Surf Zone Sediment Size Variation, Morphodynamics, and Hydrodynamics during Sea/Land Breeze and El-Norte Storm in Sisal, Yucatan, Mexico

This study compares the effects of a mesoscale pressure system (i.e., cold front: referred to as El-Norte) and local pressure systems (land and sea breezes) on the hydrodynamics, beach profile, and particle size distribution of sediments within the surf zone. The effect of onshore and offshore wind has been investigated using measurements of hydrodynamics (water elevation, current velocities and direction), geomorphology (surface sediment samples and beach profiles), and meteorological observations (wind, temperature and atmospheric pressure). The experiment was conducted on Sisal beach located in the Gulf of Mexico along the northern coast of the Yucatan Peninsula from March 27th 2014 to April 11th 2014. For a 50 m cross section of the beach (i.e., the surf zone) hydrodynamics were analyzed by estimating turbulent kinetic energy, kinetic energy dissipation rate and bed shear stress using the measurements obtained from Acoustic Doppler Velocimeters (ADV). Significant wave height and wave period in the surf zone were computed using pressure sensors from ADVs. A pressure transducer located in the swash zone provided additional water free-surface elevation data to help assess wave energy dissipation. During sea breeze cycles with wind velocities reaching up to 15 ms-1, rapid changes in wave height over a short period of time were observed. One El-Norte storm event affected the study site during the field campaign with maximum wind speeds of 15 ms-1, and significant wave heights of 1.5 m and 0.3 m in water depths of 10 m and 0.4 m, respectively. This study will test five hypotheses: (1) El-Norte is more effective in skewing sediment size distributions toward coarser grain sizes compared to regular sea-breeze events, (2) sea-breeze events result in deposition of sediment within the surf zone and erosion in the swash zone, in addition to onshore sandbar migration, (3) an individual El-Norte event can cause significant alterations to the beach profile resulting in a steeper beach profile and significant erosion in the swash zone and surf zone, (4) the undertow currents are stronger during El-Norte than during sea/land-breezes and play an important role in the offshore sandbars migration

Fe-MOF Materials as Precursors for the Catalytic Dehydrogenation of Isobutane.

We investigate the use of a series of iron-based metal-organic frameworks as precursors for the manufacturing of isobutane dehydrogenation catalysts. Both the as-prepared and spent catalysts were characterized by PXRD, XPS, PDF, ICP-OES, and CHNS+O to determine the physicochemical properties of the materials and the active phases responsible for the catalytic activity. In contrast to the previous literature, our results indicate that (i) the formation of metallic Fe under reaction conditions results in secondary cracking and coke formation; (ii) the formation of iron carbide only contributes to coke formation; and (iii) the stabilization of the Fe2+ species is paramount to achieve stable and selective catalysts. In this sense, promotion with potassium and incorporation of titanium improve the catalytic performance. While potassium is well known to improve the selectivity in iron-catalyzed dehydrogenation reactions, the unprecedented effect of titanium in the stabilization of a nanometric titanomaghemite phase, even under reductive reaction conditions, results in a moderately active and highly selective catalyst for several hours on stream with a remarkable resistance to coke formation

DOX-Vit D, a Novel Doxorubicin Delivery Approach, Inhibits Human Osteosarcoma Cell Proliferation by Inducing Apoptosis While Inhibiting Akt and mTOR Signaling Pathways

This work is licensed under a Creative Commons Attribution 4.0 International License.Doxorubicin (DOX) is a very potent and effective anticancer agent. However, the effectiveness of DOX in osteosarcoma is usually limited by the acquired drug resistance. Recently, Vitamin D (Vit-D) was shown to suppress the growth of many human cancer cells. Taken together, we synthesized DOX-Vit D by conjugating Vit-D to DOX in order to increase the delivery of DOX into cancer cells and mitigate the chemoresistance associated with DOX. For this purpose, MG63 cells were treated with 10 µM DOX or DOX-Vit D for 24 h. Thereafter, MTT, real-time PCR and western blot analysis were used to determine cell proliferation, genes and proteins expression, respectively. Our results showed that DOX-Vit D, but not DOX, significantly elicited an apoptotic signal in MG63 cells as evidenced by induction of death receptor, Caspase-3 and BCLxs genes. Mechanistically, the DOX-Vit D-induced apoptogens were credited to the activation of p-JNK and p-p38 signaling pathway and the inhibition of proliferative proteins, p-Akt and p-mTOR. Our findings propose that DOX-Vit D suppressed the growth of MG63 cells by inducing apoptosis while inhibiting cell survival and proliferative signaling pathways. DOX-Vit D may serve as a novel drug delivery approach to potentiate the delivery of DOX into cancer cells.Canadian Institutes of Health Research [Grant 106665]U.S. National Cancer Institute [Grant R01CA173292

Pharmaceutical Characterization of MyoNovin, a Novel Skeletal Muscle Regenerator: in silico, in vitro and in vivo Studies.

