Cyanobacteria blooms induced precipitation of calcium carbonate and dissolution of silica in a subtropical lagoon, Florida Bay, USA.

In recent decades, annual cyanobacteria blooms in Florida Bay displayed spatial and temporal patterns that are consistent with changes in alkalinity and dissolved silicon in water. In early summer, the blooms developed in the north-central bay and spread southward in fall. The blooms drew down dissolved inorganic carbon and increased water pH, causing in situ precipitation of calcium carbonate.

Why is calcite a strong phosphorus sink in freshwater? Investigating the adsorption mechanism using batch experiments and surface complexation modeling.

One of the primary drivers of Phosphorus (P) limitation in aquatic systems is P adsorption to sediments. Sediments adsorb more P in freshwater compared to other natural solutions, but the mechanism driving this difference is poorly understood. To provide insights into the mechanism, we conducted batch experiments of P adsorption to calcite in freshwater and seawater, and used computer software to develop complexation models.

Small-world effects in a modified epidemiological model with mutation and permanent immune mechanism.

Pandemic with mutation and permanent immune spreading in a small-world network described is studied by a modified SIR model, with consideration of mutation-immune mechanism. First, a novel mutation-immune model is proposed to modify the classical SIR model to simulate the transmission of mutable viruses that can be permanently immunized in small-world networks. Then, the influences of the size, coordination number and disorder parameter of the small-world network on the spread of the epidemic are analyzed in detail.

Sustained microglial depletion with CSF1R inhibitor impairs parenchymal plaque development in an Alzheimer's disease model.

Many risk genes for the development of Alzheimer's disease (AD) are exclusively or highly expressed in myeloid cells. Microglia are dependent on colony-stimulating factor 1 receptor (CSF1R) signaling for their survival. We designed and synthesized a highly selective brain-penetrant CSF1R inhibitor (PLX5622) allowing for extended and specific microglial elimination, preceding and during pathology development.

BRD4 Profiling Identifies Critical Chronic Lymphocytic Leukemia Oncogenic Circuits and Reveals Sensitivity to PLX51107, a Novel Structurally Distinct BET Inhibitor.

Bromodomain and extra-terminal (BET) family proteins are key regulators of gene expression in cancer. Herein, we utilize BRD4 profiling to identify critical pathways involved in pathogenesis of chronic lymphocytic leukemia (CLL). BRD4 is overexpressed in CLL and is enriched proximal to genes upregulated or expressed in CLL with known functions in disease pathogenesis and progression.

An estimate of diapycnal nutrient fluxes to the euphotic zone in the Florida Straits.

A recent hydrographic survey of the Florida Current at 27°N revealed an enhanced upward flux of nutrients along the Florida coast. Geostrophic flow of the Gulf Stream through the narrow Florida Straits causes an uplift of the nutricline toward its western edge, shoaling the mixed layers into the base of the euphotic zone. At a nearshore station, nitrate, phosphate, and silicate concentrations reached 19, 1.

A Route to Chaotic Behavior of Single Neuron Exposed to External Electromagnetic Radiation.

Non-linear behaviors of a single neuron described by Fitzhugh-Nagumo (FHN) neuron model, with external electromagnetic radiation considered, is investigated. It is discovered that with external electromagnetic radiation in form of a cosine function, the mode selection of membrane potential occurs among periodic, quasi-periodic, and chaotic motions as increasing the frequency of external transmembrane current, which is selected as a sinusoidal function. When the frequency is small or large enough, periodic, and quasi-periodic motions are captured alternatively.

Energy Transfer and 1.8 µm Emission in Tm³⁺/Yb³⁺ Co-Doped LiYF₄Crystal.

LiYF₄ single crystals co-doped with various Tm³⁺/Yb³⁺ concentrations were grown using the Bridg- man method. The luminescent properties of the crystals were investigated through emission spectra, emission cross section, and decay curves under excitation by 980 nm. Compared with the Tm³⁺ single-doped LiYF₄ crystal, an enhanced emission band from 1600 to 2150 nm was observed upon excitation of a 980 nm laser diode.

