Search

In the context of international trade, merchants are primarily concerned with concluding a secure sale in the shortest possible time frame. This approach allows them to mitigate risks, reduce costs, and conserve time. Sale by sample is one of the recognized methods to achieve this objective. Particularly in international trade, merchants, before entering into a transaction, request a sample of the goods from sellers to ensure quality and, after testing and approving it, place their order. The need for speed, the long distances involved, the unavailability of all the goods at the time of sale and the difficulty of inspecting the goods in order to eliminate any ambiguities all point to the need for this type of sale in the field of international trade. Sale by sample is a type of sales contract in which the buyer becomes aware of all or part of the characteristics of the subject matter of the transaction based on the sample provided by the seller, and the delivered goods must conform to the mentioned sample. This method is used to describe the goods in order to eliminate ambiguity and specify the object of the sale. When the goods are not available, and the seller wishes to give a full explanation of them, they can present a sample to the buyer. A sample differs from a model. A model may represent all or only some of the characteristics of the goods being ordered for manufacture, while the sample pertains to existing goods. Jurists have differed in their opinions regarding the validity of sale by sample, particularly on whether the sample constitutes part of the sold goods and whether presenting the sample can replace a description of the goods. They agree that if the sample is part of the existing goods, the contract is valid; otherwise, they consider the contract void due to the lack of determination and description of the goods, as they do not see the presentation of a sample as a substitute for the description of the goods. However, contrary to this earlier view, most jurists consider viewing the sample as providing more clarity about the goods than a mere description. The Civil Code follows the majority opinion and recognizes the validity of the sale by sample. After the transaction is completed, the buyer expects the goods delivered to conform to the sample, and if the delivered goods differ from the sample, it is considered a breach of the seller's obligation, and in the absence of an agreement, the buyer can reject the goods. The International Sale of Goods Convention also recognizes this type of sale, with the seller's primary obligation being to deliver goods that conform to the agreed-upon sample. This research aims, through a comparative study of Iranian law and the International Sale of Goods Convention, with an emphasis on judicial practice, to explore how disputes between parties are resolved in cases where the characteristics of the goods are or are not specified in the contract, and to determine on whom the burden of proof for the non-conformity of the delivered goods with the sample falls in Iranian law and the mentioned convention. Previous research indicates that studies conducted in this area have only addressed the consequences of nonconformity of goods with the sample and have offered a general statement regarding the destruction of the sample by the buyer before the delivery of the goods, without delving into different scenarios or details. A review of the regulations on sale by sample in Iranian law and the International Sale of Goods Convention reveals no explicit guidance on the impact of sample destruction on the obligations of the parties involved. The findings of this research, using a descriptive-analytical method, indicate that if the sample is lost before the seller's obligation is fulfilled, there is a slight difference between Iranian law and the said Convention. In Iranian Civil Code, provided that the characteristics of the goods are mentioned in the contract, the delivery of the sample to the buyer is supplementary, and the seller is discharged of the obligation by delivering goods that match the contractual quality. If the characteristics of the goods are not mentioned in the contract, the seller has the discretion to choose the goods, and the burden of proving non-conformity with the lost sample rests with the buyer, as they are making an additional claim after delivery. However, according to the provisions of the Convention, if the characteristics of the goods are mentioned in the contract and a notice of non-conformity is sent by the buyer to the seller, the burden of proving that the delivered goods conform to the offered sample lies with the seller. In the absence of a specific mention of the characteristics of the goods in question in the contract, the burden of proof regarding any alleged non-conformity rests with the buyer. [ABSTRACT FROM AUTHOR]

Understanding the fluid flow on paperfluidic substrates is crucial due to an increasing interest in affordable sensors for diagnosis, environmental testing, food testing, etc. Charged dyes are the most commonly used model analytes for characterizing the fluid flow in paperfluidic devices. Here, we propose a framework to quantify the concentration-dependent loss during transport of four charged dyes (e.g., rhodamine B, methylene blue, tartrazine and amaranth). At concentrations lower than a critical value (Cc), electrostatic interaction of the dye molecules with the filter paper retards the flow of cationic dyes rhodamine B and methylene blue, resulting in 75%–99% sample loss. We determined Ccto be 20 μM for rhodamine B and 5 mM for methylene blue. The large difference in their Ccvalues is explained by the molecular structures of these dyes. While anionic dyes (e.g., tartrazine and amaranth) are not retarded during flow on filter paper due to negligible electrostatic interaction with the substrate, they form strong coffee ring patterns in the detection zone when the dye concentration is below Cc. We introduced a new parameter called the ‘coffee ring index’ (CRI) to quantify the non-uniform sample distribution in the detection zone, and from this, determined Ccto be 250 μM for amaranth and 1.25 mM for tartrazine. Finally, we demonstrated that an increase in the dye viscosity by adding 30% glycerol can lower Ccof tartrazine from 1.25 mM to 100 μM. These results provide useful guidelines for the paperfluidics community to design more effective sensors.

