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There is a need for updated survey literature collected from correctional mental health professionals working within prison settings. Up to date research can add to the literature addressing the best practices for mental health treatment of the transgender incarcerated population in order to provide health care professionals and correctional staff with more effective, efficient, and widely understood intervention practices to facilitate the well‐being and safety of this population. Guided by three research aims, 50 mental health professionals from 21 states throughout the United States were surveyed in this quantitative survey regarding their work with the transgender incarcerated population. Results are discussed in terms of implications for the type of care and coordination of care provided by correctional mental health professionals. [ABSTRACT FROM AUTHOR]

Coordination of enzymatic activities in the course of base excision repair (BER) is essential to ensure complete repair of damaged bases. Two major mechanisms underlying the coordination of BER are known today: the "passing the baton" model and a model of preassembled stable multiprotein repair complexes called "repairosomes." In this work, we aimed to elucidate the coordination between human apurinic/apyrimidinic (AP) endonuclease APE1 and DNA polymerase Polβ in BER through studying an impact of APE1 on Polβ-catalyzed nucleotide incorporation into different model substrates that mimic different single-strand break (SSB) intermediates arising along the BER pathway. It was found that APE1's impact on separate stages of Polβ′s catalysis depends on the nature of a DNA substrate. In this complex, APE1 removed 3′ blocking groups and corrected Polβ-catalyzed DNA synthesis in a coordinated manner. Our findings support the hypothesis that Polβ not only can displace APE1 from damaged DNA within the "passing the baton" model but also performs the gap-filling reaction in the ternary complex with APE1 according to the "repairosome" model. Taken together, our results provide new insights into coordination between APE1 and Polβ during the BER process. • APE1 affects the different steps of Polβ nucleotide incorporation into DNA. • APE1's impact on Polβ′s catalysis depends on nature of DNA substrate. • Effect of APE1 on Polβ realized by formation of ternary APE1-Polβ-DNA complex. [ABSTRACT FROM AUTHOR]

Base excision repair (BER) is one of the important systems for the maintenance of genome stability via repair of DNA lesions. BER is a multistep process involving a number of enzymes, including damage-specific DNA glycosylases, apurinic/apyrimidinic (AP) endonuclease 1, DNA polymerase β, and DNA ligase. Coordination of BER is implemented by multiple protein–protein interactions between BER participants. Nonetheless, mechanisms of these interactions and their roles in the BER coordination are poorly understood. Here, we report a study on Polβ's nucleotidyl transferase activity toward different DNA substrates (that mimic DNA intermediates arising during BER) in the presence of various DNA glycosylases (AAG, OGG1, NTHL1, MBD4, UNG, or SMUG1) using rapid-quench-flow and stopped-flow fluorescence approaches. It was shown that Polβ efficiently adds a single nucleotide into different types of single-strand breaks either with or without a 5′-dRP–mimicking group. The obtained data indicate that DNA glycosylases AAG, OGG1, NTHL1, MBD4, UNG, and SMUG1, but not NEIL1, enhance Polβ's activity toward the model DNA intermediates. [ABSTRACT FROM AUTHOR]

The human N-glycosylases SMUG1 and MBD4 catalyze the removal of uracil residues from DNA resulting from cytosine deamination or replication errors. For polymorphic variants of SMUG1 (G90C, P240H, N244S, N248Y) and the MBD4cat catalytic domain (S470L, G507S, R512W, H557D), the structures of enzyme-substrate complexes were obtained by molecular dynamic simulation. It was experimentally found that the SNP variants of SMUG1, N244S and N248Y, had increased catalytic activity compared to the wild-type enzyme, probably due to the acceleration of the dissociation of the enzyme–product complex and an increase in the enzyme turnover rate. All other SNP variants of SMUG1 (G90C, P240H) and MBD4cat, in which amino acid substitutions disrupted the substrate binding region and/or active site, had significantly lower catalytic activity than the wild-type enzymes. [ABSTRACT FROM AUTHOR]

When light is incident upon a diffraction grating, images of the grating appear at periodic intervals behind the grating. This phenomenon and the associated self-imaging distance were named after Talbot, who first observed them in the nineteenth century. A century later, this effect held new surprises with the discovery of sub-images at regular fractional distances of the Talbot length. In this paper, we show that water waves enable one to observe the Talbot effect in a classroom experiment. Quantitative measurements, of for example the Talbot distances, can be performed with an easy-to-use digital Schlieren method. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to investigate the effects of regulation of nutritional habits on quality of life by applying Short Form (SF-36) Quality of Life Scale.Methods: SF-36 was administered through face-to-face interviews to a total of 129 individuals (112 female, 17 male) aged 18-65 years. Anthropometric measurements, body mass index, and waist circumference measurement were undertaken simultaneously. The changes in weight, body mass index, waist circumference measurement, and SF-36 scores were compared at baseline and three months after modification of dietary habits.Results: At three months after the regulation of dietary habits, a statistically significant decrease was found in weight, body mass index, and waist circumference measurements (p<0.05). Overall improvement was observed in all the quality of life parameters assessed with SF-36, and among them, the sub-scales of general health, bodily pain and vitality were statistically significant (p<0.05). The improvement in these sub-scale scores was similar to the literature.Conclusion: The individuals who lost weight through adopting healthy dietary habits had increased SF-36 scores, indicating the positive effect of regulating diet on their quality of life. [ABSTRACT FROM AUTHOR]

