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Upcoming Encyclopedia of Doris readings

My book is coming out next week!
Upcoming Reading Tours:
August 11: Asheville NC, Malaprops Bookstore 7:00
September 23: Baltimore MD, Anarchist book fair; 6:00
September 24: Philadelpia PA, Wooden Shoe Bookstore; 7:00
September 25: NYC, Bluestockings Bookstore
September 26: Brooklyn, Bookthug Nation
September 27: North Hampton, MA, Food For Thought
September 28: may be somewhere in Vermont
September 29-30: Montreal
October 1-2:
October 3: Toronto
October 4: Pittsburgh




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Nietzsche’s PC…

Photo courtesy of Glenn T.




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ViacomCBS CEO Doesn’t Rule Out Direct-To-VOD Release For Upcoming ‘Spongebob’ Movie

"The Spongebob Movie: Sponge on the Run" is currently due to hit theaters on August 7 — among the earliest scheduled releases in the calendar.

The post ViacomCBS CEO Doesn’t Rule Out Direct-To-VOD Release For Upcoming ‘Spongebob’ Movie appeared first on Cartoon Brew.




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Coronavirus Stories: How Animators On The Upcoming ‘Tom And Jerry’ Feature Are Staying Connected

An animation supervisor and a senior animator at Framestore discuss the challenges — and surprising upsides — of working remotely.

The post Coronavirus Stories: How Animators On The Upcoming ‘Tom And Jerry’ Feature Are Staying Connected appeared first on Cartoon Brew.




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CCPC simplifies merger notification system

The Competition and Consumer Protection Commission (CCPC) has simplified the system for certain mergers to be notified to it.




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Michelle Obama will be the focus of the upcoming Netflix documentary ‘Becoming’

"Becoming" will be the third Netflix documentary from Barack and Michelle Obama's Higher Ground Productions.




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How to Open Numbers File on Windows PC with iCloud

Need to open a Numbers file but you’re on a Windows PC? No problem, you can use iCloud to access, edit, and open Numbers files, even if you don’t have an iPhone, iPad, or Mac with an official Numbers app handy. Today, we live in an era where people own multiple devices that are powered ... Read More




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oscon: Just 1 week left to take advantage of #OSCON early registration prices. Register by 6/6 to save http://t.co/E0JKpcj1Rp #opensource

oscon: Just 1 week left to take advantage of #OSCON early registration prices. Register by 6/6 to save http://t.co/E0JKpcj1Rp #opensource




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oscon: Only 48 hours left to get discounted tickets to #OSCON. Early registration prices end tomorrow at midnight http://t.co/E0JKpcj1Rp

oscon: Only 48 hours left to get discounted tickets to #OSCON. Early registration prices end tomorrow at midnight http://t.co/E0JKpcj1Rp




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oscon: Alumnus of #OSCON can save an extra 20% on their 2013 registration. Use code ALUMNI when you register http://t.co/E0JKpcj1Rp #opensource

oscon: Alumnus of #OSCON can save an extra 20% on their 2013 registration. Use code ALUMNI when you register http://t.co/E0JKpcj1Rp #opensource




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oscon: Last chance - today is the last day for #OSCON early registration pricing. Register by midnight PT to save http://t.co/E0JKpcj1Rp

oscon: Last chance - today is the last day for #OSCON early registration pricing. Register by midnight PT to save http://t.co/E0JKpcj1Rp




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Air gap security beaten by turning PC capacitors into speakers

Researchers have poked another small hole in air gapped security by showing how the electronics inside computer power supply units (PSUs) can be turned into covert data transmission devices.




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CBD News: Joint press-release by GEF and CBD on the approval by the GEF Council of a special initiative designed to build global awareness and catalyze decisive action during the upcoming 2010 International Year of Biodiversity (IYB).