Capillary gel electrophoresis is a widely used method for rapid separation of fluorophore labeled carbohydrates. Even though, many publications conferred about this popular technique, no report yet investigated the possible sample losses during the purification process of the fluorophore labeling reaction mixture. In the present work, normal polarity capillary zone electrophoresis separation mode was applied to take advantage of the opposite migration directions of the electroosmotic flow and the negatively charged sample components using Tris-hexanoic acid running buffer at basic pH. For purification free oligosaccharide analysis, the separation parameters were designed in such a way that the triple charged labeling reagent of aminopyrenetrisulfonate (APTS) could not enter the separation capillary in contrary to the labeled sample components of interest, therefore, the APTS did not have to be removed before analysis. The method was used to show electrophoretic profile differences possibly caused by the cleanup process that was immediately apparent by comparing the electropherograms of the purified and non-purified APTS labeled maltooligosaccharides. Furthermore, qualitative and quantitative N-glycosylation profile alterations were revealed during CZE separation of the fluorophore labeling reaction mixtures before and after purification along with the analysis of the consecutively used washing solutions for the well characterized standard glycoproteins of IgG, ribonuclease B and fetuin. [Display omitted] • The CZE profile of APTS-maltooligosaccharides differed after purification. • At basic pH the sample components entered the capillary but the APTS not. • Separation parameters were established using the maltooligosaccharides. • The method was applied to analyze the washing fluids during the purification steps. • N-glycans pools from glycoproteins were analyzed before and after purification. [ABSTRACT FROM AUTHOR]

The field of microfluidic paper-based analytical devices (μPADs) is most notably characterized by portable and low-cost analysis; however, struggles to achieve the high sensitivity and low detection limits needs required for many environmental applications hinder widespread adoption of this technology. Loss of analyte to the device material represents an important problem impacting sensitivity. Critically, we found that at least 50% of a Ni(II) sample is lost when being transported down a 30 mm paper channel that is representative of structures commonly found in μPADs. In this work, we report simple strategies such as adding a waste zone, enlarging the detection zone, and using an elution step to increase device performance. A μPAD combining the best performing functionalities led to a 78% increase in maximum signal and a 28% increase in sensitivity when transporting Ni(II) samples. Using the optimized μPAD also led to a 94% increase in maximum signal for Mn(II) samples showing these modifications can be applied more generally. [ABSTRACT FROM AUTHOR]

Protein nonspecific adsorption that occurred at the solid-liquid interface has been subjected to intense physical and chemical characterizations due to its crucial role in a wide range of applications, including food and pharmaceutical industries, medical implants, biosensing, and so on. Protein-adsorption caused sample loss has largely hindered the studies of single-cell proteomics; the prevention of such loss requires the understanding of protein-surface adsorption at the proteome level, in which the competitive adsorption of thousands and millions of proteins with vast dynamic range occurs. To this end, we feel the necessity to review current methodologies on their potentials to characterize - more specifically to quantify - the proteome-wide adsorption. We hope this effort can help advancing single-cell proteomics and trace proteomics. [ABSTRACT FROM AUTHOR]

Cyanobacteria can produce heptapetides called microcystins (MC) which are harmful to humans due to their ability to inhibit cellular protein phosphatases. Quantitation of these toxins can be hampered by their adsorption to common laboratory-ware during sample processing and analysis. Because of their structural diversity (>100 congeners) and different physico-chemical properties, they vary in their adsorption to surfaces. In this study, the adsorption of ten different MC congeners (encompassing non-arginated to doubly-arginated congeners) to common laboratory-ware was assessed using different solvent combinations. Sample handling steps were mimicked with glass and polypropylene pipettes and vials with increasing methanol concentrations at two pH levels, before analysis by liquid chromatography-tandem mass spectrometry. We demonstrated that MC adsorb to polypropylene surfaces irrespective of pH. After eight successive pipet actions using polypropylene tips ca. 20% of the MC were lost to the surface material, which increased to 25%-40% when solutions were acidified. The observed loss was alleviated by changing the methanol (MeOH) concentration in the final solvent. The required MeOH concentration varied depending on which congener was present. Microcystins only adsorbed to glass pipettes (loss up to 30% after eight pipet actions) when in acidified aqueous solutions. The latter appeared largely dependent on the presence of ionizable groups, such as arginine residues. [ABSTRACT FROM AUTHOR]

