Effects of aging on attachment of Candida albicans to conventional heat-polymerized, CAD-CAM milled, and CAD-CAM 3D-printed acrylic resin bases.

PURPOSE: The aim of this study was to assess Candida albicans attachment on conventionally fabricated (polymethylmethacrylate, PMMA), CAD-CAM milled, and 3D-printed acrylic resin bases pre- and post-simulated thermal aging, along with examining material surface changes after aging. MATERIALS AND METHODS: Forty-six samples (10 mm × 10 mm × 2 mm) for each of four material groups (conventional heat-polymerized PMMA, CAD-CAM milled acrylic resin base, CAD-CAM 3D-printed methacrylate resin base, CAD-CAM 3D-printed urethane methacrylate resin base) were subjected to 0, 1, or 2 years of simulated thermal aging. Microscopic images were taken before and after aging, and C. albicans attachment was quantified using cell proliferation assay (XTT). Statistical analysis employed analysis of variance (α = 0.05). RESULTS: Two-way factorial analysis showed no significant differences based on acrylic resin type or thermal aging (p = 0.344 and p = 0.091 respectively). However, C. albicans attachment significantly differed between 0- and 2-year thermally aged groups (p = 0.004), mainly due to elevated initial attachments on CAD-CAM milled acrylic resin base and CAD-CAM 3D-printed urethane methacrylate resin base. CONCLUSIONS: Regardless of the fabrication technique and material combination, no significant differences were found in C. albicans adhesion pre- or post- thermal aging. Milled and 3D-printed bases compared favorably with heat- polymerized PMMA in their affinity for C. albicans attachment and surface characteristics after aging. These findings indicate that the risk of patients developing denture stomatitis might not be linked to the type of acrylic resin or fabrication method used.

Politics, ideology, and medical theory: interview with Christopher Hamlin.

An interview with Christopher Hamlin in November 2020 in which he explains how he became interested in the history of public health. He talks about the outcomes of epidemics, the relationship between trust in science and moral imagination, why historians use previous public health experiences to think about the present, the role of discipline and ideology in problem-solving arrangements to deal with public health issues, and his new article on legal medicine.

Politics, ideology, and medical theory: interview with Christopher Hamlin / Política, ideologia e teoria médica: entrevista com Christopher Hamlin

Abstract An interview with Christopher Hamlin in November 2020 in which he explains how he became interested in the history of public health. He talks about the outcomes of epidemics, the relationship between trust in science and moral imagination, why historians use previous public health experiences to think about the present, the role of discipline and ideology in problem-solving arrangements to deal with public health issues, and his new article on legal medicine.

Resumo Entrevista com Christopher Hamlin, feita em novembro de 2020, na qual ele explica como se interessou pela história da saúde pública, fala sobre as consequências das epidemias, sobre a relação entre confiança na ciência e imaginação moral, por que historiadores levantam experiências passadas de saúde pública para pensar a respeito do presente, sobre o papel da disciplina e da ideologia nos arranjos para resolução de problemas de saúde pública e comenta a respeito do seu novo artigo sobre medicina legal.

Retentive Forces of Removable Partial Denture Clasp Assemblies Made from Polyaryletherketone and Cobalt-Chromium: A Comparative Study.

PURPOSE: To compare retentive forces of removable partial denture clasps traditionally fabricated with cobalt-chromium (CoCr) material and two computer-aided design and computer-aided manufactured (CAD/CAM) thermoplastic polymers. MATERIALS AND METHODS: Forty-eight clasp assemblies (16 CoCr, 16 polyetheretherketone (PEEK) and 16 polyetherketoneketone (PEKK) thermoplastic polymer) were fabricated for 48 mandibular tooth analogs. Individual clasps were inserted and removed on the tooth analogs utilizing a chewing simulator for 15,000 cycles to simulate 10 years of use. Retentive forces were measured utilizing a mechanical load tester at baseline and intervals of 1500 cycles. Data were analyzed with one-way Analysis of Variance, Tukey post-hoc, and paired T tests. RESULTS: Mean retentive forces between all groups were significantly different (p < 0.001). Retentive forces of CoCr clasps were significantly higher than both polymers (p < 0.001). The mean retentive forces for PEEK were not significantly different from PEKK (p = 0.23). A significant increase in retentive forces was observed for all three clasps after the first period of cycling, followed by continual decrease for the remaining cycles. At the endpoint of 15,000 cycles, no clasp assemblies showed lower retentive forces than at initial baseline. CONCLUSION: Thermoplastic polymer clasps demonstrated lower retentive forces compared to CoCr clasps. All three groups displayed a similar pattern of initial increase, followed by a gradual decrease, of retentive force. Despite this observation, the clasps maintained similar or higher retentive forces than measured at baseline. This resistance to fatigue and ability to fabricate with CAD/CAM technologies provides support for clinical use of these high-performance polymer (HPP) materials.

