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Recently, Terahertz (THz) band communications at various atmospheric altitudes have been studied due to larger bandwidth availability and reduced water vapor concentrations at higher atmospheric altitudes as compared to sea level. In this paper, as special cases of 6G aerial communication networks, we consider: (1) Low Altitude Platform-to-High Altitude Platform (LAP-to-HAP), (2) HAP-to-HAP, and (3) HAP-to-Satellite (HAP-to-SAT) GHz-to-THz broadband communications over (1-1000) GHz by analyzing total path loss and total usable bandwidth. For obtaining realistic absorption loss at practical altitudes, we employ the International Telecommunications Union's (ITU) model using the standard weather profile. We consider four practical carrier frequencies offering low absorption loss values i.e., f1 = 0.140 THz (D band: 110-170 GHz), f2 = 0.300 THz (275-325 GHz), f3 = 0.750 THz, and f4 = 0.875 THz for analyzing total path loss. Numerical results show that due to improved atmospheric conditions particularly above 23 km altitudes, increasing the Rx-HAP altitude in HAP-to-HAP communications promises a lower total path loss of up to 7.7 %, even at the cost of an increase in the Tx-Rx-HAP distance from 1 km to 34 km, promising Tbps rates for 6G non-terrestrial communications. Additionally, total usable bandwidth analysis demonstrates that with total antenna gains of 80 dBi, bandwidth in the order of 100s of GHz is usable for the LAP-to-HAP scenario, the entire considered broadband is usable for the HAP-to-HAP scenario between 16 km to 50 km, and the HAP-to-SAT scenario between a HAP at 19 km and SAT at 100 km, truly showcasing the potential of employing GHz-to-THz broadband communications cognitively over (1-1000) GHz for various practical 6G non-terrestrial networks.

In this letter, we devise a frequency, distance, and altitude-dependent, analytical model for THz band path loss. This model is obtained from cascaded regression of transmittance data from Line-by-Line Radiative Transfer Model (LBLRTM) propagation analysis tool, considering altitudes from the sea-level to 1 km, distances from 1 m to 100 m and frequencies within 0.79-0.91 THz and 0.93-0.94 THz. The proposed approach yields high accuracy with respect to propagation data while providing a simple, closed-form expression to help the design of Terahertz (THz) band drone communications.

The present study investigates the hydrolysis, microstructural profiling and utilization of guar gum (Cyamopsis tetragonoloba) as a prebiotic in a yoghurt. Guar galactomannans (GG) was purified and partially depolymerized using an acid, alkali and enzyme to improve its characteristics and increase its utilization. The prebiotic potential of hydrolyzed guar gum was determined using Basel and supplemented media. Crude guar galactomannans (CGG), purified guar galactomannans (PGG), base hydrolyzed guar galactomannans (BHGG), acid hydrolyzed guar galactomannans (AHGG) and enzymatic hydrolyzed guar galactomannans (EHGG) were analyzed using scanning electron microscope (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Yoghurt was prepared with a starter culture and incorporating guar gum, its hydrolyzed forms (0.1, 0.5 and 1%) and Bifidobacterium bifidum. The results showed that PHGG significantly improved the viability of B. bifidum. SEM revealed a significant change in the surface morphology of guar gum after acidic and enzymatic hydrolysis. Enzymatic hydrolysis developed a well-defined framework within guar gum molecules. The XRD pattern of CGG, PGG and AHGG presented an amorphous structure and showed low overall crystallinity while EHGG and BHGG resulted in slightly increased crystallinity regions. FTIR spectral analysis suggested that, after hydrolysis, there was no major transformation of functional groups. The addition of the probiotic and prebiotic significantly improved the physiochemical properties of the developed yoghurt. The firmness, cohesiveness, adhesiveness and syneresis were increased while consistency and viscosity were decreased during storage. In sum, a partial hydrolysis of guar gum could be achieved using inexpensive methods with commercial significance.

In this work, 0.75-10 THz band is explored for non-terrestrial communications, by leveraging the improved atmospheric conditions at various altitudes. A channel model for aerial communications at THz band is proposed to calculate the common flat bands for frequency-selective path gain and the colored noise spectrums, both of which are highly affected by the atmospheric conditions. With capacity computation based on common flat bands, we consider aerial vehicles at different altitudes and distances, under realistic weather and channel fading conditions, due to beam misalignment and also multi path fading. An extensive capacity analysis is presented, considering equal and water-filling power allocation. It is shown that, when there is no fading, capacity for aerial links is several orders of magnitude larger than the sea-level capacity. When ergodic capacity is computed for the fading scenarios, it is shown that the impact of fading vanishes with altitude. Sea-level ergodic capacity is increased by an order of magnitude for drone-to-drone communications, providing several Tbps at 10 m range, while 10s of Tbps is achievable among jet planes and UAVs, and several 100s of Tbps is possible for satellites/cubesats at 1 km under fading, suggesting that THz band is a promising alternative for aerial communications.