INTRODUÇÃO/OBJETIVO: O microarranjo tecidual, ou tissue microarray (TMA), permite avaliar múltiplas amostras de tecido em um único bloco. Um dos problemas do TMA é o descolamento dos cortes teciduais, por isso, para reduzir essa perda, tem-se utilizado fita adesiva especial comercial. Não há relatos comparando o uso dessas fitas adesivas com a técnica de silanização modificada. O objetivo desse estudo foi comparar as perdas de cortes entre lâminas usando fitas adesivas comerciais, lâminas silanizadas por técnica convencional e lâminas silanizadas por técnica modificada, com menor consumo de acetona. MATERIAL E MÉTODO: O TMA foi construído com blocos de tecido hepático, em dispositivo de base fixa, colocando-se 32 cilindros de 2 mm de diâmetro em duplicata e espaçamento de 2,2 mm. Quinze secções de 4 µm foram colocadas em lâminas silanizadas a 4% por técnica convencional (grupo 1), 15 em lâminas silanizadas com técnica modificada (6% de silano e com uso mínimo de acetona) (grupo 2) e 15 em lâminas com fita adesiva comercial de acordo com as recomendações do fabricante (grupo 3). Todas as lâminas foram processadas por imuno-histoquímica para citoqueratina 18, com recuperação antigênica em tampão citrato pH 6, em microondas. As perdas de amostras foram quantificadas e expressas como: perda total (> 80%), quase total (75% a 79%) ou parcial (50% a 74%). RESULTADOS: A perda de tecidos foi semelhante nos três grupos: com silanização tradicional, modificada ou fita adesiva comercial (4,9 vs. 3,1 vs. 8,1, respectivamente) (análise de variância [ANOVA], p = 0,3654). Uma das lâminas com a fita adesiva apresentou descolamento artefatual de todos os tecidos e outra de 20 tecidos em um dos lados. Nenhuma das lâminas silanizadas apresentou tal artefato. CONCLUSÃO: Lâminas silanizadas têm resultados satisfatórios, requerem menos treinamento técnico e reduzem os custos da utilização do TMA, justificando seu uso em pesquisa. Mais ainda, o uso da técnica modificada de silanização, com redução do volume de acetona, barateia o processo e diminui a produção de resíduos químicos.INTRODUCTION/OBJECTIVE: The tissue microarray (TMA) technique allows the evaluation of multiple tissue samples in a single block. One of the problems of TMA is the ungluing of tissue sections, thus commercial adhesive tape has been used to reduce this loss. There are no reports comparing the use of the commercial adhesive tape with the use of the modified silane-coated technique. The objective of this study was to compare section loss in slides using commercial adhesive tape, silane-coated microslides with the conventional technique or with the modified technique. MATERIAL AND METHOD: The TMA was constructed with hepatic tissue blocks embedded in paraffin, using a fixed base device, placing 32 cylinders of 2 mm in diameter in duplicate and 2.2 mm apart from each other. Fifteen 4-µm sections were placed on conventional silane-coated microslides at 4% (Group 1), 15 on silane-coated microslides with a modified technique (6% of silane and minimum use of acetone) (Group 2), and 15 on slides using commercial adhesive tape, according to the manufacturer's recommendations (Group 3). All microslides were processed by immunohistochemistry for cytokeratin 18, with antigen retrieval accomplished by incubation with citrate buffer pH 6.0 with microwave enhancement. Samples loss was quantified and expressed as: total (> 80%), almost complete (75% to 79%) or partial (50% to 74%). RESULTS: The loss of sections was similar in all three groups (4.9 vs. 3.1 vs. 8.1, respectively) (analysis of variance [ANOVA], p = 0.3654). One slide using commercial adhesive tape showed artifactual ungluing of all sections and another one showed loss of 20 samples on one side of the slide. None of the silane-coated microslides showed such artifact. CONCLUSIONS: Silane-coated microslides show adequate results, require less technical training and reduce the cost of TMA procedure, what justifies their use in research. Moreover, the use of the modified silane-coating technique, with the reduction of acetone volume, lowers the costs and reduces chemical residues.