What's Scientific About Forensic Science? Three Versions of American Forensics, 1903-1965, and One Modest Proposal.

Growing attention to the philosophy of forensic science in recent decades has sometimes included the question: "what kind of science is forensic science"? Yet there has been little discussion of how that question has been differently construed in terms of period, place, and prevailing anxieties. Following an examination of the unique character this question must have in an American legal context, this article reviews three modes/phases of response, rooted successively in individual authority, comprehensive method, and institutions of flexible problem-solving. The conclusion applies this complex legacy in two ways: first to clarify areas of incoherence and tension in recent attempts to underwrite forensic sciences, and second to supply a fuller framework for Max Houck's argument for the essentially historical character of forensic science.

COVID-19's Impact on the African American Community: A Stakeholder Engagement Approach to Increase Public Awareness Through Virtual Town Halls.

COVID-19 has created a rapidly evolving public health crisis disproportionately impacting African Americans due to persistent inequities. The changing COVID-19 guidelines have resulted in concerns expressed by the American public, including unique concerns expressed by African Americans. To increase COVID-19-related awareness and dialogue among the African American community, the University of Alabama at Birmingham School of Public Health and the Housing Association of the Birmingham District convened a virtual town hall. This process of stakeholder engagement underscored the importance of cross-disciplinary expertise and collaboration and of community education and outreach by trusted sources.

Effect of Screw Channel Angulation on Reverse Torque Values of Dental Implant Abutment Screws.

PURPOSE: To compare the reverse torque values (RTVs) of abutment screws tightened from three different angles. MATERIALS AND METHODS: Implant abutment screws (n = 48), abutments (3), and regular platform implant analogs (3) were divided into three angulation groups (n = 16/group). Custom guides of 0°, 10°, and 20° were fabricated to verify driver angulation. The implant components for each group were assembled and all screws torqued to 35 Ncm using a universal screwdriver in a manual torque wrench at the appropriate angle. Torque was reapplied 10 minutes after initial torque. A digital gauge was then used to measure reverse torque at a position parallel (0°) to the implant analog. RTVs were recorded and compared using one-way ANOVA and Tukey HSD post-hoc comparisons (α = 0.05). RESULTS: All mean RTVs fell below the targeted torque value of 35Ncm, with some values in each angulation group 10% below of the target value. Mean RTVs in descending order from targeted torque value were: 10° group = 32.07 ± 0.97 Ncm, 0° group = 31.16 ± 1.12 Ncm, and 20° group = 30.08 ± 0.88 Ncm. One-way ANOVA revealed significant differences between angulation groups (F = 15.954, p < 0.001). Tukey HSD post hoc comparisons revealed that the mean RTVs of the three angulation groups were significantly different from each other (0° vs. 10°: p = 0.033; 0° vs. 20°: p = 0.011; 10° vs. 20°: p < 0.001). CONCLUSIONS: All RTVs did not reach the targeted torque value of 35 Ncm. Mean screw RTVs were significantly influenced by screwdriver insertion angulation.

Correction: Trinh, H.V., et al. Humoral Response to the HIV-1 Envelope V2 Region in a Thai Early Acute Infection Cohort. Cells 2019, 8, 365.

In the original version of our article [...].

Humoral Response to the HIV-1 Envelope V2 Region in a Thai Early Acute Infection Cohort.

