Application of a molecular beacon-real-time PCR technology to detect Salmonella species contaminating fruits and vegetables

An oligonucleotide probe that becomes fluorescent upon hybridization to the target DNA (molecular beacon; MB) was evaluated in a real-time polymerase chain reaction (PCR) assay to detect the presence of Salmonella species. As few as 1-4 colony-forming units (CFU) per PCR reaction could be detected. The capability of the assay to detect Salmonella species from artificially inoculated fresh-cut produce such as cantaloupe, mixed-salad, cilantro, and alfalfa sprouts was demonstrated. A comparison of two commercially available kits utilizing MB-PCR (iQ-Check, Bio-Rad Laboratories) and conventional Association of Official Analytical Chemists (AOAC)-approved PCR (BAX, Dupont Qualicon) was performed on artificially inoculated produce. As few as 4 CFU/25 g of produce were detected after 16 h of enrichment in buffered peptone broth. These assays could be carried out entirely in sealed PCR tubes, enabling a rapid and high-throughput detection of Salmonella species in a large number of food and environmental samples. This is the first report of the application of MB probe being used for real-time detection of Salmonella species in whole and fresh-cut fruits and vegetables.     

School-based prevention of depression and anxiety symptoms in early adolescence: A pilot of a parent intervention component.

Previous studies suggest that school-based cognitive-behavioral interventions can reduce and prevent depressive symptoms in youth. This pilot study investigated the effectiveness of a cognitive-behavioral depression prevention program, the Penn Resiliency Program for Children and Adolescents (the PRP-CA), when combined with a parent intervention component. Forty-four middle school students and their parents were randomly assigned to the enhanced PRP (the PRP-CA plus parent program) or control conditions. Students completed measures of depression and anxiety symptoms at baseline and 2 weeks, 6 months, and 1 year after the intervention ended. The combined version of the PRP significantly reduced symptoms of depression and anxiety during the follow-up period. Children assigned to the intervention condition were less likely than controls to report clinical levels of anxiety symptoms. Findings suggest that school-based cognitive-behavioral interventions that include parents may prevent depression and anxiety symptoms in early adolescence. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Influence of strain and fermentation time on the production,composition, and properties of xanthan gum

The objective of this study was to monitor the influence of Xanthomonas spp. and fermentation time on the production, properties, and composition of xanthan gum, verifying how these variables affect the biopolymer synthesis and properties. Three strains were monitored for 168 h of fermentation. Every 24 h, a sample was collected to determine cell growth, gum production, and substrate consumption. Fourier transform infrared, X-ray diffraction, rheology, molecular characterization, thermogravimetric analysis, sugars, and acids analyzes were performed to characterize the gums produced and to identify possible differences in these properties and composition. The results showed the influence of strain and the fermentation time in production (Pr₆₄₅ = 0.047 g L⁻¹ h⁻¹, Pr₂₉₀ = 0.039 g L⁻¹ h⁻¹, Pr₁₁₅₅ = 0.149 g L⁻¹ h⁻¹) and gum quality, since the viscosity was highest in the first 48 h for strains 290 (148.71 MPa s⁻¹) and 645 (135.28 MPa s⁻¹), while for Strain 1155, the maximum value identified for this property was 90.48 MPa s⁻¹. These results are of practical importance, since they allow obtaining better quality xanthan, enabling reduction of production costs. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48557.     

Characterising variances of milk powder and instrumentation for the development of a non-targeted,Raman spectroscopy and chemometrics detection method for the evaluation of authenticity

There is a need to develop rapid tools to screen milk products for economically motivated adulteration. An understanding of the physiochemical variability within skim milk powder (SMP) and non-fat dry milk (NFDM) is the key to establishing the natural differences of these commodities prior to the development of non-targeted detection methods. This study explored the sources of variance in 71 commercial SMP and NFDM samples using Raman spectroscopy and principal component analysis (PCA) and characterised the largest number of commercial milk powders acquired from a broad number of international manufacturers. Spectral pre-processing using a gap-segment derivative transformation (gap size = 5, segment width = 9, fourth derivative) in combination with sample normalisation was necessary to reduce the fluorescence background of the milk powder samples. PC scores plots revealed no clear trends for various parameters, including day of analysis, powder type, supplier and processing temperatures, while the largest variance was due to irreproducibility in sample positioning. Significant chemical sources of variances were explained by using the spectral features in the PC loadings plots where four samples from the same manufacturer were determined to likely contain an additional component or lactose anomers, and one additional sample was identified as an outlier and likely containing an adulterant or differing quality components. The variance study discussed herein with this large, diverse set of milk powders holds promise for future use as a non-targeted screening method that could be applied to commercial milk powders.     

Correction to Frazier et al. (2011).

