Nevin Manimala

Atmosphere (Basel). 2021 Aug 14;12(8):1-1044. doi: 10.3390/atmos12081044.

ABSTRACT

Reducing PM_2.5 and ozone concentrations is important to protect human health and the environment. Chemical transport models, such as the Community Multiscale Air Quality (CMAQ) model, are valuable tools for exploring policy options for improving air quality but are computationally expensive. Here, we statistically fit an efficient polynomial function in a response surface model (pf-RSM) to CMAQ simulations over the eastern U.S. for January and July 2016. The pf-RSM predictions were evaluated using out-of-sample CMAQ simulations and used to examine the nonlinear response of air quality to emission changes. Predictions of the pf-RSM are in good agreement with the out-of-sample CMAQ simulations, with some exceptions for cases with anthropogenic emission reductions approaching 100%. NO_X emission reductions were more effective for reducing PM_2.5 and ozone concentrations than SO₂, NH₃, or traditional VOC emission reductions. NH₃ emission reductions effectively reduced nitrate concentrations in January but increased secondary organic aerosol (SOA) concentrations in July. More work is needed on SOA formation under conditions of low NH₃ emissions to verify the responses of SOA to NH₃ emission changes predicted here. Overall, the pf-RSM performs well in the eastern U.S., but next-generation RSMs based on deep learning may be needed to meet the computational requirements of typical regulatory applications.

PMID:34567797 | PMC:PMC8459679 | DOI:10.3390/atmos12081044

Microsyst Nanoeng. 2020 Oct 5;6:82. doi: 10.1038/s41378-020-00187-1. eCollection 2020.

ABSTRACT

We report on the development of a microfluidic multiplexing technology for highly parallelized sample analysis via quantitative polymerase chain reaction (PCR) in an array of 96 nanoliter-scale microcavities made from silicon. This PCR array technology features fully automatable aliquoting microfluidics, a robust sample compartmentalization up to temperatures of 95 °C, and an application-specific prestorage of reagents within the 25 nl microcavities. The here presented hybrid silicon-polymer microfluidic chip allows both a rapid thermal cycling of the liquid compartments and a real-time fluorescence read-out for a tracking of the individual amplification reactions taking place inside the microcavities. We demonstrate that the technology provides very low reagent carryover of prestored reagents < 6 × 10^-2 and a cross talk rate < 1 × 10^-3 per PCR cycle, which facilitate a multi-targeted sample analysis via geometric multiplexing. Furthermore, we apply this PCR array technology to introduce a novel digital PCR-based DNA quantification method: by taking the assay-specific amplification characteristics like the limit of detection into account, the method allows for an absolute gene target quantification by means of a statistical analysis of the amplification results.

PMID:34567692 | PMC:PMC8433415 | DOI:10.1038/s41378-020-00187-1

J Hip Preserv Surg. 2021 May 11;8(1):83-89. doi: 10.1093/jhps/hnab035. eCollection 2021 Jan.

ABSTRACT

Iliopsoas impingement is an underdiagnosed cause of groin pain after total hip arthroplasty (THA), being responsible for 4.4% of cases. Non-surgical treatment may be effective in ∼50% of cases. Endoscopic surgery has gained popularity as an option for non-responsive patients because of its non-invasive characteristics, faster recovery and encouraging results. This study compares two different sites of endoscopic psoas tenotomy performed following THA: at the edge of the acetabulum (AR) versus at the lesser trochanter (LT). This is a retrospective review of prospectively collected data from a single-surgeon case series. Thirty-five iliopsoas tenotomy cases which had >24-month follow-up were identified. There were 21 tenotomies at the lesser trochanter. Demographic data, preop and postop pain, mHHS and NAHS scores, strength and patient satisfaction data were collected and analysed. Average age at the time of surgery was 62. Mean follow-up for the LT group was 49.11 months and 42.42 months for the AR group. Pain decreased significantly for both groups (P < 0.001). Both mHHS and NAHS showed superiority in the LT group, but this difference did not reach significance (P = 0.06). LT patients showed better strength with 71.42% of them having normal strength at latest follow-up, compared with 41.6% in the AR group. There were no complications in either group. Endoscopic tenotomy is a safe and reliable surgical option, giving significant pain relief and good functional outcomes. Tenotomy at the level of the lesser trochanter might be preferable since it shows better outcomes. Larger studies are necessary to achieve statistically significant results.

PMID:34567604 | PMC:PMC8460172 | DOI:10.1093/jhps/hnab035

J Hip Preserv Surg. 2021 May 5;8(1):58-66. doi: 10.1093/jhps/hnab037. eCollection 2021 Jan.

