Flow rate test bench: automated and compliant to ISO standards

he issue of measuring the flow rate through a pneumatic component is a critical one. Several methods exist, each with its own pros and cons regarding the type of gas, measurement range, and accuracy. ISO Standards, however, consider only a few of them: orifice plates, nozzles, Venturi nozzles, Venturi tubes. Although amenable to possible criticism, the International Organization for Standardization is an important reference. Designing a test bench according to its Standards is often more than reasonable: advantages include certification, assessment of test methods and accuracy, worldwide recognition. On the other hand, however detailed the Standards may be, they often lack the designer's (and perhaps the user's) point of view. This aspect leads to complicated realizations, low usability or long test execution times. This article proposes a flow rate test bench compliant to ISO Standards allowing a partially automated testing, rational installation, high configurability, user-friendliness, and accuracy. © 2012, Society for Experimental Mechanics

Radiolabeled CCK/gastrin peptides for imaging and therapy of CCK2 receptor-expressing tumors

Cholecystokinin (CCK) receptors are overexpressed in numerous human cancers, like medullary thyroid carcinomas, small cell lung cancers and stromal ovarian cancers. The specific receptor-binding property of the endogenous ligands for these receptors can be exploited by labeling peptides with a radionuclide and using these as carriers to guide the radioactivity to the tissues that express the receptors. In this way, tumors can be visualized using positron emission tomography and single photon emission computed tomography imaging. A variety of radiolabeled CCK/gastrin-related peptides has been synthesized and characterized for imaging. All peptides have the C-terminal CCK receptor-binding tetrapeptide sequence Trp-Met-Asp-Phe-NH2 in common or derivatives thereof. This review focuses on the development and application of radiolabeled CCK/gastrin peptides for radionuclide imaging and radionuclide therapy of tumors expressing CCK receptors. We discuss both preclinical studies as well as clinical studies with CCK and gastrin peptides

The mechanisms by which polyamines accelerate tumor spread

Increased polyamine concentrations in the blood and urine of cancer patients reflect the enhanced levels of polyamine synthesis in cancer tissues arising from increased activity of enzymes responsible for polyamine synthesis. In addition to their de novo polyamine synthesis, cells can take up polyamines from extracellular sources, such as cancer tissues, food, and intestinal microbiota. Because polyamines are indispensable for cell growth, increased polyamine availability enhances cell growth. However, the malignant potential of cancer is determined by its capability to invade to surrounding tissues and metastasize to distant organs. The mechanisms by which increased polyamine levels enhance the malignant potential of cancer cells and decrease anti-tumor immunity are reviewed. Cancer cells with a greater capability to synthesize polyamines are associated with increased production of proteinases, such as serine proteinase, matrix metalloproteinases, cathepsins, and plasminogen activator, which can degrade surrounding tissues. Although cancer tissues produce vascular growth factors, their deregulated growth induces hypoxia, which in turn enhances polyamine uptake by cancer cells to further augment cell migration and suppress CD44 expression. Increased polyamine uptake by immune cells also results in reduced cytokine production needed for anti-tumor activities and decreases expression of adhesion molecules involved in anti-tumor immunity, such as CD11a and CD56. Immune cells in an environment with increased polyamine levels lose anti-tumor immune functions, such as lymphokine activated killer activities. Recent investigations revealed that increased polyamine availability enhances the capability of cancer cells to invade and metastasize to new tissues while diminishing immune cells' anti-tumor immune functions

CAPTURING AWARENESS: THE PERCEPTION OF HIGHER EDUCATION AT AN AT-RISK, URBAN MIDDLE SCHOOL

The purpose of this study is to understand at-risk, urban middle school students’ perceptions of higher education through the minds of young students from a diverse, inner city schooling background. This study sought to understand barriers preventing students from attending college and the positive contributing factors encouraging them to do so. Written interviews were conducted in an 8th grade urban middle school in the southern United States. One hundred five (105) students voluntarily participated in the research study, writing their thoughts pertaining to higher education and their feelings on the topic. The following themes were found: Family Involvement, Financial Burden, Need for a Degree, Better Self/Give Back, and The Experience. By better interpreting the perception a student has, professionals in the higher education setting can focus on implementations to ensure that all students are provided a fair opportunity to pursue a college experience, a career, and a life. This is a personal approach to make aware a vision of college access. Advisor: Debra Mulle

Engineering Dirhodium Artificial Metalloenzymes for Diazo Coupling Cascade Reactions

Artificial metalloenzymes (ArMs) are now commonly used to control the stereoselectivity of catalytic reactions, but controlling ArM chemoselectivity remains challenging. In this study, we engineer a dirhodium ArM to catalyze diazo cross-coupling to form an alkene that, in a one-pot cascade reaction, is reduced to an alkane with high enantioselectivity (typically >99% e.e.) by an alkene reductase. The numerous protein and small molecule components required for the cascade reaction had minimal effect on ArM catalysis, while the dirhodium cofactor itself provided only O-H insertion products from reaction with water and glucose under the same conditions. Directed evolution of the ArM led to improved yields and E/Z selectivities for a variety of substrates, which translated well to cascade reaction yields. MD simulations of ArM variants were used to understand the structural role of the cofactor on large-scale scaffold structural dynamics. These results highlight the ability of ArMs to control both catalyst stereoselectivity and chemoselectivity to enable reactions in complex media that would otherwise lead to undesired side reactions.</p

Necrotizing fasciitis in children: Prompt recognition and aggressive therapy improve survival

Necrotizing fasciitis (NF) is a bacterial infection of the soft tissues with a fulminant course and a high mortality rate. The authors performed a review to define the diagnosis, bacteriology, and management of NF in the pediatric population. This report of 20 cases treated over 18 years represents the largest reported pediatric experience. These infections were attributable to secondary infection of varicella lesions (5), omphalitis (4), extremity lesions (4), perineal infections (3), head and neck lesions (2), inguinal herniorrhapy (1), and breast abscess (1). Nineteen of the 20 children were healthy, without chronic disease or immunosuppression. All patients presented with an altered sensorium and signs of systemic toxicity. Fever (40%), tachycardia (70%), and abnormal white blood cell count (50%) were not uniformly present. There was marked tissue edema in all patients, with a characteristic peau d\u27orange appearance in 18. Seven infections were caused by streptococcus; the remainder were polymicrobial, involving multiple aerobes and anaerobes. Initial gram stain was of limited utility; in 14 of 19 cases the result was negative or showed only one of many organisms present. Fifteen patients survived and five died. All survivors underwent aggressive surgical debridement within 3 hours of admission. The survivors required of a mean of 3.8 operations. Fascial excision of up to 35% of total body surface area was required. One patient required amputation, two had colostomies, and six required extensive skin grafting for reconstruction. All five patients who died had delayed initial management. Conclusion: NF is a serious cause of death in previously healthy children. The diagnosis should be considered in the presence of any soft tissue infection presenting with signs of toxicity and marked wound edema, even in the absence of fever or abnormal white blood cell count. Immediate surgical debridement and coverage with penicillin, an aminoglycoside, and metronidazole are essential. Subsequent changes in antibiotics should be based on culture data because gram stain results are not reliable. More than one operation is required in almost all cases