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Human serum albumin (HSA) plays a pivotal role in drug release from its delivery vehicles such as cyclodextrins (CDs) by binding to the drugs. Here molecular recognition and binding of a drug mimic (CD1) to HSA have been explored in a microfluidic channel when CD1 is encapsulated in β-cyclodextrin (βCD) and heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin (TRIMEB), respectively, to investigate whether change of the host vehicle modulate the rate of drug binding to the serum protein. Molecular recognition of βCD encapsulated CD1 by HSA occurs by the conformational selection fit mechanism leading to rapid binding of CD1 to HSA (k1 ~ 700 s‐11) when the βCD/CD1 complex interacts with HSA. In contrary, HSA recognizes CD1 encapsulated in TRIMEB by an induced fit mechanism leading to a significantly slower binding rate (k1 ~ 20.8 s−1) of the drug mimic to the protein. Thus molecular recognition controls the rate of HSA binding by CD1 which in turn modulates the rate of delivery of the drug mimic from its macrocyclic hosts. The remarkable change in the molecular recognition pathway of CD1 by HSA, upon change of the host from βCD to TRIMEB, originates from significantly different conformational flexibility of the host/drug mimic complexes.

Urinary bladder cancer (UBC) is one of the most common cancers and has notoriously high risk of recurrence and mortality across the globe. Current clinical initial diagnostic approaches are either invasive or lacks sensitivity. In this study, an attempt has been made to invent a cost-effective, novel, portable diagnostic device based on the environmental sensitive fluorophores namely Nile Red (NR), Eosin Y (EY) and Rose Bengal (RB). They act as sensing agents for detecting volatile organic compounds (VOC) exclusively present in the urine sample of UBC patients and differentiate the UBC samples from the healthy control group. Upon exposure with a particular group of VOCs, a significant amount of increment in fluorescence intensities of NR, EY and RB were detected and recorded in our indigenously developed "NABIL" device. To check the performance of NABIL, the data collected from the device was compared with the conventional techniques by arranging a clinical trial with 21 healthy controls and 52 UBC patients. With the assistance of our analysis technique based on LabVIEW platform, very high sensitivity and accuracy from healthy controls have been achieved. For UBC patients, it shows impressive diagnostic results. In addition, depending on the sample processing mechanism, NABIL device can also reveal the grade of UBC and prognosis under treatment. Overall, this study contributes a novel, non-invasive, easy-to-use, inexpensive, real-time, accurate method for selectively UBC diagnosis, which can be useful for personalized care/diagnosis and postoperative surveillance, resulting in saving more lives.

Antimicrobial infection has emerged as one of the principal health problems in the world that requires urgent effective prevention. In order to deal with this reality, antibacterial photodynamic therapy of photosensitizers such as IR820 is one of the most encouraging and innovative methodologies to combat bacteria-caused infections. However, their activity is limited due to low photostability, short circulation, and lack of targeted bio-distribution. Herein, we have developed a user-friendly and universal approach to overcome such limitations of cyanine dye IR820 by encapsulating it with zeolitic imidazolate framework-8 (ZIF-8) keeping its activity intact. The synthesized ZIF8-IR820 nano-MOFs are characterized using electron microscopic and optical spectroscopic techniques. Moreover, the formation of hybrids is confirmed from the charge transfer process obtained from time resolved fluorescence transient and first principles DFT based analysis. The ultrafast charge transfer dynamic enhances the red-light sensitive reactive oxygen species (ROS) production capability which is further catalyzed in acidic pH and DFT based calculation validates the experimental results. The enhanced ROS production of ZIF8-IR820 nano-MOFs makes it superior in NIR induced antibacterial activity. Overall, the study demonstrates a detailed physical understanding of photosensitizer encapsulated nano-MOF system which shows efficient NIR light induced photo-dose dependent antibacterial activity that can be beneficial for potential bacterial remediation.

Pedestrian fatalities and injuries are a major public health burden in developing countries. In the safety literature, pedestrian crashes have been modelled predominately using single equation regression models, assuming a single underlying source of risk factors. In contrast, the fatal pedestrian crash counts at a site may be an outcome of multiple sources of risk factors, such as poor road infrastructure, land use type, traffic exposures, and operational parameters, site-specific socio-demographic characteristics, as well as pedestrians' poor risk perception and dangerous crossing behavior, which may be influenced by poor road infrastructure and lack of information, etc. However, these multiple sources are generally overlooked in traditional single equation crash prediction models. In this background, this study postulates, and demonstrates empirically, that the total fatal pedestrian crash counts at the urban road network level may arise from multiple simultaneous and interdependent sources of risk factors, rather than one. Each of these sources may distinctively contribute to the total observed crash count. Intersection-level crash data obtained from the "Kolkata Police", India, is utilized to demonstrate the present modelling methodology. The three-components mixture model and a joint econometric model are developed to predict fatal pedestrian crashes. The study outcomes indicate that the multiple-source risk models perform significantly better than the single equation regression model in terms of prediction ability and goodness-of-fit measures. Moreover, while the single equation model predicts total fatal crash counts for individual sites, the multiple risk source model predicts crash count proportions contributed by each source of risk factors and predicts crashes by a particular source.