Reduced risk of HIV-1 infection correlated with antibody responses to the envelope variable 1 and 2 regions in the RV144 vaccine trial. To understand the relationship between antibody responses, V2 sequence, and structure, plasma samples (n = 16) from an early acute HIV-1 infection cohort from Thailand infected with CRF01_AE strain were analyzed for binding to V2 peptides by surface plasmon resonance. Five participants with a range of V2 binding responses at week 24 post-infection were further analyzed against a set of four overlapping V2 peptides that were designed based on envelope single-genome amplification. Antibody responses that were relatively consistent over the four segments of the V2 region or a focused response to the C-strand (residues 165-186) of the V2 region were observed. Viral escape in the V2 region resulted in significantly reduced antibody binding. Structural modeling indicated that the C-strand and the sites of viral variation were highly accessible in the open conformation of the HIV-1 Env trimer. V2 residues, 165-186 are preferentially targeted during acute infection. Residues 169-184 were also preferentially targeted by the protective immune response in the RV144 trial, thus emphasizing the importance of these residues for vaccine design.

Control of Heterologous Simian Immunodeficiency Virus SIVsmE660 Infection by DNA and Protein Coimmunization Regimens Combined with Different Toll-Like-Receptor-4-Based Adjuvants in Macaques.

We developed a method of simultaneous vaccination with DNA and protein resulting in robust and durable cellular and humoral immune responses with efficient dissemination to mucosal sites and protection against simian immunodeficiency virus (SIV) infection. To further optimize the DNA-protein coimmunization regimen, we tested a SIVmac251-based vaccine formulated with either of two Toll-like receptor 4 (TLR4) ligand-based liposomal adjuvant formulations (TLR4 plus TLR7 [TLR4+7] or TLR4 plus QS21 [TLR4+QS21]) in macaques. Although both vaccines induced humoral responses of similar magnitudes, they differed in their functional quality, including broader neutralizing activity and effector functions in the TLR4+7 group. Upon repeated heterologous SIVsmE660 challenge, a trend of delayed viral acquisition was found in vaccinees compared to controls, which reached statistical significance in animals with the TRIM-5α-resistant (TRIM-5α R) allele. Vaccinees were preferentially infected by an SIVsmE660 transmitted/founder virus carrying neutralization-resistant A/K mutations at residues 45 and 47 in Env, demonstrating a strong vaccine-induced sieve effect. In addition, the delay in virus acquisition directly correlated with SIVsmE660-specific neutralizing antibodies. The presence of mucosal V1V2 IgG binding antibodies correlated with a significantly decreased risk of virus acquisition in both TRIM-5α R and TRIM-5α-moderate/sensitive (TRIM-5α M/S) animals, although this vaccine effect was more prominent in animals with the TRIM-5α R allele. These data support the combined contribution of immune responses and genetic background to vaccine efficacy. Humoral responses targeting V2 and SIV-specific T cell responses correlated with viremia control. In conclusion, the combination of DNA and gp120 Env protein vaccine regimens using two different adjuvants induced durable and potent cellular and humoral responses contributing to a lower risk of infection by heterologous SIV challenge.IMPORTANCE An effective AIDS vaccine continues to be of paramount importance for the control of the pandemic, and it has been proven to be an elusive target. Vaccine efficacy trials and macaque challenge studies indicate that protection may be the result of combinations of many parameters. We show that a combination of DNA and protein vaccinations applied at the same time provides rapid and robust cellular and humoral immune responses and evidence for a reduced risk of infection. Vaccine-induced neutralizing antibodies and Env V2-specific antibodies at mucosal sites contribute to the delay of SIVsmE660 acquisition, and genetic makeup (TRIM-5α) affects the effectiveness of the vaccine. These data are important for the design of better vaccines and may also affect other vaccine platforms.

Generation and characterization of a bivalent protein boost for future clinical trials: HIV-1 subtypes CR01_AE and B gp120 antigens with a potent adjuvant.