The effect of quantum collapse and revival is a fascinating interference phenomenon. In this paper the phenomenon is studied analytically and numerically for a simple system, a slightly anharmonic oscillator. The initial wave-function corresponds to a displaced ground state of a harmonic oscillator. Possible experimental realizations for cold atoms are discussed in detail. [ABSTRACT FROM AUTHOR]

The base excision repair (BER) pathway involves sequential action of DNA glycosylases and apurinic/apyrimidinic (AP) endonucleases to incise damaged DNA and prepare DNA termini for incorporation of a correct nucleotide by DNA polymerases. It has been suggested that the enzymatic steps in BER include recognition of a product–enzyme complex by the next enzyme in the pathway, resulting in the "passing-the-baton" model of transfer of DNA intermediates between enzymes. To verify this model, in this work, we aimed to create a suitable experimental system. We prepared APE1 site-specifically labeled with a fluorescent reporter that is sensitive to stages of APE1–DNA binding, of formation of the catalytic complex, and of subsequent dissociation of the enzyme–product complex. Interactions of the labeled APE1 with various model DNA substrates (containing an abasic site) of varied lengths revealed that the enzyme remains mostly in complex with the DNA product. By means of the fluorescently labeled APE1 in combination with a stopped-flow fluorescence assay, it was found that Polβ stimulates both i) APE1 binding to an abasic-site–containing DNA duplex with the formation of a catalytically competent complex and ii) the dissociation of APE1 from its product. These findings confirm DNA-mediated coordination of APE1 and Polβ activities and suggest that Polβ is the key trigger of the DNA transfer between the enzymes participating in initial steps of BER. • Interaction of fluorescently labeled APE1 with damaged DNA and Polβ was analyzed. • Labeled APE1 was sensitive to DNA binding, catalysis and release of cleaved product. • DNA-mediated coordination of APE1 and Polβ activities was analyzed by stopped-flow assay. • Polβ stimulates both APE1 binding to abasic DNA and its dissociation from product. [ABSTRACT FROM AUTHOR]

Human apurinic/apyrimidinic endonuclease APE1 catalyzes endonucleolytic hydrolysis of phosphodiester bonds on the 5′ side of structurally unrelated damaged nucleotides in DNA or native nucleotides in RNA. APE1 additionally possesses 3′-5′-exonuclease, 3′-phosphodiesterase, and 3′-phosphatase activities. According to structural data, endo- and exonucleolytic cleavage of DNA is executed in different complexes when the excised residue is everted from the duplex or placed within the intrahelical DNA cavity without nucleotide flipping. In this study, we investigated the functions of residues Arg177, Arg181, Tyr171 and His309 in the APE1 endo- and exonucleolytic reactions. The interaction between residues Arg177 and Met270, which was hypothesized recently to be a switch for endo- and exonucleolytic catalytic mode regulation, was verified by pre–steady-state kinetic analysis of the R177A APE1 mutant. The function of another DNA-binding–site residue, Arg181, was analyzed too; it changed its conformation when enzyme–substrate and enzyme–product complexes were compared. Mutation R181A significantly facilitated the product dissociation stage and only weakly affected DNA-binding affinity. Moreover, R181A reduced the catalytic rate constant severalfold due to a loss of contact with a phosphate group. Finally, the protonation/deprotonation state of residues Tyr171 and His309 in the catalytic reaction was verified by their substitution. Mutations Y171F and H309A inhibited the chemical step of the AP endonucleolytic reaction by several orders of magnitude with retention of capacity for (2 R ,3 S)-2-(hydroxymethyl)-3-hydroxytetrahydrofuran-containing-DNA binding and without changes in the pH dependence profile of AP endonuclease activity, indicating that deprotonation of these residues is likely not important for the catalytic reaction. • Endo- and exonuclease cleavage of a DNA by mutant forms of human APE1 was analyzed. • Process of protein-substrate interaction was analyzed by pre-steady state kinetics. • Conformational changes in APE1 and substrates were observed during their interactions. • The role of certain important amino acids during enzyme pathway was specified. [ABSTRACT FROM AUTHOR]

The quantum fidelity was introduced by Peres to study some fingerprints of classically chaotic behavior in the quantum dynamics of the corresponding systems. In the present paper the signatures of classical dynamics near elliptic points and of interactions between particles are characterized for kicked systems. In particular, the period of the fidelity resulting of the interactions is found using analytical and numerical calculations. A mechanism leading to the oscillations with the intermediate period is proposed. It is of a classical origin and results of the interplay between the oscillations of the width of the wave packets and the rotation of their center around the elliptic fixed point. [ABSTRACT FROM AUTHOR]

