Synthesis and stability of the [45Ti]Ti-DOTA complex: en route towards aza-macrocyclic 45Ti-based radiopharmaceuticals.

We report the use of DOTA as a chelator for titanium. The resulting complex is fully characterised and in vitro stability studies reveal its high kinetic inertness against transmetallation and transchelation. The radiolabeling of DOTA with 45Ti, via a guaiacol-based liquid-liquid extraction method, leads to a high radiochemical conversion up to 98%.

Confluence of Newborn's sex and their Mother's characteristics resulting in fetal macrosomia among Indian neonates.

BACKGROUND: A newborn's birth weight ≥4000 g is defined as fetal macrosomia, which is recognized as a reproductive and serious child health concern. OBJECTIVES: Our study aims to reveal existence of any connection between maternal factors and newborn sex in giving birth to newborn ≥4000 g in an Indian context. METHODS: Data were drawn from the fifth round of National Family Health Survey (NFHS-5). A cross-sectional observational study was carried out with a total of 152,827 children born to women in reproductive age group (15-49) who had most recent live birth in the five years preceding the survey. Descriptive analyses, cross-tabulation, test of association and multivariate logistic regression analyses were performed. RESULTS: In India, the prevalence of macrosomia was found in 3.8% of the total study participants. Considering newborn characteristics, fetal macrosomia was more prevalent among male neonates than female (AOR: 0.730; 95% CI: 0.687-0.775). Regarding maternal characteristics, overweight (AOR: 1.468; 95% CI: 2.042-2.559) and obese (AOR: 2.764; 95% CI: 2.394-3.192) motherswith gestational diabetes (AOR: 1.731, 95% CI: 1.385-2.164) and hypertension (AOR: 1.288, 95% CI: 1.116-1.488) were more likely to giving birth of macrosomic babies. Multiparous mothers (AOR: 1.207, 95% CI: 1.128-1.293) and women who did not undergo proper antenatal care (ANC) follow up had also greater risk of developing fetal macrosomia. Muslim women (AOR: 1.223, 95% CI: 1.119-1.338), and women belonging to a tribe (AOR: 1.476, 95% CI: 0.922-2.361) were significantly associated with the risk of having newborn ≥4000 g. CONCLUSION: Emphasis should be given on counseling for mothers for desired weight management before and during pregnancy, gestational diabetes and hypertension screening, physical activity during pregnancy, adequate ANC follow up and balanced dietary intake among pregnant women.

Investigating key latent factors influencing alcohol consumption among the tribal male adolescents in Dooars region, West Bengal.

BACKGROUND: Alcohol consumption among tribal male adolescents in India is a significant social concern. Tribal adolescents are particularly vulnerable and tend to lean toward alcohol addiction. Therefore, it is crucial to introduce some necessary footsteps to reduce alcohol consumption. The primary objective of this study is to investigate the association of various latent factors with the alcohol-drinking behavior of tribal adolescents. METHODS: The study collected data from 600 tribal adolescents from the Dooars region, with 241 of them reported consuming alcohol. The study aimed to confirm the theoretical development of hypotheses regarding peer pressure, parental discord, stress, attitude toward alcohol, and food insecurity as exogenous latent factors influencing the alcohol-drinking behavior of tribal adolescents. In this context, the study adopted both measurement and structural models using Partial Least Squares-Structural Equation Modeling (PLS-SEM). RESULTS: The findings revealed a significant path relationship between alcohol drinking behavior and various exogenous factors like peer pressure (ß = 0.214, p = .000), parental discord (ß = 0.121, p = .009), stress (ß = 0.170, p = .000), attitude toward alcohol (ß = 0.110, p = .004), and food insecurity (ß = 0.510, p = .000). This study developed a reflective measurement model, and the evaluation of reflective measurement models was conducted, assessing internal consistency, convergent validity, and discriminant validity, yielding satisfactory results. CONCLUSION: To tackle alcohol issues among tribal adolescents in the Dooars region, effective strategies should be employed. These include educating in schools, highlighting tribal role models, aiding peers with alcohol dependence, providing life skills training, and addressing parental discord and food insecurity through awareness campaigns, workshops, and better infrastructure.

A study about the impact of indoor air pollution on cognitive function among middle-aged and older adult people in India.

