Updated Classification Research Articles

An Updated Infrageneric Classification of the North American Oaks (Quercus Subgenus Quercus): Review of the Contribution of Phylogenomic Data to Biogeography and Species Diversity

The oak flora of North America north of Mexico is both phylogenetically diverse and species-rich, including 92 species placed in five sections of subgenus Quercus, the oak clade centered on the Americas. Despite phylogenetic and taxonomic progress on the genus over the past 45 years, classification of species at the subsectional level remains unchanged since the early treatments by WL Trelease, AA Camus, and CH Muller. In recent work, we used a RAD-seq based phylogeny including 250 species sampled from throughout the Americas and Eurasia to reconstruct the timing and biogeography of the North American oak radiation. This work demonstrates that the North American oak flora comprises mostly regional species radiations with limited phylogenetic affinities to Mexican clades, and two sister group connections to Eurasia. Using this framework, we describe the regional patterns of oak diversity within North America and formally classify 62 species into nine major North American subsections within sections Lobatae (the red oaks) and Quercus (the white oaks), the two largest sections of subgenus Quercus. We also distill emerging evolutionary and biogeographic patterns based on the impact of phylogenomic data on the systematics of multiple species complexes and instances of hybridization.

Evolutionary history and spatiotemporal dynamic of GIII norovirus: From emergence to classification in four genotypes.

Noroviruses belong to a genetically diverse group of viruses infecting a wide range of mammalian host species, and those detected in cattle and sheep are classified within genogroup III (GIII). The current classification of norovirus in genogroups and genotypes is based on phylogenetic clustering and average distances within and between these phylogenetic clusters; however, the classification studies have been focused mainly on human norovirus, being GIII norovirus relegated. Due to the increasing number of studies on GIII norovirus, the need of an updated and extensive classification is evident. The aim of this study was to update the classification of norovirus within GIII, to describe the emergence of a circulating recombinant strain, and to reconstruct the evolutionary history of this genogroup. Two P-types (GIII.P1-2) and four genotypes (GIII.1-4) were described. For the genogroup GIII, the evolutionary rate estimated was 2.78E-3 s/s/y (95%HPD, 1.79E-3 s/s/y-3.78E-3 s/s/y), and the tMRCA was estimated around 1500 (95%HPD, 1247-1688). Despite the long history of this genogroup, the genotypes detected at present emerged in the last 100 years. Interestingly, most of the recombinant GIII.2P[1] strains detected worldwide were originated from a single recombination event and this recombinant strain was later dispersed through the world. Finally, our results indicate that a scenario of genotypes replacement through the time is highly probable.

Refined staging classification of cardiac damage associated with aortic stenosis and outcomes after transcatheter aortic valve implantation.

A new staging classification of aortic stenosis (AS) characterizing the extent of cardiac damage was established and validated in patients undergoing transcatheter aortic valve implantation (TAVI). We aimed to validate an updated classification system in patients undergoing TAVI. In a prospective TAVI registry, AS patients were categorized into the following stages: no cardiac damage (Stage 0), left ventricular damage (Stage 1), left atrial or mitral valve damage (Stage 2), pulmonary vasculature or tricuspid valve damage (Stage 3), or right ventricular (RV) damage or low-flow state (Stage 4). Stage 3 was sub-divided into Stage 3a (≤moderate pulmonary hypertension) and Stage 3b (severe pulmonary hypertension). Stage 4 was sub-divided into Stage 4a (low-flow without RV dysfunction), Stage 4b (RV dysfunction without low-flow), and Stage 4c (RV dysfunction with low-flow). The primary endpoint was all-cause death at 1 year. Among 1156 eligible patients, 14 were classified as Stage 0, 38 as Stage 1, 105 as Stage 2278 as Stage 3, and 721 as Stage 4. There was a stepwise increase in mortality according to advancing stages of cardiac damage: 3.9% (Stage 0-1), 9.6% (Stage 2), 14.1% (Stage 3), and 17.4% (Stage 4) (P = 0.002). After multivariable adjustment, only Stage 3b, Stage 4b, and Stage 4c conferred a significantly increased risk of mortality compared to Stage 0-1. More than one-third of patients had advanced cardiac damage (severe pulmonary hypertension or RV dysfunction) before TAVI, associating with a five- to seven-fold increased risk of mortality at 1 year. https://www.clinicaltrials.gov. NCT01368250.

Cutaneous T-cell lymphomas-An update 2021.

