Application of the membrane interphase probe (MIP): an evaluation   总被引：1，自引：0，他引：1  

Jan Bronders  Ilse Van Keer  Kaatje Touchant  Guido Vanermen  Daniel Wilczek 《Journal of Soils and Sediments》2009,9(1):74-82

Background, aim, and scope

The membrane interphase probe (MIP?) from Geoprobe Systems® has frequently been applied in different countries for the characterization of soil contaminated with volatile organic carbons (VOCs). Experience shows that misinterpretation of the collected data is common. This is mainly due to the lack of understanding and knowledge related to the detectors used, their detection limits, and the sensitivity of the MIP system. It has been noticed that the sensitivity of the system given by the producer and by different users are rather optimistic, e.g., the values given are lower (= better) than those actually experienced in the field. A need for a better understanding of the MIP system sensitivity, combined with a more scientifically based interpretation of the collected data, exists.

Materials and method

Both laboratory tests (using solutions) as well as field measurements were carried out using different detector configurations to allow a better interpretation of the detector signals/system sensitivity and to collect qualitative information. These configurations were: (1) detectors stand alone; (2) the use of a 2-ml sample loop, and (3) a purge and trap system. The configurations (2) and (3) are used in combination with a capillary column to carry out on-site qualitative and semiquantitative analyses.

Results and discussion

With respect to the configuration of “detectors stand alone,” detection limits for toluene (in aqueous solutions) range between 4 ppm (flame ionization detector—FID) and 10 ppm [photo ionization detector (PID)]. For chlorinated aliphatic hydrocarbons (CAHs), observed limits are 10 ppm (FID), 4–50 ppm (PID), and 3–10 ppm [dry electrolytic conductivity detector (DELCD)]. When using the 2-ml sample loop, relatively high concentrations have to be initially present in the soil. Observed detection limits for mono-aromatic hydrocarbons are 5–100 ppm; for CAHs, 1–50 ppm; for alkanes, 250–400 ppm; and for MTBE, 25 ppm. The application of purge and trap results in a better resolution and the detection of lower concentrations. Consequently, a better identification of the pollution with depth is possible. In this case, the detection limits are a function of the concentrations and the flushing time. In relation to the qualitative analyses, it was found that the configuration of the MIP-system with the built-in capillary column and the 2-ml sample loop or the purge and trap preconcentrator, respectively, are useful to carry out on-site analyses, thus allowing a better identification of the pollution in a vertical profile.

Conclusions

The measurements carried out using the MIP with detectors stand-alone or in combination with a loop or trap, or connected to a column, confirm that analysis is indeed very useful to characterize VOC source zones when knowing and understanding its performance. This relates mainly to the detection limits of the MIP system. For a selection of parameters, such limits have been obtained. These values seem to be more realistic than those found in the few references where numbers are given. For the qualitative measurements, it can be concluded that a better resolution is obtained, and pollutants present in lower concentrations will be detected when using the purge and trap. It is advised to determine the optimal flushing time and the detection limit of the expected pollutants in advance.

Recommendations and perspectives

This study indicates that there is still a need for further measurements and discussion between users. Finally, additional data should result in a better interpretation of the collected field data.  相似文献   

Detection and identification of beta-lactam residues in milk using a hybrid biosensor     

Ferrini AM  Mannoni V  Carpico G  Pellegrini GE 《Journal of agricultural and food chemistry》2008,56(3):784-788

A novel application of a hybrid biosensor is here employed as an analytical method for the detection and presumptive identification of beta-lactam residues in milk. The method is based on measurements of carbon dioxide (CO2), the production of which is related to the microbial growth of the test microorganism Bacillus stearothermophilus var. calidolactis. The presence of beta-lactams in milk inhibits microbial growth and, consequently, the CO2 production rate. The analysis is based on the variation of CO2 between a milk sample spiked with beta-lactams and a twin milk sample containing beta-lactams plus a broad spectrum beta-lactamase, using an electrochemical device of biosensor. A blank milk sample is included as control. The result is obtained starting from the first 120 min. Moreover, the ability to recognize all of the beta-lactams speeds the total time of analysis when chemical identification and quantification are required. The analytical method appears to be adequate for milk control for qualitative screening purposes, complying with the requirements stated in Decision 2002/657/EC.  相似文献   

Storage and stability of organic matter and fossil carbon in a Luvisol and Phaeozem with continuous maize cropping: A synthesis   总被引：1，自引：0，他引：1  

Heiner Flessa  Wulf Amelung  Mirjam Helfrich  Guido L. B. Wiesenberg  Gerd Gleixner  Sonja Brodowski  Janet Rethemeyer  Christiane Kramer  Pieter M. Grootes 《植物养料与土壤学杂志》2008,171(1):36-51

