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This innovative work attempts to piece together the cultural biography of Mesoamerica's precolonial codices. Today less than twenty extant manuscripts are all that remains of the Mesoamerican book-making tradition. These pictographic and hieroglyphic texts have often been studied for their content, but in doing so their nature as physical objects faded into the background. By tracing the paths these books have followed over the past five hundred years, this study acquaints the reader with their production, use and re-use, destruction, rediscovery and reinvention. Even today, in fact, these books continue to add new chapters to their biography. That is, thanks to the most cutting-edge technology currently available, it has now been possible to uncover a completely new text from inside one of these precious and fragile manuscripts.

Prokaryotes acquire virus resistance by integrating short fragments of viral nucleic acid into clusters of regularly interspaced short palindromic repeats (CRISPRs). Here we show how virus-derived sequences contained in CRISPRs are used by CRISPR-associated (Cas) proteins from the host to mediate an antiviral response that counteracts infection. After transcription of the CRISPR, a complex of Cas proteins termed Cascade cleaves a CRISPR RNA precursor in each repeat and retains the cleavage products containing the virus-derived sequence. Assisted by the helicase Cas3, these mature CRISPR RNAs then serve as small guide RNAs that enable Cascade to interfere with virus proliferation. Our results demonstrate that the formation of mature guide RNAs by the CRISPR RNA endonuclease subunit of Cascade is a mechanistic requirement for antiviral defense.

Head and neck squamous cell carcinomas (HNSCCs) arise in the mucosal linings of the upper aerodigestive tract and are unexpectedly heterogeneous in nature. Classical risk factors are smoking and excessive alcohol consumption, and in recent years, the role of human papillomavirus (HPV) has emerged, particularly in oropharyngeal tumours. HPV-induced oropharyngeal tumours are considered a separate disease entity, which recently has manifested in an adapted prognostic staging system while the results of de-intensified treatment trials are awaited. Carcinogenesis caused by HPV in the mucosal linings of the upper aerodigestive tract remains an enigma, but with some recent observations, a model can be proposed. In 2015, The Cancer Genome Atlas (TCGA) consortium published a comprehensive molecular catalogue on HNSCC. Frequent mutations of novel druggable oncogenes were not demonstrated, but the existence of a subgroup of genetically distinct HPV-negative head and neck tumours with favourable prognoses was confirmed. Tumours can be further subclassified based on genomic profiling. However, the amount of molecular data is currently overwhelming and requires detailed biological interpretation. It also became apparent that HNSCC is a disease characterized by frequent mutations that create neoantigens, indicating that immunotherapies might be effective. In 2016, the first results of immunotherapy trials with immune checkpoint inhibitors were published, and these may be considered as a paradigm shift in head and neck oncology.

In 2019, we are looking back in Flanders and in Brussels at the crucial role that Pieter Bruegel the Elder played in the art-historical landscape of the sixteenth century. The 450th anniversary of his death is a good moment at which to rediscover the work of Jan Brueghel the Elder. The Snyders&Rockox House is therefore taking a closer look at the drawings of Jan Brueghel I (1568-1625), son of Pieter Bruegel the Elder and brother of Pieter the Younger. Together with Peter Paul Rubens, Jan was one of the most successful Flemish artists of the first quarter of the seventeenth century. He was at home in every market - an inspired painter of landscapes, seascapes, still lifes, historical themes, hunting scenes and allegorical and mythological subjects. Jan is seen as the inventor of the floral still, but he was also an important innovator in the depiction of landscapes, in which his father's artistic legacy and his visit to Italy played no small part. The art of painting is underpinned by that of drawing, by which the artist's talent and creativity can be measured. No previous exhibition has been dedicated solely to the drawn oeuvre of Jan Brueghel I. This major event is curated by Jan Brueghel scholars Dr Teréz Gerszi and Dr Louisa Wood Ruby, supported by Bernadett Tóth. The exhibition will feature some fifty drawings and several paintings, loaned by leading institutions like the Louvre, Rijksmuseum and British Museum. Exhibition: Snijders & Rockoxhuis, Antwerp, Belgium (05.10.2019-26.01.2020).

Summary Background In four randomised trials, human papillomavirus (HPV)-based screening for cervical cancer was compared with cytology-based cervical screening, and precursors of cancer were the endpoint in every trial. However, direct estimates are missing of the relative efficacy of HPV-based versus cytology-based screening for prevention of invasive cancer in women who undergo regular screening, of modifiers (eg, age) of this relative efficacy, and of the duration of protection. We did a follow-up study of the four randomised trials to investigate these outcomes. Methods 176 464 women aged 20–64 years were randomly assigned to HPV-based (experimental arm) or cytology-based (control arm) screening in Sweden (Swedescreen), the Netherlands (POBASCAM), England (ARTISTIC), and Italy (NTCC). We followed up these women for a median of 6·5 years (1 214 415 person-years) and identified 107 invasive cervical carcinomas by linkage with screening, pathology, and cancer registries, by masked review of histological specimens, or from reports. Cumulative and study-adjusted rate ratios (experimental vs control) were calculated for incidence of invasive cervical carcinoma. Findings The rate ratio for invasive cervical carcinoma among all women from recruitment to end of follow-up was 0·60 (95% CI 0·40–0·89), with no heterogeneity between studies (p=0·52). Detection of invasive cervical carcinoma was similar between screening methods during the first 2·5 years of follow-up (0·79, 0·46–1·36) but was significantly lower in the experimental arm thereafter (0·45, 0·25–0·81). In women with a negative screening test at entry, the rate ratio was 0·30 (0·15–0·60). The cumulative incidence of invasive cervical carcinoma in women with negative entry tests was 4·6 per 105 (1·1–12·1) and 8·7 per 105 (3·3–18·6) at 3·5 and 5·5 years, respectively, in the experimental arm, and 15·4 per 105 (7·9–27·0) and 36·0 per 105 (23·2–53·5), respectively, in the control arm. Rate ratios did not differ by cancer stage, but were lower for adenocarcinoma (0·31, 0·14–0·69) than for squamous-cell carcinoma (0·78, 0·49–1·25). The rate ratio was lowest in women aged 30–34 years (0·36, 0·14–0·94). Interpretation HPV-based screening provides 60–70% greater protection against invasive cervical carcinomas compared with cytology. Data of large-scale randomised trials support initiation of HPV-based screening from age 30 years and extension of screening intervals to at least 5 years. Funding European Union, Belgian Foundation Against Cancer, KCE-Centre d'Expertise, IARC, The Netherlands Organisation for Health Research and Development, the Italian Ministry of Health.

