Best Practices for Designing an Undergraduate Engineering Curriculum

This article offer examples of best practices for planning instructional learning within the naturalistic setting and based on real learning experiences. The inquiry, based on practices and strategies proven successful in an undergraduate engineering class is the focus of this best practices article. This article is also a useful guide for administrators, practitioners, and undergraduate educators who make decisions on instructional delivery and scholarship. The instructional activities offer core instruction and curriculum modules on best practices for effective college instruction

Separation response of iron ores during gravity concentration

Two types of iron ores namely soft laminated ore and goethitic-lateritic ore is studied in details from Jilling-Langalota deposit, Singhbhum-N, Orissa Craton, Eastern India. The soft laminated iron ore contained relatively high hematite as compared to Goethitic-lateric ore which contained goethite in large quantity. Beneficiation of iron ores by gravity separation method is studied. The ore samples are beneficiated with a view to produce sinter quality concentrate. The soft laminated ore contained 61.29% total iron, 5.04% silica and 4.29% alumina while the Goethitic-lateritic ore contained 53.34% total iron, 7.4% silica and 5.49% alumina. Liberation analysis of different size fraction suggested that grain size reduction lower than 150 mm size would be necessary to achieve sufficient liberation of iron ore minerals from the associated gangue (kaolinite and gibbsite). However, the percentage of interlocking is higher in case of Goethitic-lateritic ore compared to soft laminated ore. Considering the characterisation data, the soft laminated ore is ground separately to three size fractions namely 300 mm, 250 mm and 150 mm sizes, while the goethitic ore is ground to 150 mm size and subjected to flowing film concentration in Wilfley Table. The grade of the soft laminated ore is improved from 61% Fe to 66% Fe while for the Goethitic-lateritic ore the Fe content is enriched from 53% to 64% in simple one-stage concentration operation. The nature of the ore mineral plays important role in the separation process. Due to enrichment of goethite and friable nature of Goethitic-lateritic ore significant amount of Fe is lost during the process as compared to soft laminated ore

Cloning and characterization of mutL and mutS genes of Vibrio cholerae: nucleotide sequence of the mutL gene

The mutL and mutS genes of Vibrio cholerae have been identified using interspecific complementation of Escherichia coli mutL and mutS mutants with plasmids containing the gene bank of V. cholerae. The recombinant plasmid pJT470, containing a 4.7 kb fragment of V. cholerae DNA codes for a protein of molecular weight 92,000. The product of this gene reduces the spontaneous mutation frequency of the E. coli mutS mutant. The plasmid, designated pJT250, containing a 2.5 kb DNA fragment of V. cholerae and coding for a protein of molecular weight 62,000, complements the mutL gene function of E. coli mutL mutants. These gene products are involved in the repair of mismatches in DNA. The complete nucleotide sequence of mutL gene of V. cholerae has been determined

6,6′-Diamino-1,1′,3,3′-tetra­methyl-5,5′-(4-chloro­benzyl­idene)bis­[pyrimidine-2,4(1H,3H)-dione]

The title compound, C19H21ClN6O4, is a 1:2 adduct of p-chloro­benzaldehyde and uracil. It crystallizes with two mol­ecules in the asymmetric unit. The two uracil units in the same mol­ecule are connected by a pair of strong N—H⋯O hydrogen bonds. The packing is stabilized by N—H⋯O, C—H⋯O and C—H⋯N inter­actions

6-[(Dimethyl­amino)methyl­ene­amino]-1,3-dimethyl­pyrimidine-2,4(1H,3H)-dione dihydrate

Uracil, the pyrimidine nucleobase, which combined with adenine forms one of the major motifs present in the biopolymer RNA, is also involved in the self-assembly of RNA. In the title compound, C9H14N4O2·2H2O, the asymmetric unit contains one dimethyl­amino­uracil group and two water mol­ecules. The plane of the N=C—NMe2 side chain is inclined at 27.6 (5)° to the plane of the uracil ring. Both water mol­ecules form O—H⋯O hydrogen bonds with the carbonyl O atoms of the uracil group. Additional water–water hydrogen-bond inter­actions are also observed in the crystal structure. The O—H⋯O hydrogen bonds lead to the formation of a two-dimensional hydrogen-bonded network cage consisting of two dimethyl­amino­uracil groups and six water mol­ecules

Ultrafast dynamics of excitons in semiconductor quantum dots on a plasmonically active nano-structured silver film

The excited state dynamics of core-shell type semiconductor quantum dots (QDs) of various sizes in close contact with a plasmonically active silver thin film has been demonstrated by using picosecond resolved fluorescence spectroscopy. The non-radiative energy transfer from the QDs to the metal surface is found to be of Föster resonance energy transfer (FRET) type rather than the widely expected nano-surface energy transfer (NSET) type. The slower rate of energy transfer processes compared to that of the electron transfer from the excited QDs to an organic molecule benzoquinone reveals an insignificant possibility of charge migration from the QDs to the metallic film

