Phase behavior of n-hexane confined in unconsolidated nanoporous media: an experimental investigation at varying pore sizes and temperatures.

We investigated the effect of confinement on the phase behavior of hexane in nanopores of mesoporous silica at varying pore diameters and temperatures using a patented gravimetric apparatus. The adsorption and desorption isotherms were experimentally measured, and the capillary condensation and evaporation pressures were calculated from the isotherms. The results show that, for all pore sizes and temperatures utilized here, the confinement of fluids significantly lowers the vapor-liquid phase transition pressures. However, its evaporation, i.e., liquid-vapor phase transition, occurs at a lower pressure than its capillary condensation counterpart. The experimental findings demonstrate that the confinement effect becomes weaker in wider nanopores due to the reduced solid-fluid interactions in larger spaces. Furthermore, it is evident from isotherms that hexane rapidly approaches a supercritical-like state at high temperatures when confined in smaller pores, resulting in an ambiguous vapor-liquid phase transition. In contrast, this behavior disappears in larger pores at similar temperatures. Moreover, the present study compares the fully gravimetric adsorption method against the thermogravimetric approach. The results show that the fully gravimetric method, which directly measures the mass of the adsorbed or condensed fluids, provides significant advantages over the thermogravimetric counterpart. The findings of this study are expected to be of fundamental interest to a wide range of science and engineering communities concerned about the behavior of heavier hydrocarbons in various industrial applications, and modeling the confined phase behavior of fluids and developing robust equations of state (EOS).

The effect of confinement on the phase behavior of propane in nanoporous media: an experimental study probing capillary condensation, evaporation, and hysteresis at varying pore sizes and temperatures.

Fundamental understanding of the phase behavior and properties of fluids under confinement is of great significance for multiple fields of engineering and science, as well as for many practical industrial applications. In particular, unconventional geological systems, such as shale reservoirs, possess nanometer-scale pores, which impose nanoconfinement on the fluid molecules. In large pores, the bulk phase behavior of fluids can be modeled by the well-established methods, such as equation of state (EOS) approaches. However, under confinement the thermodynamic properties of fluids deviate significantly from those in the bulk, thus rendering the traditional EOS methods ineffective in predicting the phase behavior of confined fluids. Recently, the PC-SAFT/Laplace EOS has been developed to better represent the fluid phase equilibria in nanopores, which incorporates a new parameter that needs to be determined from experimental data. In this study, a new dataset is presented to reflect the phase properties of propane confined within the MCM-41 pores, with the aim to improve both the general understanding of the phase behavior of hydrocarbons under confinement and to parameterize the PC-SAFT/Laplace EOS for the nanoconfined propane. For this purpose, propane adsorption and desorption isotherms are determined experimentally for a wide range of temperatures (-27 to 20 °C) in MCM-41 of three different pore sizes (nominal pore diameters of 60, 80, and 100 Å). The effects of temperature and pore diameter on the capillary condensation and evaporation pressures are discussed in detail. Furthermore, the adsorption-desorption hysteresis behavior and its progression for different pore sizes were discussed. The experimental data are modeled using the parameterized PC-SAFT/Laplace EOS, which accurately captured the effects of confinement on the capillary condensation of propane in MCM-41. In addition, this study enriches the field of nanoconfinement research by providing a new dataset exemplifying the thermodynamic characteristics of hydrocarbons in nanopores.

Efficacy of liquid biopsy for disease monitoring and early prediction of tumor progression in EGFR mutation-positive non-small cell lung cancer.

15-40% of non-small cell lung cancer (NSCLC) patients harbor epidermal growth factor receptor (EGFR)-sensitizing mutations. Tyrosine kinase inhibitors (TKIs) provide significant clinical benefit in this population, yet all patients will ultimately progress. Liquid biopsy can reliably identify somatic tumor-associated EGFR mutations in plasma. This study aimed to assess the feasibility and value of the quantitative assessment of EGFR driver mutations in plasma in EGFR-mutated NSCLC patients treated with EGFR-TKIs as a tool to evaluate therapeutic response to TKIs and monitor for disease progression. The study included 136 patients with tissue biopsy-confirmed EGFR-sensitizing, mutation-positive lung adenocarcinoma with plasma collected prior to TKI treatment and at least two post-initiation TKI treatment/follow-up blood samples. Plasma samples were tested with the cobas® EGFR Mutation Test v2 (cobas EGFR Test), and semi-quantitative index (SQI) values for each identified mutation were reported by the assay software. The most common baseline EGFR mutations detected in tissue were L858R (53.7%) and exon 19 deletion (39.7%). Plasma cell-free DNA analysis detected EGFR mutations in 74% of the baseline samples. Objective response rate by RECIST 1.1 was achieved in 72% of patients, while 93% had a molecular response (defined as disappearance of the EGFR mutation from plasma). 83% of patients had molecular progression (MP; 1.5X SQI increase or new T790M mutation), and 82% who had a clinical response had clinical progression. On average, MP occurred 42 days prior to clinical progression. Patients who progressed while on first-line TKI showed MP of the original EGFR-sensitizing mutations prior to the emergence of a T790M mutation, which was detected in 27% of the EGFR plasma-positive patients. Longitudinal monitoring of EGFR mutational load in plasma is feasible and can predict both response and clinical progression in EGFR-mutated NSCLC patients treated with EGFR-TKIs, as well as detect treatment-emergent EGFR mutations.

