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Stimuli-responsive, self-assembling nanomaterials hold a great promise to revolutionize medicine and technology. However, current discovery is slow and often serendipitous. Here we report a multiscale modeling study to elucidate the pH-controlled self-assembly of nanofibers from the peptide amphiphiles, palmitoyl-I-A3E4-NH2. The coarse-grained simulations revealed the formation of random-coil based spherical micelles at strong electrostatic repulsion. However, at weak or no electrostatic repulsion, the micelles merge into a nanofiber driven by the β-sheet formation between the peptide segments. The all-atom constant pH molecular dynamics revealed a cooperative transition between random coil and β-sheet in the pH range 6-7, matching the CD data. Interestingly, although the bulk pKa is more than one unit below the transition pH, consistent with the titration data, the highest pKa's coincide with the transition pH, suggesting that the latter may be tuned by modulating the pKa's of a few solvent-buried Glu side chains. Together, these data offer, to our best knowledge, the first multiresolution and quantitative view of the pH-dependent self-assembly of nanofibers. The novel protocols and insights gained are expected to advance the computer-aided design and discovery of pH-responsive nanomaterials.

Hanoi is the second largest city in Vietnam. The effects of climate change, coupled with rapid, unchecked urbanization and population increase are resulting in a severe rise in incidents of heat stress, which has serious ramifications for community health. In this study, a multivariable linear regression, heat index (HI) methods, and climate change scenarios for Vietnam in 2020 are used as input data to calculate the daily maximum heat index (HImax) for Hanoi during 2024-2028. Findings indicate that HImax at danger level has already occurred and will happen again in the future, with seasonal characteristics mainly distributed in June, July, August. For the years 2024-2028, HImax at the danger level increases in two scenarios compared to 2017-2021. Notably, the number of days with HImax at the extreme danger level, which may be the main cause of heat stroke, has 0.4 days/year occurring during 2017-2021. However, it will also appear in the years 2024-2028 in both RCP 4.5 and RCP 8.5 scenarios from June to August, at 0.6 days/year and 2.6 days/year, respectively. Knowing the daily maximum heat index for the future at specific times is crucial information for acting on the risk of heat stress in Hanoi given the current danger posed by climate change. [ABSTRACT FROM AUTHOR]

Even minor fluctuations in the carbon content in forest soil can significantly impact atmospheric carbon concentrations and future global climate patterns. Therefore, investigating the variation characteristics of soil organic carbon (SOC) in tropical forests is essential for comprehending the carbon sequestration potential of forest soil. This study delves into SOC dynamics within the natural forest types of Dongnai Culture and Nature Reserve in southeastern Vietnam. Nine 1000 m² plots were sampled across rich, medium, and poor forests. Soil samples were collected from depths ranging from 0 to 60 cm. The findings revealed increased SOC content from poor to rich forests, with a decrease in depth. The total carbon (C) stocks ranged from 92.20 Mg C ha-1 in poor forests to 124.30 Mg C ha-1 in rich forests within the top 60 cm. Over 81% of soil C was concentrated in the upper 40 cm. Factors such as soil water content and slope gradient emerged as crucial determinants affecting SOC distribution. These results underscore the potential of forest management practices to augment SOC levels, thereby offering valuable insights for estimating carbon stocks in the forest ecosystems of southeastern Vietnam. [ABSTRACT FROM AUTHOR]

The dengue virus circulates as four distinct serotypes, where a single serotype infection is typically asymptomatic and leads to acquired immunity against that serotype. However, the developed immunity to one serotype is thought to underlie the severe manifestation of the disease observed in subsequent infections from a different serotype. We developed a stochastic model of the adaptive immune response to dengue infections. We first delineated the mechanisms initiating and sustaining adaptive immune responses during primary infections. We then contrasted these immune responses during secondary infections of either a homotypic or heterotypic serotype to understand the role of pre-existing and reactivated immune pathways on disease severity. Comparison of non-symptomatic and severe cases from heterotypic infections demonstrated that overproduction of specific antibodies during primary infection induces an enhanced population of cross-reactive antibodies during secondary infection, ultimately leading to severe disease manifestations. In addition, the level of disease severity was found to correlate with immune response kinetics, which was dependent on beginning lymphocyte levels. Our results detail the contribution of specific lymphocytes and antibodies to immunity and memory recall that lead to either protective or pathological outcomes, allowing for the understanding and determination of mechanisms of protective immunity.

