effects of Siemens Memcor Memjet ® hollow fibre membrane bundle on flow field were transferred to a porous media model. This porous media model was coupled with a three-dimensional multiphase model to account for the hydrodynamic behaviour of a full-scale submerged MBR. An experimental approach was developed to calibrate the inertial loss caused by the hollow fibre bundle against various liquid velocities at different flow direction and fluid viscosity. The experimentally determined inertial losses were compared against those estimated from the empirical correlations for tube banks. These experimental calibrations were then applied to the porous media model. Significant improvement on the hydrodynamic descriptions was observed by coupling the porous media model compared with the previous developed MBR CFD model.

Histological evaluation of esophageal mucosa in children with acid gastroesophageal reflux.

histological evaluation of esophageal mucosa in children, with regard to the duration of primary acid gastroesophageal reflux (GER) and acid GER secondary to cow's milk allergy and/or other food allergy (CMA/FA) (prospective study). 264 children of both sexes suspected of GER were enrolled in the study. The age of examined children was 1.5-102 months, mean age 20.78+/-17.23 months. Pathological acid GER was confirmed with pH-monitoring in 138 children (52.3%). Taking into consideration complex differential diagnosis, including oral food challenge test with potentially noxious nutrient (open or blind study), children were assigned into study groups 1 and 2 (primary and secondary GER). Group 1: 76 patients (28.8%) aged 4-102 months (x=25.2+/-27.28 months) with primary GER. Group 2: 62 patients (23.5%) aged 4-74 months (x=21.53+/-17.79 months) with GER secondary to CMA/FA. Children with GERD underwent preliminary and control (after 1 year and 2 years of GERD diagnosis) endoscopic examination of the upper gastroinestinal tract. Intensity of esophagitis was assessed initially in 25 children from group 1 (32.9%), in 29 children from group 2 (46.8%), and in 9 children from group 3 - reference group (28.1%). Histological evaluation revealed infiltration of inflammatory cells, mainly neutrophils and intraepithelial lymphocytes, and also eosinophils in 10 children (13.2%) with primary GER. Infiltration of eosinophils and lymphocytes was found in 5 children (8.1%) with secondary GER. In 8 children (25.0%) with food allergy there were only lymphocytes. Infiltration of neutrophils and lymphocytes and basal zone hyperplasia or infiltration of eosinophils and lymphocytes with elongation of lamina propria papillae was found in 10 children (13.1%) with primary GER and in 20 children (32.2%) with secondary GER. Differentiation of particular types of inflammatory cells in mucosal infiltration characterized histological picture in the following way: neutrophils in 21 children (27.6%) with primary GER, eosinophils in 22 children (35.5%) with secondary GER, lymphocytes in 15 children (19.7%) in children with primary GER and in 15 children (24.2%) with secondary GER. Histological examination of esophageal mucosa after 1 and 2 years of clinical observation and periodical conservative treatment in children with primary and secondary GER revealed significant alleviation of inflammatory abnormalities (with regard to the type of abnormalities and the number of particular types of inflammatory cells). The value of histological findings obtained in own studies comprises the role of food allergy in pathogenesis of GER and is related to GER's contribution, both direct (primary reflux) and indirect (secondary reflux), to triggering off morphological results and clinical outcomes of esophagitis.

Aqueous extraction of residual oil from sunflower press cake using a twin-screw extruder: Feasibility study

The objective of this study was to evaluate the feasibility of an aqueous process to extract the residual oil from sunflower press cakes using a co-rotating twin-screw extruder. Two different configurations were tested: the expression from whole seeds followed by the aqueous extraction, in two successive apparatus or in the same one. For the aqueous extraction stage, the oil yield depended on the operating conditions including screw rotation speed, screw profile, and inlet flow rates of press cakes and water. Liquid/solid separation required the addition of a lignocellulosic residue (wheat straw), upstream from the filtration zone. However, even with maximum fiber inlet flow (around 20% of the inlet flow rate of the solid matters for the highest amount of wheat straw), drying of the cake meal did not improve. The lixiviation of the material was also incomplete. Oil yield was better when the expression and the aqueous extraction were conducted in the same extruder. For all the trials carried out using such a configuration, the corresponding cake meal contained less than 10% residual oil, and the total oil yield was 78% in the best operating conditions. Nevertheless, the contribution of the aqueous extraction stage was extremely limited, less than 5% in the best trial, partly due to a ratio of the water to the press cake too low. For the aqueous extraction stage, the oil was extracted in the form of an oil-in-water emulsion whose stability was minimized because of its low proteins content due to their thermo-mechanical denaturation during the expression stage.