Growth and Optical Spectra of Tb³⁺/Sm³⁺/Ce³⁺ Triply Doped LiYF₄Single Crystals for White-Light LEDs.

The Tb³⁺/Sm³⁺/Ce³⁺ triply doped LiYF4 single crystals were grown by a modified Bridgman method. The absorption spectra, excitation spectra, and fluorescence spectra of Tb³⁺/Sm³⁺/Ce³⁺ ions in LiYF₄ crystals were measured. The fluorescence spectra of several bands, mainly located at purplish blue ~413 nm (⁵D₃ --> ⁷F₅), yellowish green ~542 nm (⁵D₄ --> ⁷F₅), and red ~643 nm (⁴G₅/₂ --> ⁶H₉/₂), were observed under excitation of ultraviolet light.

Spike-like solitary waves in incompressible boundary layers driven by a travelling wave.

Nonlinear waves produced in an incompressible boundary layer driven by a travelling wave are investigated, with damping considered as well. As one of the typical nonlinear waves, the spike-like wave is governed by the driven-damped Benjamin-Ono equation. The wave field enters a completely irregular state beyond a critical time, increasing the amplitude of the driving wave continuously.

Highly Efficient LiYF4:Yb(3+), Er(3+) Upconversion Single Crystal under Solar Cell Spectrum Excitation and Photovoltaic Application.

Luminescent upconversion is a promising way to harvest near-infrared (NIR) sunlight and transforms it into visible light that can be directly absorbed by active materials of solar cells and improve their power conversion efficiency (PCE). However, it is still a great challenge to effectively improve the PCE of solar cells with the assistance of upconversion. In this work, we demonstrate the application of the transparent LiYF4:Yb(3+), Er(3+) single crystal as an independent luminescent upconverter to improve the PCE of perovskite solar cells.

RAF inhibitors that evade paradoxical MAPK pathway activation.

Oncogenic activation of BRAF fuels cancer growth by constitutively promoting RAS-independent mitogen-activated protein kinase (MAPK) pathway signalling. Accordingly, RAF inhibitors have brought substantially improved personalized treatment of metastatic melanoma. However, these targeted agents have also revealed an unexpected consequence: stimulated growth of certain cancers.

Structure-Guided Blockade of CSF1R Kinase in Tenosynovial Giant-Cell Tumor.

Background: Expression of the colony-stimulating factor 1 (CSF1) gene is elevated in most tenosynovial giant-cell tumors. This observation has led to the discovery and clinical development of therapy targeting the CSF1 receptor (CSF1R).

Methods: Using x-ray co-crystallography to guide our drug-discovery research, we generated a potent, selective CSF1R inhibitor, PLX3397, that traps the kinase in the autoinhibited conformation.

Characterizing and Overriding the Structural Mechanism of the Quizartinib-Resistant FLT3 "Gatekeeper" F691L Mutation with PLX3397.

Unlabelled: Tyrosine kinase domain mutations are a common cause of acquired clinical resistance to tyrosine kinase inhibitors (TKI) used to treat cancer, including the FLT3 inhibitor quizartinib. Mutation of kinase "gatekeeper" residues, which control access to an allosteric pocket adjacent to the ATP-binding site, has been frequently implicated in TKI resistance. The molecular underpinnings of gatekeeper mutation-mediated resistance are incompletely understood.

Carbon dynamics of Florida Bay: spatiotemporal patterns and biological control.

Carbon dynamics of Florida Bay is manifested by wide ranges of pH (7.65-8.61), dissolved inorganic carbon (DIC, 929-3223 μM) and partial pressure of CO2 (pCO2, 50-1313 μatm) observed over seven years.

A portable analyser for the measurement of ammonium in marine waters.

A portable ammonium analyser was developed and used to measure in situ ammonium in the marine environment. The analyser incorporates an improved LED photodiode-based fluorescence detector (LPFD). This system is more sensitive and considerably smaller than previous systems and incorporates a pre-filtering subsystem enabling measurements in turbid, sediment-laden waters.

