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Dental caries is an irreversible and potentially debilitating disease that can ultimately lead to the loss of the affected tooth structure. Due to a lack of awareness, caries is detected much later after its onset. Moreover, people do not have access to dental care or information in the rural areas of several developing countries. Hence, there is a need for a cheap and disposable point-of-care screening test to determine one's oral health. To cater to this unmet need, we have developed a paperfluidic chip that measures salivary pH to estimate its buffering capacity and also tests susceptibility to caries by checking for salivary reductase. The results of our paper-based reductase assay of 72 samples correlated well with the results obtained using the standard tube-based assay performed in dental clinics. Further, the results of the paper-based pH test matched with those of the caries test, i.e.those with lower saliva pH showed higher susceptibility to caries (since acidic environments promote caries). Here, we also report a new and green technique to chemically pattern paper by printing olive oil through an inkjet printer and turning paper (cellulose) hydrophobic in the oil-treated regions through heat-assisted esterification. In addition to patterning hydrophobic regions on paper, the same inkjet printer was used to print all the assay reagents, thus making our paperfluidic chip completely printable. Since our device is cheap, disposable and can be easily manufactured in large volumes by printing, it is suitable for regular monitoring of oral health as well as providing a basic screening test to those without routine access to dentists.

This paper is the fourth in a series aimed at improving the understanding and operation of conventional agitated fermenters for the production of the commercially important gum, Xanthan. In the first, reproducible fermentations were established and this protocol was used in studies of different agitator types and of bulk mixing and dissolved oxygen concentration in the next two. Here, building on the previous work, the influence of different glucose feeding strategies on Xanthan production in a 20‐L agitated fermenter under equivalent conditions of agitation and dissolved oxygen is reported. The biological performances in three types of fed‐batch cultures (a two‐step glucose addition, multiple glucose‐pulse feeding and continuous feeding of glucose) are compared to two batch fermentations with different initial glucose concentrations. The work confirmed that improved performance cannot be achieved by increasing the initial glucose concentration above 50 g/L nor by a single 10 g/L pulse addition (initial glucose concentration of 40 g/L) while significant nitrogen is still present. On the other hand, the simple pulse and continuous feeding strategies, after nitrogen has been essentially exhausted and under conditions of nonlimiting dissolved oxygen and similar bulk mixing, can result in a greatly enhanced performance compared to batch fermentations. Using the final Xanthan gum concentration, the yield on glucose and the overall productivity as performance indices, values of 62 g/L, 0.82 g of Xanthan/g of glucose, and 0.72 g/(L·h), respectively, were obtained compared to literature values for conventional stirred bioreactors of 15–30 g/L, 0.27–0.86 g of Xanthan/g of glucose, and 0.12–0.43 g/(L·h) .

40Ar-emulsion interactions are studied, to investigate the question of anomalons, in twoG- 5 emulsion stacks. In about 4600 primary interactions, projectile fragments of Z≧2 for all generations have been followed until they interact or leave the stack. After careful estimation of charges of these fragments, variation of their mean free paths is studied as a function of distance from the preceding interaction. Generation effect,Nh dependence and production angle effect are investigated. In addition multi-chain events are analysed separately. Our results do not show anomalons at the 6% level and are consistent with non-occurrence of anomalons. However, this experiment is not sensitive enough to rule out anomalons (with a mfp of the order of 2 to 3 cm) produced at about 1% (or less) level.

A sand culture experiment was conducted to study the effect of saline water on the growth and fruit quality of processing tomato (Lycopersicon esculentum Mill.) Seedlings of five tomato cultivars were transplanted in quartz-sand pots in a greenhouse at the Agricultural Experiment Station of Sultan Qaboos University. There were four saline nutrient solutions and a control consisting of half-strength Hoagland solution. Salinity treatments were: 50 raM NaCl + 3 mM K2SO4 (EC 6.75), 50 mM NaCl + 1.5 mM orthophosphoric acid (EC = 7.18), 50 mM NaCl + 1.5 mM orthophosphoric acid + 3 mM R2SO4 (EC 7.29), and 50 mM NaCL (EC = 5.6). Treatments were applied daily commencing two weeks after transplanting. Data were collected on growth, and fruit yield and quality. Partitioning of mineral elements was determined in the vegetative tissue. The results obtained clearly show that concentrations of total soluble solids were increased in fruits treated with saline nutrients. Dry matter content of fruits exposed to salinity were higher than those from the control plants. Fruit acidity was increased with salinity, possibly due to a lower water content and increased organic acid accumulation. In the saline treatments, sodium (Na) content was decreased when potassium (K) was applied with NaCl but Na was higher in stems followed by root and leaf tissues. The partitioning of K followed a trend opposite to that for Na but with higher content in leaves. A similar situation was observed for calcium (Ca) and magnesium (Mg). Accumulation of phosphorus (P) was the lowest among all the ions. These results indicated that survival under saline conditions was accompanied by high ion accumulation. The study confirmed that saline nutrients are important for improving fruit quality of processing tomatoes.

This paper is the fourth in a series aimed at improving the understanding and operation of conventional agitated fermenters for the production of the commercially important gum, Xanthan. In the first, reproducible fermentations were established and this protocol was used in studies of different agitator types and of bulk mixing and dissolved oxygen concentration in the next two. Here, building on the previous work, the influence of different glucose feeding strategies on Xanthan production in a 20-L agitated fermenter under equivalent conditions of agitation and dissolved oxygen is reported. The biological performances in three types of fed-batch cultures (a two-step glucose addition, multiple glucose-pulse feeding and continuous feeding of glucose) are compared to two batch fermentations with different initial glucose concentrations. The work confirmed that improved performance cannot be achieved by increasing the initial glucose concentration above 50 g/L nor by a single 10 g/L pulse addition (initial glucose concentration of 40 g/L) while significant nitrogen is still present. On the other hand, the simple pulse and continuous feeding strategies, after nitrogen has been essentially exhausted and under conditions of nonlimiting dissolved oxygen and similar bulk mixing, can result in a greatly enhanced performance compared to batch fermentations. Using the final Xanthan gum concentration, the yield on glucose and the overall productivity as performance indices, values of 62 g/L, 0.82 g of Xanthan/g of glucose, and 0.72 g/(L·h), respectively, were obtained compared to literature values for conventional stirred bioreactors of 15−30 g/L, 0.27−0.86 g of Xanthan/g of glucose, and 0.12−0.43 g/(L·h).