Reports an error in "Perceived past, present, and future control and adjustment to stressful life events" by Patricia Frazier, Nora Keenan, Samantha Anders, Sulani Perera, Sandra Shallcross and Samuel Hintz (Journal of Personality and Social Psychology, Vol 100[4], 749-765). There is an error on page 758. In the sentence “Present control predicted later event-specific distress in Sample 1(β = .17, p 2011-02001-001.) Perceived control is a central construct in psychology and is key to understanding individual differences in poststress outcomes (Frazier, Berman, & Steward, 2001). The goals of the current studies (using 4 samples of undergraduate students, total N = 1,421) were to examine the relations between different aspects of perceived control and poststress outcomes and to differentiate perceived control over specific events from related constructs (i.e., general control beliefs, coping strategies). To accomplish these goals, we first developed a new measure of perceived past, present, and future control over stressful life events. The data supported the content validity, factor structure, internal consistency and test–retest reliability, and convergent and discriminant validity of the new measure. Consistent with the temporal model of control (Frazier et al., 2001), these 3 forms of control had very different relations with adjustment. Present control was consistently related to lower distress levels in cross-sectional, longitudinal, and prospective analyses. Present control also predicted outcomes beyond the effects of general control beliefs and coping strategies. Past and future control had nonsignificant or positive relations with distress, although future control was associated with better outcomes (i.e., course grades) when the stressor was controllable. Thus, our measure can be used to assess the relations between perceived past, present, and future control and outcomes across a range of stressors. Because the relations between these 3 forms of control and outcomes differ markedly, measures that combine these aspects of control hinder the understanding of the important role of perceived control in adjustment to stress. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Asymmetric Transfer Hydrogenation of Ketones Using New Iron(II) (P-NH-N-P′) Catalysts: Changing the Steric and Electronic Properties at Phosphorus P′

The asymmetric transfer hydrogenation (ATH) of ketones is an efficient method for producing enantio-enriched alcohols which are used as intermediates in a variety of industrial processes. Here we report the synthesis of new iron ATH precatalysts (S,S)-[FeBr(CO)(Ph₂PCH₂CH₂NHCHPhCHPhNC=CHCH₂PR′₂)][BPh₄] (R′=Et, and ortho-tolyl (o-Tol)) where one of the phosphine groups is modified with small alkyl and large aryl substituents to probe the effect of this change on the activity and selectivity of the catalytic system. A simple reversible equilibrium kinetic model is used to obtain the initial TOF and the inherent enantioselectivity S=k_R/k_S of these catalysts along with those for the previously reported catalysts with R′=Ph and Cy for the ATH of acetophenone. With an increase in the size of the PR′₂ group, the TOF goes through a maximum at PPh₂ while the S value goes through a maximum of 510 at R′=Cy. The complex with R′=o-Tol starts with a high S value of 200 but is rapidly changed to a second catalyst with an S value of 28. For the reduction of acetophenone to (R)-1-phenylethanol, turnover numbers of up to 5200 and ee up to 98 % were achieved. The chemotherapeutic pharmaceutical precursor (R)-(3′,5′-bis(trifluoromethyl))-1-phenylethanol is synthesized in up to 95 % ee. Several other alcohols can be prepared in greater than 90 % ee by choosing the precatalyst with the correctly matched steric properties. A hydride complex derived from the catalyst with R′=Cy is characterized by NMR spectroscopy. It is proposed that low concentration trans-hydride carbonyl complexes with the FeH parallel to the NH of the ligand are the active catalysts in all of these systems.     

Changes induced by high hydrostatic pressure in acidified and non-acidified milk during Oaxaca cheese production

Oaxaca cheese, produced using the pasta filata method, is a very popular Mexican dairy products. In this work, the effect of high hydrostatic pressure (HHP) and the acidification process before and after HHP treatment of raw cow milk was studied at different pressure levels (150, 300 and 500 MPa) and holding times (10 and 30 min). Clotting time, proximal composition, microstructure, secondary protein structure and electrophoretic profile were evaluated. HHP did not influence clotting time in samples acidified before HHP, but it appears to have a positive effect at lower pressure treatments on non-acidified milk. Moisture, protein and fat were similar in cheeses treated at most HHP conditions regardless of the acidification. HHP did not influence the microstructure of cheese and the secondary structure of proteins. The use of HHP during the manufacture of Oaxaca cheese allowed preserving quality parameters evaluated without advantages in processing time and the product's proximal composition.     

Biopolymers for Antitumor Implantable Drug Delivery Systems: Recent Advances and Future Outlook

In spite of remarkable improvements in cancer treatments and survivorship, cancer still remains as one of the major causes of death worldwide. Although current standards of care provide encouraging results, they still cause severe systemic toxicity and also fail in preventing recurrence of the disease. In order to address these issues, biomaterial‐based implantable drug delivery systems (DDSs) have emerged as promising therapeutic platforms, which allow local administration of drugs directly to the tumor site. Owing to the unique properties of biopolymers, they have been used in a variety of ways to institute biodegradable implantable DDSs that exert precise spatiotemporal control over the release of therapeutic drug. Here, the most recent advances in biopolymer‐based DDSs for suppressing tumor growth and preventing tumor recurrence are reviewed. Novel emerging biopolymers as well as cutting‐edge polymeric microdevices deployed as implantable antitumor DDSs are discussed. Finally, a review of a new therapeutic modality within the field, which is based on implantable biopolymeric DDSs, is given.