A comparative analysis of stem cell differentiation on 2D and 3D substrates using Raman microspectroscopy.

Chondrogenesis is a complex cellular process that involves the transformation of mesenchymal stem cells (MSCs) into chondrocytes, the specialised cells that form cartilage. In recent years, three-dimensional (3D) culture systems have emerged as a promising approach to studying cell behaviour and development in a more physiologically relevant environment compared to traditional two-dimensional (2D) cell culture. The use of these systems provided insights into the molecular mechanisms that regulate chondrogenesis and has the potential to revolutionise the development of new therapies for cartilage repair and regeneration. This study demonstrates the successful application of Raman microspectroscopy (RMS) as a label-free, non-destructive, and sensitive method to monitor the chondrogenic differentiation of bone marrow-derived rat mesenchymal stem cells (rMSCs) in a collagen type I hydrogel, and explores the potential benefits of 3D hydrogels compared to conventional 2D cell culture environments. rMSCs were cultured on 3D substrates for 3 weeks and their differentiation was monitored by measuring the spectral signatures of their subcellular compartments. Additionally, the evolution of high-density micromass cultures was investigated to provide a comprehensive understanding of the process and complex interactions between cells and their surrounding extracellular matrix. For comparison, rMSCs were induced into chondrogenesis in identical medium conditions for 21 days in monolayer culture. Raman spectra showed that rMSCs cultured in a collagen type I hydrogel are able to undergo a distinct chondrogenic differentiation pathway at a significantly higher rate than the 2D culture cells. 3D cultures expressed stronger and more homogeneous chondrogenesis-associated peaks such as collagens, glycosaminoglycans (GAGs), and aggrecan while manifesting changes in proteins and lipidic content. These results suggest that 3D type I collagen hydrogel substrates are promising for in vitro chondrogenesis studies, and that RMS is a valuable tool for monitoring chondrogenesis in 3D environments.

New view of the adsorption of surfactants at water/alkane interfaces - Competitive and cooperative effects of surfactant and alkane molecules.

The theoretical description of the adsorption of surfactants at interfaces between aqueous solutions and oil was based over a very long time on models derived for the solution/air interface. Thus, most of the experimentally observed peculiarities could not be specifically considered but were merely interpreted in terms of a penetration of oil molecules into the alkyl chain layer of the adsorbed surfactant molecules. These penetrating oil molecules enhance the surfactant adsorption as compared to the water/air interface. Later on, for the special situations at water/oil interfaces a competitive adsorption of surfactant and oil molecules was postulated, allowing a much better description of experimental data. This picture, however, was unable to explain why the interfacial tension of the water/oil interface decreases very quickly when extremely small amounts of surfactants are added to the water. This effect cannot be of competitive nature, but a cooperativity of surfactant and oil molecules forming a mixed adsorption layer is required instead. This cooperative effect means that already few surfactant molecules adsorbed at the interface can induce a significant ordering of oil molecules in the interfacial layer. This new interfacial structure, in turn, attracts further surfactant molecules to adsorb. Improving the theoretical description of experimental data was finally achieved by applying suitable adsorption models for the two adsorbing compounds, i.e. a Frumkin adsorption model for the oil molecules and a Langmuir, Frumkin, or reorientation model for the adsorbing surfactant molecules. Here, the progress in modelling surfactant adsorption at water/oil interfaces is discussed mainly for the homologous series of the cationic surfactants CnTAB, of the anionic surfactant SDS, and members of the homologous series of the non-ionic surfactants CnDMPO at water/alkane interfaces.

Diagnostic specificity of autoantibodies to M-type phospholipase A2 receptor (PLA2R) in differentiating idiopathic membranous nephropathy (IMN) from secondary forms and other glomerular diseases.

