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2.
Magn Reson Med ; 2024 Jul 25.
Article in English | MEDLINE | ID: mdl-39051628

ABSTRACT

PURPOSE: To establish an interleaved multislice variant of the averaged magnetization inversion-recovery acquisitions (AMIRA) approach for 2D spinal cord imaging with increased acquisition efficiency compared with the conventional 2D single-slice approach(es), and to determine essential prerequisites for a working interleaved multislice AMIRA approach in practice. METHODS: The general AMIRA concept is based on an inversion recovery-prepared, segmented, and time-limited cine balanced SSFP sequence, generating images of different contrast. For AMIRA imaging of multiple, independent slices in a 2D interleaved fashion, a slice loop within the acquisition loops was programmed. The former non-selective inversions were replaced with slice-selective inversions with user-definable slice thickness. RESULTS: The thickness of the slice-selective inversion in 2D interleaved multislice AMIRA should be doubled compared with the manufacturer's standard setting to avoid an increased sensitivity to flow and pulsation effects particularly in the CSF. However, this solution also limits its practical applicability, as slices located at directly adjacent vertebrae cannot be imaged together. Successful interleaved two-slice AMIRA imaging for a "reference" in vivo protocol with 0.50 × 0.50 mm2 in-plane resolution and 8-mm slice thickness is demonstrated, therefore halving its acquisition time per slice from 3 min down to 1.5 min. CONCLUSION: The investigated 2D interleaved two-slice AMIRA variant facilitates spinal cord imaging that maintains similar contrast and the same resolution as the conventional 2D single-slice AMIRA approach, but does so with a halved acquisition time.

4.
Health Aff Sch ; 2(6): qxae056, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38915810

ABSTRACT

Safety-net hospitals have recently become targets of acquisition by health systems with the stated purpose of improving their financial solvency and preserving access to safety-net services. Whether acquisition achieves these goals is unknown. In this descriptive case series, we sought to determine the factors that contribute to safety-net hospital acquisition, and identify whether safety-net services are preserved after acquisition. We examined 22 acquisitions of safety-net hospitals from 2016 to 2021 and described characteristics of the acquired safety-net hospitals, their acquiring systems, and the operational fate of acquired hospitals. Relative to other hospitals in the same Hospital Referral Region in the year prior to acquisition, acquired safety-net hospitals tended to be smaller and have lower occupancy rates. Acquiring systems were geographically concentrated, with only 6 of 20 systems operating in more than 1 state. Safety-net hospitals frequently offered typical safety-net services prior to acquisition. However, after acquisition, 2 of the 22 acquired safety-net hospitals lost safety-net services, 3 hospitals ceased inpatient services, and 1 hospital closed entirely. These findings suggest that acquisition of safety-net hospitals may be associated with trade-offs related to the provision of safety-net services for the communities that stand to benefit from them most.

5.
Health Serv Res ; 2024 Apr 23.
Article in English | MEDLINE | ID: mdl-38652542

ABSTRACT

OBJECTIVE: To examine the impact of "cross-market" hospital mergers on prices and quality and the extent to which serial acquisitions contribute to any measured effects. DATA SOURCES: 2009-2017 commercial claims from the Health Care Cost Institute (HCCI) and quality measures from Hospital Compare. STUDY DESIGN: Event study models in which the treated group consisted of hospitals that acquired hospitals further than 50 miles, and the control group was hospitals that were not part of any merger activity (as a target or acquirer) during the study period. DATA EXTRACTION METHODS: We extracted data for 214 treated hospitals and 955 control hospitals. PRINCIPAL FINDINGS: Six years after acquisition, cross-market hospital mergers had increased acquirer prices by 12.9% (CI: 0.6%-26.6%) relative to control hospitals, but had no discernible impact on mortality and readmission rates for heart failure, heart attacks and pneumonia. For serial acquirers, the price effect increased to 16.3% (CI: 4.8%-29.1%). For all acquisitions, the price effect was 21.8% (CI: 4.6%-41.7%) when the target's market share was greater than the acquirer's market share versus 9.7% (CI: -0.5% to 20.9%) when the opposite was true. The magnitude of the price effect was similar for out-of-state and in-state cross-market mergers. CONCLUSIONS: Additional evidence on the price and quality effects of cross-market mergers is needed at a time when over half of recent hospital mergers have been cross-market. To date, no hospital mergers have been challenged by the Federal Trade Commission on cross-market grounds. Our study is the third to find a positive price effect associated with cross-market mergers and the first to show no quality effect and how serial acquisitions contribute to the price effect. More research is needed to identify the mechanism behind the price effects we observe and analyze price effect heterogeneity.