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CBD News: A draft of the updated Global Strategy for Plant Conservation (GSPC) 2011-2020, prepared by the Liaison Group on the Global Strategy for Plant Conservation in its third meeting held from 26 to 28 May 2009 in Dublin, Ireland, is now available for




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CBD News: Statement by Mr. Ahmed Djoghlaf, CBD Executive Secretary, on the occasion of the International Conference in Support of the Worldwide Implementation of the Global Partnership for Plant Conservation (GPPC)




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CBD News: Montreal, 12 September 2014 - The Secretary to the International Plant Protection Convention (IPPC) has become the seventh member of the Liaison Group of the Biodiversity-related Conventions (BLG), which includes the Convention on Biological Div




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CBD Notification SCBD/OES/EM/DC/88792 (2020-029): Update regarding COVID-19 and upcoming CBD meetings




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New and upcoming tech IPOs

Here are the tech companies that are planning to launch on the stock market this year




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Biodistribution of a CD3/EpCAM bispecific T-cell engager is driven by the CD3 arm

BiTE® (Bispecific T-cell engager) molecules are designed to engage and activate cytotoxic T-cells to kill tumor cells. Little is known about their biodistribution in immunocompetent settings. To explore their pharmacokinetics and the role of the immune cells, BiTE molecules were radiolabeled with positron emission tomography (PET) isotope zirconium-89 (89Zr) and studied in immunocompetent and immunodeficient mouse models. PET images and ex-vivo biodistribution in immunocompetent mice with 89Zr-muS110, targeting mouse CD3 (Kd = 2.9 nM) and mouse EpCAM (Kd = 21 nM), and 89Zr-hyS110, targeting only mouse CD3 (Kd = 2.9 nM), showed uptake in tumor, spleen and other lymphoid organs, while the human-specific control BiTE 89Zr-AMG 110 showed similar tumor uptake but lacked spleen uptake. 89Zr-muS110 spleen uptake was lower in immunodeficient than in immunocompetent mice. After repeated administration of non-radiolabeled muS110 to immunocompetent mice 89Zr-muS110 uptake in spleen, and other lymphoid tissues, decreased and was comparable to uptake in immunodeficient mice, indicating saturation of CD3 binding sites. Autoradiography and immunohistochemistry demonstrated colocalization of 89Zr-muS110 and 89Zr-hyS110 with CD3-positive T-cells in the tumor and spleen but not with EpCAM expression. Also, uptake in the duodenum correlated with a high incidence of T-cells. This study shows that in immunocompetent mice the BiTE 89Zr-muS110 distribution is predominantly based on its high affinity CD3 binding arm. Significance: 89Zr-muS110 biodistribution is mainly dependent on the T-cell targeting arm with limited contribution of its second arm, targeting EpCAM. These findings highlight the need for extensive biodistribution studies of novel bispecific constructs as results might have implications for their respective drug development and clinical translation.




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Multi-omic Characterization of the Mode of Action of a Potent New Antimalarial Compound, JPC-3210, Against Plasmodium falciparum [Research]

The increasing incidence of antimalarial drug resistance to the first-line artemisinin combination therapies underpins an urgent need for new antimalarial drugs, ideally with a novel mode of action. The recently developed 2-aminomethylphenol, JPC-3210, (MMV 892646) is an erythrocytic schizonticide with potent in vitro antimalarial activity against multidrug-resistant Plasmodium falciparum lines, low cytotoxicity, potent in vivo efficacy against murine malaria, and favorable preclinical pharmacokinetics including a lengthy plasma elimination half-life. To investigate the impact of JPC-3210 on biochemical pathways within P. falciparum-infected red blood cells, we have applied a "multi-omics" workflow based on high resolution orbitrap mass spectrometry combined with biochemical approaches. Metabolomics, peptidomics and hemoglobin fractionation analyses revealed a perturbation in hemoglobin metabolism following JPC-3210 exposure. The metabolomics data demonstrated a specific depletion of short hemoglobin-derived peptides, peptidomics analysis revealed a depletion of longer hemoglobin-derived peptides, and the hemoglobin fractionation assay demonstrated decreases in hemoglobin, heme and hemozoin levels. To further elucidate the mechanism responsible for inhibition of hemoglobin metabolism, we used in vitro β-hematin polymerization assays and showed JPC-3210 to be an intermediate inhibitor of β-hematin polymerization, about 10-fold less potent then the quinoline antimalarials, such as chloroquine and mefloquine. Further, quantitative proteomics analysis showed that JPC-3210 treatment results in a distinct proteomic signature compared with other known antimalarials. While JPC-3210 clustered closely with mefloquine in the metabolomics and proteomics analyses, a key differentiating signature for JPC-3210 was the significant enrichment of parasite proteins involved in regulation of translation. These studies revealed that the mode of action for JPC-3210 involves inhibition of the hemoglobin digestion pathway and elevation of regulators of protein translation. Importantly, JPC-3210 demonstrated rapid parasite killing kinetics compared with other quinolones, suggesting that JPC-3210 warrants further investigation as a potentially long acting partner drug for malaria treatment.




