Volumetric velocity measurement of aquatic predator-prey interactions

University of Minnesota Ph.D. dissertation. December 2013. Major: Aerospace Engineering and Mechanics. Advisor: Ellen K. Longmire. 1 computer file (PDF); xxvi, 244 pages, appendices A-C.The aim of this study is to develop a novel multi-scale volumetric measurement system and flow facility, and apply it to improve understanding of aquatic predator-prey interactions. A combined infrared tomographic PIV + 3D PTV system was developed and demonstrated. Tomographic PIV was used to obtain the volumetric velocity field of the flow, while the 3D PTV was used to track the prey, and the eye of the predator, in the same volume. A visual hull technique was implemented to mask out the objects (such as fish) appearing within the reconstructed tomographic PIV volumes, ensuring that velocity vectors near the object/fish were not contaminated during PIV cross-correlation. Copepods, which make up the majority of the oceanic zooplanktons, are known to sense flow disturbed by approaching predators and can execute sudden high-speed swim (or jump) to escape predation. Although their response to local flow disturbances has been studied, their sensing and swimming response to live predators (fish) is not well understood. Three series of experiments were implemented - (1): Copepod interactions with a wall-mounted cylinder in cross-flow; (2): Predator-prey interactions in still water; (3): Predator-prey interactions in unsteady/turbulent flow. From the experiments, copepods appeared to respond (jump) to a large and sudden increase in local maximum principal strain rate (MPSR) of the fluid, instead of a fixed threshold quantity. For fish predation in still water, zebrafish were first observed to approach slowly, followed by sudden acceleration (ram feeding) to feed on copepods. Using a potential flow model, it was found that this strategy might not be sufficient to capture copepods successfully. Thus, zebrafish were found to execute suction feeding simultaneously to increase chances of predation success. In uniform cross flow, a coral reef fish (blenny) used a similar slow approach - ram feeding strategy to feed on copepods, but it rarely captured them. However, turbulent cross flow increased the chances of predation by allowing the fish to approach closer to a copepod, and preventing the copepod from detecting hydrodynamic signals from the approaching predator.Adhikari, Deepak. (2013). Volumetric velocity measurement of aquatic predator-prey interactions. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/162416

Awareness regarding radiation knowledge among clinicians practicing in Bharatpur, Nepal

The major imaging tools used in diagnostic radiology is based on the use of ionizing radiation. Ionizing radiation can be harmful to health, so before referring an examination in diagnostic radiology, clinicians must be aware of its harmful effects and a justified referral guideline should be followed.  A cross-sectional study was carried out among clinicians who are not radiation professionals but do use ionizing radiation as part of their work to assess awareness regarding radiation protection and their current practice. The researcher was directly engaged in data collection using a self-administered semi-structured questionnaire. The findings of the study are presented in the socio-demographic characteristics of respondents, current practice of respondents and knowledge regarding radiation protection. The result of this study demonstrated that despite the importance of radiation and its consequent hazards, the level of knowledge among referring clinicians is only 52.08% and their current practice is 60.55%. The difference in the mean score of knowledge and practice might have resulted due to clinician’s habituation with the practice but they have not updated themselves regarding radiation protection. Also, the study revealed that there is no significant (p>0.05) difference in knowledge level of physicians practicing in different hospitals. But the mean difference in practice scores of different hospitals is significant (p<0.05) i.e. a hospital with a large volume of radiological investigations (in our context a specialized cancer hospital) had better practice as compared to other hospitals. We find that an awareness of the hazardous imaging modalities due to radiation safety, its biological effects, referral practice and its perilous consequences is lacking. The deficiency in knowledge of clinicians might alter the expected benefits, compared to the risk involved, and can cause erroneous medical diagnosis and radiation hazard. Therefore, this study emphasizes the need for all clinicians to update themselves with the appropriate knowledge and current practice about ionizing and non-ionizing radiation

The Relationship of The Mandibular Canal to The Roots of Impacted Third Molars- The Root Factor: A Panoramic Radiographic Study.