Abstract: A spectrophotometric assay for plasmin and plasminogen-derived activity in dairy products was optimised and extended to determine plasmin and plasminogen-derived activity in turbid samples of dairy products. The method was validated by assessing reproducibility, repeatability, level of detection and recovery of plasmin activity in different sample matrices. Plasmin activity in raw milk was not affected by skimming, but decreased by 30% in pasteurised and homogenised whole milk, leading to an underestimation of plasmin activity. The effects of dissociation of plasmin and caseins by ε-aminocaproic acid (EACA) plus NaCl on the plasmin activity were investigated. Comparison of pasteurised milk with a micellar casein solution showed that the dissociation of plasmin and caseins on adding EACA and NaCl decreases interference by caseins, but increases inhibition of plasmin with serum-based inhibitory components. The level of detection and repeatability of this method for plasmin activity analysis were improved compared with previous spectrophotometric assays. [Copyright &y& Elsevier]

The paper concentrates on improving the efficiency of the pumping system in which pumps are run by variable speed drives. The method is applicable to system consisting of several centrifugal pumps. Problems arising from running the pumps outside the optimal efficiency region are discussed. Common principles of operation and control of typical boosting pumping station are represented. Methods of regulation of productivity of the system are described. The proposed method is based on prediction of future efficiency of pumps before making adjustments of pumping system productivity. The proposed method is basing on tracking the working point of pump on efficiency graph. Monitoring the location of working point vs. efficiency graph enables to evaluate its current and future distances from the best efficiency point of the pump. Knowing the current number of running pumps it is possible to predict the location of working point after adjustment of productivity of the system. Ability to predict the increase or decrease of efficiency enables to enhance the adjustment of productivity of the system. Methods of graphical analysis of working state of the pumping system are representing topic for future research. [ABSTRACT FROM AUTHOR]

Zinc finger proteins that bind Zn(II) using a Cys2His2 coordination motif within a ββα protein fold are the most abundant DNA binding transcription factor domains in eukaryotic systems. These classic zinc fingers are typically unfolded in the apo state and spontaneously fold into their functional ββα folds upon incorporation of Zn(II). These metal-induced protein folding events obscure the free energy cost of protein folding by coupling the protein folding and metal-ion binding thermodynamics. Herein, we determine the formation constant of a Cys2His2/ββα zinc finger domain, the C-terminal finger of the Wilms' tumor suppressor protein (WT1-4), for the purposes of determining its free energy cost of protein folding. Measurements of individual conditional dissociation constants, Kd values, at pH values from 5 to 9 were determined using fluorescence spectroscopy by direct or competition titration. Potentiometric titrations of apo-WT1-4 followed by NMR spectroscopy provided the intrinsic pKa values of the Cys2His2 residues, and corresponding potentiometric titrations of Zn(II)-WT1-4 followed by fluorescence spectroscopy yielded the effective pKaeff values of the Cys2His2 ligands bound to Zn(II). The Kd, pKa, and pKaeff values were combined in a minimal, complete equilibrium model to yield the pH-independent formation constant value for Zn(II)-WT1-4, KfML value of 7.5 × 1012 M-1, with a limiting Kd value of 133 fM. This shows that Zn(II) binding to the Cys2His2 site in WT1-4 provides at least -17.6 kcal/mol in driving force to fold the protein scaffold. A comparison of the conditional dissociation constants of Zn(II)-WT1-4 to those from the model peptide Zn(II)-GGG-Cys2His2 over the pH range 5.0 to 9.0 and a comparison of their pH-independent KfML values demonstrates that the free energy cost of protein folding in WT1-4 is less than +2.1 kcal/mol. These results validate our GGG model system for determining the cost of protein folding in natural zinc finger proteins and support the conclusion that the cost of protein folding in most zinc finger proteins is =+4.2 kcal/mol, a value that pales in comparison to the free energy contribution of Zn(II) binding, -17.6 kcal/mol. [ABSTRACT FROM AUTHOR]

Speed inaccuracy decreases the pump efficiency, reliability, and energy saving. This research is devoted to the determination of the ways of accurate speed control of the pump drives operated under changeable loads. The impact of speed inaccuracy on the pump performance is studied. Based on the analysis of methods for the static accuracy improvement, the drawbacks of the traditional approaches have been shown with reference to the pumping applications. A new methodology of the slip compensation has been proposed for implementation to improve the scalar drive performance. It notably decreases the speed inaccuracy of the open-ended pumping applications. The enhanced quality of the drive control at different loading conditions has been shown on a laboratory test bench. Also, for the multi-pump systems this approach results in an additional benefit from the viewpoint of the operation around the best operation point providing a safe pump control both to exclude the pump damage and to improve the process quality. [ABSTRACT FROM AUTHOR]

Objectives: Varying levels of evidence exist for the contribution of indoor air pollution and environmental tobacco smoke as a risk factor for tuberculosis (TB). Despite a similar mechanism of action, the influence of outdoor air pollution exposure as an independent contributor to TB disease has yet to be explored. This area of inquiry is of increasing importance given the level of pollution in the rising economies of many TB-endemic nations. Los Angeles' unique physical environs and traffic patterns mirror other global megacities with a greater burden of TB therefore allowing for preliminary correlative studies. This preliminary study hypothesizes that individuals who reside proximal to elevated pollutant exposures are likely to have a greater burden of disease -- as evidenced by sputum smear-positive TB. Study design: Retrospective medical records review. Methods: Medical records of non-homeless individuals (n = 196) diagnosed with culture positive TB at Los Angeles County and University of Southern California Medical Center Hospital were analyzed from January 2007 to December 2008. The study population was grouped according to acid-fast bacilli (AFB) smear-positive (n = 111) and smear-negative (n = 85) status. Air pollutant exposure was captured using measurements of ozone (03) and particulate matter with an aerodynamic diameter of less than 2.5 (PM2.5). Individual assignment to O3 and PM2.5 exposures were based on residential proximity to the nearest US Environmental Protection Agency's monitoring station. Proximity of home residences to traffic-related pollutants occurred by measurement of distance to the nearest freeway and major non-freeway road. Results: Single factorial models yielded a significant correlation of smear-positive status and residential exposure to PM2.5 Residential distance to freeways and major arterial roads did not yield an association. Conclusions: This is the first report linking ambient pollution exposure as a risk factor for TB. PM2.5 may have the potential to impact TB lung pathology as evidenced by the linkage of fine particulate matter levels and smear-positive TB. [ABSTRACT FROM AUTHOR]