Autoantibody against phospholipase A2 receptor (anti-PLA2R) is a sensitive and specific biomarker of idiopathic membranous nephropathy (iMN), being found in approximately 70% of iMN patients and only occasionally in other glomerular diseases. However, whereas its diagnostic specificity vs. normal controls and other glomerulonephritides (GN) has been firmly established, its specificity vs. membranous nephropathy associated with various diseases (sMN) has given inconsistent results. The aim of our study was to evaluate the prevalence of anti-PLA2R antibodies in iMN in comparison with various control groups, including sMN. A total of 252 consecutive iMN patients, 184 pathological and 43 healthy controls were tested for anti-PLA2R antibody using indirect immunofluorescence (PLA2R IIFT, Euroimmun). Anti-PLA2R autoantibodies were detectable in 178/252 iMN patients, 1/80 primary GN, 0/72 secondary GN, 9/32 sMN and 0/43 healthy controls, with a diagnostic sensitivity of 70.6%. The diagnostic specificity of anti-PLA2R antibody vs. normal and pathological controls was 100 and 94.6% respectively. However, when the diagnostic specificity was calculated only vs. secondary forms of MN, it decreased considerably to 71.9%. Interestingly enough, 9 out of 10 anti-PLA2R positive patients in the disease control groups had membranous nephropathy associated with various diseases (7 cancer, 1 Crohn's disease, 1 scleroderma). In conclusion, anti-PLA2R positivity in a patient with MN, should not be considered sufficient to abstain from seeking a secondary cause, especially in patients with risk factors for neoplasia. The causal relationship between tumors and anti-PLA2R-induced MN remains to be established, as well as the possible mechanisms through which malignancies provoke autoimmunity.

Surface dilational rheological properties in the nonlinear domain.

The interfacial tension response to dilational deformation of interfacial area exhibits a (more or less) nonlinear behavior, depending on the amplitude of the deformation. Studies of such observable interfacial properties in the nonlinear domain suggest valuable information about the two-dimensional microstructure of the interfacial layer, as well as about the structure time-evolution. In this article, the emphasis is centered on the available mathematical methods for quantitatively analyzing and describing the magnitude and the characteristics of the nonlinear interfacial viscoelastic properties. Specifically, in periodic oscillation experiments the nonlinear behavior can be represented by the combination of a linear part (the surface dilational modulus), with an additional complementary Fourier analysis parameterizing the nonlinearity. Also asymmetric Lissajous plots, of interfacial tension versus deformation, are useful tools for expanding the response nonlinearity into four distinct components relevant to significant points of the cyclic loop. In connection with the mathematical methods, nonequilibrium thermodynamic formulations provide a powerful theoretical framework for investigating the interfacial dynamic properties of multiphase systems. Experimental results for adsorption layers of complex components, available in the literature, show notable nonlinear interfacial viscoelastic behavior. In particular in this review, data are illustrated for solutions of polymers and of polyelectrolyte/surfactant complexes. The observed nonlinear findings reveal formation of complexes, patches, and other different interfacial structures.

Prospective capillaroscopy-based study on transition from primary to secondary Raynaud's phenomenon: preliminary results.

The objective of this prospective study was to investigate the transition from primary (PRP) to secondary (SRP) Raynaud's phenomenon (RP), in a large cohort of patients affected by isolated RP. A total of 2065 patients with RP were investigated by clinical interview, laboratory examinations, and nailfold videocapillaroscopy (NVC). Patients with negative NVC at first visit were yearly followed to monitor either the appearance of specific morphological alterations at NVC, or clinical manifestations of an underlying disease. Capillary abnormalities at NVC were scored, as well as the qualitative patterns of microangiopathy (Early, Active and Late). NVC was found negative at first visit in 1500 subjects; among them, 412 patients were evaluable and they were followed for a mean time of 5±4 years (range 2-13 years). Sixty-eight patients (16%) achieved a diagnosis of SRP during follow-up, showing normal or not specific capillary alterations at NVC 4% of patients (the diagnosis was undifferentiated connective tissue diseases), Early scleroderma-pattern 57%, Active scleroderma-pattern 7%, Late scleroderma-pattern 12%, and scleroderma-like pattern 18% of patients. The time of transition from normal/not specific capillary alterations to Early scleroderma-pattern was 4.4±3.8 years. Enlarged capillaries (diameter between 20 and 50 microns) and mild reduction of capillary density were found the more frequent markers at first NVC visit in patients who progressed to a scleroderma pattern (P=0.01). This study demonstrates in a large cohort, that almost 16% of patients initially diagnosed as affected by RP with negative NVC may transit to SRP during a mean follow-up of 4.4 years. PRP patients showing major notspecific alterations of nailfold capillaries at first NVC should be strictly monitored at least once a year since at higher risk of transition to SRP.

Participatory scenario development for environmental management: a methodological framework illustrated with experience from the UK uplands.

