Kinetics of Surfactant Adsorption at Fluid-Fluid Interfaces: Surfactant Mixtures

The adsorption at the interface between an aqueous solution of several surface-active agents and another fluid (air or oil) phase is addressed theoretically. We derive the kinetic equations from a variation of the interfacial free energy, solve them numerically and provide an analytic solution for the simple case of a linear adsorption isotherm. Calculating asymptotic solutions analytically, we find the characteristic time scales of the adsorption process and observe the behavior of the system at various temporal stages. In particular, we relate the kinetic behavior of the mixture to the properties of its individual constituents and find good agreement with experiments. In the case of kinetically limited adsorption, the mixture kinetics is found to be considerably different from that of the single-surfactant solutions because of strong coupling between the species.Comment: 19 pages, 7 figures, to be published in Langmui

An analysis of globalization strategies for real estate service providers

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 1998.Includes bibliographical references (leaves 136-139).The technological advancements developed within the past decade have severely influenced the way national real estate companies do business. Geographical boundaries that once segregated companies into specific regions of dominance have all but disappeared. As other industries expand their operations overseas, real estate companies have had to devise their own international strategies in order to capitalize on the new 'global' market. This thesis will begin by stating three traditional hypotheses on how real estate companies should attempt to make the transition into becoming global real estate providers. These hypotheses include establishing a joint venture with an existing international corporation, acquiring a local presence by absorbing foreign real estate firms, and finally by marketing a firm's particular expertise to other foreign markets. The best solution depends on a particular company's strengths and weakness. Every international strategy requires a different strategic plan and implementation process. The second half of the thesis will involve three case studies on real estate providers that have already attempted the "globalization" transition. These companies include Lend Lease, CB Richard Ellis, and LaSalle Partners. The companies on the front line of any new industry venture are the first to test the academic hypotheses. We will compare and contrast the success of the aforementioned strategic plans with respect to these three companies. By carefully reviewing the successes and lessons learned by the industry leaders, other real estate companies can better understand their particular opportunities by going global. It is apparent to most of the real estate industry that the local specialized service provider is a dinosaur. Some companies have started the transition into tomorrow and it seems logical that other service providers will not want to reinvent the wheel.by James H. Gasperoni and David R. Ravin.S.M

The perceptive proletarian:Subjective Social Class Predicts Interpersonal Accuracy

Interpersonal accuracy correlates modestly across different domains. Although some research has explored factors that predict accuracy within specific domains of interpersonal judgment (e.g., social attributes), whether any variables might predict interpersonal accuracy generally across different domains remains in question. Subjective socioeconomic status (SES) has recently emerged as an important moderator of various social cognitions, such as contextual focus and empathic accuracy. Moreover, people lower in SES tend to show greater interpersonal engagement and attention; thus, we wondered whether individuals with lower subjective SES might exhibit superior interpersonal accuracy in multiple domains. Indeed, across four studies, we found that subjective SES inversely correlated with accuracy in three different domains of interpersonal accuracy: social attributes, situational affect, and emotion. These findings therefore demonstrate that subjective SES may predict broad interpersonal accuracy abilities and suggest that, despite modest relationships between different types of first impression accuracy, the correlates of such accuracy can still operate across domains

Broken replication forks trigger heritable DNA breaks in the terminus of a circular chromosome

<p><u>(A) Circular map of the <i>E</i>. <i>coli</i> chromosome</u>: <i>oriC</i>, <i>dif</i> and <i>terD</i> to <i>terB</i> sites are indicated. Numbers refer to the chromosome coordinates (in kb) of MG1655. (<u>B) Linear map of the terminus region:</u> chromosome coordinates are shown increasing from left to right, as in the marker frequency panels (see Figure 1C for example), therefore in the opposite direction to the circular map. In addition to <i>dif</i> and <i>ter</i> sites, the positions of the <i>parS</i>_pMT1 sites used for microscopy experiments are indicated. (<u>C) MFA analysis of terminus DNA loss in the <i>recB</i> mutant</u>: sequence read frequencies of exponential phase cells normalized to the total number of reads were calculated for each strain. Ratios of normalized reads in isogenic wild-type and <i>recB</i> mutant are plotted against chromosomal coordinates (in kb). The profile ratio of the terminus region is enlarged and the profile of the corresponding entire chromosomes is shown in inset. Original normalized profiles used to calculate ratios are shown in <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1007256#pgen.1007256.s005" target="_blank">S1 Fig</a>. The position of <i>dif</i> is indicated by a red arrow. The <i>ter</i> sites that arrest clockwise forks (<i>terC</i>, <i>terB</i>, green arrow) and counter-clockwise forks (<i>terA</i>, <i>terD</i>, blue arrow) are shown. <u>(D) Schematic representation of focus loss in the <i>recB</i> mutant:</u> Time-lapse microscopy experiments showed that loss of a focus in the <i>recB</i> mutant occurs concomitantly with cell division in one of two daughter cells, and that the cell that keeps the focus then generates a focus-less cell at each generation. The percentage of initial events was calculated as the percentage of cell divisions that generate a focus-less cell, not counting the following generations. In this schematic representation, two initial events occurred (generations #2 and #7) out of 9 generations, and focus loss at generation #2 is heritable. Panels shown in this figure were previously published in [<a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1007256#pgen.1007256.ref019" target="_blank">19</a>] and are reproduced here to introduce the phenomenon.</p