Cutaneous T-cell lymphomas (CTCL) represent the majority of primary cutaneous lymphomas (CL). Mycosis fungoides (MF) and cutaneous CD30+ lymphoproliferative disorders account for 80% of all CTCL. CTCL show overlapping histological features. Thus clinical-pathological correlation is of importance to achieve final diagnosis. MF shows a characteristic evolution with patches, plaques, and in a subset of patients (10%-20%) with tumors. Therapy is stage-adapted with skin-directed therapies such as UV-light therapies and corticosteroids in early disease stage (i.e., patch and limited plaque stage) and systemic therapies (retinoids, interferon, mono chemotherapy, targeted therapy) and/or radiation therapy (local or total skin beam electron) in advanced stages. Novel therapies include targeted therapy such as mogamulizumab (anti-CCR4) or brentuximab vedotin (anti-CD30) and histone deacetylase inhibitors. Considering the impact of targeted therapies, biomarkers such as CD30 are not only crucial for the diagnosis and correct classification of an individual lymphoma case, but also for therapy as they may represent therapeutic targets. In the recently revised WHO classification 2017 and the updated WHO-EORTC classification for CL 2018, primary cutaneous CD8+ acral T-cell lymphoma has been introduced as a new still provisional entity. It displays characteristic clinical, histological, and phenotypic features and exhibits an excellent prognosis. Rare, but aggressive CTCL include cutaneous primary cutaneous aggressive epidermotropic CD8-positive T-cell lymphoma and cutaneous gamma/delta T-cell lymphoma, which present with rapid onset of necrotic or ulcerated plaques and tumors. As they have a poor prognosis, treatment includes multiagent chemotherapy and hematopoietic stem cell transplantation.

Dynamics and Emerging Trends in Genodermatology: A Scientometric Analysis

Dynamics and Emerging Trends in Genodermatology: A Scientometric Analysis

Advances in the Pathogenesis of EBV-Associated Diffuse Large B Cell Lymphoma.

Simple SummaryThe last World Health Organization classification of Tumours of Haematopoietic and Lymphoid Tissues defines a new category, EBV + DLBCL, NOS, which incidence varies among different populations. Given the oncogenic characteristics of both latent and lytic viral proteins, EBV could replace some of the cellular pathways and/or mutations observed in non EBV-associated cases. In addition, the virus may turn the tumor microenvironment in a tolerogenic, in order to promote tumorigenesis, and may have also influence on survival in specific populations. The analysis of EBV pathogenesis in DLBCL may exhibit new potential targets for DLBCL treatment.Diffuse large B-cell lymphoma (DLBCL) is the most common non-Hodgkin’s lymphoma (NHL) in adults. Epstein–Barr virus (EBV) positive DLBCL of the elderly was defined by the World Health Organization (WHO) in 2008, it was restricted only to patients older than 50 years old, and it was attributed to immunesenescence associated with physiological aging. After the description of EBV-associated DLBCL in children and young adults, the WHO redefined the definition, leading to the substitution of the modifier “elderly” with “not otherwise specified” (EBV + DLBCL, NOS) in the updated classification, and it is no more considered provisional. The incidence of EBV + DLBCL, NOS varies around the world, in particular influenced by the percentage of EBV+ cells used as cut-off to define a case as EBV-associated. EBV has effect on the genetic composition of tumor cells, on survival, and at the recruitment of immune cells at the microenvironment. In this review, the role of EBV in the pathogenesis of DLBCL is discussed.

The Ethical Conundrums of “Precision Psychiatry”

The Ethical Conundrums of “Precision Psychiatry”

PULMONARY HYPERTENSION STILL AN ‘ORPHAN LUNG DISEASE’ IN PAKISTAN

In our country when it comes to diagnosis and treatment of Pulmonary Hypertension (PH) especially Pulmonary Arterial Hypertension (PAH), it seems that it is still an Orphan Lung disease. Whether it is data about its prevalence in our country, available diagnostic services or treatment options, one may easily feel the scarcity in all mentioned areas.
 Most current classification of PH, categorizes it into 5 groups.1 However this categorization requires availability of diagnostic tools especially right heart catheterization data to classify and know the severity of PH and to offer targeted treatment to patients who belong to group 1 PH i.e. Pulmonary Arterial Hypertension (PAH).
 Studies done about PH prevalence in Pakistan have mainly focused on data in selected patients group e.g. in patients with Chronic Obstructive Pulmonary Diseases (COPD) or Systemic Lupus Erythematosus (SLE).2,3 All of these studies relied on diagnosis without using the diagnostic bench mark i.e. Right heart catheterization. Moreover, effects of targeted treatment for PAH have also been studied only in selected group of patients e.g. COPD.4,5
 While above work by the learned colleagues has to be appreciated, it emphasizes the need to,
 
 Spread the awareness about PH more so to reduce inadvertent use of targeted treatment which may prove detrimental outside group 1 PH and should only be considered at specialized centers.
 Develop specialized centers with required diagnostic services especially Lung functional and anatomical evaluation and Right heart catheterization.
 Establish PH registries (at least one in each province) which can play a vital role to collect data and ensure effective evidence based patient management.
 