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Episode 44 - The Internet of Police, Camera, Action! (IoPCA!) Pebble, police cameras & Amazon Go

This week Henry Burrell is in the presenter chair and he has brought puns, sing-songs and tenuous Field of Dreams references. First up is producer Chris to discuss the Fitbit acquisition of fellow wearable maker Pebble and why owners are sad. Then online editor at Techworld Tamlin Magee is discussing the Met Police's decision to upload their body camera footage to the cloud and why this could be problematic (12:00). Finally, fellow online editor Scott Carey runs us through the Amazon Go news and how the retail giant is trying to pull off the technology behind its 'just walk out' shopping experience (24:00).  


See acast.com/privacy for privacy and opt-out information.




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Episode 51 - The Internet of Sick Burns (IoSB) Snapchat IPO, Android Wear 2.0 and Apple in India

Techworld Editor Charlotte Jee conducts the tech orchestra this week, trying to get a tune out of this cold, creaking week. Online Editor at Computerworld UK Scott Carey lets us know all about Snapchat's upcoming IPO, billions of dollars, and the gang comes to the realisation they'll perhaps never understand what it's for. Then Senior Staff Writer at PC Advisor Henry Burrell recaps on Google and LG's launch of Android Wear 2.0 and ask - frankly - is it a big deal? Finally Acting Editor at Macworld UK David Price discusses Apple's rumoured plans to move manufacturing to India, which inevitably moves us on to Tech Trumps.  


See acast.com/privacy for privacy and opt-out information.




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ANGPTL3, PCSK9, and statin therapy drive remarkable reductions in hyperlipidemia and atherosclerosis in a mouse model [Commentary]




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Revisiting Proinsulin Processing: Evidence That Human {beta}-Cells Process Proinsulin With Prohormone Convertase (PC) 1/3 But Not PC2

Insulin is first produced in pancreatic β-cells as the precursor prohormone proinsulin. Defective proinsulin processing has been implicated in the pathogenesis of both type 1 and type 2 diabetes. Though there is substantial evidence that mouse β-cells process proinsulin using prohormone convertase 1/3 (PC1/3) then prohormone convertase 2 (PC2), this finding has not been verified in human β-cells. Immunofluorescence with validated antibodies reveals that there was no detectable PC2 immunoreactivity in human β-cells and little PCSK2 mRNA by in situ hybridization. Similarly, rat β-cells were not immunoreactive for PC2. In all histological experiments, PC2 immunoreactivity in neighbouring α-cells acts as a positive control. In donors with type 2 diabetes, β-cells had elevated PC2 immunoreactivity, suggesting that aberrant PC2 expression may contribute to impaired proinsulin processing in β-cells of patients with diabetes. To support histological findings using a biochemical approach, human islets were used for pulse-chase experiments. Despite inhibition of PC2 function by temperature blockade, brefeldin-A, chloroquine, and multiple inhibitors that blocked production of mature glucagon from proglucagon, β-cells retained the ability to produce mature insulin. Conversely, suppression of PC1/3 blocked processing of proinsulin but not proglucagon. By demonstrating that healthy human β-cells process proinsulin by PC1/3 but not PC2 we suggest that there is a need to revise the longstanding theory of proinsulin processing.




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Pharmacologic PPAR-{gamma} Activation Reprograms Bone Marrow Macrophages and Partially Rescues HSPC Mobilization in Human and Murine Diabetes

Mobilization of hematopoietic stem/progenitor cells (HSPCs) from the bone marrow (BM) is impaired in diabetes. Excess oncostatin M (OSM) produced by M1 macrophages in the diabetic BM signals through p66Shc to induce Cxcl12 in stromal cells and retain HSPCs. BM adipocytes are another source of CXCL12 that blunts mobilization. We tested a strategy of pharmacologic macrophage reprogramming to rescue HSPC mobilization. In vitro, PPAR- activation with pioglitazone switched macrophages from M1 to M2, reduced Osm expression, and prevented transcellular induction of Cxcl12. In diabetic mice, pioglitazone treatment downregulated Osm, p66Shc and Cxcl12 in the hematopoietic BM, restored the effects of granulocyte-colony stimulation factor (G-CSF), and partially rescued HSPC mobilization, but it increased BM adipocytes. Osm deletion recapitulated the effects of pioglitazone on adipogenesis, which was p66Shc-independent, and double knockout of Osm and p66Shc completely rescued HSPC mobilization. In the absence of OSM, BM adipocytes produced less CXCL12, being arguably devoid of HSPC-retaining activity, whereas pioglitazone failed to downregulate Cxcl12 in BM adipocytes. In diabetic patients under pioglitazone therapy, HSPC mobilization after G-CSF was partially rescued. In summary, pioglitazone reprogrammed BM macrophages and suppressed OSM signaling, but sustained Cxcl12 expression by BM adipocytes could limit full recovery of HSPC mobilization.