A methodological framework is proposed for participatory scenario development on the basis of evidence from the literature, and is tested and refined through the development of scenarios for the future of UK uplands. The paper uses a review of previous work to justify a framework based around the following steps: i) define context and establish whether there is a basis for stakeholder engagement in scenario development; ii) systematically identify and represent relevant stakeholders in the process; iii) define clear objectives for scenario development with stakeholders including spatial and temporal boundaries; iv) select relevant participatory methods for scenario development, during initial scenario construction, evaluation and to support decision-making based on scenarios; and v) integrate local and scientific knowledge throughout the process. The application of this framework in case study research suggests that participatory scenario development has the potential to: i) make scenarios more relevant to stakeholder needs and priorities; ii) extend the range of scenarios developed; iii) develop more detailed and precise scenarios through the integration of local and scientific knowledge; and iv) move beyond scenario development to facilitate adaptation to future change. It is argued that participatory scenario development can empower stakeholders and lead to more consistent and robust scenarios that can help people prepare more effectively for future change.

Coexistence of osteopoikilosis with seronegative spondyloarthritis and Raynaud's phenomenon: first case report with evaluation of the nailfold capillary bed and literature review.

Osteopoikilosis (OPK) is a rare autosomal dominant bone disorder characterized by numerous hyperostotic areas that tend to localize in periarticular osseous regions. It is usually asymptomatic and is often diagnosed incidentally during X-rays. OPK may be an isolated finding or associated with other pathologies, e.g. skin manifestations, rheumatic and/or skeletal disorders. We report a literature review and, for the first time, the coexistence of OPK with seronegative spondyloarthritis and Raynaud's phenomenon in a 48-year old female. To the best of our knowledge, this is the first case of OPK studied by videocapillaroscopy, demonstrating the absence of specific microvascular abnormalities of nailfold capillaries.

Tratamiento quirúrgico de fractura cervical en el Hospital Regional Rancagua: análisis de un periodo de 4 años / Surgical treatment of cervical fracture in the Rancagua Regional Hospital: analysis of a period of 4 years

Introducción: La gravedad, las implicancias neurológicas y el alto costo del tratamiento de la fractura cervical, hacen de esta lesión un tema de suma importancia. Esta injuria provoca graves limitaciones e invalidez a los afectados, en su mayoría en plena actividad laboral, impactando en lo médico, social y económico. Objetivos: Describir los pacientes tratados quirúrgicamente de fractura cervical traumática en el Hospital Regional Rancagua, por el equipo de Neurocirugía dentro de un periodo de 4 años. Materiales y Métodos: Se evaluó - 24 pacientes con antecedente de fractura cervical el mecanismo del trauma, el tiempo transcurrido desde el ingreso hospitalario hasta la cirugía, nivel y compromiso de la lesión medular, tipo de abordaje quirúrgico, complicaciones médicas, quirúrgicas y seguimiento post-operatorio, entre otros. Resultados: 5 mujeres y 19 hombres, edad promedio 39 años (rango de edad 14 a 75 años), principales mecanismos de trauma fueron los accidentes automovilísticos-atropello (58 por ciento). El nivel medular más frecuentemente lesionado fue C4-C5 (25 por ciento). En el 50 por ciento de los pacientes se clasificó de entrada como Frankel A, por lo que un 50 por ciento de todos los pacientes ingresaron tetrapléjicos, y de estos, un 33 por ciento egresó tetraparéticos. Del ingreso a cirugía hubo un tiempo de espera promedio 5 días. Dentro de las complicaciones médicas la causa respiratoria (46 por ciento) fue la más frecuente, necesitando 64 por ciento de estos pacientes ventilación mecánica. Se registró 1 infección de herida operatoria donde el abordaje fue posterior. El Índice de Barthel promedio de 14 pacientes fue de 49 puntos. De 6 pacientes con puntaje Cero, 85 por ciento de estos ingresaron como Frankel A y 50 por ciento egresaron tetrapléjicos. Los pacientes se rehabilitaron en promedio de 2.5 meses. Discusión: Logramos objetivar nuestra realidad. La técnica quirúrgica fue prácticamente uniforme entre los pacientes, sin complicaciones...