 This may be an uphill task however the right direction to move forward.
 
 REFERENCES
 
 Simonneau G, Montani D, David SC, Christopher PD, Michael AG, Michael K, at el. Paul G. Haemodynamic definitions and updated clinical classification of pulmonary hypertension. Eur Respir J. 2019;53(1):1801913.
 Amir S, Azmat A, Raza U, Hamid N, Zafar I, Shahida N, at el. Frequency of Pulmonary Hypertension in COPD patients. Pak J Chest Med. 2017;23(4):144-50.
 Sadia A, Aflak R, Tafazzul H, Ahmed A. Frequency and predictors of Pulmonary Hypertension in patients with SLE. Pak J Med Sci. 2019;35(1):86-9.
 Nasir H, Faisal F, Kausar R, Saadia A, Anjum N, Shafi K, at el. Efficacy of bosentan in the treatment of pulmonary hypertension; a prospective study focusing on safety and efficacy in patients with COPD. J Lung Pulm Respir Res. 2018;5(2):67-72.
 Sharieff S. Effect of sildenafil in primary pulmonary hypertension. Pak J Med Sci. 2007;23(2):264.

Rhizomal Reclassification of Living Organisms.

Living organisms interact with each other during their lifetime, leading to genomes rearrangement and sequences transfer. These well-known phenomena give these organisms mosaic genomes, which challenge their classification. Moreover, many findings occurred between the IXXth and XXIst century, especially the discovery of giant viruses and candidate phyla radiation (CPR). Here, we tried to provide an updated classification, which integrates 216 representative genomes of the current described organisms. The reclassification was expressed through a genetic network based on the total genomic content, not on a single gene to represent the tree of life. This rhizomal exploration represents, more accurately, the evolutionary relationships among the studied species. Our analyses show a separated branch named fifth TRUC (Things Resisting Uncompleted Classifications). This taxon groups CPRs together, independently from Bacteria, Archaea (which regrouped also Nanoarchaeota and Asgard members), Eukarya, and the giant viruses (recognized recently as fourth TRUC). Finally, the broadening of analysis methods will lead to the discovery of new organisms, which justify the importance of updating the classification at every opportunity. In this perspective, our pragmatic representation could be adjusted along with the progress of evolutionary studies.

Updated Kimura-Takemoto classification of atrophic gastritis.

BACKGROUNDThe Updated Sydney system for visual evaluation of gastric mucosal atrophy via endoscopic observation is subject to sampling error and interobserver variability. The Kimura-Takemoto classification system was developed to overcome these limitations. AIMTo compare the morphological classification of atrophic gastritis between the Kimura-Takemoto system and the Updated Sydney system.METHODSA total of 169 patients with atrophic gastritis were selected according to diagnosis by the visual endoscopic Kimura-Takemoto method. Following the Updated Kimura-Takemoto classification system, one antrum biopsy and five gastric corpus biopsies were taken according to the visual stages of the Kimura-Takemoto system. The Updated Kimura-Takemoto classification system was then applied to each and showed 165 to have histological mucosal atrophy; the remaining 4 patients had no histological evidence of atrophy in any biopsy. The Updated Kimura-Takemoto classification was verified as a reference morphological method and applied for the diagnosis of atrophic gastritis. Adding one more biopsy from the antrum to the six biopsies according to the Updated Kimura-Takemoto classification, constitutes the updated combined Kimura-Takemoto classification and Sydney system. RESULTSThe sensitivity for degree of mucosal atrophy assessed by the Updated Sydney system was 25% for mild, 36% for moderate, and 42% for severe, when compared with the Updated Kimura-Takemoto classification of atrophic gastritis for morphological diagnosis. Four types of multifocal atrophic gastritis were identified: sequential uniform (type 1; in 28%), sequential non-uniform (type 2; in 7%), diffuse uniform (type 3; in 23%), diffuse non-uniform (type 4; in 24%), and "alternating atrophic – non-atrophic" (type 5; in 18%). The pattern of the spread of atrophy, sequentially from the antrum to the cardiac segment of the stomach, which was described by the Updated Kimura-Takemoto system, was histologically confirmed in 82% of cases evaluated.CONCLUSIONThe Updated Sydney system is significantly inferior to the Updated Kimura-Takemoto classification for morphological verification of atrophic gastritis.