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Throw nothing away. It's time to upcycle

1 April 2012 , Volume 68, Number 2

In the circular economy nothing is wasted. Repair, not replace, is the byword. Felix Preston on a 30-year-old idea whose day is about to dawn

Felix Preston

Former Senior Research Fellow and Deputy Research Director, Energy, Environment and Resources

Preston.jpg

Photo: AP Photo/Keystone, Walter Bieri




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Creatividad Dentro de la Crisis: Opciones Legales para Inmigrantes Venezolanos en América Latina

Convocamos un seminario en línea (webinar) en español en la ocasión del lanzamiento del informe, Creatividad dentro de la crisis: opciones legales para inmigrantes venezolanos en América Latina, que describe donde se han radicado los migrantes venezolanos; las medidas que han utilizado los gobiernos latinoamericanos para regularizar el estatus legal de los migrantes venezolanos; y los esfuerzos por integrar a los recién llegados en sus nuevas comunidades de residencia.




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ADA standards committees invite interested parties to upcoming meetings

Those interested in developing dental standards that ensure product safety and efficacy and offer useful information on new and emerging technologies can attend upcoming meetings of the American Dental Association's standards committees.




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Salted caramel popcorn chocolate and rum cheesecake

Cheesecake: 1/4 cups chocolate or coconut biscuit crumbs 80g butter, melted 500g cream cheese, softened 1/4 cup caster sugar 2 teaspoons gelatine dissolved in 1/4 cup boiling water 200g dark chocolate melted and cooled slightly 2 splashes of rum 1 cup Baffle Creek Cream, softly whipped Salted Caramel Popcorn: 1 1/2 cup caster sugar 1/2 cup water 2/3 cup brown sugar 300ml thickened cream 1/2 - 1 tablespoon sea salt flakes 200g popcorn, popped




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Sparse equisigned PCA: Algorithms and performance bounds in the noisy rank-1 setting

Arvind Prasadan, Raj Rao Nadakuditi, Debashis Paul.

Source: Electronic Journal of Statistics, Volume 14, Number 1, 345--385.

Abstract:
Singular value decomposition (SVD) based principal component analysis (PCA) breaks down in the high-dimensional and limited sample size regime below a certain critical eigen-SNR that depends on the dimensionality of the system and the number of samples. Below this critical eigen-SNR, the estimates returned by the SVD are asymptotically uncorrelated with the latent principal components. We consider a setting where the left singular vector of the underlying rank one signal matrix is assumed to be sparse and the right singular vector is assumed to be equisigned, that is, having either only nonnegative or only nonpositive entries. We consider six different algorithms for estimating the sparse principal component based on different statistical criteria and prove that by exploiting sparsity, we recover consistent estimates in the low eigen-SNR regime where the SVD fails. Our analysis reveals conditions under which a coordinate selection scheme based on a sum-type decision statistic outperforms schemes that utilize the $ell _{1}$ and $ell _{2}$ norm-based statistics. We derive lower bounds on the size of detectable coordinates of the principal left singular vector and utilize these lower bounds to derive lower bounds on the worst-case risk. Finally, we verify our findings with numerical simulations and a illustrate the performance with a video data where the interest is in identifying objects.




