Fluorescence Studies of Phosphofructokinase From Bacillus Stearothermophilus.

Phosphofructokinase catalyzes the phosphorylation of $\beta$-fructose 6-phosphate (Fru-6-P) to $\beta$-fructose 1,6-bisphosphate. The first part of this dissertation shows that phosphofructokinase from Bacillus stearothermophilus (Bs-PFK) is a tetramer in the region pH 4.5-9.5 unlike the enzymes from mammalian sources, which exhibit association-dissociation reactions. Circular dichroism, steady-state fluorescence, and static and dynamic light scattering were used to study the conformational properties of the enzyme. Inactivation of the enzyme below pH 7.0 is not due to dissociation of the tetramer to dimers or monomers. In the second part, the fluorescence of the lone tryptophan was investigated by steady-state and time-resolved techniques. The decay of Bs-PFK can be best described as a discrete double exponential with lifetimes of $\sim$1.6 and 4.4 ns. The decay-associated emission spectra of the two components are identical. Similar results were obtained in D\sb2O, suggesting that the heterogeneous emission is not due to excited-state proton transfer. The activation energy for the temperature-dependent nonradiative decay rate was $\sim$0.94 Kcal/mol. The emission had a quantum yield of 0.30 $\pm$ 0.03 with a rate constant for acrylamide quenching, 0.62 $\times$ 10\sp9 M\sp{-1} s\sp{-1} which is 4-fold lower than the value expected for a diffusion controlled reaction. The fluorescence anisotropy is 0.18 suggesting that the tryptophan environment is fairly rigid. From the anisotropy decay measurements, a single exponential decay with rotational correlation time of $\sim$40 ns with r(0) value of $\sim$0.19 was obtained. Finally, the effects of allosteric ligand binding and site-specific mutation on the conformation of Bs-PFK were studied. Addition of adenosine triphosphate (ATP) or Fru-6-P did not cause any change in fluorescence. However, there is about 7% decrease of quantum yield and 2 nm red shift of emission maximum, upon adding the inhibitor PEP. Fru-6-P restores the fluorescence parameters to those of native Bs-PFK indicating the substrate induced allosteric transition from T- to R-conformation. The Arg-252 to Ala-252 mutation caused opposite effects: increase of quantum yield and 2 nm blue shift of emission maximum

Truth is somewhere in between: an ethnographic account of Broad Based Black Economic Empowerment (BBBEE) in South Africa - a work in progress

Abstract Dissertation Title: Truth is Somewhere In Between: An Ethnographic Account of Broad Based Black Economic Empowerment (BBBEE) in South Africa Broad Based Economic Empowerment (BBBEE) policy, codes and scorecard were finalised in 2007 in South Africa. In an attempt to eradicate economic polarity, the policy’s aim is to pursue concurrent economic growth and social distribution. The goal is honourable, but is it achievable? Progress among all affected parties needs to be investigated and evaluated. In addition to much confusion arising between the policy’s discourses and practices, the uneasy logic of BBBEE in the neo‐capitalistic state of South Africa faces resistance and various challenges. Adopting an anthropological research approach, this paper makes particular use of participant observation in an effort to deconstruct the multilayered BBBEE concept and its practice. An examination of a firm that achieved broad based empowerment score provides the necessary ethnographic data. The dynamics of organisational culture, management and their BBBEE implementation, together with the perspectives of various stakeholders such as those within the community, government and among consultants, are all explored. BBBEE score, for all intents and purposes, was perceived as being irrelevant to the actual employees and their daily operations. To the degree that it may have been pertinent, the constant battles of culture and perceptions between various people and positions aggravated any hope of a possible point of reconciliation. Capitalist determination among all parties exists at the core of economic game they consent to play. Despite the policy’s effort to transform the management paradigm, the traditional organisational structure and practice is largely upheld and consequently, empowerment remains merely in the realm of discourses among both practitioners and beneficiaries. Narrow based empowerment persists as the dominant view of many and, as a result, BBBEE remains a sheer bureaucratic baby, impotent at bringing about any meaningful cultural transformation in the current economic trend of South Africa

Preparation and characterization of spray-dried valsartan-loaded Eudragit® E PO solid dispersion microparticles

AbstractThe purpose of this study was to develop the immediate release stomach-specific spray-dried formulation of valsartan (VAL) using Eudragit® E PO (EPO) as the carrier for enhancing dissolution rate in a gastric environment. Enhanced solubility and dissolution in gastric pH was achieved by formulating the solid dispersion using a spray drying technique. Different combinations of drug–polymer–surfactant were dissolved in 10% ethanol solution and spray-dried in order to obtain solid dispersion microparticles. Use of the VAL–EPO solid dispersion microparticles resulted in significant improvement of the dissolution rate of the drug at pH 1.2 and pH 4.0, compared to the free drug powder and the commercial product. A hard gelatin capsule was filled with the VAL–EPO solid dispersion powder prior to the dissolution test. The increased dissolution of VAL from solid dispersion microparticles in gastric pH was attributed to the effect of EPO and most importantly the transformation of crystalline drugs to amorphous solid dispersion powder, which was clearly shown by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and powder X-ray diffraction (P-XRD) studies. Thus, VAL, a potential antihypertensive drug in the form of a solid dispersion microparticulate powder, can be effectively delivered in the immediate release dosage form for stomach-specific drug delivery