Quantitative information about the amount and stability of organic carbon (OC) in different soil organic‐matter (OM) fractions and in specific organic compounds and compound‐classes is needed to improve our understanding of organic‐matter sequestration in soils. In the present paper, we summarize and integrate results performed on two different arable soils with continuous maize cropping (a) Stagnic Luvisol with maize cropping for 24 y, b) Luvic Phaeozem with maize cropping for 39 y) to identify (1) the storage of OC in different soil organic‐matter fractions, (2) the function of these fractions with respect to soil‐OC stabilization, (3) the importance and partitioning of fossil‐C deposits, and (4) the rates of soil‐OC stabilization as assessed by compound‐specific isotope analyses. The fractionation procedures included particle‐size fractionation, density fractionation, aggregate fractionation, acid hydrolysis, different oxidation procedures, isolation of extractable lipids and phospholipid fatty acids, pyrolysis, and the determination of black C. Stability of OC was determined by ¹³C and ¹⁴C analyses. The main inputs of OC were plant litter (both sites) and deposition of fossil C likely from coal combustion and lignite dust (only Phaeozem).  相似文献   

Life in the fast lane: Revisiting the fast growth—High survival paradigm during the early life stages of fishes     

Dominique Robert  Jun Shoji  Pascal Sirois  Akinori Takasuka  Ignacio A. Catalán  Arild Folkvord  Stuart A. Ludsin  Myron A. Peck  Su Sponaugle  Patricia M. Ayón  Richard D. Brodeur  Emily Y. Campbell  Evan K. D'Alessandro  John F. Dower  Louis Fortier  Alberto G. García  Klaus B. Huebert  Marc Hufnagl  Shin-ichi Ito  Mikimasa Joh  Francis Juanes  Mitsuo Nyuji  Yoshioki Oozeki  Guido Plaza  Motomitsu Takahashi  Yosuke Tanaka  Naoki Tojo  Shingo Watari  Naotaka Yasue  Pierre Pepin 《Fish and Fisheries》2023,24(5):863-888

Early life survival is critical to successful replenishment of fish populations, and hypotheses developed under the Growth-Survival Paradigm (GSP) have guided investigations of controlling processes. The GSP postulates that recruitment depends on growth and mortality rates during early life stages, as well as their duration, after which the mortality declines substantially. The GSP predicts a shift in the frequency distribution of growth histories with age towards faster growth rates relative to the initial population because slow-growing individuals are subject to high mortality (via starvation and predation). However, mortality data compiled from 387 cases published in 153 studies (1971–2022) showed that the GSP was only supported in 56% of cases. Selection against slow growth occurred in two-thirds of field studies, leaving a non-negligible fraction of cases showing either an absence of or inverse growth-selective survival, suggesting the growth-survival relationship is more complex than currently considered within the GSP framework. Stochastic simulations allowed us to assess the influence of key intrinsic and extrinsic factors on the characteristics of surviving larvae and identify knowledge gaps on the drivers of variability in growth-selective survival. We suggest caution when interpreting patterns of growth selection because changes in variance and autocorrelation of individual growth rates among cohorts can invalidate fundamental GSP assumptions. We argue that breakthroughs in recruitment research require a comprehensive, population-specific characterization of the role of predation and intrinsic factors in driving variability in the distribution and autocorrelation of larval growth rates, and of the life stage corresponding to the endpoint of pre-recruited life.  相似文献   

The use of insulated time-domain reflectometry sensors to measure water content in highly saline soils     

M. A. Mojid  Guido C. L. Wyseure  Derek A. Rose 《Irrigation Science》1998,18(2):55-61

In a conducting medium, the energy of a time-domain reflectometry (TDR) pulse is dissipated and the signal is attenuated. Above a certain high conductivity, however, the signal is completely attenuated and the soil short-circuits the sensor. This behaviour of the signal with conductivity severely limits the TDR technique in measuring water content in highly saline soils. By reducing the direct contact between the conductive soil and the metallic sensor the energy of the pulse is better maintained. Different combinations were tried: we insulated the central wire, outer two wires, and all wires of a three-wire sensor with two different insulators. The first insulator was an adhesive polyethylene sheet usually used as a transparent cover and the second insulator was an adhesive tape. The insulated sensors were used to measure dielectric constants in non-saline soils and water and in saline soils. The sensors with the insulated centre wire preserve maximum energy and maintain a clear signal in saline soils. The insulating materials have very small dielectric constants. The TDR exerts a larger influence in the vicinity of the wires of the sensor during measurements. Therefore, the insulated sensor measures a dielectric constant which is smaller than the apparent dielectric constant of the surrounding medium. The type of insulating material also has an effect on the dielectric constant. Therefore, it is necessary to calibrate the sensors for the specific insulator. Received: 30 December 1996  相似文献   

Characterization of difenoconazole resistance in Lasiodiplodia theobromae from papaya in Brazil     

Yuan Li  Susan Satie Tsuji  Mengjun Hu  Marcos Paz Saraiva Cmara  Sami Jorge Michereff  Guido Schnabel  Fengping Chen 《Pest management science》2020,76(4):1344-1352