Nonspecific binding between the protein and the container is an often-neglected cause of sample loss in large-scale proteomics sample preparation. In nanoproteomics, due to the small sample size, this absorption loss is no longer negligible, and researchers often adopt low binding plasticware to minimize the sample loss. However, there has been little discussion in the scientific literature on the differences in microtube performance on reducing protein/peptide binding. Therefore, the exact impact of sample loss during the sample preparation is not well understood. Here, we investigated the protein/peptide loss during the nanoproteomics experiment process. Our results showed that there are significant differences in nonspecific binding among the tested microtubes, with a protein recovery rate ranging from less than 10% to over 90% for different microtubes. Interestingly, we found that the storage temperature could also be one of the key factors that contribute to protein recovery from the plastic container. In addition, we investigated the binding preferences of different microtubes by the physical characteristics of the identified proteins and peptides, such as isoelectric point, hydrophobicity, length, and charge. Our findings help to better understand protein/peptide loss in proteomics sample preparation and provide further guidance for researchers in choosing proper containers for their precious sample.

Abstract: This overview regards some critical issues in performing flow field-flow fractionation (flow FFF, FlFFF, AF4, HF-FlFFF, HF5). It includes the channel thickness, void time, channel-flow parabolic profile, channel-flow velocity gradient, uniformity of the cross-flow, sample injection time, relaxation/focusing time, width of sample starting zone, retention level, theoretical and experimental zone broadening, hydrodynamic threshold immobilisation/re-mobilisation, sample loss and adsorption, membrane fouling, sample mass overloading, problems with symmetrical channels, non-spherical sample particles, and method development. Good method development practice (GMDP) and good fractogram practice (GFP) is suggested. [Copyright &y& Elsevier]

Single-cell proteomics is a promising field to provide direct yet comprehensive molecular insights into cellular functions without averaging effects. Here, we address a grand technical challenge impeding the maturation of single-cell proteomics─protein adsorption loss (PAL). Even though widely known, there is currently no quantitation on how profoundly and selectively PAL has affected single-cell proteomics. Therefore, the mitigations to this challenge have been generic, and their efficacy was only evaluated by the size of the resolved proteome with no specificity on individual proteins. We use the existing knowledge of PAL, protein expression, and the typical surface area used in single-cell proteomics to discuss the severity of protein loss. We also summarize the current solutions to this challenge and briefly review the available methods to characterize the physical and chemical properties of protein surface adsorption. By citing successful strategies in single-cell genomics for measurement errors in individual transcripts, we pinpoint the urgency to benchmark PAL at the proteome scale with individual protein resolution. Finally, orthogonal single-cell proteomic techniques that have the potential to cross validate PAL are proposed. We hope these efforts can promote the fruition of single-cell proteomics in the near future.

Abstract: In our earlier LC–MS experiments on the analysis of phosphocompounds like nucleotides (mono-, di- and triphosphate) and phosphopeptides and in literature, low sensitivity and severe losses of analyte to the instrumental setup were observed. Since we noticed that the stainless steel parts of the setup (e.g., the electrospray needle) adsorbed important quantities of the phosphorylated analytes, we made a LC–ESI setup without metallic surfaces. The first results were disappointing since also the fused silica surface of the LC-ESI coupler adsorbed part of the nucleotides and phosphopeptides injected in flow analysis experiments. We present experiments documenting the contribution of the different components of the setup. A number of potential solutions to the adsorption problem are proposed and tested. Only dimethyldichlorosilane deactivation of fused silica capillaries gave satisfactory results as adsorption of nucleotides and phosphopeptide was minimised. [Copyright &y& Elsevier]

A simple method, sodium dodecyl sulfate polyacrylamide gel electrophoresis coupled with direct protein adsorption analysis (SDS–PAGE/DPA), is presented here for the quantitation of adsorption-caused protein loss. No complicated steps and expensive equipment are involved, and this method is capable of measuring proteins adsorbed on sample vials at extremely low concentrations (in pg/μl). We used this method to characterize the effects of concentration, time, and volume on adsorption. We also applied this method to discover differential sample loss in protein mixtures and its utility in developing preventive strategies of adsorption. [ABSTRACT FROM AUTHOR]

Online combination of hydrophilic interaction chromatography (HILIC) and RP chromatography for separation of tryptic peptides is a challenging approach due to the incompatibility of direct loading HILIC fractions on the RP trapping column. High amounts of organic modifiers in loading solvents decrease the binding efficiency of tryptic peptides on C18 phases and lower the number of identifications. A 500 μL loop upfront of the trapping column filled with aqueous mobile phase was employed as a mixing chamber and enabled direct injections and improved saliva protein identification rates of HILIC fractions., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)