Terahertz (THz) communications has been recognized as a candidate technology for the next generation networks as the THz band offers large bandwidth and data rates, catering for the problem of spectrum scarcity. However, THz band propagation is highly affected by atmospheric absorption due to water vapor molecules, in addition to the high spread loss. Modeling of the absorption loss is essential for a realistic closed form THz path loss model, which can be employed in link level analysis and formulations. For this purpose, in this paper, we characterize the THz transmittance i.e., absorption gain using the data obtained from Line-by-Line Radiative Transfer Model (LBLRTM) tool, considering the available frequency channels selected via water-filling, altitudes from sea-level to drone altitudes and various transmission ranges. We analyze the modeling of transmittance as a function of: (1) Frequency, (2) Distance and (3) Altitude, using different statistical models including, Polynomial, Exponential and Gaussian models. Numerical results depict that modeling transmittance as a function of distance and altitude are feasible approaches using the exponential and the polynomial models, respectively. This work can be extended to characterize the transmittance for all frequencies over the entire THz band, and also for higher altitudes and longer ranges.

Climate change and variability affect virtually everyone and every region of the world but the effects are nowhere more prominent than in mountain regions and people living therein. The Hindu Kush Himalayan (HKH) region is a vast expanse encompassing 18% of the world’s mountainous area. Sprawling over 4.3 million km2, the HKH region occupies areas of eight countries namely Nepal, Bhutan, Afghanistan, Bangladesh, China, India, Myanmar, and Pakistan. The HKH region is warming at a rate higher than the global average and precipitation has also increased significantly over the last 6 decades along with increased frequency and intensity of some extreme events. Changes in temperature and precipitation have affected and will like to affect the climate-dependent sectors such as hydrology, agriculture, biodiversity, and human health. This paper aims to document how climate change has impacted and will impact, health and well-being of the people in the HKH region and offers adaptation and mitigation measures to reduce the impacts of climate change on health and well-being of the people. In the HKH region, climate change boosts infectious diseases, non-communicable diseases (NCDs), malnutrition, and injuries. Hence, climate change adaptation and mitigation measures are needed urgently to safeguard vulnerable populations residing in the HKH region.

This chapter proposes some fundamental adjustments in the basic paradigm of religious inference/decision making, remodeling the conventional paradigm of religious learning. The conventional paradigm is described in the chapter as the one-dimensional paradigm containing the perception of religion as a divinely ordained package of given set of divine commandments that is expected to be cognitively grasped by the followers of religion and to be truly applied in human practice. The chapter proposes to replace the single-dimensional paradigm by a three-dimensional paradigm.

Additional file 1. Questionnaire for Case

Additional file 2. Questionnaire for Control

In this paper, a joint power and beam-level beamwidth control scheme is proposed for full duplex (FD) millimeter wave (mmWave) indoor wireless systems. Energy efficiency of the proposed scheme is investigated considering various system parameters, such as maximum transmit power level, level of self-interference cancellation and pilot transmission overhead. With this analysis for a realistic indoor wireless communication scenario, the feasibility of FD is studied for mmWave links, considering their specific propagation characteristics, namely, narrow transmission and reception beam-level beamwidths and high absorption losses, as well as massive bandwidth which is much larger than the existing sub 6 GHz bands. We evaluate the performance of the proposed FD mmWave system for three power budget schemes (low, moderate and high) in terms of average total energy efficiency. Our simulation results show that, for currently available state-of-the-art self-interference cancellation levels, FD mmWave with proposed joint power and beam-level beamwidth control outperforms the smart half duplex (HD) mmWave with joint transmission slot and beam-level beamwidth control by a factor of up to four times and improves FD mmWave with only power control by up to 33.92 %. If higher (close to ideal) self-interference cancellation can be achieved, the net average total energy efficiency improvements over existing abovementioned schemes, are up to 4.8 times and 26.45 %, respectively. It is concluded that with the proposed joint power and beamwidth control, the current FD mmWave technology promises a good potential for indoor wireless networks.