6.
Drug Discov Today ; 29(4): 103937, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38430964

ABSTRACT

Pharmaceutical managers have been encouraged to look to acquisitions and alliances for innovation. However, the literature warns that the capacity of a company to 'absorb' new knowledge is limited. Here, we introduce corporate divestitures as a tool for freeing up managerial attention. We build a sample of 349 companies, which announced 1784 divestitures and filed 63523 patents, over a 15-year period. We show that innovating companies that divest more produce more and improved patents, and those that divest to create corporate focus also produce more breakthroughs. In doing so, we introduce divestitures as an innovation tool, highlight the importance of the absorptive capacity of a company when discussing innovation, and add nuance to the discussion on external tools for innovation.


Subject(s)
Pharmaceutical Preparations
7.
J Int AIDS Soc ; 27(3): e26235, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38528395

ABSTRACT

INTRODUCTION: Monitoring mother-infant pairs with HIV exposure is needed to assess the effectiveness of vertical transmission (VT) prevention programmes and progress towards VT elimination. METHODS: We used routinely collected data on infants with HIV exposure, born May 2018-April 2021 in the Western Cape, South Africa, with follow-up through mid-2022. We assessed the proportion of infants diagnosed with HIV at birth (≤7 days), 10 weeks (>1 to 14 weeks) and >14 weeks as proxies for intrauterine, intrapartum/early breastfeeding and late breastfeeding transmission, respectively. We used mixed-effects Poisson regression to assess factors associated with VT in mothers known with HIV by delivery. RESULTS: We included 50,461 infants born to mothers known with HIV by delivery. HIV was diagnosed in 894 (1.8%) infants. Among mothers, 51% started antiretroviral treatment (ART) before and 27% during pregnancy; 17% restarted during pregnancy after ≥6 months interruption; and 6% had no recorded ART during pregnancy. Most pregnancy ART regimens included non-nucleoside reverse transcriptase inhibitors (83%). Of mothers with available results (90% with viral load [VL]; 70% with CD4), VL nearest delivery was <100 copies/ml in 78% and CD4 count ≥350 cells/µl in 62%. HIV-PCR results were available for 86%, 67% and 48% of eligible infants at birth, 10 weeks and >14 weeks. Among these infants, 0.9%, 0.4% and 1.5% were diagnosed positive at birth, 10 weeks and >14 weeks, respectively. Among infants diagnosed with HIV, 43%, 16% and 41% were diagnosed at these respective time periods. Among mothers with VL<100, 100-999, 1000-99,000 and ≥100,000 copies/ml nearest delivery, infant HIV diagnosis incidence was 0.4%, 2.3%, 6.6% and 18.4%, respectively. Increased VT was strongly associated with recent elevated maternal VL with a seven-fold increased rate with even modestly elevated VL (100-999 vs. <100 copies/ml). VT was also associated with unknown/low maternal CD4, maternal age <20 years, no antenatal ART, later maternal ART start/restart in pregnancy and ART gaps. CONCLUSIONS: Despite high maternal ART coverage and routine postnatal prophylaxis, ongoing VT remains a concern. Timing of infant HIV diagnoses suggests intrapartum and/or breastfeeding transmission in nearly 60%. Interventions to ensure retention on ART and sustained maternal viral suppression are needed to reduce VT.


