Ping Du

Bio: Ping Du is an academic researcher from Pennsylvania State University. The author has contributed to research in topics: Extracellular matrix & Population. The author has an hindex of 22, co-authored 114 publications receiving 1392 citations. Previous affiliations of Ping Du include State Oceanic Administration & Korea Institute of Science and Technology.

Epidemiology and outcomes of COVID-19 in HIV-infected individuals: a systematic review and meta-analysis.

Abstract: Susceptibility to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the risk of mortality among people living with human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) (PLWHA) is largely unknown. PLWHA are unique due to their altered immune system from their history of chronic HIV infection and their use of antiretroviral therapy, some of which have been used experimentally to treat coronavirus disease 2019 (COVID-19). Therefore, we conducted a systematic review and meta-analysis to assess the epidemiology of SARS-COV-2/HIV coinfection and estimate associated mortality from COVID-19 (Prospero Registration ID: CRD42020187980). PubMed, SCOPUS, OVID and Cochrane Library databases, and medRxiv preprint repositories were searched from January 1, 2020, to December 12, 2020. Data were extracted from studies reporting COVID-19 attack and mortality rates in PLWHA compared to their HIV-negative counterparts. Pooled attack and mortality risks were quantified using random-effects models. We identified 22 studies that included 20,982,498 participants across North America, Africa, Europe, and Asia. The median age was 56 years, and 50% were male. HIV-positive persons had a significantly higher risk of SARS-CoV-2 infection [risk ratio (RR) 1.24, 95% CI 1.05–1.46)] and mortality from COVID-19 (RR 1.78, 95% CI 1.21–2.60) than HIV-negative individuals. The beneficial effects of tenofovir and protease-inhibitors in reducing the risk of SARS-CoV-2 infection and death from COVID-19 in PLWHA remain inconclusive. HIV remains a significant risk factor for acquiring SARS-CoV-2 infection and is associated with a higher risk of mortality from COVID-19. In support of the current Centers for Disease Control and Prevention (CDC) guidelines, persons with HIV need priority consideration for the SARS-CoV-2 vaccine.

A multilayer bending model for conducting polymer actuators

Abstract: Electroactive conducting polymers (CPs) have been frequently used for fabricating bending actuators. To model this type of actuation, the traditional double-layer beam bending theory was implemented by neglecting the thickness of the thin intermediate metal layers for the sake of simplification. However, this common assumption has not been carefully validated and the associated errors have not been well acknowledged. In this work, a generic multilayer bending model was introduced to account for the actuators consisting of an arbitrary number of layers. Our model found the bending curvature, strain, stress, and in particular work density of the multilayer actuator as explicit functions of the thickness and modulus of each individual layer. The thickness of metals and conducting polymers were controlled in thermal evaporation and electrochemical synthesis, respectively. The modulus of polypyrrole (PPy), the conducting polymer used in this work, was determined within our model by the bending curvature measured using the charge-coupled device (CCD). This gave a modulus of our electrochemically synthesized PPy of 80 MPa, corresponding to an actuation strain of 2% in our model. It was concluded that neglecting the intermediate metal layers would lead to substantial errors. For instance, using a PPy/Au/Kapton trilayer actuator, a 5% error or below in strain can only be found if the Au layer is one thousand times thinner than Kapton. To enhance the actuation, a PPy/Pt/PVDF/Pt/PPy five-layer actuator has been often used. In this case, even if the Pt layer was reduced to 10 nm, our predicted error of neglecting the two metal layers would be 12.59%. Our results showed that the work density, chosen to measure the overall performance of the actuator, was highly sensitive to the modulus of the substrate polymer layer so that it was generally desirable of using a soft polymer substrate. With the multilayer bending model, we intend to provide an accurate and reliable tool for systematically analyzing the bending behavior and performance of the CP-based actuators.