Amidst a time when there is the global pandemic of COVID-19 and high levels of stress and anxiety among people, it was pertinent to study if people have modified their health-seeking behavior. A questionnaire-based cross-sectional study was performed in Lahore to assess the change in behaviors of people before and during the pandemic. The results show that the health seeking behavior of the people has changed during the pandemic, resulting in an increased trend of self-medication and a decreased number of people visiting the hospital for their ailments. People preferred private health providers over the government facilities. This might be due to the misinformation, panic, and uncertainties spread by the social media. Governmental health care providers should consider these aspects while addressing the polices related to the pandemic.

Terahertz communications offers a massive potential for the prospective beyond 5G wireless systems, as the band offers huge bandwidth and data rates as compared to the existing sub 6 GHz bands, which are almost saturated. In this paper, we investigate the feasibility of wireless communications over the Terahertz-band (0.75–10 THz) at various atmospheric altitudes, considering different transmission distances and directions by realistically calculating the absorption loss, which is the major limiting factor affecting the propagation of THz waves through the earth’s atmosphere. Four practical altitudes are considered, corresponding to Drone-to-Drone (D2D), Jet plane-to-Jet plane (J2J), Unmanned Aerial Vehicle (UAV)-to-UAV, and near-space Satellite-to-Satellite (S2S) communications. Following comparison and validation with two real-world experimental results from the literature measured at the sea-level, Line by Line Radiative Transfer Models (LBLRTM) is used to obtain realistic THz-band transmittance values against each altitude case and setting. Subsequently, absorption loss and total path loss values are computed and mean total path loss sensitivity is further observed against a range of transmission directions via zenith angle variations from vertically-up to vertically-down communication. Numerical results show that as the altitude increases, the concentration of the water vapor molecules decreases, enabling the communication over the THz-band (0.75–10 THz) to be more feasible as compared to the sea-level communication. Moreover, the total usable bandwidth results over the THz-band (0.75–10 THz) exhibit that the upper bounds of 8.218 THz, 9.142 THz and 9.25 THz are usable up to the transmission distance of 2 km against the total antenna gains of 80 dBi for J2J, U2U and S2S communication cases, respectively.

Purpose: To identify, characterize and structurally elucidate bioactive compounds from root of Ruellia squarrosa.Methods: One kilogram of crude Ruellia squarrosa root was shade dried for 14 days, ground to a fine powder and subjected to a methanol extraction. The resultant extract underwent column chromatography for further purification. The isolated compounds were subjected to ultraviolet spectroscopy (UV), infra-red (IR), proton nuclear magnetic resonance (1H-NMR), 13C–NMR and high resolution electron ionization mass spectrometry (HR-EI-MS) for the identification, characterization and structural elucidation of bioactive compounds. The most active compounds were tested for anticancer activities against human prostate cancer cell.Results: Two active compounds, squarrosol and squarrosal, were obtained with half-maximal inhibitory concentration (IC50) of 15.6 and 26.6 μg/mL, respectively, against human prostate cancer cell lines. Squarrasol showed a significantly (p < 0.05) greater inhibition of cell proliferation than the same dose of squarrasal.Conclusion: These findings suggest that extracts of Ruellia squarrosa containing the bioactive compounds, squarrosol and squarrosal, can potentially be developed for the treatment of human prostate cancer.Keywords: Ruellia squarrosa, Prostate cancer, Squarrosol, Squarrosal, Anit-proliferative

Magnetite (Fe3O4) is getting popular due to its super-paramagnetic properties, high biocompatibility and lack of toxicity to humans. Magnetite (Fe3O4) nanoparticles have high surface energy thus these nanoparticles aggregate quickly. This aggregation strongly affects the efficiency of these nanoparticles. So these magnetite nanoparticles are coated with organic or inorganic substance to prevent aggregation. These coatings not only stabilize magnetic nanoparticles but can also be used for further functionalization. The aim of this study was to evaluate the efficiency of functionalized magnetite to remove pathogenic bacteria (E.coli and B.cereus) from milk considering binding capability of magnetite with bacterial cell wall. Magnetite (Fe3O4) was prepared by co-precipitation method and subsequently functionalized with oleic acid (OA) and ethylene diamine (EDA). In present study role of magnetite (Fe3O4) and functionalized magnetite (EDA-Fe3O4, OA-Fe3O4) in removal of pathogenic bacteria (E.coli and B.cereus) from milk was investigated. The morphology of functionalized magnetite was determined by Scanning Electron microscopy (SEM). Their removal efficiency was studied based on time (10, 20 and 30 minutes). Concentration of uncoated magnetite (Fe3O4) and coated magnetite (EDA-Fe3O4, OA-Fe3O4) was fixed at 4mg/50mL. Magnetite was successfully synthesized in range of and#177;3nm. Highest capturing efficiency (74.45%) of oleic acid magnetite (OA-Fe3O4) was observed for Bacillus cereus at 30 minutes. However for Escherichia coli, both ethylene-diamine magnetite (EDA-Fe3O4) and oleic acid magnetite (OA-Fe3O4) showed maximum capturing efficiency (61.65% and 63.91% respectively). It was concluded from the study that magnetite coated with oleic acid and ethylenediamine removed pathogenic bacteria from milk efficiently. However, more research is required to study the effect of these magnetic nanoparticles on nutritional composition of milk.