Subject(s)
Anti-HIV Agents , HIV Infections , Pregnancy Complications, Infectious , Pregnancy , Infant , Infant, Newborn , Female , Humans , Young Adult , Adult , HIV Infections/diagnosis , HIV Infections/drug therapy , HIV Infections/epidemiology , Anti-HIV Agents/therapeutic use , Retrospective Studies , South Africa/epidemiology , Anti-Retroviral Agents/therapeutic use , Cohort Studies , Infectious Disease Transmission, Vertical/prevention & control , Pregnancy Complications, Infectious/epidemiology , Pregnancy Complications, Infectious/drug therapy
8.
Ophthalmology ; 131(3): 360-369, 2024 Mar.
Article in English | MEDLINE | ID: mdl-37777118

ABSTRACT

PURPOSE: Private equity (PE) firms increasingly are acquiring ophthalmology practices; little is known of their influence on care use and spending. We studied changes in use and Medicare spending after PE acquisition. DESIGN: Retrospective cohort study. PARTICIPANTS: Seven hundred sixty-two clinicians in 123 practices acquired by PE between 2017 and 2018 and 34 807 clinicians in 20 549 never-acquired practices. METHODS: We analyzed Medicare fee-for-service claims (2012-2019) combined with a novel national database of PE acquisitions of ophthalmology practices using a difference-in-differences method within an event study framework to compare changes after a practice was acquired with changes in practices that were not acquired. MAIN OUTCOME MEASURES: Numbers of beneficiaries seen; intravitreal injections and medications used for injections; and spending on ophthalmologist and optometrist services, ancillary services, and intravitreal injections. RESULTS: Comparing PE-acquired with nonacquired practices showed a 23.92% increase (n = 4.20 beneficiaries; 95% confidence interval [CI], 1.73-6.67) in beneficiaries seen per PE optometrist per quarter and no change for ophthalmologists, while spending per beneficiary increased 5.06% ($9.66; 95% CI, -2.82 to 22.14). Spending on clinician services decreased 1.62% (-$2.37; 95% CI, -5.78 to 1.04), with ophthalmologist services increasing 5.46% ($17.70; 95% CI, -2.73 to 38.15) and optometrists decreasing 4.60% (-$5.76; 95% CI, -9.17 to -2.34) per beneficiary per quarter. Ancillary services decreased 7.56% (-$2.19; 95% CI, 4.19 to -0.22). Intravitreal injection costs increased 25.0% ($20.02; 95% CI, -1.38 to 41.41) with the number increasing 5.10% (1.83; 95% CI, -0.1 to 3.80). There was a 74.09% increase (8.38 injections; 95% CI, 0.01-16.74) in ranibizumab and a 12.91% decrease (-3.40 injections; 95% CI, -6.86 to 0.07) in bevacizumab after acquisition. The event study showed consistent and often statistically significant increases in ranibizumab injections and decreases in bevacizumab injections after acquisition. CONCLUSIONS: Although not all results reached statistical significance, this study suggested that PE acquisition of practices showed little or no overall effect on use or total spending, but increased the number of unique patients seen per optometrist and the use of expensive intravitreal injections. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.


Subject(s)
Medicare , Ophthalmology , Aged , Humans , United States , Ranibizumab/therapeutic use , Bevacizumab/therapeutic use , Retrospective Studies
9.
Magn Reson Imaging ; 105: 75-81, 2024 Jan.
Article in English | MEDLINE | ID: mdl-37939972

