Dip-pen nanolithography was used to construct arrays of proteins with 100- to 350-nanometer features. These nanoarrays exhibit almost no detectable nonspecific binding of proteins to their passivated portions even in complex mixtures of proteins, and therefore provide the opportunity to study a variety of surface-mediated biological recognition processes. For example, reactions involving the protein features and antigens in complex solutions can be screened easily by atomic force microscopy. As further proof-of-concept, these arrays were used to study cellular adhesion at the submicrometer scale.
Infection with human papillomavirus (HPV) is recognized as one of the major causes of infection-related cancer worldwide, as well as the causal factor in other diseases. Strong evidence for a causal etiology with HPV has been stated by the International Agency for Research on Cancer for cancers of the cervix uteri, penis, vulva, vagina, anus and oropharynx (including base of the tongue and tonsils). Of the estimated 12.7 million new cancers occurring in 2008 worldwide, 4.8% were attributable to HPV infection, with substantially higher incidence and mortality rates seen in developing versus developed countries. In recent years, we have gained tremendous knowledge about HPVs and their interactions with host cells, tissues and the immune system; have validated and implemented strategies for safe and efficacious prophylactic vaccination against HPV infections; have developed increasingly sensitive and specific molecular diagnostic tools for HPV detection for use in cervical cancer screening; and have substantially increased global awareness of HPV and its many associated diseases in women, men, and children. While these achievements exemplify the success of biomedical research in generating important public health interventions, they also generate new and daunting challenges: costs of HPV prevention and medical care, the implementation of what is technically possible, socio-political resistance to prevention opportunities, and the very wide ranges of national economic capabilities and health care systems. Gains and challenges faced in the quest for comprehensive control of HPV infection and HPV-related cancers and other disease are summarized in this review. The information presented may be viewed in terms of a reframed paradigm of prevention of cervical cancer and other HPV-related diseases that will include strategic combinations of at least four major components: 1) routine introduction of HPV vaccines to women in all countries, 2) extension and simplification of existing screening programs using HPV-based technology, 3) extension of adapted screening programs to developing populations, and 4) consideration of the broader spectrum of cancers and other diseases preventable by HPV vaccination in women, as well as in men. Despite the huge advances already achieved, there must be ongoing efforts including international advocacy to achieve widespread—optimally universal—implementation of HPV prevention strategies in both developed and developing countries. This article summarizes information from the chapters presented in a special ICO Monograph ‘Comprehensive Control of HPV Infections and Related Diseases’ Vaccine Volume 30, Supplement 5, 2012. Additional details on each subtopic and full information regarding the supporting literature references may be found in the original chapters.
Two series of redox-active, iron−sulfur core dendrimers of the general structure (nBu4N)2[Fe4S4(S-Dend)4] (Dend = dendrons of generations 1 through 4) were prepared. Heterogeneous electron-transfer rate constants indicated that the rigid series of dendrimers were more effective at attenuating the rate of electron transfer than were the flexible series of dendrimers. These results were rationalized using computationally derived models which indicated an offset and mobile iron−sulfur core in the flexible series of molecules and a more central and relatively immobile iron−sulfur core in the rigid series of molecules. Further consideration of these data indicated that, while the dendrimers containing rigid ligands had better encapsulated redox cores for a given molecular weight, these molecules had higher electron-transfer rates for a given molecular radius.
Previous studies have noted the presence of mesenchymal stem cells located within the connective tissue matrices of avian skeletal muscle, dermis, and heart. In these studies, clonal analysis coupled with dexamethasone treatment revealed the presence of multiple populations of stem cells composed of both lineagecommitted progenitor mesenchymal stem cells and lineage-uncommitted pluripotent mesenchyma1 stem cells. The present study was undertaken to assess the distribution of these stem cells in the connective tissues throughout various regions of the body. Day 11 chick embryos were divided into 26 separate regions. Heart, limb skeletal muscle, and limb dermis were included as control tissues. Cells were harvested enzymatically and grown using conditions optimal for the isolation, cryopreservation, and propagation of avian mesenchymal stem cells. Cell aliquots were plated, incubated with various concentrations of dexamethasone, and examined for differentiated phenotypes. Four recurring phenotypes appeared in dexamethasone-treated stem cells: skeletal muscle myotubes, fat cells, cartilage nodules, and bone nodules. These results suggest that progenitor mesenchymal stem cells and putative pluripotent mesenchymal stem cells with the potential to form at least four tissues of mesodermal origin have a widespread distribution throughout the body, being located within the connective tissue compartments of many organs and organ systems.
This paper presents a flexible approach for using Dip Pen Nanolithography (DPN) to nanopattern mixed monolayers for the selective immobilization of bioassemblies. DPN was used with a binary inksconsisting of a symmetric 11-mercaptoundecyl-penta(ethylene glycol) disulfide and a mixed disulfide substituted with one maleimide groupsto pattern nanoscale features that present functional groups for the chemospecific immobilization of cysteine-labeled biomolecules. This strategy was applied to the chemospecific immobilization of cysteine mutant cowpea mosaic virus capsid particles (cys-VCPs). The combination of DPN for defining nanopatterns and surface chemistries for controlling the immobilization of ligands will be broadly useful in basic and applied biology.