Expenditures on National Projects in the Public Spending System

The paper is devoted to analyzing the category of “public expenditure”, its comparative analysis with the category “budget expenditures” in doctrinal understanding and according to the legislative definition. On the basis of relative and absolute data, the author highlights the trend towards an increase of the share of national projects in the overall structure of public expenditure, as well as the trend towards annual increases in direct expenditures from the federal budget. The author concludes that it is necessary to consolidate the thesis on priority financing of national projects in the allocation of budgetary funds at the federal law level. The author analizes the place of allocations for the implementation of national projects in the updated Budget Classification and determines a number of features of budget financing of national projects. The paper elucidates the legal mechanisms of adjustment of national projects financing on the basis of the legislation, highlights the modernization of financial instruments in the field of public procurement, trends in the field of distribution of the inter-budgetary transfers with co-financing. The author highlights the importance of retrospective analysis of information on the performance of budgetary allocations by the key spending units of federal budget funds in the previous fiscal year for the purpose of prospective planning. The conclusion is made about facilitating the integration of the format of national projects into the system of strategic planning with the medium and long-term perspective.

Regulation and specificity of cyclic oligoadenylate synthesis by the Staphylococcus epidermidis Cas10‐Csm complex

CRISPR-Cas10 is a multiprotein complex that uses the sequence information in a bound crRNA to identify foreign RNA transcripts and initiate interference. Recently it was discovered that CRISPR-Cas10 synthesizes a previously unknown class of second messenger molecules upon detecting foreign transcripts, cyclic oligoadenylates (cOA) (1,2). cOA activate the Csm6 nuclease to promote RNA degradation and may also coordinate additional cellular responses. Using the S. epidermidis Cas10-Csm complex, a longstanding model for CRISPR-Cas function, we have reconstituted cOA synthesis and have found that it entails Mg2+ dependent synthesis of 3-6 nt cOAs (3). We have investigated the effect of target-crRNA mismatches on cOA synthesis finding that some single mismatches dramatically reduce cOA synthesis in a position dependent and sequence-context dependent manner. We have found that cOA synthesis is antagonized by Csm3-mediated target RNA cleavage. Altogether, our results establish the requirements for cOA production in a model Type III CRISPR-Cas system. Since the CRISPR-Cas10 system is present in ~20% of all prokaryotic genomes sequenced (4), its role in bacteriophage defense and regulation of horizontal gene transfer are likely important to bacterial physiology in niches such as the human microbiome. 1. Kazlauskiene, M., Kostiuk, G., Venclovas, C., Tamulaitis, G., and Siksnys, V. (2017) A cyclic oligonucleotide signaling pathway in type III CRISPR-Cas systems. Science 357, 605-609 2. Niewoehner, O., Garcia-Doval, C., Rostol, J. T., Berk, C., Schwede, F., Bigler, L., Hall, J., Marraffini, L. A., and Jinek, M. (2017) Type III CRISPR-Cas systems produce cyclic oligoadenylate second messengers. Nature 548, 543-548 3. Nasef, M., Muffly, M. C., Beckman, A. B., Rowe, S. J., Walker, F. C., Hatoum-Aslan, A., and Dunkle, J. A. (2019) Regulation of cyclic oligoadenylate synthesis by the Staphylococcus epidermidis Cas10-Csm complex. RNA 25, 948-962 4. Makarova, K. S., Wolf, Y. I., Alkhnbashi, O. S., Costa, F., Shah, S. A., Saunders, S. J., Barrangou, R., Brouns, S. J., Charpentier, E., Haft, D. H., Horvath, P., Moineau, S., Mojica, F. J., Terns, R. M., Terns, M. P., White, M. F., Yakunin, A. F., Garrett, R. A., van der Oost, J., Backofen, R., and Koonin, E. V. (2015) An updated evolutionary classification of CRISPR-Cas systems. Nat Rev Microbiol 13, 722-736

Molecular Diagnostic Approaches for Diffuse Gliomas Based on Updated WHO Classification and cIMPACT-NOW Proposals