The reasons of unsuccessful antiglaucoma operations

Abstract Purpose The study was to determinate the level excessive scarring in zone of antiglaucome operations. Methods This study 48 eyes of 46 consecutive patients with medically uncontrolled glaucoma after filtration surgery underwent reconstruction of filtration zone. IOP decompensation happened between 6 mount and 6 years after filtration surgery. Mean preoperative IOP was 35.7± 8.4 mm Hg. Results After reconstruction of filtration zone in 9 causes (18,7%) aqueous humor outflow started after revision filtration bleb, 23 causes (48%) after reconstruction scleral spit. In other causes we had to cut up zone of trabeculectomy hole. In 8 causes (16%) excessive scarring in zone of trebeculectomy hole was mean reason for IOP decompensation. Conclusion The mean reason of IOP decompensation after antiglaucoma operation is excessive scarring in zone of scleral spit (48%) and filtrations bleb (18,7%).

Absolute gravity monitoring of water storage variation in a karst aquifer on the larzac plateau (Southern France)

In this study we attempt to understand the water storage variations in a karst aquifer on the Larzac Plateau (South of France) using absolute gravimetry. On this karst system, water input is exclusively rainfall and draining occurs at the Durzon perennial spring in a karstic valley. Our basis assumption is that water storage in the vadose zone (epikarst and infiltration zone) has a significant effect on surface gravity through Newtonian attraction. The karst aquifer is hence being monitored since January 2006 with monthly absolute gravity measurements at three sites. The gravity measurements are corrected for regional scale gravity using water storage models in order to obtain gravity variations related exclusively to the local water storage variations. The gravity variations exhibit an important seasonal component (10–15 μgal corresponding to a variation of equivalent water slab thickness of ∼24–36 cm). Water storage variation seen by gravimetry is not spatially uniform on the studied karst system, corroborating current geomorphologic observations and interpretations. Finally, we use a global mass balance consideration linking rainfall, evapotranspiration and spring discharge to provide a conceptual framework for the understanding of observed gravity variations.

Kinetic analysis of PAC cake-layer formation in hybrid PAC-MF systems

Experimental studies were conducted to evaluate the effectiveness of backwashing and air-scouring to prevent cake-layer formation on the membranes in a hybrid PAC-MF process. The membrane filtration chamber used in this study was separated into two zones; namely, the PAC adsorption zone (PAZ) and the membrane filtration zone (MFZ). In MFZ tubular ceramic membranes were installed, and powdered activated carbon (PAC) was suspended in PAZ at a concentration of 20 g/L by aeration. Air-scouring and backwashing rates were gradually increased to see if these physical cleaning measures can reduce or maintain the filtration resistance due to formation of PAC cake layer on the membrane. Two types of saw-dust PAC having different sizes were used to find the difference of the effects of air-scouring and backwashing. A smaller PAC (Shirasagi C1, Japan EnviroChemicals, Co.) showed a slower increasing rate of filtration resistance than the larger PAC (Shirasagi S-10, Japan EnviroChemicals, Co.). It was found that air-scouring didn't reduce the rate of cake fouling formation of PAC S-10, but can quite effectively reduce the rate of PAC C-1 attachment to the membrane. On the contrary, backwashing was not effective for PAC C-1, but quite effective for PAC S-10. PAC C1 formed a porous cake with low specific resistance, which can be easily removed by air-scouring, but cannot be removed by backwashing. On the other hand, PAC S-10 formed a tight cake layer because suspended particles get in to the void space between the PAC S-10. A dynamic model was proposed to explain the effect of air-scouring and backwashing to removal cake layer from the membranes.