Introduction: Third molar extractions are one of the most common reasons of injury to mandibular nerve and postoperative complications. Pre-operative assessment of pending doom is a must. In order to study the relations between change in Inferior Alveolar Canal (IAC) and Type, Class, and Level of impaction with radiographic root change of impacted third mandibular molar, we designed a study to assess the relationship of the mandibular canal to the roots of impacted third molar in reference to changes in roots and factors affecting it. Methods: This was a retrospective cross-sectional study wherein the panoramic radiographic records of subjects with impacted third molar were assessed for change in root and its correlation with change in IAC, Type, Class and Level of impacted mandibular third molar. Results: Roots of impacted third molar when in contact with IAC presented most often in our study subjects with the Darkening of roots in both sides {right side (16.79%) and left side (11.29%)} and both genders {males (right-14.29%, left-8.75%) and females (right-19.39%, left-13.94%)}. They were statistically significantly associated with interruption of white line of IAC, vertically impacted third molars and Pell and Gregory Class II, Level A of impaction. Conclusion: There is a need to properly identify radiographic risk predictor signs to avoid any surprises at the time of extraction and post operation complications following it

CALIBRATION OF 1-D NUMERICAL CODES SOFTWARE FOR SITE RESPONSE ANALYSES

Ground response analyses are used to predict surface ground motions for development of design response spectra, to evaluate dynamic stresses and strains for evaluation of earthquake hazards, and to determine the earthquake induced forces that can lead to instability of earth-retaining structures. The effects of local soil on ground motion are commonly evaluated by performing numerical analyses either in frequency or time domains.In order to evaluate the differences between frequency and time domain analysis, several analyses were conducted for homogenous stiff soil deposit with respective codes which are SHAKE and D-MOD2000. Linear and non linear analyses have been conducted. The non linear analyses with D-MOD2000 code have been carried out by using different frequencies in the Rayleigh damping formulation, i.e. fundamental and predominant frequency. For linear, PGA 0.1g is used in the analysis while for non linear PGA is scaled into three different value of 0.1, 0.3, and 0.5g.The results for both linear and non linear approach are similar. For the non linear analyses, it is shown that the curves derived using predominant frequency perform better than those using fundamental frequency. Main differences are for non linear approach where the differences between two codes are higher for higher input motion. As the calibration using predominant frequency between the two codes perform good, the respective codes are applied to evaluate soil response in Sant’ Agostino and San Carlo, in terms of PGA, due to May 20th 2012 Emilia Earthquake. There are 139 accelerometric station recorded strong motion. In this analysis, we consider one record which is in Mirandola station, the closest recording station where the Magnitude in epicentral area was 5.9 and 5.8 in Mirandola station. The recorded surface motion in Mirandola is transferred to the bedrock in 112 m depth and used as input motion for the two evaluated sites, San Carlo village and nearby municipality Sant’Agostino on 17 km distance from Mirandola station. The preliminary data presented here shows the PGA recorded in the bedrock of Mirandola station is 0.75g, while in Sant’Agostino and San Carlo is 0.92g and 0.81g

Mastl is required for timely activation of APC/C in meiosis I and Cdk1 reactivation in meiosis II

In mitosis, the Greatwall kinase (called microtubule-associated serine/threonine kinase like [Mastl] in mammals) is essential for prometaphase entry or progression by suppressing protein phosphatase 2A (PP2A) activity. PP2A suppression in turn leads to high levels of Cdk1 substrate phosphorylation. We have used a mouse model with an oocyte-specific deletion of Mastl to show that Mastl-null oocytes resume meiosis I and reach metaphase I normally but that the onset and completion of anaphase I are delayed. Moreover, after the completion of meiosis I, Mastl-null oocytes failed to enter meiosis II (MII) because they reassembled a nuclear structure containing decondensed chromatin. Our results show that Mastl is required for the timely activation of anaphase-promoting complex/cyclosome to allow meiosis I exit and for the rapid rise of Cdk1 activity that is needed for the entry into MII in mouse oocytes

Red pepper seed water extract inhibits preadipocyte differentiation and induces mature adipocyte apoptosis in 3T3-L1 cells