The RV144 Phase III clinical trial with ALVAC-HIV prime and AIDSVAX B/E subtypes CRF01_AE (A244) and B (MN) gp120 boost vaccine regime in Thailand provided a foundation for the future development of improved vaccine strategies that may afford protection against the human immunodeficiency virus type 1 (HIV-1). Results from this trial showed that immune responses directed against specific regions V1V2 of the viral envelope (Env) glycoprotein gp120 of HIV-1, were inversely correlated to the risk of HIV-1 infection. Due to the low production of gp120 proteins in CHO cells (2-20 mg/L), cleavage sites in V1V2 loops (A244) and V3 loop (MN) causing heterogeneous antigen products, it was an urgent need to generate CHO cells harboring A244 gp120 with high production yields and an additional, homogenous and uncleaved subtype B gp120 protein to replace MN used in RV144 for the future clinical trials. Here we describe the generation of Chinese Hamster Ovary (CHO) cell lines stably expressing vaccine HIV-1 Env antigens for these purposes: one expressing an HIV-1 subtype CRF01_AE A244 Env gp120 protein (A244.AE) and one expressing an HIV-1 subtype B 6240 Env gp120 protein (6240.B) suitable for possible future manufacturing of Phase I clinical trial materials with cell culture expression levels of over 100 mg/L. The antigenic profiles of the molecules were elucidated by comprehensive approaches including analysis with a panel of well-characterized monoclonal antibodies recognizing critical epitopes using Biacore and ELISA, and glycosylation analysis by mass spectrometry, which confirmed previously identified glycosylation sites and revealed unknown sites of O-linked and N-linked glycosylations at non-consensus motifs. Overall, the vaccines given with MF59 adjuvant induced higher and more rapid antibody (Ab) responses as well as higher Ab avidity than groups given with aluminum hydroxide. Also, bivalent proteins (A244.AE and 6240.B) formulated with MF59 elicited distinct V2-specific Abs to the epitope previously shown to correlate with decreased risk of HIV-1 infection in the RV144 trial. All together, these results provide critical information allowing the consideration of these candidate gp120 proteins for future clinical evaluations in combination with a potent adjuvant.

The Pedagogical Roots of the History of Science: Revisiting the Vision of James Bryant Conant.

This essay examines the rise and fall of Harvard president James Bryant Conant's postwar vision for history of science-based general science education. As well as developing the foundations of Conant's vision, it considers the tension between Conant's science pedagogy-centered view of the history of science and the claims of George Sarton and I. B. Cohen that the field was a distinct discipline. It relates these themes to Conant's unease with the like-minded theorists Thomas Kuhn and Michael Polanyi and concludes by examining Conant's anticipation of later science studies approaches and reflecting on his place in the history of the history of science.

A New Approach to Produce HIV-1 Envelope Trimers: BOTH CLEAVAGE AND PROPER GLYCOSYLATION ARE ESSENTIAL TO GENERATE AUTHENTIC TRIMERS.

The trimeric envelope spike of HIV-1 mediates virus entry into human cells. The exposed part of the trimer, gp140, consists of two noncovalently associated subunits, gp120 and gp41 ectodomain. A recombinant vaccine that mimics the native trimer might elicit entry-blocking antibodies and prevent virus infection. However, preparation of authentic HIV-1 trimers has been challenging. Recently, an affinity column containing the broadly neutralizing antibody 2G12 has been used to capture recombinant gp140 and prepare trimers from clade A BG505 that naturally produces stable trimers. However, this antibody-based approach may not be as effective for the diverse HIV-1 strains with different epitope signatures. Here, we report a new and simple approach to produce HIV-1 envelope trimers. The C terminus of gp140 was attached to Strep-tag II with a long linker separating the tag from the massive trimer base and glycan shield. This allowed capture of nearly homogeneous gp140 directly from the culture medium. Cleaved, uncleaved, and fully or partially glycosylated trimers from different clade viruses were produced. Extensive biochemical characterizations showed that cleavage of gp140 was not essential for trimerization, but it triggered a conformational change that channels trimers into correct glycosylation pathways, generating compact three-blade propeller-shaped trimers. Uncleaved trimers entered aberrant pathways, resulting in hyperglycosylation, nonspecific cross-linking, and conformational heterogeneity. Even the cleaved trimers showed microheterogeneity in gp41 glycosylation. These studies established a broadly applicable HIV-1 trimer production system as well as generating new insights into their assembly and maturation that collectively bear on the HIV-1 vaccine design.