BACKGROUND: In the 21st century, people still use solid fuel for cooking at home, resulting in poor indoor air quality. Prolonged exposure to such conditions may negatively affect one's cognitive function. So, the present study examines the possible association between IAP and the cognitive function of individuals aged 45 years or above in India. METHODS: The study utilizes secondary data, procured from the longitudinal ageing study in India (2017-18). Treatment effects through regression-adjusted models were applied to represent the association between IAP and cognitive health and the results are represented by beta coefficient (ß). Three separate models with a 95% confidence interval adjusting with the other factors like housing environment, individual and behavioural were framed. RESULTS: The study revealed that households without a separate kitchen (ß = -0.64; 95%CI: -0.90 to -0.39) and electricity (ß = -0.97; 95%CI: -1.34 to -0.61) significantly affect cognitive strength. Cognitive decline is likely more pronounced among older adults (ß = -1.19; 95%CI: -1.42 to -0.96) than the middle-aged population. Moreover, the cognitive ability of rural residents (ß = -1.11; 95%CI: -1.49 to -0.73) and women (ß = -2.05; 95%CI: -2.29 to -1.81) is negatively associated with IAP exposure. Older adults with no reading habits (ß = -6.28; 95%CI: -6.72; to -5.85) and physical inactivity (ß = -0.96; 95%CI: -1.22 to -0.70) had a sign of notable decline in cognitive ability. CONCLUSIONS: Findings revealed that cognitive function is negatively associated with IAP, demanding a deep intervention plan to minimize the detrimental effect.

Assessing the modifiable and non-modifiable risk factors associated with multimorbidity in reproductive aged women in India.

BACKGROUND: Reproductive span is the foundation of every woman's health in later life. India is currently facing a growing burden of multiple morbidities among the women in their reproductive age group which may further increase over the coming decades. The purpose of the present study aimed to identify different modifiable and non-modifiable risk factors affecting multimorbidity among the women in reproductive age group in Indian context. METHODS: Secondary data were obtained from the Demography and Health Survey (DHS), conducted in India during 2019-2021. A total of 671,967 women aged 15-49 years were selected for this present study. Descriptive, association studies and multinominal logistic regression analyses were performed to accomplish the objectives. RESULTS: Currently, 6.3% of total study participant's reproductive age group women suffered from multimorbidity in India. Never consuming protein, fruits, vegetables and milk increase the chances of developing multimorbidity. Consumption of fried foods, aerated drinks and addiction towards tobacco and alcohol also has a greater influence on the prevalence of multimorbidity. The prevalence of multimorbidity is sharply increased with increasing age and Body Mass Index (BMI). Regionally, the prevalence of multimorbidity was found more among the women hailed from eastern and north-eastern India. CONCLUSION: To reduce the risk of developing multimorbidity, targeted interventions are needed in the form of educating every woman concerning the importance of having minimum health-related knowledge, maintaining healthy lifestyle, weight management and having proper and balanced diet.

Isotachophoresis with Oscillating Sample Zones to Control the Spatial Overlap of Co-focused Species.

Microfluidic isotachophoresis (ITP) is a powerful technique that can significantly increase the reaction rate of homogeneous chemical reactions by cofocusing reactants in a narrow sample zone. Correspondingly, ITP has been utilized to reduce the reaction time in various bioanalytical assays. However, in conventional ITP, it is hardly possible to control the reaction rate in real time, i.e., speeding up or slowing down a reaction on demand. Here, we experimentally demonstrate a new mode of ITP that allows the spatial overlap of two ITP zones to be precisely controlled over time, which is a crucial first step toward controlling reaction rates. Two nonreactive samples are initially focused and separated by a spacer using a DC electric field. By superimposing an oscillating field component with sufficiently high amplitude on the DC field, the spatial overlap of their concentration profiles is temporarily increased due to electromigration dispersion. The time-average of this overlap can be precisely controlled by varying the frequency and amplitude of the oscillation. We suggest that this scheme can be transferred to chemical reactions between ionic species with sufficiently different electrophoretic mobilities. Tuning the parameters of the oscillatory electric field should allow direct control of the corresponding reaction rate.

Analyzing determinants from both compositional and contextual level impeding desired linear growth of children in Indian context.

