Subradiance with Saturated Atoms: Population Enhancement of the Long-Lived States

Dipole-dipole interactions are at the origin of long-lived collective atomic states, often called subradiant, which are explored for their potential use in novel photonic devices or in quantum protocols. Here, we study subradiance beyond the single-excitation regime and experimentally demonstrate a 200-fold increase in the population of these modes, as the saturation parameter of the driving field is increased. We attribute this enhancement to a mechanism similar to optical pumping through the well-coupled superradiant states. The lifetimes are unaffected by the pump strength, as the system is ultimately driven toward the single-excitation sector. Our study is a new step in the exploration of the many-body dynamics of large open systems.

Vascular neutrophilic inflammation and immunothrombosis distinguish severe COVID-19 from influenza pneumonia

OBJECTIVE

Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can lead to severe pneumonia, but also thrombotic complications and non-pulmonary organ failure. Recent studies suggest intravascular neutrophil activation and subsequent immune cell-triggered immunothrombosis as a central pathomechanism linking the heterogenous clinical picture of coronavirus disease 2019 (COVID-19). We sought to study whether immunothrombosis is a pathognomonic factor in COVID-19 or a general feature of (viral) pneumonia, as well as to better understand its upstream regulation.

APPROACH AND RESULTS

By comparing histopathological specimens of SARS-CoV-2 with influenza-affected lungs, we show that vascular neutrophil recruitment, NETosis, and subsequent immunothrombosis are typical features of severe COVID-19, but less prominent in influenza pneumonia. Activated neutrophils were typically found in physical association with monocytes. To explore this further, we combined clinical data of COVID-19 cases with comprehensive immune cell phenotyping and bronchoalveolar lavage fluid scRNA-seq data. We show that a HLADRlow CD9low monocyte population expands in severe COVID-19, which releases neutrophil chemokines in the lungs, and might in turn explain neutrophil expansion and pulmonary recruitment in the late stages of severe COVID-19.

CONCLUSIONS

Our data underline an innate immune cell axis causing vascular inflammation and immunothrombosis in severe SARS-CoV-2 infection.

Photon Blockade with Ground-State Neutral Atoms

We show that induced dipole-dipole interactions allow for photon blockade in subwavelength ensembles of two-level, ground-state neutral atoms. Our protocol relies on the energy shift of the single-excitation, superradiant state of N atoms, which can be engineered to yield an effective two-level system. A coherent pump induces Rabi oscillation between the ground state and a collective bright state, with at most a single excitation shared among all atoms. The possibility of using clock transitions that are long-lived and relatively robust against stray fields, alongside new prospects on experiments with subwavelength lattices, makes our proposal a promising alternative for quantum information protocols.

Immunothrombotic Dysregulation in COVID-19 Pneumonia Is Associated With Respiratory Failure and Coagulopathy

Supplemental Digital Content is available in the text.

Background:

Severe acute respiratory syndrome corona virus 2 infection causes severe pneumonia (coronavirus disease 2019 [COVID-19]), but the mechanisms of subsequent respiratory failure and complicating renal and myocardial involvement are poorly understood. In addition, a systemic prothrombotic phenotype has been reported in patients with COVID-19.

Methods:

A total of 62 subjects were included in our study (n=38 patients with reverse transcriptase polymerase chain reaction–confirmed COVID-19 and n=24 non–COVID-19 controls). We performed histopathologic assessment of autopsy cases, surface marker–based phenotyping of neutrophils and platelets, and functional assays for platelet, neutrophil functions, and coagulation tests, as well.