Introduction: Gravity, neurological implications and high costs of treating cervical fracture, makes of this injury an issue of most importance. This injury causes severe limitations and disability to those affected, mostly in full working activity, impacting on the medical, social and economic. Objectives: To describe patients surgically treated for traumatic cervical fracture at the Rancagua Regional Hospital, by the team of Neurosurgery Department, within a period of 4 years. Materials and Methods: We evaluated 24 patients with an history of cervical fracture mechanism of trauma, the time from hospital admission to surgery, and commitment level of spinal cord injury, type of surgery, medical and surgical complications and follow-up post -operation, among others. Results: 5 women and 19 men, average age 39 years (ranging age from 14 to 75 years), major trauma mechanisms were motor vehicle accidents (58 percent). The most frequently injured spinal level was C4-C5 (25 percent). 50 percent of patients were classified as Frankel A at the admission, so that 50 percent of all patients admitted were quadriplegics, and of these, 33 percent were discharged as tetraparétic. Admission to the surgery were an average of 5 days. Within cause respiratory medical complications (46 percent) was the most frequent, requiring 64 percent of these patients mechanical ventilation. There was only 1 wound infection where the approach was posterior. The average Barthel Index of 14 patients was 49 points. In 6 patients with zero score, 85 percent were admitted as Frankel A and 50 percent egressed as tetraplejic. Patients were rehabilitated an average of 2.5 months. Conclusions: We were able to objectify our reality. The surgical technique was nearly uniform among patients without severe postoperative surgical complications...

Capillary pressure studies under low gravity conditions.

For the understanding of short-time adsorption phenomena and high-frequency relaxations at liquid interfaces particular experimental techniques are needed. The most suitable method for respective studies is the capillary pressure tensiometry. However, under gravity conditions there are rather strong limitations, in particular due to convections and interfacial deformations. This manuscript provides an overview of the state of the art of experimental tools developed for short-time and high-frequency investigations of liquid drops and bubbles under microgravity. Besides the brief description of instruments, the underlying theoretical basis will be presented and limits of the applied methods under ground and microgravity conditions will be discussed. The results on the role of surfactants under highly dynamic conditions will be demonstrated by some selected examples studied in two space shuttle missions on Discovery in 1998 and Columbia in 2003.

Pancreas transplantation inside Emilia-Romagna, Italy: referral pattern, demand forecasting, and organ availability.

In Italy, referral of diabetic patients for pancreas transplantation (PT) is an unstructured process, resulting in a low rate of activity and late referrals, often when the patient has already undergone dialysis. In addition, the continuous improvement in pancreas transplant alone, offering the opportunity to reduce cardiovascular risk due to proteinuria and reduced glomerular filtration rate (GFR), is rarely appreciated. We therefore analyzed (1) referral activity to PT during the time frame 2001-2005 in Emilia-Romagna, Italy (four million inhabitants), by collecting ICD 9 CM codes (55.69 + 52.80; 52.86 and 52.80 alone) by residence of the patient; (2) demand for PT among a sample population of 1670 diabetes patients, whose charts were reviewed for the type of diabetes and presence of overt diabetic nephropathy (DN: proteinuria >300 mg/24 h and/or GFR <60 mL/min); (3) potential pancreas availability as the ratio between pancreas and hearts utilized (UP/HR) in different areas of our country. As a results, (1) referral activity reached 8.4 PT per million people in 5 years in the whole region, ranging from 2.6 in the province where a PT program is active, to a maximum value of 20.7 in the province where a devoted outpatient clinic is operated by nephrologists. (2) Prevalence of overt DN was 6% in our cohort, corresponding to 510 D1 patients worthy of evaluation for PT inside Emilia-Romagna region. (3) During 2006, UP/HR was 0.58 in Associazione Inter-Regionale Trapianti agency, 1.16 in Tuscany, 0.30 in Piedmont, and 0.26 in our region. Taken together, our data showed that (1) the referral of D1 to PT has to be empowered, keeping in touch with all patients suffering from diabetic nephropathy; (2) the outpatient clinic devoted to evaluation and recruitment of D1 with nephropathy plays the key role in this program of timely and widespread referral; (3) the availability of pancreata can be increased by utilizing broader criteria for harvesting, increased consent rate to donation and increased the demand for PT (recipient pool). Pancreas grafts need to increase, since the current low demand produces underutilization of the pancreas resource, due to the frequent lack of a suitable recipient.

["Terzo fuoco", lead poisoning and chronic renal failure]. / "Terzo fuoco", intossicazione da piombo e insufficienza renale cronica.