Identification of O-Linked Glycoproteins Binding to the Lectin Helix pomatia Agglutinin as Markers of Metastatic Colorectal Cancer

Background Protein glycosylation is an important post-translational modification shown to be altered in all tumour types studied to date. Mucin glycoproteins have been established as important carriers of O-linked glycans but other glycoproteins exhibiting altered glycosylation repertoires have yet to be identified but offer potential as biomarkers for metastatic cancer. Methodology In this study a glycoproteomic approach was used to identify glycoproteins exhibiting alterations in glycosylation in colorectal cancer and to evaluate the changes in O-linked glycosylation in the context of the p53 and KRAS (codon 12/13) mutation status. Affinity purification with the carbohydrate binding protein from Helix pomatia agglutinin (HPA) was coupled to 2-dimensional gel electrophoresis with mass spectrometry to enable the identification of low abundance O-linked glycoproteins from human colorectal cancer specimens. Results Aberrant O-linked glycosylation was observed to be an early event that occurred irrespective of the p53 and KRAS status and correlating with metastatic colorectal cancer. Affinity purification using the lectin HPA followed by proteomic analysis revealed annexin 4, annexin 5 and CLCA1 to be increased in the metastatic colorectal cancer specimens. The results were validated using a further independent set of specimens and this showed a significant association between the staining score for annexin 4 and HPA and the time to metastasis; independently (annexin A4: Chi square 11.45, P = 0.0007; HPA: Chi square 9.065, P = 0.0026) and in combination (annexin 4 and HPA combined: Chi square 13.47; P = 0.0002). Conclusion Glycoproteins showing changes in O-linked glycosylation in metastatic colorectal cancer have been identified. The glycosylation changes were independent of p53 and KRAS status. These proteins offer potential for further exploration as biomarkers and potential targets for metastatic colorectal cancer

Novel phages of healthy skin metaviromes from South Africa

Recent skin metagenomic studies have investigated the harbored viral diversity and its possible influence on healthy skin microbial populations, and tried to establish global patterns of skin-phage evolution. However, the detail associated with the phages that potentially play a role in skin health has not been investigated. While skin metagenome and -metavirome studies have indicated that the skin virome is highly site specific and shows marked interpersonal variation, they have not assessed the presence/absence of individual phages. Here, we took a semi-culture independent approach (metaviromic) to better understand the composition of phage communities on skin from South African study participants. Our data set adds over 130 new phage species of the skin to existing databases. We demonstrated that identical phages were present on different individuals and in different body sites, and we conducted a detailed analysis of the structural organization of these phages. We further found that a bacteriophage related to the Staphylococcus capitis phage Stb20 may be a common skin commensal virus potentially regulating its host and its activities on the ski

Genome sequence of the copper resistant and acid-tolerant Desulfosporosinus sp. BG isolated from the tailings of a molybdenum-tungsten mine in the Transbaikal area

Here, we report on the draft genome of a copper-resistant and acidophilic Desulfosporosinus sp. BG, isolated from the tailings of a molybdenum-tungsten mine in Transbaikal area. The draft genome has a size of 4.52 Mb and encodes transporters of heavy metals. The phylogenetic analysis based on concatenated ribosomal proteins revealed that strain BG clusters together with the other acidophilic copper-resistant strains Desulfosporosinus sp. OT and Desulfosporosinus sp. I2. The K+-ATPase, Na+/H+ antiporter and amino acid decarboxylases may participate in enabling growth at low pH. The draft genome sequence and annotation have been deposited at GenBank under the accession number NZ_MASS00000000

Incidence and Effects of Feeding Intolerance in Trauma Patients

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Design and Implementation of a Mobile-Based Personal Digital Assistant (MPDA)

In this work we present a mobile-based personal digital assistance for students of higher institutions of learning. These days, the need for a To-Do list or a daily plan cannot be over-emphasized. This is because so many things compete for our valuable. It appears that the 24 h of a day are no longer sufficient for our daily activities. Although this appears true, however, prioritizing our activities generally may go a long way in helping to manage our time. Several platforms and media that existed some years ago were based on the use of pen and paper to organize activities for the day. These can no longer match up recent advances in technology and information flow which are at a very great speed. This work leverages on the current proliferation of mobile devices where each student now has a mobile device for personal use. In this work a mobile-based personal digital assistant is developed specifically on the Android plat-form. The system adopts Google’s material guidelines for the design of its user interface. Android Java was used for the implementation of the core aspects of the system while SQLite was used for the database. The application will help students in prioritizing and organizing their daily activities thereby making them more responsible