Design and pharmacology of a highly specific dual FMS and KIT kinase inhibitor.

Inflammation and cancer, two therapeutic areas historically addressed by separate drug discovery efforts, are now coupled in treatment approaches by a growing understanding of the dynamic molecular dialogues between immune and cancer cells. Agents that target specific compartments of the immune system, therefore, not only bring new disease modifying modalities to inflammatory diseases, but also offer a new avenue to cancer therapy by disrupting immune components of the microenvironment that foster tumor growth, progression, immune evasion, and treatment resistance. McDonough feline sarcoma viral (v-fms) oncogene homolog (FMS) and v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog (KIT) are two hematopoietic cell surface receptors that regulate the development and function of macrophages and mast cells, respectively.

Vemurafenib: the first drug approved for BRAF-mutant cancer.

The identification of driver oncogenes has provided important targets for drugs that can change the landscape of cancer therapies. One such example is the BRAF oncogene, which is found in about half of all melanomas as well as several other cancers. As a druggable kinase, oncogenic BRAF has become a crucial target of small-molecule drug discovery efforts.

Phosphorus sorption on marine carbonate sediment: phosphonate as model organic compounds.

Organophosphonate, characterized by the presence of a stable, covalent, carbon to phosphorus (C-P) bond, is a group of synthetic or biogenic organophosphorus compounds. The fate of these organic phosphorus compounds in the environment is not well studied. This study presents the first investigation on the sorption of phosphorus (P) in the presence of two model phosphonate compounds, 2-aminothylphosphonoic acid (2-AEP) and phosphonoformic acid (PFA), on marine carbonate sediments.

Effect of temperature and salinity on phosphate sorption on marine sediments.

Our previous studies on the phosphate sorption on sediments in Florida Bay at 25 °C in salinity 36 seawater revealed that the sorption capacity varies considerably within the bay but can be attributed to the content of sedimentary P and Fe. It is known that both temperature and salinity influence the sorption process and their natural variations are the greatest in estuaries. To provide useful sorption parameters for modeling phosphate cycle in Florida Bay, a systematic study was carried out to quantify the effects of salinity and temperature on phosphate sorption on sediments.

Avoiding spurious correlation in analysis of chemical kinetic data.

This communication demonstrates that improperly formulated data analyses can inflate the strength of statistical correlations and result in drawing incorrect conclusions. The widespread misuse of a second-order kinetic model in the recent literature reveals that many chemists are not aware of the dangers of spurious correlation.

Spatial variation in sediment-water exchange of phosphorus in Florida Bay: AMP as a model organic compound.

Dissolved organic phosphorus (DOP) has been recognized as dominant components in total dissolved phosphorus (TDP) pools in many coastal waters, and its exchange between sediment and water is an important process in biogeochemical cycle of phosphorus. Adenosine monophosphate (AMP) was employed as a model DOP compound to simulate phosphorus exchange across sediment-water interface in Florida Bay. The sorption data from 40 stations were fitted to a modified Freundlich equation and provided a detailed spatial distribution both of the sediment's zero equilibrium phosphorus concentration (EPC(0-T)) and of the distribution coefficient (K(d-T)) with respect to TDP.

Clinical efficacy of a RAF inhibitor needs broad target blockade in BRAF-mutant melanoma.

B-RAF is the most frequently mutated protein kinase in human cancers. The finding that oncogenic mutations in BRAF are common in melanoma, followed by the demonstration that these tumours are dependent on the RAF/MEK/ERK pathway, offered hope that inhibition of B-RAF kinase activity could benefit melanoma patients. Herein, we describe the structure-guided discovery of PLX4032 (RG7204), a potent inhibitor of oncogenic B-RAF kinase activity.

A simple, effective mixing chamber used in conjunction with a syringe pump for flow analysis.

A simple, effective mixing chamber used in conjunction with a syringe pump for flow analysis is described and evaluated. A mixing chamber was constructed using a conventional 5mL pipette tip and its performance compared with a widely used mixing coil. The results demonstrate that the mixing coil does not rapidly and completely mix solutions.