We examined the relationship between intrapulmonary particle distribution of carbonaceous and mineral dusts and remodeling of the airways along anatomically distinct airway paths in the lungs of Hispanic males from the central valley of California. Lung autopsy specimens from the Fresno County Coroner's Office were prepared by intratracheal instillation of 2% glutaraldehyde at 30 cm H(2)O pressure. Two distinct airway paths into the apico-posterior and apico-anterior portions of the left upper lung lobe were followed. Tissue samples for histologic analysis were generally taken from the intrapulmonary second, fourth, sixth, and ninth airway generations. Parenchymal tissues beyond the 12th airway generation of each airway path were also analyzed. There was little evidence of visible particle accumulation in the larger conducting airways (generations 2-6), except in bronchial-associated lymphoid tissues and within peribronchial connective tissue. In contrast, terminal and respiratory bronchioles arising from each pathway revealed varying degrees of wall thickening and remodeling. Walls with marked thickening contained moderate to heavy amounts of carbonaceous and mineral dusts. Wall thickening was associated with increases in collagen and interstitial inflammatory cells, including dust-laden macrophages. These changes were significantly greater in first-generation respiratory bronchioles compared to second- and third-generation respiratory bronchioles. These findings suggest that accumulation of carbonaceous and mineral dust in the lungs is significantly affected by lung anatomy with the greatest retention in centers of lung acini. Furthermore, there is significant remodeling of this transitional zone in humans exposed to ambient particulate matter.

This report is one of a series detailing the results of the CAL/APT program, a research effort being performed jointly by the University of California, Berkeley Pavement Research Center and the California Department of Transportation (Caltrans). It contains an evaluation of the performance of asphalt treated permeable base (ATPB) in asphalt concrete pavements based on observation, laboratory testing of ATPB, and computer simulation of representative pavement structures. The evaluation includes: 1) a summary of Caltrans experience with ATPB and drainage systems relative to their development and implementation, together with observations of field performance with respect to maintainability and stripping of asphalt treated materials; 2) a summary of the characteristics and performance of ATPB materials and drainage systems used by two other highway agencies; 3) results of laboratory investigation of the stiffness and permanent deformation characteristics of ATPB mixes, including the effects of soaking and loading while saturated on these parameters; and 4) the results of analyses of representative pavement structures to quantify the expected effects of as-compacted and soaked ATPB on pavement performance.

This report is the third in a series which describe the results of tests and their interpretation on full-scale pavements designed and constructed according to the procedures of the California Department of Transportation (Caltrans) at the Richmond Field Station (RFS) of the University of California at Berkeley (UCB). It describes the results of the Heavy Vehicle Simulator (HVS) test on the third of four pavement test sections, an asphalt-concrete section containing an asphalt treated permeable base (ATPB) designated Section 502CT. The tests on these four test sections have been performed as part of Goal 1 of the Strategic Plan of the Caltrans Accelerated Pavement Testing, or CAL/APT program (1). One objective of the test program is to obtain data to quantitatively verify existing Caltrans pavement design methodologies for asphalt treated permeable base (ATPB) pavements and conventional aggregate base pavements with regard to failure under trafficking at moderate temperatures (Goal 1), while preparing a uniform platform on which overlays (Goal 3) will be constructed to be trafficked. Other objectives are: to quantify the effective elastic moduli of the various pavement layers, based on an ad-hoc use of layered elastic analysis; to quantify the stress dependence of the pavement layers; to determine the failure mechanisms of the various layers; and to determine and compare the fatigue lives of the two types of pavement structure.

Meteorological factors, especially temperature and humidity, have a great impact on human physiology. In the context of climate change, the impact of temperature on people's health in Thai Binh city (Vietnam) is becoming more and more serious. Based on meteorological data for the period of 1991-2021 and Vietnam climate change scenario data, the daily maximum heat index (HImax) scenario for the period of 2024-2054 is calculated by the method of correlation evaluation and regression equations. The results show that in the future the trend of HImax is 0.0875°C per year under the RCP 4.5 scenario (Medium Low Greenhouse Gases Concentration Scenario) and 0.0919°C per year under the RCP 8.5 scenario (High Greenhouse Gases Concentration Scenarios). The number of weeks per 5 years having daily HImax at danger level (HIwave) tends to increase 6.14 times for scenario RCP 4.5; 7.0 times for scenario RCP 8.5. Especially, the number of days at risk of heat stroke in the past 31-year period is 5 days, then in the future 31-year period there are 77 days with scenario RCP 4.5 and 116 days with scenario RCP 8.5 and this phenomenon mainly concentrated in the months of June, July, August. [ABSTRACT FROM AUTHOR]