The updated 2016 World Health Organization(WHO)classification of tumors of the central nervous system(CNS)has incorporated molecular parameters into the histopathological diagnosis of the tumor in the name of "integrated diagnosis." It has enabled more prognostically precise diagnoses of brain tumor entities; however, its practical application has also raised concerns about whether genotypes predominate over phenotypes in tumor diagnostics. In response, cIMAPCT-NOW(the Consortium to Inform Molecular and Practical Approaches to CNS Tumor Taxonomy-"Not Official WHO")was established to provide a forum for evaluating and recommending proposed changes to future CNS tumor classifications. cIMPACT has thus far published seven updates on the proposal and clarification of existing and new terms and entities. Herein, we highlight the current status of clinical application of the 2016 WHO classification and cIMPACT proposals, and the future endeavor to incorporate comprehensive genomic and epigenomic profiling of CNS tumors with the aid of artificial intelligence technology for better clinical decision-making to achieve the goal of precision medicine for each patient with brain tumors.

Neuropathology of Pituitary Adenomas and Sellar Lesions.

The pituitary gland is the site of numerous neoplastic and inflammatory processes. The overwhelmingly most frequent tumors arise from cells of the anterior lobe, the pituitary neuroendocrine tumors (PitNETs). Immunohistochemistry assay staining for pituitary hormones is the core tool for classifying PitNETs, resulting in the diagnosis of somatotroph PitNETs, lactotroph PitNETs, and so on. For cases showing no hormonal expression, the updated WHO classification system now considers the assessment of several transcription factors: PIT-1 (pituitary-specific POU-class homeodomain transcription factor); T-PIT (T-box family member TBX19); and SF-1 (steroidogenic factor regulating gonadotroph cell differentiation) before rendering a diagnosis of null cell adenoma. Other tumors and disease processes of this site often mimic PitNETs radiographically and sometimes even clinically (ie, compression of the optic chiasm). These potpourri of processes include germ cell neoplasms (especially germinomas), tumors that originate from Rathke's pouch (craniopharyngiomas, Rathke's cleft cyst), tumors that originate from the posterior lobe of the pituitary (pituicytoma, spindle cell oncocytoma, granular cell tumor), and tumors that originate from the meninges (especially meningiomas). In addition to neoplasms, several described inflammatory and related conditions exist that need to be distinguished from PitNETs. These include lymphocytic hypophysitis and Langerhans cell histiocytosis, a neoplastic disorder of histiocytes. In this review, we aim to briefly describe the main pituitary and sellar lesions, with emphasis on the most common tumors, the PitNETs.

New northern snowpack classification linked to vegetation cover on a latitudinal mega-transect across northeastern Canada

ABSTRACT Changes in mass, extent, duration, and physical properties of snow are key elements for studying associated climate change feedbacks in northern regions. In this study, we analyzed snowpack physical properties along a ‘mega’ transect from 47°N to 83°N (4,000 km) in northeastern Canada, which includes marked transitions between ecozones from boreal forest to subarctic and arctic ecosystems. Our unique dataset of 391 detailed snowpits acquired over the last 20 years, complemented with snow data from weather stations, shows that snowpack properties such as snow water equivalent, snow depth, density, grain size and basal depth hoar fraction (DHF) are strongly linked to vegetation type. Based on these results, we propose an updated classification of snow types in three classes: boreal forest snow (47–58°N), tundra snow (58–74°N) and polar desert snow (74–83°N), which is more appropriate to the study area than the general north hemisphere classification commonly used. We also show that shrub presence along the transect contributes to a significant increase in DHF development which contributes most strongly to the thermal insulation properties of the snowpack. Overall, our analysis suggests that snow–vegetation interactions have a positive feedback effect on warming at northern latitudes.

Updated WHO classification of tumors of the breast: the most important changes

The development of the WHO classification of tumors of the breast is driven by new knowledge from research whose translation into daily practice is considered clinically relevant. The fifth edition represents an update of the fourth edition and essentially follows the previously known systematics. The histologic features of the lesions continue to form the basis of the classification in the update. This also applies to the definition of invasive tumor types. However, several new molecular classifications as well as additional prognostic and predictive factors are presented and discussed, which improve prognosis estimation and therapy decisions. This paper aims to present the main changes in the current WHO classification. These include the revised definition of mixed invasive carcinomas, the introduction of new special invasive entities (tall cell carcinoma with reversed polarity, mucinous cystadenocarcinoma), the deletion of special invasive types and their classification as variants of invasive carcinoma, NST (no special type, including medullary, lipid-rich, glycogen-rich, among others), the typing of primary neuroendocrine neoplasms of the breast by analogy with other organ systems, changes in the dignity criteria of phyllodes tumors, and the revised subtyping of lobular carcinoma in situ (LCIS). In addition to improvements in the fifth edition of the classification, flaws are also highlighted. Asection is devoted to new molecular parameters.