ABSTRACT

PURPOSE: To apply multi-shot high-resolution multi inversion spin and gradient echo (MI-SAGE) acquisition for simultaneous liver T1, T2 and T2* mapping. METHODS: Inversion prepared spin- and gradient-echo EPI was developed with ascending slice order across measurements for efficient acquisition with T1, T2, and T2⁎ weighting. Multi-shot EPI was also implemented to minimize distortion and blurring while enabling high in-plane resolution. A dictionary-matching approach was used to fit the images to quantitative parameter maps, which were compared to T1 measured by modified Look-Locker (MOLLI), T1 measured by variable flip angle (VFA), T2 measured by multiple echo time-based Half Fourier Single-shot Turbo spin-Echo (HASTE), T2 measured by radial turbo-spin-echo (rTSE) and T2⁎ measured by multiple gradient echo (MGRE) sequences. RESULTS: The multi-shot variant of the sequence achieved higher in-plane resolution of 1.7 × 1.7 mm2 with good image quality in 28 s. Derived quantitative maps showed comparable values to conventional mapping methods. As measured in phantom and in vivo, MOLLI, MESE and MGRE give closest values to MISAGE. VFA, HASTE and rTSE show obvious overestimation. CONCLUSIONS: The proposed multi-shot inversion prepared spin- and gradient-echo EPI sequence allows for high-resolution quantitative T1, T2 and T2 liver tissue characterization in a single breath-hold scan.


Subject(s)
Liver , Magnetic Resonance Imaging , Magnetic Resonance Imaging/methods , Liver/diagnostic imaging , Breath Holding , Phantoms, Imaging
10.
Environ Plan A ; 55(6): 1618-1627, 2023 Sep.
Article in English | MEDLINE | ID: mdl-37810992

ABSTRACT

Mergers and acquisitions (M&As) are on the rise. Interlocking processes of globalization and financialization have increased their attractiveness and incentivized an upward spiral of M&A activity in recent years. This rise is profoundly spatial, as M&As reshape the geographies of production, consumption and finance, while aggravating uneven power-geometries through the concentration of corporate control. Despite this growth and inherent spatiality, economic geography research into M&As has waned. The aim this article is to demonstrate the value of M&As to economic geographers and highlight avenues for future research. This is achieved by explaining how qualitative and quantitative research into the motivations, outcomes and geographies of M&A activity can provide fresh empirical and conceptual insights surrounding wider geographical debates.

11.
Heliyon ; 9(8): e19014, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37654454

ABSTRACT

Many state-owned enterprises have mergers and acquisitions (M&A) with private enterprises, which has caused private enterprises to worry about their living space being squeezed. Based on 572 data records about equity transfers of Chinese listed companies extracted from CSMAR4.0 from 2013 to 2020, this paper categorized ownership structures into three categories: privatization of state-owned enterprises (Category 1), state-owned enterprises merging private enterprises (Category 2), and state-owned enterprises merging state-owned enterprises (Category 3). The categorical regression of ex-ante equity transfer motivation revealed that the motives for Category 1 conformed to the phenomenon of the "pretty girl gets married first" and "embezzlement view." Category In contrast, the motives for Category 2 conformed to the "fiscal revenue view." The categorical regression of ex-post equity transfer motivation showed that all three types significantly improved various efficiencies and represented an optimal allocation of resources. Moreover, it was revealed that the transfer of equity to state-owned enterprises by inefficient private firms in Category 2 also significantly improved enterprise efficiency. Thus, it can be considered as a rational behavior of market selection and never squeezed the space crowding. Further analysis showed that the efficiency improvement is due to the symbiotic development relationship rather than the antagonistic relationship between heterogeneous shareholders. Therefore, it is suggested to initiate market-oriented reform by actively developing ownership mixed-ownership economy and adhering to the "two unwavering" basic economic system.

12.
Magn Reson Med ; 90(6): 2375-2387, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37667533

ABSTRACT

PURPOSE: EPI with blip-up/down acquisition (BUDA) can provide high-quality images with minimal distortions by using two readout trains with opposing phase-encoding gradients. Because of the need for two separate acquisitions, BUDA doubles the scan time and degrades the temporal resolution when compared to single-shot EPI, presenting a major challenge for many applications, particularly fMRI. This study aims at overcoming this challenge by developing an echo-shifted EPI BUDA (esEPI-BUDA) technique to acquire both blip-up and blip-down datasets in a single shot. METHODS: A 3D esEPI-BUDA pulse sequence was designed by using an echo-shifting strategy to produce two EPI readout trains. These readout trains produced a pair of k-space datasets whose k-space trajectories were interleaved with opposite phase-encoding gradient directions. The two k-space datasets were separately reconstructed using a 3D SENSE algorithm, from which time-resolved B0 -field maps were derived using TOPUP in FSL and then input into a forward model of joint parallel imaging reconstruction to correct for geometric distortion. In addition, Hankel structured low-rank constraint was incorporated into the reconstruction framework to improve image quality by mitigating the phase errors between the two interleaved k-space datasets. RESULTS: The 3D esEPI-BUDA technique was demonstrated in a phantom and an fMRI study on healthy human subjects. Geometric distortions were effectively corrected in both phantom and human brain images. In the fMRI study, the visual activation volumes and their BOLD responses were comparable to those from conventional 3D echo-planar images. CONCLUSION: The improved imaging efficiency and dynamic distortion correction capability afforded by 3D esEPI-BUDA are expected to benefit many EPI applications.