Background Surgery is the main modality of cure for solid cancers and was prioritised to continue during COVID-19 outbreaks. This study aimed to identify immediate areas for system strengthening by comparing the delivery of elective cancer surgery during the COVID-19 pandemic in periods of lockdown versus light restriction. Methods This international, prospective, cohort study enrolled 20 006 adult (≥18 years) patients from 466 hospitals in 61 countries with 15 cancer types, who had a decision for curative surgery during the COVID-19 pandemic and were followed up until the point of surgery or cessation of follow-up (Aug 31, 2020). Average national Oxford COVID-19 Stringency Index scores were calculated to define the government response to COVID-19 for each patient for the period they awaited surgery, and classified into light restrictions (index <20), moderate lockdowns (20–60), and full lockdowns (>60). The primary outcome was the non-operation rate (defined as the proportion of patients who did not undergo planned surgery). Cox proportional-hazards regression models were used to explore the associations between lockdowns and non-operation. Intervals from diagnosis to surgery were compared across COVID-19 government response index groups. This study was registered at ClinicalTrials.gov , NCT04384926 . Findings Of eligible patients awaiting surgery, 2003 (10·0%) of 20 006 did not receive surgery after a median follow-up of 23 weeks (IQR 16–30), all of whom had a COVID-19-related reason given for non-operation. Light restrictions were associated with a 0·6% non-operation rate (26 of 4521), moderate lockdowns with a 5·5% rate (201 of 3646; adjusted hazard ratio [HR] 0·81, 95% CI 0·77–0·84; p<0·0001), and full lockdowns with a 15·0% rate (1775 of 11 827; HR 0·51, 0·50–0·53; p<0·0001). In sensitivity analyses, including adjustment for SARS-CoV-2 case notification rates, moderate lockdowns (HR 0·84, 95% CI 0·80–0·88; p<0·001), and full lockdowns (0·57, 0·54–0·60; p<0·001), remained independently associated with non-operation. Surgery beyond 12 weeks from diagnosis in patients without neoadjuvant therapy increased during lockdowns (374 [9·1%] of 4521 in light restrictions, 317 [10·4%] of 3646 in moderate lockdowns, 2001 [23·8%] of 11 827 in full lockdowns), although there were no differences in resectability rates observed with longer delays. Interpretation Cancer surgery systems worldwide were fragile to lockdowns, with one in seven patients who were in regions with full lockdowns not undergoing planned surgery and experiencing longer preoperative delays. Although short-term oncological outcomes were not compromised in those selected for surgery, delays and non-operations might lead to long-term reductions in survival. During current and future periods of societal restriction, the resilience of elective surgery systems requires strengthening, which might include...
This paper studies the degree of downward rigidity in nominal wages in the United Kingdom using micro-data. Around 9% of employees who remain in the same job from one year to the next have zero pay growth. But on investigating the causes of rigidity we ®nd that up to ninetenths can be attributed to`symmetric' causes (such as contracts and menu costs) or to error. Thus only 1% of workers have pay that may be downwardly rigid. This suggests asymmetric, downward rigidity is not large enough to have serious macroeconomic consequences. The labour market provides almost no evidence to support a positive in¯ation target.The idea that nominal wages might be rigid has a long history, stretching back at least as far as Keynes (1936). In addition to any intrinsic interest in the behaviour of the price of labour, the issue has important implications for the macroeconomy. Downwardly rigid nominal wages could provide a rationale for a positive optimal rate of in¯ation and hence for the pursuance of a positive in¯ation target. As Tobin (1972) argued, if wages are rigid downwards, negative demand or positive supply shocks leave real wages higher than marginal product, resulting in unemployment. Higher in¯ation could alleviate this unemployment by reducing the real wage. Thus the cost of downward nominal rigidity ± which can also be interpreted as the cost of very low in¯ation where downward rigidity exists ± is unemployment.Downward rigidity implies asymmetry in wage changes: nominal wages are more likely to rise than to fall. Symmetric rigidities, whereby nominal wages are sticky in both directions, can also have detrimental macroeconomic implications. Unemployment is a feature of many models of long-term or staggered contracts (see, for example, Mankiw and Romer, 1991). However, symmetric rigidities do not have the same implications for the optimal rate of in¯ation: the effects of symmetric rigidities cannot be alleviated by a higher in¯ation rate.In this paper, nominal rigidity is taken to mean a 0% nominal pay change. Clearly wages are in some sense`rigid' if they do not move as much as theỳ should'. It is almost impossible in practice to calculate how much pay`should' change, although a simple conception of this warranted growth might be related to the change in the individual's productivity. A 0% nominal wage change has potentially special features, however. Psychological studies, which focus on downward rigidity, suggest that zero is a barrier of special importance (Kahneman et al., 1986;Blinder and Choi, 1990). Menu costs also impart
Several molecular structure-property relationships are presented and compared to illustrate our current understanding of macromolecular encapsulation using dendrimers. Specifically, the effect that dendrimer architectures have on encapsulating photoactive and redox-active units fixed at the molecular core is considered.
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