Odontogenic fibroma amyloid-variant: a typical case and brief considerations about mimickers

SummaryThe World Health Organization’s (WHO) updated classification of head and neck tumors (2017) defined odontogenic fibroma as a rare neoplasm. In this report, we describe an unusual, typical and rare variant of a central odontogenic fibroma with diffuse amyloid-like protein stromal deposition, and discuss the differential diagnosis with other entities. Radiographically, this lesion presented as a well-defined radiolucency of the mandible, partially cystic. Histologically, the lesion showed a unique confluence of odontogenic epithelial rests in a moderately cellular connective tissue. Immunohistochemical staining highlighted a mixture of benign epithelial and Langerhans cells within connective tissue with diffuse amyloid-like stromal deposition. The importance of recognizing this variant of odontogenic fibroma is due to its benign prognosis and clinical course.

The prognostic value of vitamin D receptor and its up-stream miR-27b and miR-125a expression in breast cancer patients

Breast cancer is a heterogeneous disease that is conventionally classified according to histology and immunopathology. An updated classification of breast cancer is dependent upon messenger RNA (mRNA) expression profiling, and micro-RNA (miRNA) expression signature due to their role in regulating malignant progression. The aim of this study was to investigate the expression patterns of VDR and aromatase genes expression in malignant breast cancer tissues in comparison with the adjacent normal tissues together with the expression pattern of two micro RNAs (miR-27b and 125a) as an upstream factors that regulate the stability of VDR mRNA as tumor suppressors. The present study was carried out on 50 female breast cancer patients (30 postmenopausal, 20 premenopausal). Breast tissues were used for total RNA isolation from malignant breast tissue and adjacent normal breast tissues, gene expression analysis of VDR and aromatase in breast tissues at mRNA using RT-PCR, gene expression analysis of miR-27b, miR-125a using RT-PCR. The gene expression of VDR is up-regulated in the malignant breast tissues compared to adjacent normal tissues and controlled by the expression of miR-125a and miR-27b. The tumor suppressor miR-125a was downregulated in breast malignant tissues. VDR gene expression is affected by aromatase gene expression which showed up-regulation in malignant breast tissues. The crosstalk between VDR and miR-125a, miR27b and aromatase may determine the subset of patients that could be responsive to adjuvant treatment with vitamin D agonist. According to the results of VDR expression and other parameters, postmenopausal patients may be more sensitive to vitamin D therapy than premenopausal patients.

Epidemiology, Pathogenesis, and Clinical Approach in Group 5 Pulmonary Hypertension.

Pulmonary hypertension (PH) is recognized to be associated with a number of comorbid conditions. Based on these associations, PH is classified into 5 groups, considering common pathophysiologic drivers of disease, histopathologic features, clinical manifestations and course, and response to PH therapy. However, in some of these associated conditions, these characteristics are less well-understood. These include, among others, conditions commonly encountered in clinical practice such as sarcoidosis, sickle cell disease, myeloproliferative disorders, and chronic kidney disease/end stage renal disease. PH in these contexts presents a significant challenge to clinicians with respect to disease management. The most recent updated clinical classification schemata from the 6th World Symposium on PH classifies such entities in Group 5, highlighting the often unclear and/or multifactorial nature of PH. An in-depth review of the state of the science of Group 5 PH with respect to epidemiology, pathogenesis, and management is provided. Where applicable, future directions with respect to research needed to enhance understanding of the clinical course of these entities is also discussed.

Measurement and analysis of photoluminescence in GaN

Photoluminescence (PL) spectroscopy is a powerful tool in studying semiconductor properties and identifying point defects. Gallium nitride (GaN) is a remarkable semiconductor material for its use in a new generation of bright white LEDs, blue lasers, and high-power electronics. In this Tutorial, we present details of PL experiments and discuss possible sources of mistakes. A brief analysis of near-band-edge emission includes basic characterization of GaN, essential findings about excitons in this material, and the explanation of less known details. We review modern approaches of quantitative analysis of PL from point defects in GaN. The updated classification of defects in undoped GaN and their latest identifications are presented. Typical mistakes in the interpretation of PL spectra from GaN are discussed, and myths about PL are refuted.