Infection of cervical epithelium with high-risk human papilloma virus (hrHPV) might result in productive or transforming cervical intraepithelial neoplasia (CIN) lesions, the morphology of which can overlap. In transforming CIN lesions, aberrations in host cell genes accumulate over time, which is necessary for the ultimate progression to cancer. On the basis of (epi)genetic changes, early and advanced transforming CIN lesions can be distinguished. This paves the way for new molecular tools for cervical screening, diagnosis and management of cervical cancer precursor lesions.

Summary Background Screening for human papillomavirus (HPV) infection is more effective in reducing the incidence of cervical cancer than screening using Pap smears. Moreover, HPV testing can be done on a vaginal sample self-taken by a woman, which offers an opportunity to improve screening coverage. However, the clinical accuracy of HPV testing on self-samples is not well-known. We assessed whether HPV testing on self-collected samples is equivalent to HPV testing on samples collected by clinicians. Methods We identified relevant studies through a search of PubMed, Embase, and CENTRAL. Studies were eligible for inclusion if they fulfilled all of the following selection criteria: a cervical cell sample was self-collected by a woman followed by a sample taken by a clinician; a high-risk HPV test was done on the self-sample (index test) and HPV-testing or cytological interpretation was done on the specimen collected by the clinician (comparator tests); and the presence or absence of cervical intraepithelial neoplasia grade 2 (CIN2) or worse was verified by colposcopy and biopsy in all enrolled women or in women with one or more positive tests. The absolute accuracy for finding CIN2 or worse, or CIN grade 3 (CIN3) or worse of the index and comparator tests as well as the relative accuracy of the index versus the comparator tests were pooled using bivariate normal models and random effect models. Findings We included data from 36 studies, which altogether enrolled 154 556 women. The absolute accuracy varied by clinical setting. In the context of screening, HPV testing on self-samples detected, on average, 76% (95% CI 69–82) of CIN2 or worse and 84% (72–92) of CIN3 or worse. The pooled absolute specificity to exclude CIN2 or worse was 86% (83–89) and 87% (84–90) to exclude CIN3 or worse. The variation of the relative accuracy of HPV testing on self-samples compared with tests on clinician-taken samples was low across settings, enabling pooling of the relative accuracy over all studies. The pooled sensitivity of HPV testing on self-samples was lower than HPV testing on a clinician-taken sample (ratio 0·88 [95% CI 0·85–0·91] for CIN2 or worse and 0·89 [0·83–0·96] for CIN3 or worse). Also specificity was lower in self-samples versus clinician-taken samples (ratio 0·96 [0·95–0·97] for CIN2 or worse and 0·96 [0·93–0·99] for CIN3 or worse). HPV testing with signal-based assays on self-samples was less sensitive and specific than testing on clinician-based samples. By contrast, some PCR-based HPV tests generally showed similar sensitivity on both self-samples and clinician-based samples. Interpretation In screening programmes using signal-based assays, sampling by a clinician should be recommended. However, HPV testing on a self-sample can be suggested as an additional strategy to reach women not participating in the regular screening programme. Some PCR-based HPV tests could be considered for routine screening after careful piloting assessing feasibility, logistics, population compliance, and costs. Funding The 7th Framework Programme of the European Commission, the Belgian Foundation against Cancer, the International Agency for Research on Cancer, and the German Guideline Program in Oncology.

Highlights ► HPV16 is necessary for initiation/malignant phenotype of some oropharynx cancers. ► Infection by HPV16 is associated with elevated odds of oropharynx cancer. ► Tumor HPV status is an important prognostic factor for oropharynx cancer. ► HPV-positive oropharynx cancer incidence is increasing in developed countries. ► Respiratory papillomatosis is caused by peripartum/sexual transmission of HPV6/11.

Statistical models for social networks as dependent variables must represent the typical network dependencies between tie variables such as reciprocity, homophily, transitivity, etc. This review first treats models for single (cross-sectionally observed) networks and then for network dynamics. For single networks, the older literature concentrated on conditionally uniform models. Various types of latent space models have been developed: for discrete, general metric, ultrametric, Euclidean, and partially ordered spaces. Exponential random graph models were proposed long ago but now are applied more and more thanks to the non-Markovian social circuit specifications that were recently proposed. Modeling network dynamics is less complicated than modeling single network observations because dependencies are spread out in time. For modeling network dynamics, continuous-time models are more fruitful. Actor-oriented models here provide a model that can represent many dependencies in a flexible way. Strong model development is now going on to combine the features of these models and to extend them to more complicated outcome spaces.