Dynamic activation of bone morphogenetic protein signaling in collagen-induced arthritis supports their role in joint homeostasis and disease

IntroductionRheumatoid arthritis is a chronic systemic autoimmune disease affecting peripheral joints and leading to loss of joint function. The severity and outcome of disease are dependent on the balance between inflammatory/destructive and homeostatic or repair pathways. Increasing evidence suggests a role for bone morphogenetic protein (BMP) signaling in joint homeostasis and disease.MethodsActivation of BMP signaling in collagen-induced arthritis as a model of rheumatoid arthritis was studied by immunohistochemistry and Western blot for phosphorylated SMAD1/5 at different time points. Expression of different BMP ligands and noggin, a BMP antagonist, was determined on synovium and cartilage extracts of arthritic knees, at different time points, with quantitative polymerase chain reaction. At the protein level, BMP2 and BMP7 were studied with immunohistochemistry. Finally, the effect of anti-tumor necrosis factor-alpha (TNFα) treatment on the expression of BMP2, BMP7, and growth and differentiation factor-5 (GDF5) in synovium and cartilage of arthritic knees was investigated.ResultsA time-dependent activation of the BMP signaling pathway in collagen-induced arthritis was demonstrated with a dynamic and characteristic expression pattern of different BMP subfamily members in synovium and cartilage of arthritic knees. As severity increases, the activation of BMP signaling becomes more prominent in the invasive pannus tissue. BMP2 is present in cartilage and the hyperplastic lining layer. BMP7 is found in the sublining zone and inflammatory infiltrate. Treatment with etanercept slowed down progression of disease, but no change in expression of GDF5, BMP2, and BMP7 in synovium was found; in the cartilage, however, blocking of TNFα increased the expression of BMP7.ConclusionsBMP signaling is dynamically activated in collagen-induced arthritis and is partly TNFα-independent. TNFα blocking increased the expression of BMP7 in the articular cartilage, possibly enhancing anabolic mechanisms. Different types of source and target cells are recognized. These data further support a role for BMP signaling in arthritis.

Direct extraction of oil from sunflower seeds by twin-screw extruder according to an aqueous extraction process: Feasibility study and influence of operating conditions

The objective of this study was to evaluate the feasibility of an aqueous process to extract sunflower seed oil using a co-rotating twin-screw extruder. Aqueous extraction was carried out using whole seeds and the influence of the operating conditions on oil yield was examined. Operating conditions included screw profile, screw rotation speed, and input flow rates of sunflower seeds and water. Liquid/solid separation required the addition of a lignocellulosic residue upstream from the filtration zone. However, even with maximum fiber input flow, drying of the cake meal did not improve. The lixiviation of the sunflower seeds was also incomplete. The aqueous extraction of the oil was more efficient in the twin-screw extruder than the reference trial conducted in a batch reactor. The best oil extraction yield obtained was approximately 55% and the residual oil content of the cake meal was approximately 30%. The hydrophobic phases produced were oil-in-water emulsions. These emulsions were stabilized by phospholipids and proteins at the interface, which are natural surface-active agents co-extracted during the process.

Removal of organics and viruses using hybrid ceramic MF system without draining PAC

Ceramic microfiltration combined with powdered activated carbon adsorption (PAC-MF) was tested for organic and microbial control using river water laden with sewerage effluents. The PAC-MF was compactly configured with PAC adsorption and MF filtration zones in one reactor. It was operated with PAC addition of 20 g/L at the beginning without PAC drain. Organic matter was largely removed in the adsorption zone and then additional removal was obtained in the filtration zone. Selective adsorption of hydrophobic organic compounds onto PAC resulted in greater UV 260 removal of 90.3 ± 3.2% than DOC removal of 80.2 ± 8.6%. Efficient organic control of the PAC-MF onsiderably decreased chlorine consumption to less than 0.5 ± 0.08 mg/L, and thus THMFP was brought down to less than 8.8 ± 2.2 μg/L in permeate. Furthermore, adsorption or attraction potential of microorganisms by PAC addition as well as virus capture in the PAC cake layer also assisted ceramic MF to remove viruses to less than detection limit after 60 days of operation. Therefore, the hybrid PAC-MF is a prospective advanced water treatment process that is capable of simultaneous organic and microbial removal by adsorption and filtration mechanisms.