In her interview with Kurt R. Eissler, Joan Riviere talked about her analysis with Freud and her translation of his writings. Other subjects covered were her discovery of Melanie Klein's work, the question of Freud's technique, her relationship with Anna Freud, in particular, her views on child analysis. With her well-known severity, Riviere assessed Freud as an analyst. She provided a testimony of his approach to training analyses. [ABSTRACT FROM AUTHOR]

The effect of proteolysis on oxidation in low-fat cheese was investigated. The accumulation of dityrosine during storage increased significantly in the cheese with a high degree of proteolysis, while hexanal and heptanal were lower in the cheese with high proteolytic activity, indicating that the peptides/free amino acids acted as antioxidants on the propagating step in lipid oxidation. Dimethyl disulphide concentration was also lower in the cheese with a higher level of peptides. Therefore, oxidation of tyrosine residues seemed to function as antioxidants both regarding secondary lipid oxidation products and protein-derived oxidation products through formation of dityrosine, being a termination reaction. [ABSTRACT FROM AUTHOR]

Transfer pipelines are developed for the supply of feedstock from a furnace to a fractionating tower. A feature of the development is absence of temperature compensators and preliminary loading of pipelines. In order to monitor stresses that may arise in the area of pipeline setting into a K-11 tower, and their movement, a comprehensive diagnostic monitoring system has been developed with the possibility of remote control, inspection and analysis of the monitored parameters. [ABSTRACT FROM AUTHOR]

Pancreatic duct stent placement is increasingly performed for the prevention of pancreatitis after endoscopic retrograde cholangiopancreatography (ERCP); however stents can result in injury especially in normal ducts. The clinical significance and outcomes of subsequent endoscopic therapy are unknown. This study was a retrospective review of the management of symptomatic stent-induced pancreatic duct injury following stent placement for prevention of post-ERCP pancreatitis in eight patients with previously normal pancreatic ducts. Subsequent treatment included pancreatic sphincterotomy, balloon dilation of stricture, and placement of multiple 3?-?5-Fr soft polymer pancreatic stents. All patients showed improvement or resolution of pancreatic strictures. Five patients had resolution or substantial improvement of pain, one patient showed a fair response with repeated ERCPs, and two patients failed to respond and underwent total pancreatectomy with islet autotransplantation. Pancreatic duct stent-induced ductal injury with significant clinical consequences can occur with conventional polyethylene stents. Endoscopic therapy is moderately effective but some patients develop irreversible damage. Caution should be used when placing standard polyethylene stents in normal ducts. Further research is required to identify safer materials and configurations of pancreatic stents. [ABSTRACT FROM AUTHOR]

Abstract: During the rapid filling phase of the heart cycle, the internal volumes of the two ventricular cavities approximately double, while the intraventricular pressures rise typically only by an amount of less than 1kPa. Such a small pressure increase cannot be the sole driving mechanism for the large inflow of blood associated with ventricular expansion during this period. Instead, the rapid filling phase is to be interpreted as being mediated primarily by the heart recoiling elastically from its contracted state, causing blood to be aspirated rapidly into the ventricles. In order to study the role of this mechanism, elastic finite element (FE) simulations of ventricular expansion were performed, taking into account the large deformations occurring during this period and the effective compressibility of the myocardium due to intramural fluid flow. Thereby, a realistic three-dimensional geometry derived from magnetic resonance imaging (MRI) measurements of both human ventricles was used. To validate our FE analyses, the results were compared with published measurements relating to the rapid filling phase of the human left ventricle. Our study shows that, under normal physiological conditions, ventricular aspiration plays a key role in the ventricular filling process. [Copyright &y& Elsevier]

The psychoanalyst Joan Riviere (1883–1962), who came from an established family, was one of the first to translate Freud in Britain. After a failed analysis with Ernest Jones, she became Freud's patient in 1922. Freud recognized her talent and entrusted her with translations of his works. Over her head, he negotiated her position as Translation Editor of the International Journal with Jones and secured her nomination against his resistance. Some examples are given to demonstrate the special quality of Riviere's translations of Freud's writings. [ABSTRACT FROM AUTHOR]

The article discusses the study which examines the impact of preoperative endoscopic ultrasound (EUS) on non-small cell lung cancer staging. It aims to determine if the addition of preoperative endoscopic ultrasound to non-small cell lung cancer staging can reduce the proportion of patients in whom malignant mediastinal lymph nodes were discovered at surgery. The study found that preoperative EUS helps reduce the unnecessary surgery for lung cancer patients.