Forensic cultures in historical perspective: technologies of witness, testimony, judgment (and justice?).

This article explores the history of forensic science in terms of ideologies and institutions rather than developing technique. It presents an analytical framework for characterising forensic institutions and practices, past and present. That framework highlights the distinct issues of means of witness, accredited testimony, and the reaching of juridical decisions. The article applies the framework by comparing four forensic 'formations,' (or 'cultures') which have been prominent at various times and places in the western world from the early modern period onward: these are the central European heritage of the Caroline code, a eugenically-oriented forensic enterprise of late nineteenth-century America, the forensic perspective in nineteenth-century British India, and the representation of forensic certainty in contemporary American popular culture. The article concludes with a critique of what seems an increasingly common expectation: that forensic science evolves independently of legal institutions, and can ultimately displace them.

Short communication routine HIV testing in the emergency department: assessment of patient perceptions.

The CDC released revised HIV testing guidelines in 2006 recommending routine, opt-out HIV testing in acute care settings including emergency departments (ED). Patient attitudes have been cited as a barrier to implementation of routine HIV testing in the ED. We assessed patients' perceptions of HIV testing in the ED through a contextual qualitative approach. The study was conducted during a 72-h period. All adults presenting to the ED without life-threatening trauma or psychiatric crisis completed a standardized questionnaire. The questionnaire explored HIV testing history, knowledge of testing resources, and qualitative items addressing participant perceptions about advantages and disadvantages to ED testing. After completion of the interview, participants were offered a free, confidential, rapid HIV test. Among 329 eligible individuals approached, 288 (87.5%) completed the initial interview. Participants overwhelmingly (n=247, 85.8%) reported support for testing and identified increased knowledge (41%), prevention (12.5%), convenience (11.8%), and treatment (4.9%) among the advantages. Fear and denial about one's HIV status, reported by <5% of patients, were identified as the most significant barriers to ED testing. Bivariate analysis determined race and ethnicity differences between individuals completing the interview and those who refused (p<0.05). Among individuals consenting for testing (n=186, 64.6%), no positives were detected. Most patients support HIV testing in the ED, noting knowledge of status, prevention, convenience, and linkage to early treatment as distinct advantages. These data are of particular benefit to decision makers considering the addition of routine HIV testing in EDs.

Recruitment of volunteers for a home-delivered meals programme serving homebound older adults: a theoretically derived programme among faith communities.

OBJECTIVE: Home-delivered nutrition programmes that are federally subsidized by the US Administration on Aging seek to ensure that socially isolated older adults who are unable to purchase and prepare their own food have nutritious meals delivered to them regularly by both employed and volunteer staff. Unfortunately, there are long waiting lists in some neighbourhoods that are often due to a shortage of volunteers. The present paper describes a theoretically driven community-based project designed to increase volunteer participation in serving Meals on Wheels (MOW) clients. DESIGN: A Support Team model was applied in the project wherein existing social capital among religious faith communities, and social networks within those organizations, was joined with a local MOW programme to create a sustainable meal delivery route to vulnerable homebound older adults. SETTING: The programme participants were in one underserved neighbourhood in Birmingham, Alabama, an urban city in the south-eastern USA. SUBJECTS: The subjects under consideration are both MOW clients and volunteers. MOW clients are those individuals aged 60 years and above who qualify for the service; the volunteers are from community churches. RESULTS: One volunteer route, comprising six congregations that delivered meals to sixteen homebound older adults, was created. The route served more than 2000 meals in 2006 (the year the programme began) and continues to serve clients today. CONCLUSIONS: The programme's successful implementation provides evidence that reliance on theory is critical in planning and developing effective community-based programme interventions.

"Cholera forcing". The myth of the good epidemic and the coming of good water.

It has been frequently claimed that cholera epidemics, both in the 19th century and today, were and can be the key stimulus for procurement of safe water and sanitation, an idea that I call "cholera forcing." "Technology forcing" refers to imposition of exogenous factors that suddenly make possible achievements that had not seemed so; cholera has been seen in this light. I argue that this view oversimplifies and underrepresents the importance of industrialization in securing water supplies. Careful study of the financial, political, and administrative foundations of such changes will be more fruitful.