Results:

We provide evidence that organ involvement and prothrombotic features in COVID-19 are linked by immunothrombosis. We show that, in COVID-19, inflammatory microvascular thrombi are present in the lung, kidney, and heart, containing neutrophil extracellular traps associated with platelets and fibrin. Patients with COVID-19 also present with neutrophil-platelet aggregates and a distinct neutrophil and platelet activation pattern in blood, which changes with disease severity. Whereas cases of intermediate severity show an exhausted platelet and hyporeactive neutrophil phenotype, patients severely affected with COVID-19 are characterized by excessive platelet and neutrophil activation in comparison with healthy controls and non–COVID-19 pneumonia. Dysregulated immunothrombosis in severe acute respiratory syndrome corona virus 2 pneumonia is linked to both acute respiratory distress syndrome and systemic hypercoagulability.

Conclusions:

Taken together, our data point to immunothrombotic dysregulation as a key marker of disease severity in COVID-19. Further work is necessary to determine the role of immunothrombosis in COVID-19.

Pretreatment resistance mutations and treatment outcomes in adults living with HIV-1: a cohort study in urban Malawi

Background

Pre-treatment drug resistance (PDR) among antiretroviral drug-naïve people living with HIV (PLHIV) represents an important indicator for the risk of treatment failure and the spread of drug resistant HIV variants. We assessed the prevalence of PDR and treatment outcomes among adults living with HIV-1 in Lilongwe, Malawi.

Methods

We selected 200 participants at random from the Lighthouse Tenofovir Cohort Study (LighTen). Serum samples were drawn prior to treatment initiation in 2014 and 2015, frozen, and later analyzed for the presence of HIV-1 drug resistance mutations. Amplicons were sequenced and interpreted by Stanford HIVdb interpretation algorithm 8.4. We assessed treatment outcomes by evaluating clinical outcome and viral suppression at the end of the follow-up period in October 2019.

Results

PDR testing was successful in 197 of 200 samples. The overall NNRTI- PDR prevalence was 13.7% (27/197). The prevalence of intermediate or high level NNRTI- PDR was 11.2% (22/197). The most common mutation was K103N (5.6%, 11/197), followed by Y181C (3.6%, 7/197). In one case, we detected an NRTI resistance mutation (M184V), in combination with multiple NNRTI resistance mutations. All HIV-1 isolates analyzed were of subtype C. Of the 27 patients with NNRTI- PDR, 9 were still alive, on ART, and virally suppressed at the end of follow-up.

Conclusion

The prevalence of NNRTI- PDR was above the critical level of 10% suggested by the Global Action Plan on HIV Drug Resistance. The distribution of drug resistance mutations was similar to that seen in previous studies from the region, and further supports the introduction of integrase inhibitors in first-line treatment in Malawi. Furthermore, our findings underline the need for continued PDR surveillance and pharmacovigilance in Sub-Saharan Africa.

Use of nuclear medicine methods in surgical treatment of lumbar spine degeneration

INTRODUCTION

Chronic back pain (CBP) is a very common symptom. Multiple modalities are used in its evaluation. However, according to current evidence, none of them can be used with certainty to predict the success of fusion surgery. Given the growing experience with bone tissue examination using the methods of nuclear medicine, we have used this possibility in patients with CBP without disc herniation, degenerative spinal stenosis or instability.

CASE REPORTS

We present case reports of 11 patients who underwent lumbar fusion (during two years period) for degenerative disc disease or facet arthropathy with adequate activity on PET or SPECT/CT examination. Rolland-Morris Questionnaire (RMQ), Oswestry Disability Index (ODI), and Visual Analogue Scale (VAS) were filled out pre-operatively and 24 months after surgery.

RESULTS

Six patients after one-level stabilization for active osteochondrosis and one for active facet arthropathy improved on average by 82% (64-92%) in RMQ, by 72% (48-100%) in ODI and 75% (55-100%) in VAS. Results in cases after multilevel stabilizations were slightly worse, but still very significant in most parameters. Only one patient with the most severe morphological and clinical findings did not benefit from surgery.

CONCLUSION

In 10 out of 11 patients, the lower back pain and quality of life improved significantly after lumbar fusion performed in levels diagnosed by PET or SPECT/CT. These methods certainly have their place in the evaluation of CBP, especially in the case of unclear findings or multiple degenerative changes.