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Alternating Maximization: Unifying Framework for 8 Sparse PCA Formulations and Efficient Parallel Codes. (arXiv:1212.4137v2 [stat.ML] UPDATED)

Given a multivariate data set, sparse principal component analysis (SPCA) aims to extract several linear combinations of the variables that together explain the variance in the data as much as possible, while controlling the number of nonzero loadings in these combinations. In this paper we consider 8 different optimization formulations for computing a single sparse loading vector; these are obtained by combining the following factors: we employ two norms for measuring variance (L2, L1) and two sparsity-inducing norms (L0, L1), which are used in two different ways (constraint, penalty). Three of our formulations, notably the one with L0 constraint and L1 variance, have not been considered in the literature. We give a unifying reformulation which we propose to solve via a natural alternating maximization (AM) method. We show the the AM method is nontrivially equivalent to GPower (Journ'{e}e et al; JMLR 11:517--553, 2010) for all our formulations. Besides this, we provide 24 efficient parallel SPCA implementations: 3 codes (multi-core, GPU and cluster) for each of the 8 problems. Parallelism in the methods is aimed at i) speeding up computations (our GPU code can be 100 times faster than an efficient serial code written in C++), ii) obtaining solutions explaining more variance and iii) dealing with big data problems (our cluster code is able to solve a 357 GB problem in about a minute).




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5 critical things we learned from the latest IPCC report on climate change

Today leading international experts on climate change, the IPCC, presented their latest report on the impacts of climate change on humanity, and what we can do about it. It’s a lengthy report, so we’ve shrunk it down to Oxfam's five key takeaways on climate change and hunger. 1. Climate change: the impacts on crops are worse than we thought Climate change has [...]




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2008-08-25_NEC_PC-8201a




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10 Ways to Tidy Up Your Phones and PCs for the New Year

Organize your phone, tablet, and computer with these quick and easy tips from productivity expert Jill Duffy. Investing just a little time here at the beginning of the year could make a big difference for all of 2020.




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Upcycled Art Contest becomes popular event at Shenango Earth Fest

Penn State Shenango's Upcycled Art Contest will be held in conjunction with the campus' annual Earth Fest on Saturday, April 4.




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Detection of Kingella kingae Osteoarticular Infections in Children by Oropharyngeal Swab PCR

There is evidence that Kingella kingae, the major bacterial cause of osteoarticular infection in children <4 years of age, first colonizes the oropharynx before penetrating the bloodstream and invading distant organs. Diagnosis remains challenging because clinical findings at admission may be normal.

Our study demonstrated for the first time that a simple technique of detecting of K kingae DNA in the oropharynx can provide strong evidence that this microorganism is responsible for the OAI, or even stronger evidence that it is not. (Read the full article)




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Invasive Pneumococcal Disease in Infants Younger Than 90 Days Before and After Introduction of PCV7

Introduction of the pneumococcal conjugate vaccine was associated with decreased invasive pneumococcal disease (IPD) in children. Few data exist on the impact in infants aged 1 to 90 days, who are too young to be fully immunized.

The incidence and proportion of IPD in Utah infants aged 1–90 days remained stable after vaccine introduction. IPD caused by PCV7 serotypes decreased significantly in the post-vaccine period. Serotype 7F emerged as the predominant serotype and commonly resulted in meningitis. (Read the full article)




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Clinical Utility of PCR for Common Viruses in Acute Respiratory Illness

Quantitative real-time polymerase chain reaction allows sensitive detection of respiratory viruses. The clinical significance of detection of specific viruses is not fully understood, however, and several viruses have been detected in the respiratory tract of asymptomatic children.

Our results indicate that quantitative real-time polymerase chain reaction is limited at distinguishing acute infection from detection in asymptomatic children for rhinovirus, bocavirus, adenovirus, enterovirus, and coronavirus. (Read the full article)




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Herpes PCR Testing and Empiric Acyclovir Use Beyond the Neonatal Period

Herpes encephalitis outside the neonatal period is typically severe and recognizable to clinicians. Excessive testing for herpes encephalitis is associated with increased medical costs and hospital length of stay, and risks patient harm.

Herpes testing and empirical acyclovir treatment in older and less unwell patients has been increasing in US pediatric hospitals over the past decade, which may reflect a more fundamental problem in current approaches to clinical decision-making. (Read the full article)




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13-Valent Pneumococcal Conjugate Vaccine (PCV13) in Preterm Versus Term Infants

Preterm infants are at an increased risk of infections; therefore, vaccination is of particular importance. Because immune response data reported for preterm infants may vary according to gestational age and vaccination timing, vaccine responses in this population warrant additional research.

This study evaluated 13-valent pneumococcal conjugate vaccine in preterm infants. Results suggest that this vaccine was well tolerated and immunogenic; most subjects achieved serotype-specific immunoglobulin G antibody levels and functional antibody responses likely to correlate with protection against invasive disease. (Read the full article)




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PCMAG CHOOSE YOUR PRIZE GIVEAWAY RULES

Enter our giveaway for a chance to win rad tech prizes




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PCMAG Lenovo ThinkPad Edge E545 SWEEPSTAKES RULES

NO PURCHASE NECESSARY TO ENTER OR WIN.