MyoNovin is a novel skeletal muscle-regenerating compound developed through synthesis of two nitro groups onto a guaifenesin backbone to deliver nitric oxide to skeletal muscle with a potential to treat muscle atrophy. The purpose of this study was to utilize in silico, in vitro, and in vivo approaches to characterize MyoNovin and examine its safety, biodistribution, and feasibility for drug delivery. In silico software packages were used to predict the physicochemical and biopharmaceutical properties of MyoNovin. In vitro cardiotoxicity was assessed using human cardiomyocytes (RL-14) while effects on CYP3A4 metabolic enzyme and antioxidant activity were examined using commercial kits. A novel HPLC assay was developed to measure MyoNovin concentration in serum, and delineate initial pharmacokinetic and acute toxicity after intravenous administration (20 mg/kg) to male Sprague-Dawley rats. MyoNovin showed relatively high lipophilicity with a LogP value of 3.49, a 20-fold higher skin permeability (19.89 cm/s*107) compared to guaifenesin (0.66 cm/s*107), and ~10-fold higher effective jejunal permeability (2.24 cm/s*104) compared to guaifenesin (0.26 cm/s*104). In vitro, MyoNovinwas not cytotoxic to cardiomyocytes at concentrations below 8 μM and did not inhibit CYP3A4 or show antioxidant activity. In vivo, MyoNovin had a short half-life (t1/2) of 0.16 h, and a volume of distribution Vss of 0.62 L/kg. Biomarkers of MyoNovincardiac and renal toxicity did not differ significantly from baseline control levels. The predicted high lipophilicity and skin permeability of MyoNovin render it a potential candidate for transdermal administration while its favourable intestinal permeation suggests it may be suitable for oral administration. Pharmacokinetics following IV administration of MyoNovin were delineated for the first time in a rat model. Preliminary single 20 mg/kg dose assessment of MyoNovin suggest no influenceon cardiac troponin or β-N-Acetylglucosaminidase. This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page

Validation of Cadherin HAV6 Peptide in the Transient Modulation of the Blood-Brain Barrier for the Treatment of Brain Tumors

This work is licensed under a Creative Commons Attribution 4.0 International License.The blood-brain barrier (BBB) poses a major obstacle by preventing potential therapeutic agents from reaching their intended brain targets at sufficient concentrations. While transient disruption of the BBB has been used to enhance chemotherapeutic efficacy in treating brain tumors, limitations in terms of magnitude and duration of BBB disruption exist. In the present study, the preliminary safety and efficacy profile of HAV6, a peptide that binds to the external domains of cadherin, to transiently open the BBB and improve the delivery of a therapeutic agent, was evaluated in a murine brain tumor model. Transient opening of the BBB in response to HAV6 peptide administration was quantitatively characterized using both a gadolinium magnetic resonance imaging (MRI) contrast agent and adenanthin (Ade), the intended therapeutic agent. The effects of HAV6 peptide on BBB integrity and the efficacy of concurrent administration of HAV6 peptide and the small molecule inhibitor, Ade, in the growth and progression of an orthotopic medulloblastoma mouse model using human D425 tumor cells was examined. Systemic administration of HAV6 peptide caused transient, reversible disruption of BBB in mice. Increases in BBB permeability produced by HAV6 were rapid in onset and observed in all regions of the brain examined. Concurrent administration of HAV6 peptide with Ade, a BBB impermeable inhibitor of Peroxiredoxin-1, caused reduced tumor growth and increased survival in mice bearing medulloblastoma. The rapid onset and transient nature of the BBB modulation produced with the HAV6 peptide along with its uniform disruption and biocompatibility is well-suited for CNS drug delivery applications, especially in the treatment of brain tumors

Three-Dimensional Evaluation of Root and Alveolar Ridge Width of Maxillary Lateral Incisors in Patients with Unilateral Agenesis