History, development and use of classification of thoracolumbar spine fractures

The main goal of this comprehensive paper is to clarify the way of thoracolumbar spine The main goal of this summary paper is to describe the way of thoracolumbar spine injury classification development and to provide a detailed description of two of the most commonly used classifications - the Thoracolumbar Injury Classification and Severity Scale (TLICS) and the AOSpine Classification for Traumatic Fracture of the Thoracolumbar Spine, including their comparison and clarification of the merits introduced by the second one. The paper also formulates a recommendation of a simple algorithm enabling even less experienced clinicians to distinguish between an injury indicated for conservative treatment and one that requires surgery.

Liquid Chromatographic Method for the Determination of Nine Phenolic Antioxidants in Butter Oil: Collaborative Study

Ten laboratories collaboratively studied a liquid chromatographic (LC) method for the determination of propyl, octyl, and dodecyl gallate (PG, OG, and DG, respectively), 2,4,5-trihydroxybutyrophenone (THBP), ferf-butylhydroquinone (TBHQ), nordihydroguaiaretic acid (NDGA), 2- and 3-tert-butyl-4- hydroxyanisole (BHA), 2,6-di-ferf-butyl-4-hydroxymethylphenol (lonox-100), and 3,5-di-terf-butyl-4- hydroxytoluene (BHT) in butter oil. The 10 samples analyzed were spiked in matched pairs at about 100,50, and 10 μg/g. In the method studied, antioxidants are extracted as in AOAC LC method 983.15, but different LC eluants are used to separate the 9 antioxidants. Results from 1 laboratory were rejected as not valid and were not included in any calculations. For the remaining 9 laboratories, the overall mean recoveries for PG, THBP, TBHQ, NDGA, BHA, OG, lonox, BHT, and DG were 100.9, 97.8,103.4,95.4, 97.4,93.6,95.5,79.0, and 96.2%, respectively. The overall reproducibility relative standard deviations were 8.55,17.4,25.6,14.5,6.60, 9.64,10.8,11.4, and 7.35%, respectively. The method was adopted first action by AOAC International as a modification of AOAC method 983.15.

Collective Multimode Vacuum Rabi Splitting

We report the experimental observation of collective multimode vacuum Rabi splitting in free space. In contrast to optical cavities, the atoms couple to a continuum of modes, and the optical thickness of the cloud provides a measure of this coupling. The splitting, also referred as normal mode splitting, is monitored through the Rabi oscillations in the scattered intensity, and the results are fully explained by a linear-dispersion theory.

Robust Coherent Transport of Light in Multilevel Hot Atomic Vapors

Using a model system, we demonstrate both experimentally and theoretically that coherent scattering of light can be robust in hot atomic vapors despite a significant Doppler effect. By operating in a linear regime of far-detuned light scattering, we also unveil the emergence of interference triggered by inelastic Stokes and anti-Stokes transitions involving the atomic hyperfine structure.

Rapid Detection and Quantitation of Precipitating Streptokinase-Antibodies

Streptokinase-therapy is regularly followed by a marked increase of precipitating streptokinase-antibodies. These antibodies cause a significant inhibition of streptokinase-induced plasminogen activation. Counterelectrophoresis is a useful method of tracing the antibodies in serum. For quantitative estimation a modified radial immunodiffusion method is presented. The antibodies were identified as IgG.

Serological and Virological Markers of Human Parvovirus B19 Infection in Sera of Hemophiliacs