ABSTRACT

Estimation of pelvic tilt on anteroposterior (AP) pelvis radiograph is often done by indirect methods based on the midline pelvic landmarks. The purpose of this cadaveric study is to describe a new radiographic landmark and reference measurements to estimate the coronal tilt of the pelvis, independent of the midline references. The new radiologic reference is called ‘rear drop’, and its anatomic location is described with the cadaveric pelvis AP radiographs in various pelvic inclination. The parameters derived from the new reference were used to assess the pelvic tilt, and the results were compared with the previously established method using ‘sacrococcygeal joint to symphysis distance’ (SCSD). The shape of the new figure is used to determine the position of the pelvis, and its relationship with the previously described acetabular retroversion indicators was statistically analyzed. The new reference figure corresponds to the posteroinferior edge of the horseshoe shape of the acetabular margin. The newly derived reference parameters, rear to tear distance and rear to tear angle, changes with pelvic tilt and are strongly correlated with SCSD. The shape of the rear drop changes with the changing pelvic tilt and correlates statistically with the previously described acetabular retroversion indicators. Rear drop and its derivative measurements can be used as a reliable and reproducible indicator to estimate the coronal pelvic tilt, free of midline reference points. This new reference will be a base for future clinical studies on pelvic tilt, rotation and their application in intraoperative hip fluoroscopy.

PMID:34567601 | PMC:PMC8460171 | DOI:10.1093/jhps/hnab037

J Hip Preserv Surg. 2021 Jul 31;8(1):22-27. doi: 10.1093/jhps/hnab002. eCollection 2021 Jan.

ABSTRACT

ChondroFiller gel is an absorbable collagen implant. It serves as a protective cover for the cartilage defects, allowing chondrocyte migration into the lesion. The implant consists of collagen (Type I) and is derived from veterinary monitored rats. This study evaluates the use of ChondroFiller gel in the treatment of cartilage lesions during hip joint arthroscopy. A prospective study was conducted on a group of 26 adult patients. All patients had an existing femoroacetabular impingement together with acetabular cartilage lesions >2 cm². All patients underwent hip arthroscopic surgery and the lesions were treated using ChondroFiller gel. The cartilage tissue healing was evaluated postoperatively using MRI. A total of 26 patients, including 5 females and 21 males, all with articular cartilage lesions, were included in the study. Cartilage healing conditions were evaluated for all patients, and the difference between pre- and post-surgery conditions was statistically significant. The follow-up scores have been acquired from 21 out of initial 26 patients (2 were disqualified after receiving THR, 3 could not be reached by researchers) after 3, 4 and 5 years consecutively with 17/21 patients having good/excellent results. The use of ChondroFiller gel during arthroscopy of the hip for acetabular cartilage lesions is an effective treatment technique. Encouraging long-term results have been observed, but further research on larger group of patient is required to better assess the full value of this technique. Patients with pre-existing osteoarthritis (Tönnis 2-3) have poor results.

PMID:34567597 | PMC:PMC8460160 | DOI:10.1093/jhps/hnab002

R Soc Open Sci. 2021 Sep 22;8(9):211379. doi: 10.1098/rsos.211379. eCollection 2021 Sep.

ABSTRACT

The temporal evolution of second and subsequent waves of epidemics such as Covid-19 is investigated. Analytic expressions for the peak time and asymptotic behaviours, early doubling time, late half decay time, and a half-early peak law, characterizing the dynamical evolution of number of cases and fatalities, are derived, where the pandemic evolution exhibiting multiple waves is described by the semi-time SIR model. The asymmetry of the epidemic wave and its exponential tail are affected by the initial conditions, a feature that has no analogue in the all-time SIR model. Our analysis reveals that the immunity is very strongly increasing in several countries during the second Covid-19 wave. Wave-specific SIR parameters describing infection and recovery rates we find to behave in a similar fashion. Still, an apparently moderate change of their ratio can have significant consequences. As we show, the probability of an additional wave is however low in several countries due to the fraction of immune inhabitants at the end of the second wave, irrespective of the ongoing vaccination efforts. We compare with alternate approaches and data available at the time of submission. Most recent data serves to demonstrate the successful forecast and high accuracy of the SIR model in predicting the evolution of pandemic outbreaks as long as the assumption underlying our analysis, an unchanged situation of the distribution of variants of concern and the fatality fraction, do not change dramatically during a wave. With the rise of the α variant at the time of submission the second wave did not terminate in some countries, giving rise to a superposition of waves that is not treated by the present contribution.

