Differentiation of Mechanically and Chemically Extracted Hazelnut Oils Based on their Sterol and Wax Profiles

The sterol and wax content of solvent extracted (SEHO) and cold pressed hazelnut oils (CPHO) were compared. A total of 48 samples from 19 hazelnut varieties were collected for two successive crop years from four different geographical districts in Turkey. Hazelnuts were processed to oil with a laboratory scale press, than the remaining oil in cake was extracted with n‐hexane. CPHO and SEHO were evaluated for their wax, sterol and squalene contents. Results showed that sterol, squalene and wax contents of all individual cultivars were higher in SEHO than those of CPHO, indicating the higher solubility of these compounds in solvent. Total sterol contents ranged between 1088.56 (Kargalak)—1609.39 mg/kg (Mincane) for CPHO and 1590.86 (Çak?ldak)—2897.26 mg/kg (Mincane) for SEHO. Hazelnut oils were found to be richer of C36‐38 esters than C40‐46 group. Total wax content was between 24.19 (Kargalak)—94.58 mg/kg (Ku?) for CPHO and 81.46 (Kargalak)—160.92 mg/kg (Akçakoca) for SEHO. The squalene amounts of the samples obtained by hexane extraction were between 499.75 (Allahverdi)—885.36 mg/kg (Cavcava), while it varied between 288.55 (Kargalak)—647.68 mg/kg (Mincane) in cold pressed oils. Significant and obvious variations between SEHO and CPHO were verified by principal component and hierarchical cluster analysis. Geographical discrimination was also achieved by discriminant analysis.     

MXene Materials for Designing Advanced Separation Membranes

MXenes are emerging rapidly as a new family of multifunctional nanomaterials with prospective applications rivaling that of graphenes. Herein, a timely account of the design and performance evaluation of MXene-based membranes is provided. First, the preparation and physicochemical characteristics of MXenes are outlined, with a focus on exfoliation, dispersion stability, and processability, which are crucial factors for membrane fabrication. Then, different formats of MXene-based membranes in the literature are introduced, comprising pristine or intercalated nanolaminates and polymer-based nanocomposites. Next, the major membrane processes so far pursued by MXenes are evaluated, covering gas separation, wastewater treatment, desalination, and organic solvent purification. The potential utility of MXenes in phase inversion and interfacial polymerization, as well as layer-by-layer assembly for the preparation of nanocomposite membranes, is also critically discussed. Looking forward, exploiting the high electrical conductivity and catalytic activity of certain MXenes is put into perspective for niche applications that are not easily achievable by other nanomaterials. Furthermore, the benefits of simulation/modeling approaches for designing MXene-based membranes are exemplified. Overall, critical insights are provided for materials science and membrane communities to navigate better while exploring the potential of MXenes for developing advanced separation membranes.     

2-D DOA estimation in case of unknown mutual coupling for multipath signals

In this paper, two dimensional (2-D) direction-of-arrival (DOA) estimation problem in case of unknown mutual coupling and multipath signals is investigated for antenna arrays. A new technique is proposed which uses a special array structure consisting of parallel uniform linear array (PULA). PULA structure is complemented with auxiliary antennas in order to have a structured mutual coupling matrix (MCM). MCM has a symmetric banded Toeplitz structure which allows the application of the ESPRIT algorithm for 2-D paired DOA estimation. The advantage of the PULA structure is exploited by dividing it into overlapping linear sub-arrays (triplets) and spatial smoothing is employed to mitigate multipath signals. Closed form expressions are presented for search-free, paired and unambiguous 2-D DOA estimation. Two algorithms PULA-1 and PULA-2 are proposed to effectively solve the problem. Several simulations are done and the accuracy of the proposed solution is shown.     

Luteinization of porcine preovulatory follicles leads to systematic changes in follicular gene expression

The LH surge initiates the luteinization of preovulatory follicles and causes hormonal and structural changes that ultimately lead to ovulation and the formation of corpora lutea. The objective of the study was to examine gene expression in ovarian follicles (n = 11) collected from pigs (Sus scrofa domestica) approaching estrus (estrogenic preovulatory follicle; n = 6 follicles from two sows) and in ovarian follicles collected from pigs on the second day of estrus (preovulatory follicles that were luteinized but had not ovulated; n = 5 follicles from two sows). The follicular status within each follicle was confirmed by follicular fluid analyses of estradiol and progesterone ratios. Microarrays were made from expressed sequence tags that were isolated from cDNA libraries of porcine ovary. Gene expression was measured by hybridization of fluorescently labeled cDNA (preovulatory estrogenic or -luteinized) to the microarray. Microarray analyses detected 107 and 43 genes whose expression was decreased or increased (respectively) during the transition from preovulatory estrogenic to -luteinized (P<0.01). Cells within preovulatory estrogenic follicles had a gene-expression profile of proliferative and metabolically active cells that were responding to oxidative stress. Cells within preovulatory luteinized follicles had a gene-expression profile of nonproliferative and migratory cells with angiogenic properties. Approximately, 40% of the discovered genes had unknown function.