Abstract: During the rapid diastolic filling phase at rest, the ventricles of the human heart double approximately in volume. In order to investigate whether the ventricular filling pressures measured under physiological conditions can give rise to such an extensive augmentation in ventricular volumes, a finite element model of the human right and left ventricles has been developed, taking into account the nonlinear mechanical behavior and effective compressibility of the myocardial tissue. The results were compared with the filling phase of the human left ventricle as extrapolated from measurements documented in the literature. We arrived at the conclusion that the ventricular pressures measured during the rapid filling phase cannot be the sole cause of the rise of the observed ventricular volumes. We rather advocate the assumption that further dilating mechanisms might be part of ventricular activity thus heralding a multiple function of the ventricular muscle body. A further result indicates that under normal conditions the influence of the viscoelasticity of the tissue should not be disregarded in ventricular mechanics. [Copyright &y& Elsevier]

We report the repair of a giant hiatal hernia by laparoscopic Collis gastroplasty and Nissen fundoplication in a patient with situs inversus totalis, highlighting the unique anatomic challenges in this case. The 52-year old female patient had Kartageners syndrome, a giant hiatal hernia, and a history of chronic severe gastroesophageal reflux disease with uncontrolled regurgitation. The laparoscopic procedure was accomplished with five ports placed in a mirror-image configuration, reversed from our standard positions. After visual confirmation of the complete reversal of the intraabdominal anatomy, we performed a modified Collis gastroplasty and Nissen fundoplication. Significant technical challenges were encountered intraoperatively. To the best of our knowledge, this report is the first of its kind in the literature. The use of advanced laparoscopic techniques is highly adaptable to unusual anatomy. Laparoscopic hiatal hernia surgery is feasible in patients with situs inversus. [ABSTRACT FROM AUTHOR]

Two new methods are proposed for determining the polarization of vacuum ultraviolet radiation which permit the determination of an arbitrary polarization mode for photons with energies of 10–100 eV. The essence of these methods is to create and detect a nonequilibrium population of the magnetic sublevels of atoms and molecules excited by the original VUV radiation and then determine the polarization of this radiation based on these measurements in accordance with known formulas. © 1999 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Objective: The aim of the present study is to investigate the change in emotional/behavioral problems of children with autism spectrum disorder (ASD) and the perceived social support of parents during the coronavirus disease 2019 (COVID-19) pandemic. Methods: A total of 51 children with ASD aged between 6 and 18 years took part in the study. The Aberrant Behavior Checklist (ABC), the Strengths and Difficulties Questionnaire (SDQ), and the Multidimensional Scale of Perceived Social Support (MSPSS) were used to evaluate ASD symptoms, emotional/behavioral problems, and perceived social support, respectively. The cases were assessed before and 6 months after the pandemic. Results: Our findings indicated that after the onset of the pandemic hyperactivity scores of children with ASD increased, whereas perceived social support of their parents decreased, compared to their pre-pandemic levels (P-value < .05). The increase in hyperactivity and irritability levels among children were positively associated with the presence of a chronic illness in the family and medication discontinuation (P-value < .05). Conclusion: Quarantine in the COVID-19 pandemic may cause or worsen behavioral problems among children with ASD possibly due to problems related to poor medication adherence and lowered perceived social support among their parents. Clinicians working with children with special needs may be pro-active to assess and manage emotional/behavioral problems among this special population particularly during difficult times such as pandemic. [ABSTRACT FROM AUTHOR]

Edge localization is a fascinating quantum phenomenon. In this paper, the underlying mechanism generating it is presented analytically and verified numerically for a weakly kicked three-dimensional rotor. We expand the eigenstates of the one-kick propagator of the kicked rotor in the basis of the free rotor eigenstates, which are defined by the quantum number of angular momentum. Since this quantum number must be non-negative, there is an edge near zero angular momentum, and an edge state is created. Analogy to tight binding model in solid state physics is used. [ABSTRACT FROM AUTHOR]

The article presents a case study of Focal fibrocartilaginous dysplasia (FFCD) in a 15 month old baby-girl. Plain radiography images showing medial concave bowing of the left tibia and an MRI showing characteristic lucency in the medial cortex, which is an uncommon lesion that effects the tibia in children under 2 years are presented.

Milk gels (acid or rennet) are used by dairy industry to produce dairy products such as yogurt and cheese. Enrichment of milk with calcium salts and heat treatment are known to produce 'calcium-milk coagulum' as a new type of milk gels, due to reduction of milk protein charges through calcium binding. The combination of heat treatment and calcium addition to milk results in gel structures, but the effect of calcium addition and pH adjustment during heating of milk is still unclear. The role of added calcium and decreasing pH were investigated by addition of calcium chloride (30 mM) to reconstituted skim milk followed by pH adjustment by hydrochloric acid and sodium hydroxide (4.6 < pH < 6.6 investigated), followed by heating at 90 °C for 10 min and overnight storage at 22 °C. In parallel, samples with no addition of calcium chloride were produced under the same conditions. The time and temperature to reach the gelation point, as detected by dynamic measurements of storage modulus (G′), were decreasing as pH decreased without addition of calcium, while calcium addition made gelation time and temperature independent of pH except for pH 4.6. Heat treatment combined with calcium addition was found, using confocal laser microscopy, to provide a fine and dense gel structure for skim milk with higher pH, while at pH lower than 5.6, the gel structure was similar to the structure of acid-induced gels. The last observation helps to establish a pH limit for production of calcium gels. [ABSTRACT FROM AUTHOR]