Childhood stunting is recognized as significant public health concern in India. It is a form of malnutrition with impaired linear growth and creates a range of adversaries among children, including under-5 mortality, morbidity, and physical and cognitive growth. The purpose of the present study was to recognize the various leading determinants causing childhood stunting from both individual and contextual level in Indian context. Data were obtained from the India's Demography and Health Survey (DHS) conducted in 2019-2021. A total of 1, 46,521 children aged 0-59 months were included in this present study. The study applied a multilevel mixed-effect logistic regression model in which individual factors nested within community based contextual-level factors estimating the likelihood of childhood stunting phenomena among Indian children. The variance explained in full model accounted for about 35.8% of the odds of stunting across the communities. The present study elucidates that the recognized factors from individual level characteristics have really increased the odds of childhood stunting: gender of child, multiple births, low birth weight, low BMI among mothers, less educational attainment by mothers, maternal anemic status, breast feeding duration longer than usual, < 4 antenatal care (ANC) visits during gestation period. Similarly, contextual-level factors like rural places of residence, western Indian children, and communities with high poverty rates, lower literacy rates, improper sanitation, and unsafe drinking water were also found to have a significant positive association with childhood stunting. The study finally concludes that cross level interaction between individual and contextual-level factors are identified as significant determinants of linear growth retardation among child in India. In order to reduce this type of malnutrition among the child one should more concentrate on both individual and contextual-level factors as a notable reasons.

Detecting Isotachophoresis Zones Hidden in Noise Using Signal Processing.

Lowering the limit of detection in chemical or biochemical analysis is key to extending the application scope of sensing schemes. Usually, this is related to an increased instrumentation effort, which in turn precludes many commercial applications. We demonstrate that the signal-to-noise ratio of isotachophoresis-based microfluidic sensing schemes can be substantially increased merely by postprocessing of recorded signals. This becomes possible by exploiting knowledge about the physics of the underlying measurement process. The implementation of our method is based on microfluidic isotachophoresis and fluorescence detection, for which we take advantage of the physics of electrophoretic sample transport and the structure of noise in the imaging process. We demonstrate that by processing only 200 images, the detectable concentration, compared to the detection from a single image, is already lowered by 2 orders of magnitude without any additional instrumentation effort. Furthermore, we show that the signal-to-noise ratio is proportional to the square root of the number of fluorescence images, which leaves room for further lowering of the detection limit. In the future, our results could be relevant for various applications where the detection of minute sample amounts plays a role.

Accelerated epithelial layer healing induced by tactile anisotropy in surface topography.

Mammalian cells respond to tactile cues from topographic elements presented by the substrate. Among these, anisotropic features distributed in an ordered manner give directionality. In the extracellular matrix, this ordering is embedded in a noisy environment altering the contact guidance effect. To date, it is unclear how cells respond to topographical signals in a noisy environment. Here, using rationally designed substrates, we report morphotaxis, a guidance mechanism enabling fibroblasts and epithelial cells to move along gradients of topographic order distortion. Isolated cells and cell ensembles perform morphotaxis in response to gradients of different strength and directionality, with mature epithelia integrating variations of topographic order over hundreds of micrometers. The level of topographic order controls cell cycle progression, locally delaying or promoting cell proliferation. In mature epithelia, the combination of morphotaxis and noise-dependent distributed proliferation provides a strategy to enhance wound healing as confirmed by a mathematical model capturing key elements of the process.

Acyl Amidines by Pd-Catalyzed Aminocarbonylation: One-Pot Cyclizations and 11C Labeling.

A protocol for the carbonylative synthesis of acyl amidines from aryl halides, amidines, and carbon monoxide catalyzed by Pd(0) is reported herein. Notably, carbon monoxide is generated ex situ from a solid CO source, and several productive palladium ligands were identified with complementary benefits and substrate scope. Furthermore, sequential one-pot, two-step protocols for the synthesis of 1,2,4-triazoles and 1,2,4-oxadiazoles via acyl amidine intermediates are reported. In addition, this approach was extended to isotopic labeling using [11C]carbon monoxide to allow, for the first time, synthesis of 11C-labeled acyl amidines as well as a 11C-labeled 1,2,4-oxadiazole.

A new methodology for measuring solid/liquid interfacial energy.