BACKGROUND/OBJECTIVES: Reducing the number of adipocytes by inducing apoptosis of mature adipocytes as well as suppressing differentiation of preadipocytes plays an important role in preventing obesity. This study examines the anti-adipogenic and pro-apoptotic effect of red pepper seed water extract (RPS) prepared at 4°C (RPS4) in 3T3-L1 cells. MATERIALS/METHODS: Effect of RPS4 or its fractions on lipid accumulation was determined in 3T3-L1 cells using oil red O (ORO) staining. The expressions of AMP-activated protein kinase (AMPK) and adipogenic associated proteins [peroxisome proliferator-activated receptor-γ (PPAR-γ), CCAAT/enhancer-binding proteins α (C/EBP α), sterol regulatory element binding protein-1c (SREBP-1c), fatty acid synthase (FAS), and acetyl-CoA carboxylase (ACC)] were measured in 3T3-L1 cells treated with RPS4. Apoptosis and the expression of Akt and Bcl-2 family proteins [B-cell lymphoma 2 (Bcl-2), Bcl-2-associated death promoter (Bad), Bcl-2 like protein 4 (Bax), Bal-2 homologous antagonist/killer (Bak)] were measured in mature 3T3-L1 cells treated with RPS4. RESULTS: Treatment of RPS4 (0-75 ug/mL) or its fractions (0-50 ug/mL) for 24 h did not have an apparent cytotoxicity on pre and mature 3T3-L1 cells. RPS4 significantly suppressed differentiation and cellular lipid accumulation by increasing the phosphorylation of AMPK and reducing the expression of PPAR-γ, C/EBP α, SREBP-1c, FAS, and ACC. In addition, all fractions except ethyl acetate fraction significantly suppressed cellular lipid accumulation. RPS4 induced the apoptosis of mature adipocytes by hypophosphorylating Akt, increasing the expression of the pro-apoptotic proteins, Bak, Bax, and Bad, and reducing the expression of the anti-apoptotic proteins, Bcl-2 and p-Bad. CONCLUSIONS: These finding suggest that RPS4 can reduce the numbers as well as the size of adipocytes and might useful for preventing and treating obesity

Prevalence, determinants and care-seeking behaviour for anxiety and depression in Nepalese population: a secondary analysis of data from Nepal Demographic and Health Survey 2022

Objective To determine the prevalence and factors associated with anxiety and depression and the care-seeking behaviour among Nepalese population. Design and settings Secondary analysis of the data from nationally representative Nepal Demographic and Health Survey 2022. Participants Analysed data of 12 355 participants (7442 females and 4913 males) aged 15–49 years. Outcome measures Depression and anxiety were assessed using Patient Health Questionnaire-9 (PHQ-9) and Generalised Anxiety Disorder Assessment (GAD-7) tools, respectively. Statistical analysis We performed weighted analysis to account for the complex survey design. We presented categorical variables as frequency, per cent and 95% confidence interval (CI), whereas numerical variables were presented as median, inter-quartile range (IQR) and 95% CI. We performed univariate and multivariable logistic regression to determine factors associated with anxiety and depression, and results were presented as crude OR (COR), adjusted OR (AOR) and their 95% CI. Results The prevalence of depression and anxiety were 4.0% (95% CI 3.5 to 4.5) and 17.7% (95% CI 16.5 to 18.9), respectively. Divorced or separated participants were found to have higher odds of developing anxiety (AOR 2.40, 95% CI 1.74 to 3.31) and depression (AOR 3.16, 95% CI 1.84 to 5.42). Among ethnic groups, Janajati had lower odds of developing anxiety (AOR 0.77, 95% CI 0.65 to 0.92) and depression (AOR 0.67, 95% CI 0.49 to 0.93) compared with Brahmin/Chhetri. Regarding disability, participants with some difficulty had higher odds of developing anxiety (AOR 1.81, 95% CI 1.56 to 2.10) and depression (AOR 1.94, 95% CI 1.51 to 2.49), and those with a lot of difficulty had higher odds of anxiety (AOR 2.09, 95% CI 1.48 to 2.96) and depression (AOR 2.04, 95% CI 1.06 to 3.90) compared with those without any disability. Among those who had symptoms of anxiety or depression, only 32.9% (95% CI 30.4 to 34.4) sought help for the conditions. Conclusions Marital status and disability status were positively associated with anxiety and depression, whereas Janajati ethnicity had relatively lower odds of experiencing anxiety and depression. It is essential to develop interventions and policies targeting females and divorced individuals to help reduce the burden of anxiety and depression in Nepal.publishedVersio