Introduction: The objective of this study was to measure the maxillary lateral incisor root dimensions and quantify the labial and palatal bone in patients with unilateral maxillary lateral incisor agenesis (MLIA) and compare them to non-agenesis controls using cone beam computed tomography. Methods: The labiopalatal and mesiodistal root dimension and labiopalatal bone width of maxillary lateral incisors were assessed on pre-treatment and post-treatment cone beam computed tomography scans of 23 subjects (mean age 14.5 years, 17 females and 6 males) with maxillary lateral incisor agenesis and 23 gender-matched subjects (mean age 13.5 years, 17 females and 6 males) with no dental agenesis or anterior Bolton discrepancy. The Mann-Whitney Test was used to distinguish any differences in root width, crown width or changes in labial or palatal bone between the two groups. The Wilcoxon Signed Rank Test was used to compare the pre-treatment and post-treatment findings within each group. Results: The mean labiopalatal root width was narrower in the maxillary lateral incisor agenesis group than controls by 1.25mm (P≤0.000) at the level of the CEJ. The mesiodistal root width did not differ significantly between the groups. Both groups had thin labial bone with a mean post-treatment labial bone of 0.4mm and 0.8 mm at 4mm apical to CEJ for the maxillary lateral agenesis group and the control group, respectively. At the end of orthodontic treatment the MLIA group lost about 60% of labiopalatal bone width. The mesiodistal crown width was significantly smaller in the maxillary lateral agenesis group at both the incisal edge and at crown midpoint by an average of 1.5mm and 1.4mm, respectively. Conclusion: The buccolingual root, the mesiodistal crown widths, and the labial bone width at 10mm apical to the CEJ of the maxillary lateral incisor in patients with unilateral agenesis were significantly smaller than normal controls

Wind-Driven Nearshore Dynamics in the Gulf of Mexico

Coastlines around the Gulf of Mexico are dynamic, due to prevailing energetic wind systems such as frequent cold fronts and diurnal wind systems. In the last two decades, more research has focused on the surf zone’s complex coupling effects between winddriven waves and currents. However, there is still a need for further field based experiment to elucidate, (1) how offshore cold fronts impact nearshore morphodynamics and sediment dynamics, when compared to onshore fronts, (2) what is the main physical forcing that controls the surf zone and the inner-shelf region current circulation during relatively intense onshore and offshore wind events, and (3) does the cumulative effect of sea breeze cycles result in more morphodynamic variation than cold fronts? Therefore, two field based studies were conducted in the Gulf of Mexico to advance our understanding of the complex coupling effects between wind-driven waves and currents, including turbulence quantities, sediment transport parameters, and morphodynamic processes. Both field experiments included time-series of highly resolved hydrodynamics and suspended sediment concentration obtained at different cross-shore locations across the surf zone. The first field experiment was conducted at a sea breeze dominated beach on Sisal, Yucatán Peninsula, México. Time-series observations suggest that the impact of sea breeze cycles on the nearshore hydrodynamics and morphodynamics is comparable to the effect of onshore-directed cold front, and cumulatively the sea breeze cycles will result in higher sediment loss. Regardless, it is also suggested that the cumulative accretional of the land breeze cycles can be sufficient to compensate for the loss of sediment by either the sea breeze cycles or the cold fronts. The second field experiment evaluated surf zone hydrodynamics and sediment dynamic processes within the upper Texas coast during three offshore cold front events and three onshore Gulf breeze events. Observations show enhanced eastward suspended sediment transport following the passage of cold fronts, while westward transport was experienced during the Gulf breeze events. The study suggests that during late fall and early spring seasons, Galveston Island will experience higher erosion rates in the eastside, while accretion of sediment on the west side will occur

Wind-Driven Nearshore Dynamics in the Gulf of Mexico

Coastlines around the Gulf of Mexico are dynamic, due to prevailing energetic wind systems such as frequent cold fronts and diurnal wind systems. In the last two decades, more research has focused on the surf zone’s complex coupling effects between winddriven waves and currents. However, there is still a need for further field based experiment to elucidate, (1) how offshore cold fronts impact nearshore morphodynamics and sediment dynamics, when compared to onshore fronts, (2) what is the main physical forcing that controls the surf zone and the inner-shelf region current circulation during relatively intense onshore and offshore wind events, and (3) does the cumulative effect of sea breeze cycles result in more morphodynamic variation than cold fronts? Therefore, two field based studies were conducted in the Gulf of Mexico to advance our understanding of the complex coupling effects between wind-driven waves and currents, including turbulence quantities, sediment transport parameters, and morphodynamic processes. Both field experiments included time-series of highly resolved hydrodynamics and suspended sediment concentration obtained at different cross-shore locations across the surf zone. The first field experiment was conducted at a sea breeze dominated beach on Sisal, Yucatán Peninsula, México. Time-series observations suggest that the impact of sea breeze cycles on the nearshore hydrodynamics and morphodynamics is comparable to the effect of onshore-directed cold front, and cumulatively the sea breeze cycles will result in higher sediment loss. Regardless, it is also suggested that the cumulative accretional of the land breeze cycles can be sufficient to compensate for the loss of sediment by either the sea breeze cycles or the cold fronts. The second field experiment evaluated surf zone hydrodynamics and sediment dynamic processes within the upper Texas coast during three offshore cold front events and three onshore Gulf breeze events. Observations show enhanced eastward suspended sediment transport following the passage of cold fronts, while westward transport was experienced during the Gulf breeze events. The study suggests that during late fall and early spring seasons, Galveston Island will experience higher erosion rates in the eastside, while accretion of sediment on the west side will occur