HYPOTHESIS: The interfacial energy γsl between a solid and a liquid designates the affinity between these two phases, and in turn, the macroscopic wettability of the surface by the fluid. This property is needed for precise control of fluid-transport phenomena that affect the operation/quality of commercial devices/products. Although several indirect or theoretical approaches can quantify the solid/liquid interfacial energy, no direct experimental procedure exists to measure this property for realistic (i.e. rough) surfaces. Makkonen hypothesized that the frictional resistance force per unit contact-line length is equal to the interfacial energy on smooth surfaces, which, however, are rarely found in practice. Consequently, the hypothesis that Makkonen's assumption may also hold for rough surfaces (which are far more common in practice) arises naturally. If so, a reliable and simple experimental methodology of obtaining γsl for rough surfaces can be put forth. This is accomplished by performing dynamic contact-angle experiments on rough surfaces that quantify the relationship between the frictional resistance force per unit contact-line length acting on an advancing liquid (Fp,a) and the surface roughness in wetting configurations. EXPERIMENT: We perform static and advancing contact-line experiments with aqueous and organic liquids on different hydrophilic surfaces (Al, Cu, Si) with varying Wenzel roughnesses in the range 1-2. These parameters are combined with the liquid's known surface tension to determine Fp,a. FINDINGS: Fp,a rises linearly with the surface roughness. Analysis based on existing theories of wetting and contact-angle hysteresis reveals that the slope of Fp,a vs.Wenzel roughness is equal to the solid/liquid interfacial energy, which is thus determined experimentally with the present measurements. Interfacial energies obtained with this experimental approach are within 12% of theoretically predicted values for several solid/liquid pairs, thereby validating this methodology.

A Formal Appraisal About High-Risk Sexual Behaviour on the Pretext of Substances Use Among Indian Men.

All behaviors' that satisfy a person's biological needs and desires are considered sexual behaviors. Despite the fact that sexual behavior and expression are universal to all animals, especially humans, the context in which the behaviors are expressed may make it risky or even dangerous. High risk sexual behaviors' and substance use disorders are frequently been linked. This study's main goal is to investigate the relationship between substance use by Men and their participation in high risk sexual behaviors. In the current study data were taken from NFHS 5 (2019-2021) and methods like Pearson's chi-squared test, bivariate and multivariate binary logistic regression models were used to established the relationship that risky sexual behavior is a consequence of substances use. Result revealed that Men's alcohol consumption in daily basis is strongly associated with premature sex (AOR: 1.05; 95%CI: 1.08-1.26; p < 0.05), sex with multiple partners (AOR: 2.35; 95%CI: 1.86-2.97; p < 0.05), and unprotected sexual intercourse (AOR: 2.06; 95%CI: 1.91-2.19; p < 0.05). Apart from alcohol consumption smoking cigarette, use of smokeless tobacco, and use of guthka are also significantly associated with risky sexual behavior of Men on Women. The concern of substances use among Indian men may be dwindled through adoption of appropriate footsteps like incorporating moral education in school curriculum; upbringing socio-economic status; more socialization; increasing social awareness among individual or community through mass media exposure like print or virtual media even which may ultimately reduce the practice of risky sexual behaviour.

Size-selective mortality fosters ontogenetic changes in collective risk-taking behaviour in zebrafish, Danio rerio.

Size-selective mortality is common in fish populations and can operate either in a positive size-selective fashion by harvesting larger-than-average fish or be negatively size-selective by harvesting smaller-than-average fish. Through various mechanisms (like genetic correlations among behaviour and life-history traits or direct selection on behaviour co-varying with growth rate or size-at-maturation), size-selection can result in evolutionary changes in behavioural traits. Theory suggests that both positive and negative size-selection without additional selection on behaviour favours boldness, while evolution of shyness is possible if the largest fish are harvested. Here we examined the impact of size-selective mortality on collective boldness across ontogeny using three experimental lines of zebrafish (Danio rerio) generated through positive (large-harvested), negative (small-harvested) and random (control line) size-selective mortality for five generations and then relaxed selection for 10 generations to examine evolutionarily fixed outcomes. We measured collective risk-taking during feeding (boldness) under simulated aerial predation threat, and across four contexts in presence/absence of a cichlid. Boldness decreased across ontogeny under aerial predation threat, and the small-harvested line was consistently bolder than controls. The large and small-harvested lines showed higher behavioural plasticity as larvae and developed personality earlier compared to the controls. The large-harvested line showed increased variability and plasticity in boldness throughout ontogeny. In the presence of a live predator, fish did not differ in boldness in three contexts compared to the controls, but the large-harvested line showed reduced behavioural plasticity across contexts than controls. Our results confirmed theory by demonstrating that size-selective harvesting evolutionarily alters collective boldness and its variability and plasticity.

2-Alkyl substituted benzimidazoles as a new class of selective AT2 receptor ligands.