Bacteriological quality of water and diarrhoea among ethnic and non-ethnic communities of rural area of West Tripura, India

Background: Waterborne diseases are the major causes of health seeking by ethnic and non-ethnic communities of West Tripura district of India. Safe and wholesome water is a basic requirement for good health. Microbiological contamination of water is responsible for most of the waterborne diseases and diarrhoea is still a major killer of childhood.Methods: A community based cross-sectional study was conducted among 177 ethnic and non-ethnic households chosen by multi stage sampling from West Tripura District of North East India during June - July 2016 to assess the bacteriological quality of water and to find out its association with the occurrence of diarrhoea.Results: Among the ethnic and non-ethnic households shallow tube wells were the source for 52.18% and 62.35 %, deep tube wells for 19.56% and 29.41%, and pipe water for 20.65 % and 5.89 households respectively. Sanitary latrines ware used in 46.73% ethnic and 50.59% non-ethnic households. In both the group filtration was practiced by 85% and no purification by 1%. Covered vessels were used for storing water in 94.57% ethnic and 95.30% non-ethnic households. Source of water was mildly contaminated in 15% ethnic and 10% non-ethnic, moderate and heavy contaminations were 11% and 8% each respectively in both the groups. At the point of consumption moderate and heavy contaminations were 2% each in ethnic households. Mild and severe contaminations were 3% and 1% respectively in non-ethnic group. Diarrhoea was significantly more frequent among households consuming coliform contaminated water (p<0.05).Conclusions: Half of the study population was using insanitary latrine and one fifth were collecting water from contaminated sources. Hence provision of safe water and promotion of sanitary latrine is needed to prevent waterborne diseases in this community

Repressor of temperate mycobacteriophage L1 harbors a stable C-terminal domain and binds to different asymmetric operator DNAs with variable affinity

<p>Abstract</p> <p>Background</p> <p>Lysogenic mode of life cycle of a temperate bacteriophage is generally maintained by a protein called 'repressor'. Repressor proteins of temperate lambdoid phages bind to a few symmetric operator DNAs in order to regulate their gene expression. In contrast, repressor molecules of temperate mycobacteriophages and some other phages bind to multiple asymmetric operator DNAs. Very little is known at present about the structure-function relationship of any mycobacteriophage repressor.</p> <p>Results</p> <p>Using highly purified repressor (CI) of temperate mycobacteriophage L1, we have demonstrated here that L1 CI harbors an N-terminal domain (NTD) and a C-terminal domain (CTD) which are separated by a small hinge region. Interestingly, CTD is more compact than NTD at 25°C. Both CTD and CI contain significant amount of α-helix at 30°C but unfold partly at 42°C. At nearly 200 nM concentration, both proteins form appreciable amount of dimers in solution. Additional studies reveal that CI binds to <it>O</it>₆₄and <it>O</it>_{<it>L </it>}types of asymmetric operators of L1 with variable affinity at 25°C. Interestingly, repressor – operator interaction is affected drastically at 42°C. The conformational change of CI is most possibly responsible for its reduced operator binding affinity at 42°C.</p> <p>Conclusion</p> <p>Repressors encoded by mycobacteriophages differ significantly from the repressor proteins of λ and related phages at functional level but at structural level they are nearly similar.</p

Malabaricone-A Induces A Redox Imbalance That Mediates Apoptosis in U937 Cell Line

BACKGROUND: The 'two-faced' character of reactive oxygen species (ROS) plays an important role in cancer biology by acting both as secondary messengers in intracellular signaling cascades and sustaining the oncogenic phenotype of cancer cells, while on the other hand, it triggers an oxidative assault that causes a redox imbalance translating into an apoptotic cell death. PRINCIPAL FINDINGS: Using a tetrazolium [{3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl}-2H-tetrazolium] based cell viability assay, we evaluated the cytotoxicity of a plant derived diarylnonanoid, malabaricone-A on leukemic cell lines U937 and MOLT-3. This cytotoxicity hinged on its ability to cause a redox imbalance via its ability to increase ROS, measured by flow cytometry using 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate and by decreasing glutathione peroxidase activity. This redox imbalance mediated apoptosis was evident by an increase in cytosolic [Ca(2+)], externalization of phosphatidyl serine as also depolarization of the mitochondrial membrane potential as measured by flow cytometry. There was concomitant peroxidation of cardiolipin, release of free cytochrome c to cytosol along with activation of caspases 9, 8 and 3. This led to cleavage of the DNA repair enzyme, poly (ADP-ribose) polymerase that caused DNA damage as proved by labeling with 4',6-diamidino-2-phenylindole (DAPI); furthermore, terminal deoxy ribonucleotide transferase catalysed incorporation of deoxy uridine triphosphate confirmed DNA nicking and was accompanied by arrest of cell cycle progression. CONCLUSIONS: Taken together, compounds like MAL-A having pro-oxidant activity mediate their cytotoxicity in leukemic cells via induction of oxidative stress triggering a caspase dependent apoptosis