The initial stage of the Maillard reaction, protein lactosylation, occurs during heat treatment of milk and continues during subsequent storage. We compared the initial lactosylation as well as the rate of lactosylation of milk proteins during storage in UHT milk subjected to direct or indirect heat treatment using liquid chromatography ( LC) coupled with electrospray injection mass spectrometry ( ESI- MS). Furosine content was used as an overall marker to allow for a quantitative correlation of lactosylation measured by LC- ESI- MS in the UHT milks. Protein lactosylation increased during the storage period of 6 months at 20 °C. Both the initial extent and the rate of lactosylation positively correlated with the number of lysine residues in the different proteins. An exponential or linear correlation with furosine concentration could be established for major and minor lactosylated proteins, respectively. [ABSTRACT FROM AUTHOR]

The effect of enzymatic activity in direct steam infusion heat treated milk with ultra-short holding times (>150 °C for <0.2 s) on age gelation during storage was investigated. Preheating at either 72 or 95 °C for 180 s was performed. Milk pre-heated at 72 °C showed extensive proteolysis and exhibited bitter off flavour and contained <40% intact αS- and β-caseins after 6 weeks storage at 20 °C. No proteolysis of κ-casein was detected. Plasmin was identified as active protease and activation of plasminogen was observed as an increase in the rate of casein hydrolysis. Proteolysis in the stored samples correlated with a decrease in pH and with changes in colour. Gelation occurred after 10 weeks along with an increase in viscosity and extensive proteolysis of αS- and β-caseins. In conclusion, plasmin activity was involved in age gelation and bitterness caused by proteolysis was the shelf-life limiting factor. [ABSTRACT FROM AUTHOR]

The paper describes a study on the variation of coagulation properties in individual cow's milk measured by a novel free oscillation rheometry-based method. The work is part of a study on the occurrence and underlying causes of poorly and even non-coagulating (NC) milk in Denmark, and based on that, the paper reports on the frequency of non- and poorly coagulating milk in a herd of the three main Danish dairy breeds, Jersey, Danish red (RDM), and Danish Holstein-Friesian (SDM). The cows were milked by automatic milking. The rennet coagulation time, the coagulum firmness by storage modulus G′, and the curd firming rate of fresh skimmed milk were determined. More than 20% of the milk samples exhibited poor coagulation properties by the criteria set. Of these, the 17% resulted in a weak coagulum after addition of rennet, while another 3% were due to NC milk that did not aggregate to form a curd within the 40 min of measurement. Milk from Jersey cows exhibited superior coagulation properties when compared to milk from SDM and RDM cows. The dependence of curd firming rate on protein concentration was investigated, and found to depend on milk protein concentration to the power of three, emphasizing the importance of protein interactions, and not just the protein concentration itself. The paper gives a basis for the subsequent selection of NC milk samples with the aim to look in more detail for the underlying reasons for the phenomenon of NC milk. [ABSTRACT FROM AUTHOR]

The paper describes a study on the variation of coagulation properties in individual cow's milk measured by a novel free oscillation rheometry-based method. The work is part of a study on the occurrence and underlying causes of poorly and even non-coagulating (NC) milk in Denmark, and based on that, the paper reports on the frequency of non- and poorly coagulating milk in a herd of the three main Danish dairy breeds, Jersey, Danish red (RDM), and Danish Holstein-Friesian (SDM). The cows were milked by automatic milking. The rennet coagulation time, the coagulum firmness by storage modulus G′, and the curd firming rate of fresh skimmed milk were determined. More than 20% of the milk samples exhibited poor coagulation properties by the criteria set. Of these, the 17% resulted in a weak coagulum after addition of rennet, while another 3% were due to NC milk that did not aggregate to form a curd within the 40 min of measurement. Milk from Jersey cows exhibited superior coagulation properties when compared to milk from SDM and RDM cows. The dependence of curd firming rate on protein concentration was investigated, and found to depend on milk protein concentration to the power of three, emphasizing the importance of protein interactions, and not just the protein concentration itself. The paper gives a basis for the subsequent selection of NC milk samples with the aim to look in more detail for the underlying reasons for the phenomenon of NC milk. [ABSTRACT FROM AUTHOR]

Photo-oxidation of cheese products has become an issue due to the fact that packaging of cheeses in transparent materials is very frequently used. The present study aimed to give new aspects of the possible antioxidative activity of whey proteins in photo-oxidation of cheese and the whey proteins were expected to act as scavenger and thereby reduce lipid oxidation. Oxidation was investigated in low-fat model cheese with whey protein isolate (WPI) added and compared to a low-fat control cheese. The cheeses were packed in air or in vacuum, respectively, and stored under light. Accumulations of lipid hydroperoxides, pentanal, hexanal, heptanal, 1-hexanol, dimethyl disulfide and dityrosine were all found to be dependent on the availability of oxygen. The presence of WPI reduced the accumulation of both lipid and protein oxidation products. The consumption of the naturally occurring antioxidant α-tocopherol was not affected by the added WPI. After the seventh day of light-exposed storage during which all riboflavin was decomposed and the concentration of α-tocopherol had found a stable level, the presence of WPI resulted in an extension of the observed lag phase in the accumulation of secondary lipid oxidation products. As WPI reduced the accumulation of protein oxidation products as well, it is suggested that WPI is not a typical radical scavenger. [ABSTRACT FROM AUTHOR]