Ligands comprising a benzimidazole rather than the imidazole ring that is common in AT2R ligands e.g. in the AT2R agonist C21, can provide both high affinity and receptor selectivity. In particular, compounds encompassing benzimidazoles, substituted in the 2-position with small bulky groups such as an isopropyl (Ki = 4.0 nM) or a tert-butyl (Ki = 5.3 nM) or alternatively a thiazole heterocycle (Ki = 5.1 nM) demonstrate high affinity and AT2R selectivity. An n-butyl chain, as found in the AT1R selective sartans, makes the ligand less receptor selective. The isobutyl group on the biaryl scaffold present in most AT2R selective ligands reported so far was originally derived from the nonselective potent AT1R/AT2R ligand L-162,313. Notably, in all ligands discussed herein, the isobutyl group was substituted by an n-propyl group and ligands with high affinity to AT2R were provided and in addition the majority of them demonstrate a favorable AT2R/AT1R selectivity. The introduction of fluoro atoms in various positions had no pronounced effect on the affinity data. Ligands with a thiazole or a tert-butyl group attached to the 2-position and with a terminal trifluoromethyl butoxycarbonyl sidechain exhibited a similar stability as C21 in human liver microsomes, while other ligands examined were less stable in the microsome assay.

Bistability of Dielectrically Anisotropic Nematic Crystals and the Adaptation of Endothelial Collectives to Stress Fields.

Endothelial monolayers physiologically adapt to flow and flow-induced wall shear stress, attaining ordered configurations in which elongation, orientation, and polarization are coherently organized over many cells. Here, with the flow direction unchanged, a peculiar bi-stable (along the flow direction or perpendicular to it) cell alignment is observed, emerging as a function of the flow intensity alone, while cell polarization is purely instructed by flow directionality. Driven by the experimental findings, the parallelism between endothelia is delineated under a flow field and the transition of dual-frequency nematic liquid crystals under an external oscillatory electric field. The resulting physical model reproduces the two stable configurations and the energy landscape of the corresponding system transitions. In addition, it reveals the existence of a disordered, metastable state emerging upon system perturbation. This intermediate state, experimentally demonstrated in endothelial monolayers, is shown to expose the cellular system to a weakening of cell-to-cell junctions to the detriment of the monolayer integrity. The flow-adaptation of monolayers composed of healthy and senescent endothelia is successfully predicted by the model with adjustable nematic parameters. These results may help to understand the maladaptive response of in vivo endothelial tissues to disturbed hemodynamics and the progressive functional decay of senescent endothelia.

Global research on syndemics: a meta-knowledge analysis (2001-2020).

BACKGROUND: Syndemics or synergies of cooccurring epidemics are widely studied across health and social sciences in recent years. METHODS: We conducted a meta-knowledge analysis of articles published between 2001 to 2020 in this growing field of academic scholarship. RESULTS: We found a total of 830 articles authored by 3025 authors, mostly from high-income countries. Publications on syndemics are gradually increasing since 2003, with rapid development in 2013. Each article was cited more than 15 times on average, and most (n = 604) articles were original studies. Syndemics research focused on several areas, including HIV/AIDS, substance abuse, mental health, gender minority stressors, racism, violence, chronic physical and mental disorders, food insecurity, social determinants of health, and coronavirus disease 2019. Moreover, biopsychosocial interactions between multiple health problems were studied across medical, anthropological, public health, and other disciplines of science. CONCLUSIONS: The limited yet rapidly evolving literature on syndemics informs transdisciplinary interests to understand complex coexisting health challenges in the context of systematic exclusion and structural violence in vulnerable populations. The findings also suggest applications of syndemic theory to evaluate clinical and public health problems, examine the socioecological dynamics of factors influencing health and wellbeing, and use the insights to alleviate health inequities in the intersections of synergistic epidemics and persistent contextual challenges for population health.

Reintegration with family and intimate partner violence (IPV) against women among the returnee migrant worker's family during COVID-19 induced lockdown: A Block-level analysis using multinomial logistic regression model.

Worldwide the incidents of intimate partner violence (IPV) have increased due to lockdowns related to the COVID-19 pandemic. This paper aims to identify the association between IPV and different socio-economic factors of women & their most recent partner during the COVID-19 pandemic in returnee migrant worker families in Balurghat Block (area 363.9 sq. km), Dakshin Dinajpur district, West Bengal, India. A total of 159 ever-married women were included in this present study, whose husbands were engaged as workers elsewhere at least two years before the lockdown. The result of the multinomial logistic regression model revealed that, after controlling for other variables, the women who had the poorest wealth background were 37% more likely (RRR: 1.37; 95% CI [1.18, 1.47]) to experience IPV almost every day in a week than those who had a middle wealth background. Conversely, the women who had the poorest wealth background were 37% (95% CI [0.57, 0.82]) less likely to experience IPV for three to four days in a week. Furthermore, the women whose partners were currently unemployed were 21% more likely (RRR: 1.21; 95% CI [1.16, 1.36]) to experience IPV almost every day in a week than those whose husbands were currently employed. The women whose husband's had a loan were 26% more likely (RRR: 1.26; 95% CI [1.25, 1.33]) to experience IPV for three to four days in a week than those whose husbands did not have any loans. The likelihood to experience IPV almost every day in a week is higher among those women whose husbands attain weekly (31%) loan instalment pattern and consume alcohol daily (31%). Interventions are needed at the grassroots level and some economic planning is required at an urgent basis.