It is known that parvovirus B19 (B19) is transmitted to hemophiliacs by clotting factors prepared from human plasma. However, it is not clear whether B19 is also transmitted by the more recently used inactivated clotting factor preparations. Therefore, we investigated 69 hemophiliacs, mostly children, receiving only virus-inactivated clotting factors. 49 of them (71%) were B19 IgG-positive and 18 of the IgG-positive hemophiliacs (37%) were also B19 IgM-positive. In contrast, out of 73 age-matched controls only 10 (14%) were IgG-positive, two of them being also IgM-positive. In hemophiliacs treated before 1984 with noninactivated clotting factors, seroprevalence was very similar: 94/136 (69%) presented B19 IgG antibodies as compared to their age-matched controls with 16/50 (32%). Out of the 94 IgG-positive patients 24 (26%) were IgM-positive, whereas IgM antibodies were never found in 16 sera of 16 IgG-positive controls. In 4 out of 24 IgM positive hemophiliacs, B19 DNA was detected in the sera by using the polymerase chain reaction. However, B19 DNA was also found in 3/69 anti-B19 IgM-negative, HIV-infected hemophiliacs (all three patients in CDC stage IV). Since it seems unlikely that the results only represent passive acquisition of B19 DNA from blood products and induction of antibodies by immunization with inactivated antigen, the observations rather suggest that infection with B19 is transmitted by clotting factors, including those treated for virus inactivation.

Meralgia paresthetica

Meralgia paresthetica is a compression neuropathy of the lateral femoral cutaneous nerve. Despite its rarity, it is the most common nerve entrapment of the lower limbs. It produces similar symptoms as those associated with the more common L4 or L5 radiculopathy. Therefore, it is often diagnosed late (sometimes only after several years of latency) or not at all. This diagnosis should be considered especially in patients with obesity and diabetes who have chronic irritation of the ventrolateral areas of the thigh not responding to conservative therapy and a negative finding on lumbar MRI. We present our experience with surgical nerve decompression in three patients with pain, paresthesias, and sensory loss within the distribution of the lateral cutaneous nerve of the thigh. They all suffered from severe abdominal obesity. All conservative treatments, including weight reduction attempts, were unsuccessful. Nerve release caused an immediate effect in two cases. One patient experienced a temporary worsening of pain, which gradually improved within one month. In spite of the controversy surrounding the surgical treatment of meralgia (neurolysis or nerve resection), it can be concluded that nerve decompression has a good effect. Nerve resection is, in our view, considered to be a reserve option when primary surgery fails. Key words: meralgia paresthetica - nerve entrapment - peripheral nerve.

Qualitative Assessment of Vaccination Hesitancy Among Members of the Apostolic Church of Zimbabwe: A Case Study

Vaccine hesitancy or lack of confidence in vaccines is considered a threat to the success of vaccination programs. The rise and spread of measles outbreaks in southern Africa in 2009-2010 were linked to objections among Apostolic Church members, estimated at about 3.5 million in Zimbabwe as of 2014. To inform planning of interventions for a measles-rubella vaccination campaign, we conducted an assessment of the factors contributing to vaccine hesitancy using data from various stakeholders. Among nine districts in three regions of Zimbabwe, we collected data on religious attitudes toward, and perceptions of, vaccines through focus group discussions with health workers serving Apostolic communities and members of the National Expanded Programme on Immunization; semi-structured interviews with religious leaders; and open-ended questions in structured interviews with Apostolic parents/caregivers. Poor knowledge of vaccines, lack of understanding and appreciation of the effectiveness of vaccinations, religious teachings that emphasize prayers over the use of medicine, lack of privacy in a religiously controlled community, and low levels of education were found to be the main factors contributing to vaccine hesitancy among key community members and leaders. Accepting vaccination in public is a risk of sanctions. Poor knowledge of vaccines is a major factor of hesitancy which is reinforced by religious teachings on the power of prayers as alternatives. Because parents/caregivers perceive vaccines as dangerous for their children and believe they can cause death or disease, members of the Apostolic Church have more confidence in alternative methods such as use of holy water and prayers to treat diseases. Under these circumstances, it is important to debunk the myths about the power of holy water on the one hand and disseminate positive information of the efficacy of vaccines on the other hand in order to reduce hesitancy. Education about vaccines and vaccination in conjunction with government intervention, for example, through the use of social distancing policies can provide a framework for reducing hesitancy and increasing demand for vaccination.