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PCMag.com RSS Feeds

Subscribe to PCMag's RSS feeds to get the latest technology news, tips, and product reviews.




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PCMag.com 2017 Editorial Calendar

Lineup is subject to change. Please see our masthead for editorial contacts.




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PCMag Tech Addiction Survey

Is tech addiction a thing? Help us find out.




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PCMag.com Readers' Choice/ Business Choice Survey Sweepstakes Rules

Enter PCMag.com's Readers' Choice/Business Choice Survey sweepstakes for a chance to win!




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Impact of KPC-production and high-level meropenem resistance on all-cause mortality of ventilator-associated pneumonia in association with Klebisella pneumoniae [Clinical Therapeutics]

Objectives: Carbapenemase-producing Enterobacterales and specifically KPC-producing Klebsiella pneumoniae (KPC-Kp) are rapidly spreading worldwide. The prognosis of ventilator-associated pneumonia (VAP) caused by KPC-producing Klebsiella pneumoniae (KPC-Kp) is not well known. Our study tries to assess whether ventilator-associated pneumonia caused by a KPC-Kp strain is associated with higher all-cause mortality than if caused by carbapenem-susceptible isolates.

Study design and methods: This is a retrospective cohort study of patients with VAP due to K. pneumoniae from a 35-bed polyvalent Intensive Care Unit in a university hospital (> 40,000 annual admissions) between January 2012 and December 2016. Adjusted multivariate analysis was used to study the association of KPC-Kp with 30-day all-cause mortality (Cox regression).

Results. We analyze 69 cases of K. pneumoniae VAP of which 39 were produced by a KPC-Kp strain with high-level resistance to meropenem (MIC > 16 mg/mL). All-cause mortality at 30 days was 41% in the KPC-Kp group (16/39) and 33.3% in the carbapenem-susceptible cases (10/30). KPC-Kp etiology was not associated with higher mortality when controlled for confounders (adjusted hazard ratio [lsqb]HR[rsqb] 1.25; 95% CI: 0.46–3.41). Adequate targeted therapy (HR 0.03; 95% CI: <0.01–0.23) was associated with all-cause mortality.

Conclussion. Assuming the limitations due to the available sample size, the prognosis of VAP caused by KPC-Kp is similar to VAPs caused by carbapenem-susceptible K. pneumoniae when appropriate treatment is used.




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OPC-167832, a novel carbostyril derivative with potent anti-tuberculosis activity as a DprE1 inhibitor [Pharmacology]

There is an urgent need for new, potent anti-tuberculosis (TB) drugs with novel mechanisms of action that can be included in new regimens to shorten the treatment period for TB. After screening a library of carbostyrils, we optimized 3, 4-dihydrocarbostyril derivatives and identified OPC-167832 as having potent anti-tuberculosis activity. The minimum inhibitory concentrations of the compound for Mycobacterium tuberculosis ranged from 0.00024 to 0.002 μg/mL. It had bactericidal activity against both growing and intracellular bacilli, and the frequency of spontaneous resistance for Mycobacterium tuberculosis H37Rv was less than 1.91 x 10-7. It did not show antagonistic effects with other anti-TB agents in an in vitro checkerboard assay. Whole genome and targeted sequencing of resistant isolates to OPC-167832 identified the decaprenylphosphoryl-β-D-ribose 2'-oxidase (DprE1), an essential enzyme for cell wall biosynthesis, as the target of this compound, and further studies demonstrated inhibition of the DprE1 enzymatic activity by OPC-167832. In a mouse model of chronic TB, OPC-167832 showed potent bactericidal activities starting at a dose of 0.625 mg/kg. Further, it exhibited significant combination effects in 2-drug combinations with delamanid, bedaquiline, or levofloxacin. Finally, 3-4 drug regimens comprised of delamanid and OPC-167832 as the core along with bedaquiline, moxifloxacin, or linezolid showed superior efficacy in reducing bacterial burden and preventing relapse compared to the standard treatment regimen. In summary, these results suggest that OPC-167832 is a novel and potent anti-TB agent and regimens containing OPC-167832 and new or repurposed anti-TB drugs may have the potential to shorten the duration of treatment for TB.