Purpose Study to investigate the effects of collagen cross-linking on the ultrastructural organization of the corneal stroma in the human keratoconus cornea (KC). Methods Three normal, three keratoconus (KC1, KC2, KC3), and three cross-linked keratoconus (CXL1, CXL2, CXL3) corneas were analyzed. The KC corneas were treated with a riboflavin-ultraviolet A (UVA) treatment (CXL) method described by Wollensak et al. Penetrating keratoplasty (PKP) was performed 6 months after treatment. All samples were processed for electron microscopy. Results The riboflavin-UVA-treated CXL corneal stroma showed interlacing lamellae in the anterior stroma followed by well-organized parallel running lamellae. The lamellae contained uniformly distributed collagen fibrils (CFs) decorated with normal proteoglycans (PGs). The CF diameter and interfibrillar spacing in the CXL cornea were significantly increased compared to those in the KC cornea. The PG area in the CXL corneas were significantly smaller than the PGs in the KC cornea. The epithelium and Bowman’s layer were also normal. On rare occasions, a thick basement membrane and collagenous pannus were also observed. Conclusions Corneal cross-linking leads to modifications of the cornea stroma. The KC corneal structure showed a modification in the CF diameter, interfibrillar spacing, and PG area. This resulted in a more uniform distribution of collagen fibrils, a key feature for corneal transparency.

Purpose The stroma is the major part of the cornea, in which collagen fibrils and proteoglycans are distributed uniformly. We describe the ultrastructure of corneal layers, collagen fibrils (CF), and proteoglycans (PGs) in the tree shrew cornea. Methods Tree shrew corneas (5, 6, and 10 week old animals) and normal human corneas (24, 25, and 54 years old) were fixed in 2.5% glutaraldehyde containing cuprolinic blue in a sodium acetate buffer. The tissue was processed for electron microscopy. The ‘iTEM Olympus Soft Imaging Solutions GmbH’ program was used to measure the corneal layers, collagen fibril diameters and proteoglycan areas. Results The tree shrew cornea consists of 5 layers: the epithelium, Bowman’s layer, stroma, Descemet’s membrane, and endothelium. The epithelium was composed of squamous cells, wing cells and basal cells. The Bowman’s layer was 5.5±1.0 µm thick and very similar to a normal human Bowman’s layer. The stroma was 258±7.00 µm thick and consisted of collagen fibril lamellae. The lamellae were interlaced with one another in the anterior stroma, but ran parallel to one another in the middle and posterior stroma. Collagen fibrils were decorated with proteoglycan filaments with an area size of 390 ±438 nm2. The collagen fibril had a minimum diameter of 39±4.25 nm. The interfibrillar spacing was 52.91±6.07 nm. Within the collagen fibrils, very small electron-dense particles were present. Conclusions The structure of the tree shrew cornea is very similar to that of the normal human cornea. As is the case with the human cornea, the tree shrew cornea had a Bowman's layer, lamellar interlacing in the anterior stroma and electron-dense particles within the collagen fibrils. The similarities of the tree shrew cornea with the human cornea suggest that it could be a good structural model to use when studying changes in collagen fibrils and proteoglycans in non-genetic corneal diseases, such as ectasia caused after LASIK (laser-assisted in situ keratomileusis).