Acute Kidney Injury Network: report of an initiative to improve outcomes in acute kidney injury

Abstract: Acute kidney injury (AKI) is a complex disorder for which currently there is no accepted definition. Having a uniform standard for diagnosing and classifying AKI would enhance our ability to manage these patients. Future clinical and translational research in AKI will require collaborative networks of investigators drawn from various disciplines, dissemination of information via multidisciplinary joint conferences and publications, and improved translation of knowledge from pre-clinical research. We describe an initiative to develop uniform standards for defining and classifying AKI and to establish a forum for multidisciplinary interaction to improve care for patients with or at risk for AKI. Members representing key societies in critical care and nephrology along with additional experts in adult and pediatric AKI participated in a two day conference in Amsterdam, The Netherlands, in September 2005 and were assigned to one of three workgroups. Each group's discussions formed the basis for draft recommendations that were later refined and improved during discussion with the larger group. Dissenting opinions were also noted. The final draft recommendations were circulated to all participants and subsequently agreed upon as the consensus recommendations for this report. Participating societies endorsed the recommendations and agreed to help disseminate the results. The term AKI is proposed to represent the entire spectrum of acute renal failure. Diagnostic criteria for AKI are proposed based on acute alterations in serum creatinine or urine output. A staging system for AKI which reflects quantitative changes in serum creatinine and urine output has been developed. We describe the formation of a multidisciplinary collaborative network focused on AKI. We have proposed uniform standards for diagnosing and classifying AKI which will need to be validated in future studies. The Acute Kidney Injury Network offers a mechanism for proceeding with efforts to improve patient outcomes.

Production of a tissue-like structure by contraction of collagen lattices by human fibroblasts of different proliferative

Abstract: Fibroblasts can condense a hydrated collagen lattice to a tissue-like structure 1/28th the area of the starting gel in 24 hr. The rate of the process can be regulated by varying the protein content of the lattice, the cell number, or the con- centration of an inhibitor such as Colcemid. Fibroblasts of high population doubling level propagated in vitro, which have left the cell cycle, can carry out the contraction at least as efficiently as cycling cells. The potential uses of the system as an immu- nologically tolerated "tissue" for wound hea ing and as a model for studying fibroblast function are discussed.

Mechanical characterization of bulk Sylgard 184 for microfluidics and microengineering

Abstract: Polydimethylsiloxane (PDMS) elastomers are extensively used for soft lithographic replication of microstructures in microfluidic and micro-engineering applications. Elastomeric microstructures are commonly required to fulfil an explicit mechanical role and accordingly their mechanical properties can critically affect device performance. The mechanical properties of elastomers are known to vary with both curing and operational temperatures. However, even for the elastomer most commonly employed in microfluidic applications, Sylgard 184, only a very limited range of data exists regarding the variation in mechanical properties of bulk PDMS with curing temperature. We report an investigation of the variation in the mechanical properties of bulk Sylgard 184 with curing temperature, over the range 25 ◦ C to 200 ◦ C. PDMS samples for tensile and compressive testing were fabricated according to ASTM standards. Data obtained indicates variation in mechanical properties due to curing temperature for Young’s modulus of 1.32‐2.97 MPa, ultimate tensile strength of 3.51‐7.65 MPa, compressive modulus of 117.8‐186.9 MPa and ultimate compressive strength of 28.4‐51.7 GPa in a range up to 40% strain and hardness of 44‐54 ShA.

The United Nations Children's Fund

Abstract: The United Nations Children's Fund, or UNICEF, was originally created to provide relief for children in countries devastated by the destruction of World War II. After 1950, UNICEF turned to focus on general programs for the improvement of children's welfare worldwide, and in 1965, it was awarded the Nobel Prize for Peace for its humanitarian efforts. The organization concentrates on areas in which relatively small expenditures can have a significant impact on the lives of the most disadvantaged children in developing countries, such as the prevention and treatment of disease, child healthcare, malnutrition, illiteracy, and other welfare services.