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Ceftazidime-avibactam resistance mediated by the N346Y substitution in various AmpC {beta}-lactamases [Mechanisms of Resistance]

Chromosomal and plasmid-borne AmpC cephalosporinases are a major resistance mechanism to β-lactams in Enterobacteriaceae and Pseudomonas aeruginosa. The new β-lactamase inhibitor avibactam effectively inhibits class C enzymes and can fully restore ceftazidime susceptibility. The conserved amino acid residue Asn346 of AmpC cephalosporinases directly interacts with the avibactam sulfonate. Disruption of this interaction caused by the N346Y amino acid substitution in Citrobacter freundii AmpC was previously shown to confer resistance to the ceftazidime-avibactam combination (CAZ-AVI). The aim of this study was to phenotypically and biochemically characterize the consequences of the N346Y substitution in various AmpC backgrounds. Introduction of N346Y into Enterobacter cloacae AmpC (AmpCcloacae), plasmid-mediated DHA-1, and P. aeruginosa PDC-5, led to 270-, 12,000-, and 79-fold decreases in the inhibitory efficacy (k2/Ki) of avibactam, respectively. The kinetic parameters of AmpCcloacaeand DHA-1 for ceftazidime hydrolysis were moderately affected by the substitution. Accordingly, AmpCcloacaeand DHA-1 harboring N346Y conferred CAZ-AVI resistance (MIC of ceftazidime of 16 µg/ml in the presence of 4 µg/ml of avibactam). In contrast, production of PDC-5 N346Y was associated with a lower MIC (4 µg/ml) since this β-lactamase retained a higher inactivation efficacy by avibactam in comparison to AmpCcloacaeN346Y. For FOX-3, the I346Y substitution did not reduce the inactivation efficacy of avibactam and the substitution was highly deleterious for β-lactam hydrolysis, including ceftazidime, preventing CAZ-AVI resistance. Since AmpCcloacaeand DHA-1 display substantial sequence diversity, our results suggest that loss of hydrogen interaction between Asn346 and avibactam could be a common mechanism of acquisition of CAZ-AVI resistance.




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Structural basis of reduced susceptibility to ceftazidime-avibactam and cefiderocol in Enterobacter cloacae due to AmpC R2 loop deletion [Mechanisms of Resistance]

Ceftazidime–avibactam and cefiderocol are two of the latest generation β-lactam agents that possess expanded activity against highly drug-resistant bacteria, including carbapenem-resistant Enterobacterales. Here we show that structural changes in AmpC β-lactamases can confer reduced susceptibility to both agents. A multidrug-resistant Enterobacter cloacae clinical strain (Ent385) was found to be resistant to ceftazidime–avibactam and cefiderocol without prior exposure to either agent. The AmpC β-lactamase of Ent385 (AmpCEnt385) contained an alanine–proline deletion at positions 294–295 (A294_P295del) in the R2 loop. AmpCEnt385 conferred reduced susceptibility to ceftazidime–avibactam and cefiderocol when cloned into Escherichia coli TOP10. Purified AmpCEnt385 showed increased hydrolysis of ceftazidime and cefiderocol compared with AmpCEnt385Rev, in which the deletion was reverted. Comparisons of crystal structures of AmpCEnt385 and AmpCP99, the canonical AmpC of E. cloacae, revealed that the two-residue deletion in AmpCEnt385 induced drastic structural changes of the H-9 and H-10 helices and the R2 loop, which accounted for the increased hydrolysis of ceftazidime and cefiderocol. The potential for a single mutation in ampC to confer reduced susceptibility to both ceftazidime–avibactam and cefiderocol requires close monitoring.

Importance Ceftazidime–avibactam and cefiderocol are newly approved β-lactam agents that possess broad spectrum activity against multidrug-resistant (MDR) Gram-negative bacteria. We show here that a two amino-acid deletion in the chromosomal AmpC β-lactamase, identified in a clinical strain of Enterobacter cloacae, confers reduced susceptibility to both agents. By crystallographic studies of free and drug-bound forms of enzyme, we demonstrate that this deletion in AmpC induces slanting of the H-9 helix that is directly connected with the R2 loop, and disappearance of the H-10 helix, is directly responsible for increased hydrolysis of ceftazidime and cefiderocol. These findings provide novel insights into how MDR Gram-negative bacteria may evolve their β-lactamases to survive selective pressure from these newly developed β-lactam agents.