Pakistan is facing an acute shortage of electricity power since former few decades. The main reason behind the fact is that there has always been a lack of courtesy by the policy and decision makers of the country towards enhancing the installed capacity of the sector, as well as discovering other ways to implore the power from renewable resources. Pakistan is an agricultural country whose economy is primarily based on the agronomic yields, one of which is sugarcane — a cash crop. Thru the process of extraction of sugar from the sugarcane, a stuff named Bagasse is leftover which has been evidenced as a viable bio-fuel. Numerous countries across the globe are consuming Bagasse to generate electricity, but regrettably in our country, this valued renewable resource has mostly been thrown away as a mere trash. Keeping in view the country's existing yield of Bagasse, Pakistan has an estimated capacity of about 3000 MW of electricity generation by its usage. The rest of the paper is structured as follows: The first part involves a brief description of Bagasse, its recent usage and significance as a bio-fuel across the globe. The second part highlights its existing usage in Pakistan — stressing its importance. The third part focuses the prospects of its consumption in the country, based on both the existing as well as the projected outputs. In the concluding part, some recommendations are underscored for its optimal usage to counter the electricity shortfall.

UV-visible spectrophotometric technique was used to study the interaction of polyvinylpyrrolidone (PVP) with co-solutes: phenol, benzoic acid, sodium benzoate, salicylic acid and acetyl salicylic acid in aqueous medium. Changes in the absorption spectra of the co-solutes were observed in the presence of PVP from 200 to 210 nm. The changes were attributed to interaction of PVP molecules with the co-solute molecules. As the concentration of the co-solute increased, a red shift in the bands was observed indicating an increase in interaction between PVP and the co-solute.

The electrical conductivity of sodium dodecyl sulfate (SDS) in aqueous solution was determined up to a concentration of 10 times the critical micelle concentration. The effects of solution concentration on the various interaction parameters of SDS have been studied. The mass action model was applied to micelle formation to calculate the micellization parameters: micellization constant, K c ; aggregation number, n ; and number of counterions per micelle, m . The micellization parameters also made it possible to evaluate the concentration change of monomeric surfactant ion with total surfactant concentration. The Debye–Huckel–Onsager equations have been applied to the experimental data for aqueous solution of SDS. An average degree of counterion binding to a micelle ( m / n ) and aggregation number ( n ) were determined to be 0.72 and 64, respectively. As aggregation number decreases monotonously with increase in concentration, this trend has been employed to calculate the electrical conductivity of the micelle ( λ M ).

Structural, rheological, and mechanical properties of ternary blends of a liquid crystalline copolyester (LCP) composed of p-hydroxybenzoic acid and 2,6-hydroxy-naphthoic acid, poly(ehtylene naphthalate)(PEN), and poly(ethylene terephtalate) (PET) were investigated using capillary rheometry, tensile testing, scanning electron microscopy, and X-ray diffraction. Viscosity-shear rate behavior of the ternary blends is very similar to that of pure polymers and their binary blends. The activation energy of flows of the ternary blends was smaller than those of PEN and PET. Tensile modulus and strength of extruded strands of the blends increased with increasing LCP content. The extruded strands of the blends consist of a crystalline and oriented LCP phase and an amorphous and unoriented PEN/PET blended phase. Tensile mechanical properties and structures of the ternary blends were discussed.

Structural, Theological, thermal, and mechanical properties of blends of poly(ethylene naphthalate) (PEN) and poly(ethylene terephthalate) (PET) obtained by melt blending were investigated using capillary rheometry, differential scanning calorimetry (DSC), scanning electron microscopic (SEM) observation, tensile testing. X-ray diffraction, and 1H nuclear magnetic resonance (NMR) measurements. The melt Theological behavior of the PEN/PET blends was very similar to that of the two parent polymers. The melt viscosity of the blends was between that of PEN and that of PET. Thermal properties and NMR measurement of the blends revealed that PEN is partially miscible with PET in the as molded blends, indicating that an interchange reaction occurs to some extent on melt processing. The blend of 50/50 PEN/PET was more difficult to crystallize compared with blends of other PEN/PET ratios. The blends, once melted during DSC measurements, almost never showed cold crystallization and subsequent melting and def...

Flory Fox, Kurata-Stockmayer, Berry, Inagaki-Suzuki-Kurata, Stockmayer-Fixman and Ahmad-Baloch methods based on the excluded volume theory have been applied to poly(vinyl chloride)-cyclohexanone system to obtain Kq and the radius of gyration. A discussion on the reliability of these methods is given. The Stockmayer-Fixman and Ahmad-Baloch methods are found to be equally applicable.