BACKGROUND: In ceramics, "Terzo fuoco" (Third fire) means a third firing of clay to fix colors on tiles or pottery. The low firing temperatures (800-900 degrees C) and the use of a spray gun are risk factors for lead poisoning. Because of their small size, handicraft companies often fail to implement the preventive measures that are utilized efficiently in large tile factories. We report a case of chronic lead poisoning with special emphasis on diagnostic tools and treatment goals. CASE REPORT: A 38-year-old woman was hospitalized in 2005 because of grade 3 chronic renal failure (serum creatinine 1.69 mg%, Cockroft-Gault glomerular filtration rate [GFR] 45 mL/min), hypertension and elevated serum uric acid (13.4 mg%) without gout. She had been previously hospitalized elsewhere and diagnosed as suffering from hypertensive nephropathy. Her occupational history included acute lead poisoning 12 years before, which was treated with a short leave from work. She subsequently continued her job, using a spray gun for decorative drawing in a small tile company until 2004. Because of a low GFR she underwent a 3-day chelation test with 750 mg CaNaEDTA i.v., and excreted 1056 microg Pb (n.v < 600 microg) -- (PbU/EDTA ratio 1.41; n.v < 0.6). A renal biopsy showed chronic interstitial nephropathy with severe arteriolosclerosis. The patient was treated with 5 courses of EDTA, resulting in a final Pb excretion of 517 microg/72 h (PbU/EDTA 0.69). Her serum creatinine fell to 1.32 mg% (CFR 58 mL/min). A further course of chelation therapy is planned. DISCUSSION AND CONCLUSIONS: The EDTA chelation test allows to determine the lead body burden (PbBB) and to titrate subsequent chelation therapy. Recent papers have shown that PbBB is a major factor in the progression of chronic renal failure besides pressure control, and have indicated a PbBB safety level of less than 100 microg/test (PbU/EDTA < 0.1). In order to prevent the development of chronic renal failure, it is important that not only occupational but also environmental lead exposure be identified and adequately treated.

Rheological surface properties of C12DMPO solution as obtained from amplitude- and phase-frequency characteristics of an oscillating bubble system.

The experimental data on the surface rheological characteristics of dodecyl dimethyl phosphine oxide solutions obtained in a fully automatic oscillating bubble device under microgravity conditions in the frequency range 0.01-100 Hz are presented. The complex surface elasticity modulus is obtained form the amplitude- and phase-frequency characteristics of established pressure oscillations in a closed cell without calibration experiments by direct calculation of the necessary coefficients. The characteristics of the adsorption layers obtained from the elasticity modulus are in good agreement with adsorption isotherms and equations of state accounting for the intrinsic (2D) monolayer compressibility.

Adsorption and surface rheology of n-dodecanol at the water/air interface.

Adsorption layers of n-dodecanol at the water/air interface show phase transitions at low temperatures [Vollhardt, Fainerman, Emrich, J. Phys. Chem. B 104 (2000) 8536]. Using a drop shape technique it is shown that the dilational elasticity disappears in the coexistence region of the adsorption layer. The relaxation time between the condensed and liquid-like surface states is in the sub-second time range.

[Acute effects of peritoneal dialysis on muscle protein turnover]. / Effetti acuti della dialisi peritoneale sul metabolismo proteico.

BACKGROUND: Despite continuing glucose absorption and stimulation of insulin secretion, wasting is common in patients with chronic renal failure (CRF) treated with peritoneal dialysis. METHODS: To evaluate if peritoneal dialysis per se has any effect(s) on muscle protein turnover we employed the forearm perfusion method associated with the kinetics of 3H-phenylalanine in seventeen patients with CRF in the basal state and: a) during the systemic hyperinsulinemia associated with peritoneal dialysis (6 patients) (200-240 min); b) during locally-induced hyperinsulinemia, without systemic effects on aminoacid (AA) availability (6 patients) (80-120 min); c) in time-controls (5 patients) (80-240 min). RESULTS: Peritoneal dialysis and local infusion of insulin in the brachial artery (0.01 mU/min/kg) induced a similar degree of systemic or local, moderate hyperinsulinemia (19+/-4 e 21+/-3 microU/ml, respectively). During both protocols an insulin-related inhibition of muscle protein degradation occurred; however peritoneal dialysis caused a 20% decrease in forearm phenylalanine rate of disposal (an index of muscle protein synthesis), which correlated with the decline of arterial BCAA and potassium, which were removed via the peritoneal fluid. Furthermore, a persistent negative net phenylalanine and AA balance across the forearm was observed during peritoneal dialysis, while the negative basal net phenylalanine and AA balance was reversed to a positive or neutral one during local hyperinsulinemia. CONCLUSIONS: We conclude that in CRF patients even a modest elevation in local insulin levels is followed by an anabolic muscle response, while the same effect is not observed during the systemic hyperinsulinemia associated with substrate removal which occurs during peritoneal dialysis. In this setting the antiproteolytic effect of hyperinsulinemia is offset by a decrease in muscle protein synthesis which is accounted for by a decrease in AA availability. Our data indicate that protein metabolism during peritoneal dialysis is characterized not only by decreased, but also less efficient, turnover rates.

