11 research outputs found
Increased yield of smear positive pulmonary TB cases by screening patients with >2 weeks cough, compared to >3 weeks and adequacy of 2 sputum smear examinations for diagnosis
Background
RNTCP recommends examining three sputum smears for AFB from Chest Symptomatics (CSs) with cough of >3 weeks
for diagnosis of Pulmonary TB (PTB). A previous multi-centric study from Tuberculosis Research centre (TRC) has
shown that the yield of sputum positive cases can be increased if duration of cough for screening was reduced to >2 weeks.
Other studies have shown that two smear examinations are adequate for diagnosis of smear positive PTB . To validate the
above findings, a cross sectional multi-centric study was repeated in different settings in five geographical areas in India.
Methods
Three primary and secondary level health facilities with high out-patient attendance were selected from two Tuberculosis
Units (TU) in each of the 15 selected districts to screen about 10,000 new adult outpatients from each state. For patients
who did not volunteer history of cough, symptoms were elicited using a structured simple questionnaire. All the CSs were
referred for sputum examination.
Results
A total of 96,787 out-patients were registered. Among them 69,209 (72%) were new adult out-patients. Using >2 weeks
of cough instead of > 3 weeks as the criterion for screening, there was an overall increase of 58% in CS and 23% increase
in the detection of smear-positive cases. Among 211 patients, 210 were positive at least by one smear from the initial
two specimens. Increase in the work-load if 2 smears were done for patients with cough of >2 weeks cough were 2
specimens (i.e.13 to 15) per day for an adult OPD of 150.
Conclusion
The yield of sputum positive PTB cases can be improved by screening patients with >2 weeks cough and two specimens
are adequate for diagnosis
Ionic Polymeric Amphiphiles with Cholesterol Mesogen: Adsorption and Organization Characteristics at the Air/Water Interface from Langmuir Film Balance Studies
<SUP>1</SUP>H NMR spectroscopic investigations on the conformation of amphiphilic aromatic amino acid derivatives in solution: effect of chemical architecture of amphiphiles and polarity of solvent medium
In this study, the conformation of the amphiphilic lauryl esters of l-tyrosine (LET) and l-phenylalanine (LEP) in water and dimethyl sulfoxide is established. The alkyl chain protons of LEP in D2O appear at d 1.010-1.398 and show an upfield shift and large line width, suggesting the proximity of the phenyl ring to the alkyl chain in contrast to that of LET. Quite interestingly, in DMSO-d6, the 1H NMR spectra of LET and LEP show a strong similarity that is suggestive of an orientation that positions the aromatic ring and aliphatic chain away from each other. These results are substantiated with two-dimensional nuclear Overhauser enhancement spectroscopy (2D NOSEY). Theoretical molecular models of the conformation at the interface corroborate the experimental findings. Investigations of the solvent polarity and chemical structure-dependent conformation are discussed
Self organisation behaviour at the interface and in aqueous solution of the cationic gemini surfactants from dioctyl ester of cystine
The cationic surfactant, dioctyl ester of cystine hydrochloride (DOEC), was characterized for interfacial adsorption and aggregation behavior in water. The cmc of DOEC was measured as 1.42 ± 0.27 × 10-5 mol dm-3 using the techniques of tensiometry, conductivity and fluorimetry. From specific conductivity measurements, the degree of dissociation (α ) of the amine hydrochloride was measured as 0.612. The standard free energy change of micellization (Δ Gmo)and adsorption (Δ Gao)were calculated to be -25.07 and -44.37 kJ mol-1, respectively. The aggregated structures provide non-polar microdomains as inferred from the I3/I1 emission intensity ratio of 1.05 of pyrene fluoroprobe and also a blue shift of fluorescence emission wave length (λ emi.) maximum down to 470 nm with enhanced intensity of ANS probe in micellar solutions. From Langmuir film balance experiments, it is shown that DOEC forms stable viscoelastic films at the interface with A0 at 0.69 nm2 molecule-1 that agree with the result from surface tension measurements. Molecular modeling suggests the tilted orientation of DOEC at the interface. A large packing parameter (P) of 0.58 and the fibril structures as observed from microscopy studies demonstrate that DOEC favors one-dimensional growth to form elongated micelles
Adsorption and emulsification properties of amphiphilic poly(styrene-co-octodecyl maleamic acid salt) with comb like architecture
Amphiphilic poly(styrene-co-octadecyl maleamic acid salt) (PS-co-ODMAS) with a comb-like architecture was synthesized employing a heterophase aqueous polymerization reaction. The side-chain comonomer from octadecyl maleamic acid salt exhibited hydrogelation characteristics and provided conditions for a controlled polymerization reaction. PS-co-ODMAS polymers consisting of 5 and 10 mol% side-chain monomer showed a high molecular weight on the order of 106 and narrow polydispersity index at 1.33 + 0.02. The polymer consisting of 10 mol% side-chain monomer was shown to exhibit properties that are significantly different from those with 5 mol%, and the control poly(styrene) synthesized using sodium dodecyl sulfate surfactant. The polymer consisting of 10 mol% side-chain monomer formed hollow spherical spheres of 30 nm size. It also showed close-packed structures of the side-chain monomer on the polymer surface. Detailed adsorption studies at the liquid/liquid interface were carried out to evaluate and understand the scope for modification in surface energy characteristics of polymers in the presence of additives drawn from simple surfactants. Triton X-100 was shown to undergo effective adsorption on the polymer consisting of 10 mol% side-chain monomer and thus could generate stable emulsions with different volume fractions of heptadecane. The results from electron microscopy studies and viscosity of emulsions are discussed