  相似文献   

Es merden zum Rauf offerirf     

Guido v. Schmarger 《European Journal of Forest Research》1870,14(1):80-80

Ohne Zusammenfassung  相似文献   

Toxocara canis infection induces antigen-specific IL-10 and IFNgamma production in pregnant dogs and their puppies     

Torina A  Caracappa S  Barera A  Dieli F  Sireci G  Genchi C  Deplazes P  Salerno A 《Veterinary immunology and immunopathology》2005,108(1-2):247-251

Toxocara canis (T. canis) is originally a parasite of canine bitches and their pups. The pathogenicity of T. canis infection is enhanced during pregnancy and puppyhood. The aim of this study was to investigate if modification of IFNgamma and IL-10 secretion occurs during infection in pregnant dogs and puppies. Analysis of cytokines secreted could let us hypothesize a role for IL-10 and/or IFNgamma in T. canis infection. We tested T. canis-specific production of IFNgamma and IL-10 by lymphocytes of pregnant dogs and their puppies after in vitro re-exposure to purified excretory/secretory antigen (ESAg) from T. canis. Blood mononuclear cells (BMC) isolated from pregnant dogs and their puppies were cultured in the presence of ESAg. Cultures' supernatants were tested for cytokine levels by ELISA. Results obtained showed that IL-10 concentrations increased during pregnancy in infected animals and in the meantime IFNgamma production decreased. In puppyhood, we observed that, IL-10 concentration decreased with the age of puppies mainly in infected animals while IFNgamma increased. In conclusion, our data suggests that BMC of infected dogs have a particular modification of IL-10 and IFNgamma synthesis. These data could be the basis to design immunotherapeutic approaches.  相似文献   

Transanal pull-through rectal amputation for treatment of colorectal carcinoma in 11 dogs     

Morello E  Martano M  Squassino C  Iussich S  Caccamo R  Sammartano F  Zabarino S  Bellino C  Pisani G  Buracco P 《Veterinary surgery : VS》2008,37(5):420-426

Objective— To evaluate outcome after transanal rectal pull-through amputation of single colorectal adenocarcinoma and in situ carcinoma (T is ) in dogs.
Study Design— Retrospective case series.
Animals— Dogs (n=11) with colorectal cancer.
Methods— Full-thickness colorectal amputation by either simple transanal (7 dogs) or combined abdominal–transanal (4) pull-through technique.
Results— Adenocarcinoma (8) and T is (2) were removed with 3–6 cm of grossly normal tissue, cranial and caudal to the tumor, or in 1 T is with 2 cm grossly normal tissue, cranial and caudal. Two dogs that had a combined abdominal–transanal approach died within 4 days. In the other dogs, postoperative complications included short-term tenesmus (6 dogs), rectal bleeding (11), rectal stricture (3), and long-term fecal incontinence (1). Postoperative recurrence and metastatic rates for adenocarcinoma were 18.2% and 0%, respectively. Median disease-free interval and survival time were not reached. Mean disease-free and overall survival times were 44.3 and 44.6 months (range, 0–75 months), respectively.
Conclusion— En bloc excision of colorectal T is and adenocarcinoma may be followed by a long survival. Complications of the transanal approach are usually moderate and self-limiting, but complications are more common and severe when more extensive resections are performed through a combined abdominal–transanal approach.
Clinical Relevance— Transanal rectal pull-through amputation is suitable for en bloc resection of colorectal neoplasia. A combined abdominal–transanal approach should be reserved for tumors extending from the mid-cranial region of the rectum to the descending colon.  相似文献   

Clinical approach to prostatic diseases in the dog     

Marco Cunto  Elisa Mariani  Eleonora Anicito Guido  Giulia Ballotta  Daniele Zambelli 《Reproduction in domestic animals》2019,54(6):815-822

In small animal practice, prostatic diseases are increasingly encountered. All dogs may experience prostatic disease, but particular care should be addressed to breeding dogs, in which prostatic affection may lead to decrease in semen quality and fertility. The most common prostatic disease is the benign prostatic hyperplasia (BPH) followed by prostatitis, prostatic neoplasia and prostate squamous metaplasia. These diseases do not have pathognomonic symptoms, therefore, making a correct diagnosis may not be easy. An accurate clinical examination and a correct diagnostic protocol are essential in order to begin the most appropriate treatment, and also to do a good prophylaxis where it is possible. BPH therapy is usually recommended when mild‐severe signs are present or if symptoms disturb the patient. New therapeutic approaches, both medical and surgical, allow to maintain fertility in most animals with prostatic disorders. Prostate cancer is relatively infrequent. Elective therapy is the surgical one, but it is considered palliative and can result in important post‐operative complications. The aim of this paper is to lay down the most appropriate diagnostic process describing the aetiologies of prostatic disease, their symptoms, the right investigative tools and therapy.  相似文献