Attitudes pratiques: Lentilles de contact après chirurgie du glaucome

New soft therapeutic contact lenses after glaucoma surgery provide good results, both in terms of tolerance and efficacy (60% pressure increase in a personal series of ten patients with the Trabeculens contact lens). Indicated for moderate immediate postoperative leakage, their use remains transitory and they should be removed as soon as intraocular pressure is (rapidly) corrected. After glaucoma surgery, wearing contact lenses can be discussed if there are no contraindications and 6-12 months after the intervention in a compliant patient. Evaluation of the risk-benefit ratio is important. Gas-permeable, small-diatmeter hard contact lenses, bi- or trifocal spherical or posterior toric - the most stable - should be favored. Soft contact lenses can also be used, but because of their presence on the conjunctiva, notably in the filtration zone, they are less frequently recommended. Contact lens wear should in all cases be strictly limited to the daytime.

Peripheral T-cell lymphoma with involvement of the expanded mantle zone

Peripheral T-cell lymphoma (PTCL) with a nodular architecture is rare. Recently, two variants have been described with infiltration of the B-cell follicle, one variant that localizes to the marginal zone with a so-called perifollicular growth pattern, and a variant that localizes to the germinal center. These lymphomas have a CD4+ phenotype and may express Bcl-6. We have studied five similar cases of PTCL with involvement of the B-cell follicle. However, our cases differ from the cases previously described by their predominant and frequently patchy involvement of the expanded mantle zone of the B-cell follicle at onset. Later biopsies in three of the cases show diffuse infiltration of the lymph node, without features of angioimmunoblastic TCL (AILT). All cases expressed Bcl-6 in addition to CD4. Cytogenetics was available in four of the cases but revealed no recurrent chromosomal aberrations or changes associated with other types of PTCL. No mutations of the BCL-6 gene were observed. Together, the cases seem to have an intermediately aggressive clinical behavior. Whether our cases are part of a spectrum of PTCLs that encompasses previously described variants with predominant marginal zone or germinal center infiltration or they represent a separate T-cell lymphoma type remains to be demonstrated by a study of more of such cases.

Intralobar sequestration with tuberculous infection confined to the sequestrated lung

A 22-year-old female was referred to the hospital suffering from a persistent, non-productive cough and repeated exacerbations of a right lower zone infiltrate suggestive of pulmonary sequestration. Angiography revealed an aberrant artery that originated from the left side of the descending aorta, crossed the aorta anteriorly, flowed through the right lower lobe and drained into the right inferior pulmonary vein. Right lower lobectomy was conducted by open thoracotomy. Gross examination revealed mucoid impaction of bronchi in the sequestration. Microscopy demonstrated a clear boundary between sequestrated and normal lung, as well as caseating epitheloid granulomas confined to the sequestration. As the aberrant artery fed both sequestrated and adjacent normal lung and the boundary did not involve the pleura, the lesion was classified as a Pryce's type II intralobar sequestration. No acid-fast bacilli were observed, but homogenates of the sequestration were positive for Mycobacterium tuberculosis by polymerase chain reaction. The patient was treated with isoniazid and rifampicin daily for 9 months, and 6 years later her clinical status remained excellent. Tuberculosis confined to a sequestration is extremely rare and characteristics of the aberrant artery suggested this intralobar sequestration was likely to be congenital in origin.