Stability of a Jensen type equation in the space of generalized functions

AbstractWe reformulate and solve the stability problem of a Jensen type functional equation3f(x+y+z3)+f(x)+f(y)+f(z)−2f(x+y2)−2f(y+z2)−2f(z+x2)=0, in the spaces of some generalized functions such as tempered distributions and Fourier hyperfunctions

anti-9,10-Di(1-naphth­yl)anthracene pyridine disolvate

In the title compound, C34H22·2C5H5N, there is a crystallographic inversion center in the middle of the anthracene ring system. The dihedral angle between the mean planes of the anthracene and naphthalene ring systems is 83.96 (4)°. The crystal structure is stabilized by weak inter­molecular C—H⋯N and C—H⋯π inter­actions

SubrenaI CapsuIe Tumor ImpIant Assay with Frozen Tumor Tissue: A Preliminary Study Using Mouse Sareoma and Human Uterine Cervix Cancer

The purpose of this study is to evaluate the possibility of application of SHeA to previously frozen tumor tissue. Mouse sarcoma-I80 and human squamous cell carcinoma of the uterine cervix were used as implanting tumor specimens. The fresh tumor specimens were frozen by rapid freezing method and stored in a liquid nitrogen tank. On the 7th day of freezing, the specimens were thawed and diced into 1 cubic millimeter pieces, and implanted beneath the subrenal capsule of ICH mice. The average viabilities before freezing and after thawing were 86.7% and 10.5% in mouse sarcoma-I80 respectively. And those of human uterine cervix cancer were 73.3% and 9.5% respectively. The evaluability of implanted tumor was 83.3% on the 6th day and 73.7% on the 12th day in mouse sarcoma, and in human cervix cancer, 75.0% and 66.7% respectively. The growth of previously frozen implanted mouse sarcoma was significant, 2.1 times on the 6th day and 73.9 times on the 12th day in volume. In the case of cervix cancer, the previously frozen tumor implants also grew significantly, 1.7 times on the 6th day and 2.1 times on the 12th day in volume. In conclusion, this preliminary laboratory study showed that SHCA could be applied to frozen tumor tissue as well as to fresh tissue for chemosensitivity test

Notified Incidence of Tuberculosis in Foreign-born Individuals in Jeju Province, Republic of Korea

Objectives In the Republic of Korea (ROK), the notified incidence of tuberculosis in foreign-born individuals (NITFBI) has increased recently, as has the rate of multidrug-resistant (MDR) and rifampicin-resistant (RR) tuberculosis in foreigners staying in the ROK. As Jeju Province in ROK has a no-visa entry policy, control programs for NITFBI should be consolidated. The aim was to evaluate the status of NITFBI, with a focus on the distribution of MDR/RR tuberculosis by nationality. Methods Data on tuberculosis incidence in individuals born in Jeju Province and in foreign-born individuals were extracted from the Korean Statistical Information Service of Statistics Korea, and the Infectious Disease Surveillance Web Statistics of the Korea Centers for Disease Control and Prevention, respectively. Results Among all notified incident cases of tuberculosis, the proportion of NITFBI increased from 1.46% in 2011 to 6.84% in 2017. China- and Vietnam-born individuals accounted for the greatest proportion of the 95 cases of NITFBI. Seven cases of MDR/RR tuberculosis were found, all involving patients born in China. Conclusions In Jeju Province, ROK, NITFBI might become more common in the near future. Countermeasures for controlling active tuberculosis in immigrants born in high-risk nations for tuberculosis should be prepared in Jeju Province, since it is a popular tourist destination

Interrupted aortic arch diagnosed with loss of femoral pulse in a patient undergoing patent ductus arteriosus ligation -A case report-

A 12-year-old boy with ventricular septal defect and patent ductus arteriosus was presented to the operating room. Upon clamping the patent ductus arteriosus, the femoral arterial pressure curve was lost; however, it returned upon unclamping. Upon further dissection, an interrupted aortic arch was found between the left subclavian artery and patent ductus arteriosus. The surgery was discontinued for further evaluation

A STUDY OF MOTION CHARACTERISTICS LED BY CONNECTION METHODS AND POSITIONS OF A WAVE-ENERGY CONVERTER IN A REGULAR WAVE

The potential of wave power as an alternative energy resource is being studied to address problems associated with fossil fuel exhaustion and environmental pollution. In this paper, to improve the power generation efficiency of a floating-type wave-energy converter that has an activating body, the effects of the positions of a connecting bridge and different connecting methods between a main body and the activating body of the wave-energy converter were studied. In order to research the activating body’s motion characteristics that are caused by the changes of connecting bridge’s position and connecting methods; hinged or fixed connector, the wave-energy converter was modeled and simulated by using a commercial software. The moment and angular velocity of the axis of power generation were measured from the results of simulations and then the power outputs were calculated based on the moment and angular velocity. The outputs, which were analyzed under several regular wave conditions, were compared to each other