Size Selective Harvesting Does Not Result in Reproductive Isolation among Experimental Lines of Zebrafish, Danio rerio: Implications for Managing Harvest-Induced Evolution.

Size-selective mortality is common in fish stocks. Positive size-selection happens in fisheries where larger size classes are preferentially targeted while gape-limited natural predation may cause negative size-selection for smaller size classes. As body size and correlated behavioural traits are sexually selected, harvest-induced trait changes may promote prezygotic reproductive barriers among selection lines experiencing differential size-selective mortality. To investigate this, we used three experimental lines of zebrafish (Danio rerio) exposed to positive (large-harvested), negative (small-harvested) and random (control line) size-selective mortality for five generations. We tested prezygotic preferences through choice tests and spawning trials. In the preference tests without controlling for body size, we found that females of all lines preferred males of the generally larger small-harvested line. When the body size of stimulus fish was statistically controlled, this preference disappeared and a weak evidence of line-assortative preference emerged, but only among large-harvested line fish. In subsequent spawning trials, we did not find evidence for line-assortative reproductive allocation in any of the lines. Our study suggests that size-selection due to fisheries or natural predation does not result in reproductive isolation. Gene flow between wild-populations and populations adapted to size-selected mortality may happen during secondary contact which can speed up trait recovery.

Jet Impact on Superhydrophobic Metal Mesh.

Liquid-jet impact on porous, relatively thin solids has a variety of applications in heat transfer, filtration, liquid-fuel atomization, incontinence products, and solid-substrate erosion, among others. Many prior studies focused on liquid-jet impact on impermeable substrates, and some have investigated the hydraulic jump phenomenon. In the present work, the liquid jet strikes a superhydrophobic, permeable, metal mesh orthogonally, and the radial spreading and throughflow of the liquid are characterized. The prebreakthrough hydraulic jump, the breakthrough velocity, and the postbreakthrough spatial distributions of the liquid are investigated by varying the liquid properties (density, surface tension, and viscosity) and the openness of the metal mesh. The hydraulic jump radius in the prebreakthrough regime increases with jet velocity and is independent of the liquid properties and mesh geometry (pore size, wire diameter and pitch). The breakthrough velocity increases with surface tension of the liquid and decreases with the mesh opening diameter and liquid viscosity. A simple analytical model predicts the jet breakthrough velocity; its predictions are in accordance with the experimental observations. In the postbreakthrough regime, as the jet velocity increases, the liquid flow rate penetrating the mesh shows an initially steep increase, followed by a plateau, which is attributed to a Cassie-Baxter-to-Wenzel transition at the impact area of the mesh.

Revisiting the supplementary relationship of dynamic contact angles measured by sessile-droplet and captive-bubble methods: Role of surface roughness.

HYPOTHESIS: Quantitative characterization of surface wettability through contact angle (CA) measurement using the sessile droplet (SD) or captive bubble (CB) methods is often limited by the intrinsic wetting properties of the substrate. Situations may arise when an extreme surface wettability may preclude using one of the two methods for predicting the behaviors of droplets or bubbles on the surface. This warrants a relationship between the dynamic CAs measured via the SD and CB methods. While the two dynamic CAs (e.g., the advancing CA of SD and receding CA of CB) add up to 180° on a smooth surface, the simple geometric supplementary principle may not apply for rough surfaces. EXPERIMENTS: We perform a systematic wettability characterization of solid substrates with varying degrees of roughness using the sessile-droplet and captive-bubble methods, and interpret the experimental observations using a theoretical model. FINDINGS: The dynamic contact angles measured by the sessile-droplet and captive-bubble methods deviate from the supplementary principle as the surface roughness is increased. We present a theoretical explanation for this disparity and predict the values of the contact angles using prevalent thermodynamic models of wetting and contact-angle hysteresis on rough substrates. The theoretical prediction is in good agreement with the experimental observations.