Frequency characteristics of amplitude and phase of oscillating bubble systems in a closed measuring cell.

The amplitude- and phase-frequency characteristics of oscillating bubble systems with a closed measuring cell are analyzed. The shape of the frequency characteristics is qualitatively different for bubbles smaller or larger than a hemisphere, respectively, and also for diluted and concentrated surfactant solutions. Moreover, the presence of a surfactant in the solution strongly influences the characteristic frequencies of the system. The experiments performed under ground and microgravity conditions show a good qualitative agreement with theoretically predicted amplitude- and phase-frequency characteristics and confirm the adequacy of the proposed theory. The comparison of high-frequency limits of the surface dilatational elasticity with the theoretical Gibbs elasticities calculated according to the respective adsorption isotherm shows good agreement for small surfactant concentrations. At higher concentrations large discrepancies are observed which can possibly be explained by the violation of the linearity condition for the surface layer.

Adsorption and partitioning of surfactants in liquid-liquid systems.

The adsorption at liquid-liquid interfaces is a phenomenon with a remarkable impact on many scientific and technological fields concerning multiphasic systems. Though in principle similar to liquid-vapour, the study and the description of the dynamic aspects of the adsorption processes at liquid-liquid interfaces deserves some specific considerations. In fact, these systems are often characterised by the partitioning of the surfactant between the two liquid phases, which makes much more complex both their modelling and investigation. In some conditions, the partitioning can be the main process controlling the adsorption dynamics. This paper is aimed at reviewing the state-of-the-art of the theoretical modelling and experimental investigation of the adsorption dynamics of surfactants at liquid-liquid interfaces. After a brief introduction to the problem of adsorption dynamics, the principal models utilised to describe the process at liquid-liquid interfaces under different assumptions are critically presented, underlining the influence of the surfactant partitioning, with respect to the relative volumes of the liquid phases and of the initial partitioning conditions. The most important experimental methodologies for the measurement of the dynamic interfacial tension are also critically reviewed by pointing out the specific problems related with the investigation of the adsorption dynamics of surfactants at liquid-liquid interfaces. Moreover, the problem of the measurement of the thermodynamic quantities characterising the partitioning--mainly the partition coefficient--is also addressed, reporting some literature data. Finally, a review of the literature about the experimental work on the subject and an overview of the needs and of the open questions is given.

Adsorption Kinetics of Alkylphosphine Oxides at Water/Hexane Interface

A pendant drop technique has been used to study the adsorption of a nonionic surfactant, an alkyldimethylphosphine oxide (C13DMPO), at the water/hexane interface. The measured interfacial tensions exhibit a steep initial decrease, pass through a minimum, and then level off at a value which depends on the initial surfactant concentration in the drop. This time dependence of the interfacial tension can be interpreted by an adsorption with a subsequent transfer of the surfactant into the second bulk phase, hexane. Measurements of the distribution coefficient show that the solubility of C13DMPO is much higher in hexane than in water. A qualitative model is proposed which describes the observed dynamic interfacial tensions.

Adsorption Kinetics of Alkylphosphine Oxides at Water/Hexane Interface

A theoretical model is presented to describe the adsorption of surfactant molecules at the water/oil interface for the case when transport across the interface must be considered due to the solubility of the surfactant in both liquid phases (aqueous solution drop in an oil phase). The theory is based on a diffusion-controlled adsorption model and a numerical difference scheme is used to solve the problem for closed finite systems. By simulating adsorption-desorption processes, the influence of the geometrical and thermodynamic parameters on the dynamic adsorption behavior is studied. In particular, the effects of the volume ratio, surfactant concentration, diffusion coefficients, and distribution coefficient on the process are analyzed. The model allows quantitative interpretation of the experimental data obtained for an alkyldimethylphosphine oxide at the water/hexane interface. The interfacial tension signals, presenting a minimum under some conditions, are fitted by the theoretical curves.