Subject(s)
Algorithms , Arthroplasty, Replacement , Humans , Brain/diagnostic imaging , Healthy Volunteers , Phantoms, Imaging
13.
Proc Natl Acad Sci U S A ; 120(32): e2207398120, 2023 08 08.
Article in English | MEDLINE | ID: mdl-37523529

ABSTRACT

Land inequality stalls economic development, entrenches poverty, and is associated with environmental degradation. Yet, rigorous assessments of land-use interventions attend to inequality only rarely. A land inequality lens is especially important to understand how recent large-scale land acquisitions (LSLAs) affect smallholder and indigenous communities across as much as 100 million hectares around the world. This paper studies inequalities in land assets, specifically landholdings and farm size, to derive insights into the distributional outcomes of LSLAs. Using a household survey covering four pairs of land acquisition and control sites in Tanzania, we use a quasi-experimental design to characterize changes in land inequality and subsequent impacts on well-being. We find convincing evidence that LSLAs in Tanzania lead to both reduced landholdings and greater farmland inequality among smallholders. Households in proximity to LSLAs are associated with 21.1% (P = 0.02) smaller landholdings while evidence, although insignificant, is suggestive that farm sizes are also declining. Aggregate estimates, however, hide that households in the bottom quartiles of farm size suffer the brunt of landlessness and land loss induced by LSLAs that combine to generate greater farmland inequality. Additional analyses find that land inequality is not offset by improvements in other livelihood dimensions, rather farm size decreases among households near LSLAs are associated with no income improvements, lower wealth, increased poverty, and higher food insecurity. The results demonstrate that without explicit consideration of distributional outcomes, land-use policies can systematically reinforce existing inequalities.


Subject(s)
Agriculture , Income , Farms , Tanzania , Family Characteristics
14.
J Environ Manage ; 344: 118439, 2023 Oct 15.
Article in English | MEDLINE | ID: mdl-37364490

ABSTRACT

The impact of climate risk on the payment method in cross-border M&A remains largely unknown in the literature. Using a large sample of UK outbound cross-border M&A deals in 73 target countries from 2008 to 2020, we find that a UK acquirer is more likely to employ an all-cash offer to signal its confidence in a target's value if the target country faces a higher level of climate risk. This finding is consistent with the confidence signalling theory. Our results also suggest that acquirers are less likely to target vulnerable industries if target countries' climate risk is high. In addition, we document that the presence of geopolitical risk would weaken the association between payment method and climate risk. Our findings are robust to the use of an instrumental variable approach and alternative measures of climate risk.


Subject(s)
Climate
15.
J Innov Entrep ; 12(1): 30, 2023.
Article in English | MEDLINE | ID: mdl-37200553