Formation of Self-Aggregated Structures of Different Types in Water of Chiral Polymerizable Amphiphiles from l-Tyrosine and l-Phenylalanine
Sodium salts of maleamic acid derivatives from lauryl
esters of l-tyrosine (MTNa) and l-phenylalanine
(MPNa) were synthesized
and characterized. The aggregated structures of MTNa and MPNa in water
were investigated, employing several independent methods. MPNa showed
secondary aggregated structures in contrast to MTNa at concentrations
of >1 × 10<sup>–3</sup> M. The results from dynamic
light
scattering, transmittance, conductivity, and viscosity measurements
suggested the formation of aggregated structures of different types
in MTNa and MPNa solutions. The measured fluorescence anisotropy (<i>r</i>) at 0.180 of the fluoroprobe, 1,6-diphenyl-1,3,5-hexatriene
(DPH), and the <i>d</i> spacing of 38 Ã… from small-angle
X-ray diffraction (SAXD) experiments confirmed the bilayer structures
in MPNa. Scanning electron microscope (SEM) images provided the morphological
features. The emulsion produced using MPNa solution was more stable.
The confocal fluorescence microscopy image of the emulsion from MPNa
confirmed the entrapment of water-soluble dye, rhodamine. The models
of MTNa and MPNa molecules and the aggregated structures are presented
Unprecedented Relationship Between the Size of Spherical Chiral Micellar Aggregates and Their Specific Optical Rotations
Transmission
electron microscopy (TEM) images and fluorescence
quenching methods indicated that lauryl ester of L-phenylalanine (LEP)
and lauryl ester of L-tyrosine (LET) form spherical chiral micelles
in the 50–200 mM range and their size increases with concentration.
The number of molecules present in these spherical chiral aggregates
varied from 80 to 160 for LEP and 80–100 for LET. The specific
optical rotation, representing circular birefringence, for LEP at
405 nm and 32 °C is found to increase linearly from 37 deg cc
g<sup>–1</sup> dm<sup>–1</sup> for an isolated molecule
to 56 deg cc g<sup>–1</sup> dm<sup>–1</sup> for ∼200
nm size aggregate. A similar trend was found for temperatures up to
70 °C and at other visible wavelengths. A linear relation between
specific optical rotation and the size of aggregate is also observed
for LET. Circular dichroism, as measured in both the visible and infrared
wavelength regions, however did not reveal any concentration dependent
changes. The unique sensitivity uncovered for specific optical rotation
as a function of the size of spherical chiral aggregates is unprecedented
and opens new areas of enquiry for physical chemists
Amphiphilic Lauryl Ester Derivatives from Aromatic Amino Acids: Significance of Chemical Architecture in Aqueous Aggregation Properties
Awareness among Patients with T2DM regarding the Disease at a Tertiary Care Referral Center
Alkaliphiles : The Emerging Biological Tools Enhancing Concrete Durability
Concrete is one of the most commonly used building materials ever used. Despite it is a very important and common construction material, concrete is very sensitive to crack formation and requires repair. A variety of chemical-based techniques and materials have been developed to repair concrete cracks. Although the use of these chemical-based repair systems are the best commercially available choices, there have also been concerns related to their use. These repair agents suffer from inefficiency and unsustainability. Most of the products are expensive and susceptible to degradation, exhibit poor bonding to the cracked concrete surfaces, and are characterized by different physical properties such as thermal expansion coefficients which are different to that of concrete. Moreover, many of these repair agents contain chemicals that pose environmental and health hazards. Thus, there has been interest in developing concrete crack repair agents that are efficient, long lasting, safe, and benign to the environment and exhibit physical properties which resemble that of the concrete. The search initiated by these desires brought the use of biomineralization processes as tools in mending concrete cracks. Among biomineralization processes, microbially initiated calcite precipitation has emerged as an interesting alternative to the existing chemical-based concrete crack repairing system. Indeed, results of several studies on the use of microbial-based concrete repair agents revealed the remarkable potential of this approach in the fight against concrete deterioration. In addition to repairing existing concrete cracks, microorganisms have also been considered to make protective surface coating (biodeposition) on concrete structures and in making self-healing concrete. Even though a wide variety of microorganisms can precipitate calcite, the nature of concrete determines their applicability. One of the important factors that determine the applicability of microbes in concrete is pH. Concrete is highly alkaline in nature, and hence the microbes envisioned for this application are alkaliphilic or alkali-tolerant. This work reviews the available information on applications of microbes in concrete: repairing existing cracks, biodeposition, and self-healing. Moreover, an effort is made to discuss biomineralization processes that are relevant to extend the durability of concrete structures