Human apurinic/apyrimidinic endonuclease APE1 is one of participants of the DNA base excision repair pathway. APE1 processes AP-sites and many other types of DNA damage via hydrolysis of the phosphodiester bond on the 5′ side of the lesion. APE1 also acts as an endoribonuclease, i.e., can cleave undamaged RNA. Using pre-steady-state kinetic analysis we examined the role of certain catalytically important amino acids in APE1 enzymatic pathway and described their involvement in the mechanism of the target nucleotide recognition. Comparative analysis of the cleavage efficiency of damaged DNAs containing an abasic site, 5,6-dihydrouridine, or α-anomer of adenosine as well as 3′-5′-exonuclease degradation of undamaged DNA and endonuclease hydrolysis of RNA substrates by mutant APE1 enzymes containing a substitution of an active-site amino acid residue (D210N, N212A, T268D, M270A, or D308A) was performed. Detailed pre–steady-state kinetics of conformational changes of the enzyme and of DNA substrate molecules during recognition and cleavage of the abasic site were studied. It was revealed that substitution T268D significantly disturbed initial DNA binding, whereas Asn212 is critical for the DNA-bending stage and catalysis. Substitution D210N increased the binding efficacy and blocked the catalytic reaction, but D308A decreased the binding efficacy owing to disruption of Mg2+ coordination. Finally, the substitution of Met270 also destabilized the enzyme–substrate complex but did not affect the catalytic reaction. It was found that the tested substitutions of the active-site amino acid residues affected different stages of the complex formation process as well as the catalytic reaction. • Target nucleotide recognition and cleavage of a DNA or RNA by human APE1 was analyzed • Efficiency of enzymatic hydrolysis of different substrates was compared • Process of protein-substrate interaction was analyzed by pre-steady state kinetics • Conformational changes in APE1 and substrates were observed during their interactions • The role of certain important amino acids during enzyme pathway was specified [ABSTRACT FROM AUTHOR]

Chymosin-induced cleavage of κ-casein (κ-CN) occurs during the first enzymatic phase in milk coagulation during cheese manufacturing, where the hydrophilic C-terminal peptide of κ-CN, named caseino-macropeptide (CMP), is released into the whey. The CMP peptide is known for its rather heterogeneous composition with respect to both genetic variation and multiple posttranslational modifications, including phosphorylation and O-linked glycosylation. An approach of liquid chromatography coupled with mass spectrometry was used to investigate (1) the overall protein profile and (2) the release of various forms of CMP after addition of chymosin to individual cow milk samples from 2 breeds, Danish Jersey (DJ) and Danish Holstein-Friesian (DH). The cows were selected to represent distinct homo- and heterozygous types of the κ-CN genetic variants A, B, and E (i.e., genotypes AA, BB, AB, EE, and AE). Initially, investigation of the protein profile showed milk with κ-CN BB exhibited the highest relative content of κ-CN, whereas AE milk exhibited the lowest, and after 40 min of renneting >90% of intact κ-CN was hydrolyzed by chymosin in milk representing all κ-CN genotype. By in-depth analysis of the CMP chromatographic profile, multiple CMP isoforms with 1 to 3 O-linked glycans (1-3 G) and 1 to 3 phosphate groups (1-3 P) were identified, as well as nonmodified CMP isoforms. The number of identified CMP isoforms varied to some extent between breeds (21 CMP isoforms identified in DJ, 26 CMP isoforms in DH) and between κ-CN genetic variants (CMP variant A being the most heterogeneous compared with CMP B and E), as well as between individual samples within each breed. The predominant forms of glycans attached to CMP were found to be the acidic tetrasaccharide {N-acetyl-neuraminic acid α(2-3)galactose β(1-3)[N-acetyl-neuraminic acid α(2-6)]N-acetyl galactose} or trisaccharides {N-acetyl-neuraminic acid α(2-3)galactose β(1-3)N-acetyl galactose and galactose β(1-3)[N-acetyl-neuraminic acid (α2-6)]N-acetyl galactose}. The CMP release was calculated to follow first-order kinetics and was determined by the measurement of CMP content during renneting. The highest rate of release for all CMP isoforms occurred from 0 to 2 min after chymosin addition. Concurring results from both breeds showed that CMP variant A with 1-2 P had the highest reaction rate of CMP release, followed by CMP B 1-2 P and then by CMP E 1-2 P (only in DH). All the identified glycosylated CMP isoforms had lower reaction rates of release compared with that of nonglycosylated CMP, thus glycan modifications seemed to negatively influence the reaction rate of chymosin-induced hydrolysis of κ-CN. [ABSTRACT FROM AUTHOR]