ABSTRACT

Companies in difficult financial situations may seek to survive through mergers and acquisitions. Managers must be able to use company resources efficiently to maintain and improve competitiveness and sustainable advantages. Managers' ability to make strategic decisions may determine whether a merger and acquisition is successful. This study aims to reveal the role of the acquirer's managerial ability in mergers and acquisitions based on short- and long-term performance as well as the type of M&A. Two metrics are used to assess short- and long-term performance: the market-to-book ratio (MTBR) as an indicator of operating performance and the buy-and-hold abnormal return (BHAR) as an indicator of stock return performance. The research sample consists of 153 M&A cases conducted by companies registered with the Business Competition Supervisory Commission in Indonesia between 2010 and 2017, and the performance till 2020. We used regression and difference analysis to analyze the data. We find that managerial ability has a positive impact on MTBR operating and BHAR stock performance. This result confirms that the higher ability of the acquirer's manager will ensure a successful M&A in the long run. Investors and potential investors might consider managerial ability in choosing investments in companies after an M&A. This study contributes to the M&A literature by examining the role of MA in the short- and long-term performance of acquiring firms following M&As in Indonesia.

16.
J Environ Manage ; 340: 117973, 2023 Aug 15.
Article in English | MEDLINE | ID: mdl-37119626

ABSTRACT

This paper is to discuss the impact of green mergers and acquisitions (GMA) on illegal pollution discharge (ILP). The diurnal difference pollution data of the nearest monitoring station around heavy polluting enterprises are used to measure ILP. Results show that: (1) Compared with polluting firms that have not conducted GMA, GMA can reduce ILP by 2.9%. (2) Large scale, strong industrial correlation and cash payment of GMA is more conducive to controlling ILP. GMA in the same city is easier to inhibit ILP. (3) Impact paths of GMA on ILP mainly include cost effect, technology effect and responsibility effect. GMA aggravates ILP by increasing management costs and risk control risks. GMA inhibits ILP by increasing green innovation, environmental protection investment, social responsibility performance and environmental information disclosure. (4) GMA has a greater inhibition effect on ILP in state-owned firms, technology-intensive firms and eastern firms. (5) The industrial spillover effect of GMA is more obvious than that of the same city. This paper provides implications for curbing ILP from the perspective of GMA.


Subject(s)
Disclosure , Environmental Pollution , Industry , Investments , Technology , China , Conservation of Natural Resources
17.
Mol Cell Proteomics ; 22(5): 100534, 2023 05.
Article in English | MEDLINE | ID: mdl-36958627

ABSTRACT

Huntington's disease (HD) is a neurodegenerative disease caused by a CAG repeat expansion in the Huntingtin (HTT) gene. The resulting polyglutamine (polyQ) tract alters the function of the HTT protein. Although HTT is expressed in different tissues, the medium-spiny projection neurons (MSNs) in the striatum are particularly vulnerable in HD. Thus, we sought to define the proteome of human HD patient-derived MSNs. We differentiated HD72-induced pluripotent stem cells and isogenic controls into MSNs and carried out quantitative proteomic analysis. Using data-dependent acquisitions with FAIMS for label-free quantification on the Orbitrap Lumos mass spectrometer, we identified 6323 proteins with at least two unique peptides. Of these, 901 proteins were altered significantly more in the HD72-MSNs than in isogenic controls. Functional enrichment analysis of upregulated proteins demonstrated extracellular matrix and DNA signaling (DNA replication pathway, double-strand break repair, G1/S transition) with the highest significance. Conversely, processes associated with the downregulated proteins included neurogenesis-axogenesis, the brain-derived neurotrophic factor-signaling pathway, Ephrin-A:EphA pathway, regulation of synaptic plasticity, triglyceride homeostasis cholesterol, plasmid lipoprotein particle immune response, interferon-γ signaling, immune system major histocompatibility complex, lipid metabolism, and cellular response to stimulus. Moreover, proteins involved in the formation and maintenance of axons, dendrites, and synapses (e.g., septin protein members) were dysregulated in HD72-MSNs. Importantly, lipid metabolism pathways were altered, and using quantitative image analysis, we found that lipid droplets accumulated in the HD72-MSN, suggesting a deficit in the turnover of lipids possibly through lipophagy. Our proteomics analysis of HD72-MSNs identified relevant pathways that are altered in MSNs and confirm current and new therapeutic targets for HD.