Purpose: The maintenance of stromal hydration by the corneal endothelium relies on active transendothelial anion transport, with bicarbonate and chloride the major anions carrying the current. However, the ion transport pathways that operate to maintain stromal hydration have yet to be fully elucidated. Methods: We used RT-PCR to identify the gene expression profile of members of the ClC family of chloride channels in freshly isolated samples of rabbit corneal endothelium, stroma, and epithelium. The expression of a separate group of genes was also examined to confirm the purity of the sample collection protocol. The expression of the ClC-2 and ClC-3 channel protein in the cornea was also evaluated by light and electron microscopic immunolabelling. Results: The mRNA for ClC-2, ClC-3, ClC-5, ClC-6, and ClC-7 were expressed in both the corneal epithelium and endothelium, and in the stroma. The mRNA for the skeletal muscle specific channel ClC-1 and the kidney specific chloride channel ClC-Ka were not detectable. ClC-4 mRNA was not detected in any rabbit tissue examined. The expression pattern of the mRNAs for collagens V, VI, VII, and VIII demonstrated the absence of contamination in epithelial and endothelial samples. ClC-2 and ClC-3 immunolabelling confirmed the presence of these proteins in corneal endothelium, stroma, and epithelium. Conclusions: Together with cystic fibrosis transmembrane conductance regulator (CFTR) and calcium activated chloride channel-1 (CLCA1), these results bring the number of chloride channel genes known to be expressed in the corneal endothelium and epithelium to seven. These channels are likely to be important for the maintenance of corneal transparency.

\ud Aim: To carry out a detailed morphological study of the cornea of a 16 year old female with a Maroteaux-Lamy syndrome (MLS). \ud \ud Methods: Following a penetrating keratoplasty in July 1999, ultrastructural changes in the cornea were examined using electron microscopy. Proteoglycans were visualised using cuprolinic blue dye; and ßig-h3 and keratan sulphate were detected by immunoelectron microscopy. \ud \ud Results: The epithelial cells were degenerate and contained apoptotic nuclei. Proteoglycans were present in epithelial cells, intercellular spaces, and in swollen desmosomes. An abnormally large quantity of proteoglycans was present throughout the stroma. Keratocytes throughout the stroma had no cell organelles, were vacuolated, and contained a large quantity of abnormal proteoglycans. Labelling for ßig-h3 was intense around electron lucent spaces in stroma. No labelling was seen in keratocytes or endothelial cells. In normal cornea, keratan sulphate labelling was regular throughout the stroma. In MLS VI type B cornea, keratan sulphate labelling was weak in the anterior stroma but very intense in the posterior stroma and in keratocyte lysosomes and vacuoles. \ud \ud Conclusion: A deficiency of aryl sulfatase B results in the deposition of keratan sulphate proteoglycan and other proteoglycans in lysosomes, causing the death of keratocytes and an abnormal build-up of proteoglycans in the stroma. This might be responsible for the lateral aggregation of collagen fibrils and impaired fibrillogenesis in MLS VI. Degenerate swollen keratocytes, together with gross changes in epithelial, stromal, and endothelial cells, would be expected to increase light scattering significantly in these corneas.

Calculations [1] of rheological properties of polymeric solutions have usually been restricted to very dilute o r to very concentrated solutions. In either case, one starts with a model for the micro- structure. Between these two conceptual extremes lies the broad class of moderately concentrated solutions. To cover this region theoretically, two approaches have been used; 1) network theories focusing attention on entanglement junctions, and 2) single-molecule theories focusing attention on single molecules but including inter- molecular interactions. Williams, Wang, and Zimm introduced a double model; one for a particular macromolecule and another for solutions containing like molecules in which the chosen macro- molecule is suspended. This approach has turned out to be quite successful because spheres immersed in a suspension of like spheres behave as i f suspended in a Newtonian fluid, and the resulting ex- pression for viscosity is quite simple in form and qualitatively correct for moderate c...

It is universally accepted that diets rich in fruit and vegetables lead to reduction in the risk of common forms of cancer and are useful in cancer prevention. Indeed edible vegetables and fruits contain a wide variety of phytochemicals with proven antioxidant, anti-carcinogenic, and chemopreventive activity; moreover, some of these phytochemicals also display direct antiproliferative activity towards tumor cells, with the additional advantage of high tolerability and low toxicity. The most important dietary phytochemicals are isothiocyanates, ellagitannins (ET), polyphenols, indoles, flavonoids, retinoids, tocopherols. Among this very wide panel of compounds, ET represent an important class of phytochemicals which are being increasingly investigated for their chemopreventive and anticancer activities. This article reviews the chemistry, the dietary sources, the pharmacokinetics, the evidence on chemopreventive efficacy and the anticancer activity of ET with regard to the most sensitive tumors, as well as the mechanisms underlying their clinically-valuable properties.