Interlaboratory variation in the performance of liquid-based cytology: insights from the ATHENA trial.

Although it is recognized that cervical cytology is highly subjective, and that there is considerable interlaboratory variation in how slides are evaluated, little is known as to how this impacts the performance of cytology. In the ATHENA trial, liquid-based cytology specimens from 46,887 eligible women ≥21 years of age were evaluated at four large regional US laboratories, providing a unique opportunity to evaluate the impact of interlaboratory variations on the performance of cervical cytology. All women with abnormal cytology (atypical squamous cells of undetermined significance or higher) were referred to colposcopy, as were all high-risk human papillomavirus (hrHPV)-positive women ≥25 years of age and a random subset of those ≥25 years of age who were negative by both hrHPV testing and cytology. Sociodemographics, risk factors for cervical disease, and prevalence of cervical intraepithelial neoplasia (CIN) were similar across the laboratories. There were considerable differences among the laboratories both in overall cytological abnormal rates, ranging from 3.8 to 9.9%, and in sensitivity of cytology to detect CIN grade 2 or worse (CIN2+), from 42.0 to 73.0%. In contrast, the hrHPV positivity rate varied only from 10.9 to 13.4%, and the sensitivity of hrHPV testing from 88.2 to 90.1%. These observations suggest that hrHPV testing without cytology should be considered as the initial method for cervical cancer screening.

Entomological studies for surveillance and prevention of dengue in arid and semi-arid districts of Rajasthan, India.

BACKGROUND & OBJECTIVES: Rajasthan is one of the dengue endemic states of India. Very few studies have been published on entomological aspects of dengue in this state. Owing to water scarcity, inhabitants in desert areas overstore domestic water which leads to the persistence of dengue vectors within the domestic premises. Area specific knowledge on breeding, key containers and seasonal rhythms of vector population is essential for preparing an effective prevention plan against dengue. Present paper reports results of entomological investigations on dengue vectors in arid and semi-arid districts of Rajasthan. METHODS: Longitudinal studies were undertaken during 2004-06 in one arid and two semi-arid dengue endemic districts of Rajasthan. Adult and larval Aedes were collected from the randomly selected houses in representative towns and villages with associated details of container types and water storage practices of inhabitants. RESULTS: In urban areas during all the seasons adult house index (AHI) of Aedes aegypti was maximum in desert zone (25) and least in semi-arid area with saline river III (1). The difference of AHI during three seasons was statistically significant (chi2 = 16.1, p < 0.01 for urban; and chi2 = 50.71, p < 0.001 for rural). Breeding of Ae. aegypti among urban settings was maximum in desert zone. During all the seasons cement tanks were the key breeding habitats for Ae. aegypti in desert as well as semi-arid areas. INTERPRETATION & CONCLUSION: Water storage habits during summer season emerged to be the risk factor of vector abundance in urban areas of arid and semi-arid settings. A carefully designed study of key containers targeting cement tanks as the primary habitats of mosquito control may lead to commendable results for dengue prevention.

Importance of socioeconomic status and tree holes in distribution of Aedes mosquitoes (Diptera: Culicidae) in Jodhpur, Rajasthan, India.

Immature Aedes mosquitoes were found in domestic, peridomestic, and tree hole habitats within three socioeconomic strata of Jodhpur, a city within an arid area of Rajasthan, India, endemic for dengue. Peridomestic habitats served as a persistent source of Aedes vectors, especially those used for watering cows for religious reasons that were located within high socioeconomic areas. Domestic (indoor) containers within low socioeconomic strata showed a higher container index (27.0%) than periurban areas with cattle sheds (14.3%) or high socioeconomic areas (18.1%). Mosquitoes were collected in tree holes at zoos and gardens supporting several species of monkeys. Six of 67 Aedes albopictus Skuse reared from immatures collected in tree holes tested positive for dengue antigen acquired through vertical transmission, possibly indicating a persistence mechanism for dengue virus within an urban environment.

Entomological studies on malaria in irrigated and non-irrigated areas of Thar desert, Rajasthan, India.

BACKGROUND & OBJECTIVES: Malaria is the major health problem in western Rajasthan yet its vector fauna and transmission dynamics thereof is not understood properly. The present investigations report complete profile of qualitative and quantitative aspects of anopheline species occurring in different settings of desert ecosystem. METHODS: Area with irrigation through canal for more than 20 years (setting I), area with irrigation through canal for 10 years (setting II) and area without any irrigation (setting III) have been selected for studies. Species identification and their densities (per man hour) was made as per standard methods. RESULTS: In village of setting I, during rainy season, An. subpictus and An. stephensi were present while during winter season four species--An. subpictus, An. stephensi, An. culicifacies and An. annularis were collected. In all the villages of setting I, II and III no Anopheles mosquito was observed during summer season. In the villages of desert region without any irrigation facilities through any canal, the anopheline species were present only during rainy season. INTERPRETATION & CONCLUSION: An. stephensi is the major malaria vector of desert irrespective of whether the area is canal irrigated or not. During summer season absence of vector species in all the villages require further studies on micro-ecology of the species under desert conditions.