Subject(s)
Huntington Disease , Neurodegenerative Diseases , Humans , Animals , Neurons/metabolism , Medium Spiny Neurons , Huntington Disease/metabolism , Neurodegenerative Diseases/metabolism , Lipid Droplets/metabolism , Proteomics , Corpus Striatum/metabolism , Disease Models, Animal
18.
J Struct Biol X ; 7: 100082, 2023.
Article in English | MEDLINE | ID: mdl-36618437

ABSTRACT

The assignment of aromatic side-chain spins has always been more challenging than assigning backbone and aliphatic spins. Selective labeling combined with mutagenesis has been the approach for assigning aromatic spins. This manuscript reports a method for assigning aromatic spins in a fully protonated protein by connecting them to the backbone atoms using a low-power TOBSY sequence. The pulse sequence employs residual polarization and sequential acquisitions techniques to record HN- and HC-detected spectra in a single experiment. The unambiguous assignment of aromatic spins also enables the characterization of 1H-1H distance restraints involving aromatic spins. Broadband (RFDR) and selective (BASS-SD) recoupling sequences were used to generate HN-ΗC, HC-HN and HC-HC restraints involving the side-chain proton spins of aromatic residues. This approach has been demonstrated on a fully protonated U-[13C,15N] labeled GB1 sample at 95-100 kHz MAS.

19.
J Magn Reson ; 346: 107338, 2023 Jan.
Article in English | MEDLINE | ID: mdl-36463686

ABSTRACT

Proton-detected solid-state NMR spectroscopy is emerging as a unique tool for atomic characterization of organic solids due to the boost of resolution and sensitivity afforded by the combined use of high magnetic field and ultrafast magic angle spinning (MAS). Here, we proposed a new set of proton-detected solid-state NMR sequences that hybrid multi-dimensional 1H-1H homonuclear chemical shift correlation (HOMCOR) and two-dimensional 1H-13C heteronuclear chemical shift correlation (HETCOR) sequences into a single experiment, enabling the simultaneous acquisition of multidimensional HOMCOR and HETCOR spectra and thus significant time savings. Based on the core idea of exhausting 1H polarization in each transient scan, we firstly demonstrated that 3D 1H multiple-quantum (MQ) HOMCOR sequence can be combined with 2D HETCOR sequence into a single experiment, leading to the simultaneous acquisition of a 3D 1H MQ HOMCOR and a 2D 1H-13C HETCOR spectrum. Besides, we also showed that 2D 1H/1H double-quantum/single-quantum (DQ/SQ) and single-quantum/single-quantum (SQ/SQ) HOMCOR sequence can be simultaneously combined with HETCOR sequence either, and thus three spectra can be simultaneously obtained from one experiment, including 2D 1H DQ/SQ, 2D 1H SQ/SQ and 2D 1H-13C HETCOR spectra. Since there is only one recycle delay in each experiment, experimental time is substantially reduced compared to separate acquisition of each multi-dimensional solid-state NMR spectrum. Furthermore, those new sequences can be implemented on any standard solid-state spectrometer with only one receiver. Thus, we foresee that these approaches can be valuable for the study of a broad range of molecular systems, including polymers, pharmaceuticals, covalent-organic frameworks (COF) and so on.

20.
Environ Sci Pollut Res Int ; 30(11): 29369-29379, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36414901

ABSTRACT

We analyze how the mergers and acquisitions (M&As) and greenfield foreign direct investment (GFDI) outflows impact the host countries' air pollution at the sectoral level. Following the recent advent of multinationals from emerging economies, we examine outflows rather than inflows. Evidence indicates that there are important distinctive effects of FDI mode of exit. GFDI outflows benefit the environment in the full sample and developing countries, supporting the reverse-pollution haven hypothesis, and at the industry level in the electrical power industry and building. The positive impact of M&A outflows on the environment is revealed only when data is disaggregated further into the industry level in the transport industry of developed economies and the electrical power industry of developing countries. We find that heterogeneities caused by countries' development levels and the FDI's two exit modes, M&As deteriorate the environment less than GFDI.


Subject(s)
Air Pollution , Economic Development , Carbon Dioxide/analysis , Environmental Pollution/analysis , Internationality , Investments
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