Fabrication and Physical Properties of SiC-GaAs Nano-Composites

Nano-composites consisting of primary phase of hard nanocrystalline SiC matrix and the secondary nanocrystalline semiconductor (GaAs) phase were obtained by high-pressure zone infiltration. The synthesis process occurs in three stages: (i) at room temperature the nanopowder of SiC is compacted along with GaAs under high pressure up to 8 GPa, (ii) the temperature is increased above the melting point of GaAs up to 1600 K and, the pores are being filled with liquid, (iii) upon cooling GaAs nanocrystallites grow in the pores. Synthesis of nano-composites was performed using a toroid-type high-pressure apparatus (IHPP of the Polish Academy of Sciences, Warsaw) and six-anvil cubic press (MAX-80 at HASYLAB, Hamburg). X-ray diffraction studies were performed using a laboratory D5000 Siemens diffractometer. Phase composition, grain size, and macrostrains present in the synthesized materials were examined. Microstructure of the composites was characterized using scanning electron microscopy and high resolution transmission electron microscopy. Far-infrared reflectivity measurements were used to determine built-in strain.

Clinical and Radiographic Correlates of Primary and Reactivation Tuberculosis

The traditional teaching that pulmonary tuberculosis characterized by lymphadenopathy, effusions, and lower or mid lung zone infiltrates on chest radiography represents "primary" disease from recently acquired infection, whereas upper lobe infiltrates and cavities represent secondary or reactivation disease acquired in the more distant past, is not based on well-established clinical evidence. Furthermore, it is not known whether the atypical radiograph common in human immunodeficiency virus (HIV)-associated tuberculosis is due to a preponderance of primary progressive disease or altered immunity. To analyze the relationship between recently acquired and remotely acquired pulmonary tuberculosis, clinical and demographic variables, and radiographic features by using molecular fingerprinting and conventional epidemiology. A retrospective, hospital-based series of 456 patients treated at a New York City medical center between 1990 and 1999. Eligible patients had to have had at least 1 positive respiratory culture for Mycobacterium tuberculosis and available radiographic data. Radiographic appearance as measured by the presence or absence of 6 features: upper lobe infiltrate, cavitary lesion, adenopathy, effusions, lower or mid lung zone infiltrate, and miliary pattern. Radiographs were considered typical if they had an upper lobe infiltrate or cavity whether or not other features were present. Atypical radiographs were those that had adenopathy, effusion, or mid lower lung zone infiltrates or had none of the above features. Human immunodeficiency virus infection was most commonly associated with an atypical radiographic appearance on chest radiograph with an odds ratio of 0.20 (95% confidence interval, 0.13-0.31). Although a clustered fingerprint, representing recently acquired disease, was associated with typical radiograph in univariate analysis (odds ratio, 0.68; 95% confidence interval, 0.47-0.99), the association was lost when adjusted for HIV status. Time from acquisition of infection to development of clinical disease does not reliably predict the radiographic appearance of tuberculosis. Human immunodeficiency virus status, a probable surrogate for the integrity of the host immune response, is the only independent predictor of radiographic appearance. The altered radiographic appearance of pulmonary tuberculosis in HIV is due to altered immunity rather than recent acquisition of infection and progression to active disease.

The application of ground penetrating radar attenuation tomography in a vadose zone infiltration experiment

Cross-borehole ground penetrating radar (XBGPR) is used in monitoring a long-term vadose zone infiltration experiment at a test site in Socorro, NM in order to examine contaminant transport in the vadose zone. XBGPR attenuation tomography is conducted in order to test the ability of using images of electromagnetic attenuation for hydrogeologic investigations. The results of four pre-infiltration attenuation inversions shows standard deviations below 0.1 Np/m, and demonstrate the consistency of the XBGPR tomography technique for making time-lapse observations. Correlation to the core records indicates that XBGPR attenuation tomograms provide high-resolution images of clay distribution in the vadose zone. Water infiltration at the ground surface was initiated in February 1999 at a constant rate of 2.7 cm/day, and continued at this rate throughout the data collection experiment. Time-lapse attenuation tomograms show that attenuation increases by approximately 0.3 Np/m during the water infiltration, and indicate a snowplow effect may be occurring where salts are dissolved by the water and concentrated at the front of the plume. Seasonal temperature changes may also cause changes in electromagnetic attenuation images, and masking the evidence of water infiltration. Thus caution must be taken when using time-lapse attenuation images to interpret the movement of a water plume during a long-term experiment as temperature changes.