The development of coagulation properties during cold storage of raw milks categorized as good or poorly coagulating is largely unknown. This was studied in the present investigation at individual cow's milk level in addition to elucidating the impact of cheesemaking processing steps on the resulting coagulation properties of silo tank cheesemilk. Rennet coagulation time (RCT), curd firming rate (CFR) and gel firmness (G'max); Ca, P and Mg distribution; pH; and casein micelle size of raw skim milk from individual cows classified as 'good' or 'poor' in coagulation properties were investigated over 72 h storage at 4 °C. For the cheesemilk, the impact of overnight cold storage, thermization and standardization, pasteurization, and acidification to either pH 6.45 or 6.30 on the coagulation properties were studied. After 24 h of cold storage, RCT of both good and poorly coagulating milks was significantly prolonged though recovering somewhat after prolonged storage for good coagulating samples. In contrast, G'max was significantly reduced after 72 h of cold storage for good coagulating milk. Both total and colloidal Ca were higher in good compared with poorly coagulating milk, while mineral distribution and milk pH did not change during storage. For cheesemilk, up to 14 h, cold storage did not impair coagulation properties significantly, which was markedly improved by acidification. The study shows that rheological parameters of good and poorly coagulating milks are impacted differently by the cold storage. Conversely, cheesemilk coagulation properties were not impaired by the studied cheesemaking processing steps and, further, were enhanced by acidification steps. [ABSTRACT FROM AUTHOR]

The aim of the present investigation was to study the underlying causes of noncoagulating (NC) milk. Based on an initial screening in a herd of 53 Danish Holstein-Friesians, 20 individual Holstein-Friesian cows were selected for good and poor chymosin-induced coagulation properties; that is, the 10 cows producing milk with the poorest and best coagulating properties, respectively. These 20 selected cows were followed and resampled on several occasions to evaluate possible changes in coagulation properties. In the follow-up study, we found that among the 10 cows with the poorest coagulating properties, 4 cows consistently produced poorly coagulating (PC) or NC milk, corresponding to a frequency of 7%. Noncoagulating milk was defined as milk that failed to form a coagulum, defined as increase in the storage modulus (G') in oscillatory rheometry, within 45 min after addition of chymosin. Poorly coagulating milk was characterized by forming a weak coagulum of low G'. Milk proteomic profiling and contents of different casein variants, ionic contents of Ca, P and Mg, Κ-casein (CN) genotypes, casein micelle size, and coagulation properties of the 4 NC or PC samples were compared with milk samples of 4 cows producing milk with good coagulation properties. The studies included determination of production of caseinomacropeptide to ascertain whether noncoagulation could be ascribed to the first or second phase of chymosin-induced coagulation. Caseinomacropeptide was formed in all 8 milk samples after addition of chymosin, indicating that the first step (cleavage of κ-CN) was not the cause of inability to coagulate. Furthermore, the effect of mixing noncoagulating and well-coagulating milk was studied. By gradually blending NC with well-coagulating milk, the coagulation properties of the well-coagulating samples were compromised in a manner similar to titration. Milk samples from cows that consistently produced NC milk were further studied at the udder quarter level. The coagulation properties of the quarter milk samples were not significantly different from those of the composite milk sample, showing that poor coagulation traits and noncoagulation traits of the composite milk were not caused by the milk quality of a single quarter. The milk samples exhibiting PC or NC properties were all of the κ-CN variant AA genotype, and contained casein micelles with a larger mean diameter and a lower fraction of κ-CN relative to total CN than milk with good coagulation properties. Interestingly, the relative proportions of different phosphorylation forms of α-CN differed between well-coagulating milk and PC or NC milk samples. The PC and NC milk samples contained a lower proportion of the 2 less-phosphorylated variants of α-CN (αS1-CN-8P and αS2-CN-11P) compared with samples of milk that coagulated well. [ABSTRACT FROM AUTHOR]

Tyrosine phosphorylation of phospholipase Cγ2 (PLCγ2) is a crucial activation switch that initiates and maintains intracellular calcium mobilization in response to B cell antigen receptor (BCR) engagement. Although members from three distinct families of non- receptor tyrosine kinases can phosphorylate PLCγ in vitro, the specific kinase(s) controlling BCR-dependent PLCγ activation in vivo remains unknown. Bruton's tyrosine kinase (Btk)-deficient human B cells exhibit diminished inositol 1,4,5-trisphosphate production and calcium signaling despite a normal inducible level of total PLCγ2 tyrosine phosphorylation. This suggested that Btk might modify a critical subset of residues essential for PLCγ2 activity. To evaluate this hypothesis, we generated site-specific phosphotyrosine antibodies recognizing four putative regulatory residues within PLCγ2. Whereas all four sites were rapidly modified in response to BCR engagement in normal B cells, Btk-deficient B cells exhibited a marked reduction in phosphorylation of the Src homology 2 (SH2)-SH3 linker region sites, Tyr753 and Tyr759. Phosphorylation of both sites was restored by expression of Tec, but not Syk, family kinases. In contrast, phosphorylation of the PLCγ2 carboxyl-terminal sites, Tyr1197 and Tyr1217, was unaffected by the absence of functional Btk. Together, these data support a model whereby Btk/Tec kinases control sustained calcium signaling via site-specific phosphorylation of key residues within the PLCγ2 SH2-SH3 linker. [ABSTRACT FROM AUTHOR]