Curcumin pyrazole derivatives have already been extensively studied as potent drugs in various biological fields but the information about their fundamental physical parameters is still somewhat limited. Therefore, the study of the photophysical behaviour of pyrazole derivatives of curcumin in various solvents is a very interesting and an important research area that necessarily needs to be explored in order to understand its biological efficacy. Herein, the photophysics of stable and pharmaceutically active curcumin pyrazole derivative (CPD) and curcumin phenyl pyrazole derivative (CPPD) has been studied in various solvent environments. For the investigation of photophysical properties, various spectroscopic techniques have been utilized. Steady state spectroscopic results have revealed that the excited state of both the derivatives is largely affected by changing the polarity of the medium. The molar extinction coefficient (e) for CPD and CPPD has also been determined in various solvents. From the measurement of Stokes shift values for wide range of solvents, it could be concluded that there is difference in the dipole moment of the excited state and the ground state of both the molecules. The Stokes shift values for both the derivatives were found to be correlated linearly with the normalized molar transition energy ( E T N ) of solvents with exceptions in case of polar protic solvents. This indicates that H- bonding might play a major role in the solution phase. The difference in the dipole moment of ground state and excited state of CPD and CPPD were calculated as around 5.23 D and 5.41 D. Further, using multiple regression analysis, the solute -solvent interactions were characterized as specific and non-specific. The low quantum yields obtained in polar protic solvents revealed that the positive solvatokinetic effect could take place in these solvents. The results of TCSPC study showed that the process of deactivation of the excited state of these derivatives is very slow in the presence of acetonitrile, DCM and non-polar solvents. A very fast decay of excited state of both the derivatives has been observed in the case of polar protic solvents. This could be due to the presence of strong H-bonding between the derivatives and these solvents which could result in the deactivation of excited states via non-radiative pathway.

The present work aims to decipher the photophysics of a β-diketo modified curcumin analog named isoxazole derivative of curcumin (IOC). IOC itself happens to be a potential drug molecule possessing numerous biological applications such as; anti-cancer, anti-malarial, anti-Alzheimer’s, anti-Parkinson’s etc. Herein, the photophysical properties of IOC have been explored in various sets of solvents. In order to investigate, steady state and time resolved spectroscopy have been utilized as a tool. To elucidate the experimental observations at molecular level, electronic structure calculations with density functional theory (DFT) as well as classical molecular dynamics (MD) simulations in explicit solvents have been deployed. The DFT has established that the most stable ground state electronic structure of the IOC molecule is the all trans- planar conformation where the conjugated pi-electrons are delocalized over the entire molecule. The MD simulations have provided an insight into the specific and non-specific interactions with the solvent molecules. Steady state spectroscopic techniques have shown that both the absorption and emission maxima experienced a traditional red shift upon increase in the solvent polarity. The absorption maxima for IOC got red shifted from 332 nm in hexane to 344 nm in DMSO. However, the red shift in the emission maxima is more pronounced than that of absorption maxima starting from 356 nm in hexane to 431 nm in water. The value of molar extinction coefficient has also been determined for IOC in different solvents from the concentration dependent absorption spectra. The time correlated single photon counting (TCSPC) data has revealed that the excited state of IOC molecule could relax via three probable pathways. Also, the overall process of decay of the excited state is comparatively slower in case of non-polar solvents. On the other hand, the fluorescence lifetime has been observed to be unusually low in case of dimethyl sulfoxide (DMSO) as compared to its other fellow polar aprotic solvents.

Signalized intersections with marked crosswalks enhance pedestrian safety by providing the designated right of way to pedestrians. However, a significant number of pedestrian crashes occur at signalized intersections, which may predominantly be due to pedestrians’ violation behaviors. Therefore, it is worthwhile to examine how pedestrian risk and signal violation are associated. For this purpose, pedestrians’ crossing behavior, and perception data have been collected from 55 signalized junctions in Kolkata, India, and a mathematical relationship is developed between the share of pedestrian signal violation and the frequency of fatal pedestrian crashes. The model outcome indicates that there is a significant and positive association between these two variables. Subsequently, with the help of “beta regression model” it is identified that absence of pavement marking, traffic cycle length, inadequate sight distance, on-street parking, a high share of pedestrian carrying overhead loads, pedestrian’s intended mode of transport after crossing, and pedestrian’s sociodemographic characteristics significantly influence the share of pedestrian signal violation behavior. The study finding indicates that while improvement in the design of the built environment and signal settings to increase pedestrians’ convenience and confidence are must, and there is a crucial need to integrate innovative safety management practices to address spatial and temporal needs of an intersection. For example, intersections with high commercial activities generating a high volume of pedestrian carrying overhead goods demand particular pedestrian phase with countdown signals. Further, to control pedestrians’ unruly behavior, adequate pavement marking, zebra crossing, designated bus stop facility, pedestrian signal head, and off-street parking facility should be provided along with the strict enforcement. Moreover, to enhance compliance with traffic signals, road safety campaigns, education, and awareness programs are must for better and safer road use.