PMID:34567593 | PMC:PMC8456141 | DOI:10.1098/rsos.211379

R Soc Open Sci. 2021 Sep 22;8(9):210670. doi: 10.1098/rsos.210670. eCollection 2021 Sep.

ABSTRACT

Estimating the capabilities, or inputs of production, that drive and constrain the economic development of urban areas has remained a challenging goal. We posit that capabilities are instantiated in the complexity and sophistication of urban activities, the know-how of individual workers, and the city-wide collective know-how. We derive a model that indicates how the value of these three quantities can be inferred from the probability that an individual in a city is employed in a given urban activity. We illustrate how to estimate empirically these variables using data on employment across industries and metropolitan statistical areas in the USA. We then show how the functional form of the probability function derived from our theory is statistically superior when compared with competing alternative models, and that it explains well-known results in the urban scaling and economic complexity literature. Finally, we show how the quantities are associated with metrics of economic performance, suggesting our theory can provide testable implications for why some cities are more prosperous than others.

PMID:34567588 | PMC:PMC8456143 | DOI:10.1098/rsos.210670

Zhonghua Jie He He Hu Xi Za Zhi. 2021 Oct 12;44(10):892-896. doi: 10.3760/cma.j.cn112147-20210131-00087.

ABSTRACT

Objective: To analyze the etiology of severe community-acquired pneumonia (SCAP) in immunocompromised patients, and to investigate the relationship between underlying diseases and infectious microorganisms. Methods: A retrospective analysis was performed on SCAP in immunocompromised patients admitted to the Fourth Department of Respiratory and Critical Medicine (MICU) of China-Japan Friendship Hospital from January 1, 2017 to December 31, 2019. A total of 119 SCAP patients were finally enrolled, including 65 males (54.6%), with an average age of (59.3±14.5) years. The average of Sequential Organ Failure Assessment (SOFA) score was 6.7±3.6 and the acute physiology and chronic health evaluation (APACHE) Ⅱ score was 19.4±6.8. Sixty (50%) of these patients were finally improved and discharged. Long-term glucocorticoid treatment was the main risk factor for immunocompromise. The difference of pathogenic microorganisms between patients with and without structural lung diseases, and the influence of different pathogenic microorganisms on hospital mortality were calculated, respectively. P<0.05 was considered to be statistically significant. Results: In this study, 99 (83.2%) patients were identified to have positive etiological results, and the incidence of concurrent infection was 54.5%. The top three pathogens were Pneumocystis Jiroveci (55.6%), Cytomegalovirus (47.5%) and Aspergillus (23.2%). Staphylococcus aureus was the most common bacterium, followed by Pseudomonas aeruginosa and Klebsiella pneumoniae. The risk of Pneumocystis Jiroveci infection was significantly higher in patients without underlying lung diseases as compared to those with underlying lung diseases (64.3% vs. 44.2%, P = 0.046). The in-hospital mortality was not different among patients infected with different pathogens(all P>0.05), but was higher in those with mixed infections(56.7% vs. 33.9%, P=0.013). Conclusions: Pneumocystis Jiroveci and Cytomegalovirus were the most common pathogens in immunocompromised patients with severe community-acquired pneumonia, and the incidence of Pneumocystis Jiroveci was significantly higher in patients without underlying lung diseases.

PMID:34565116 | DOI:10.3760/cma.j.cn112147-20210131-00087

Zhonghua Jie He He Hu Xi Za Zhi. 2021 Oct 12;44(10):880-885. doi: 10.3760/cma.j.cn112147-20210131-00088.

ABSTRACT

Objective: To evaluate the diagnostic value of a contact-free sleep apnea monitor in Chinese adults with obstructive sleep apnea (OSA). Methods: One hundred and ninety-eight participants with snoring were recruited between July 2018 and May 2019 in Sleep Center of Peking University People’s Hospital, using nocturnal polysomnography (PSG) and contact-free sleep apnea monitor simultaneously. We evaluated the difference between respiratory event index (REI) generated by contact-free sleep apnea monitor and PSG-Apnea-Hypopnea Index (AHI). We calculated the sensitivity and specificity of OSA diagnosis using the contact-free sleep apnea monitor by hypothesis testing for means, Pearson correlation coefficient and Bland-Altman plots. Then, we used the receiver operating characteristic (ROC) curve to find out the best cut-off of OSA diagnosis. Results: PSG-AHI and the REI of contact-free sleep apnea monitor showed no statistically significant difference [15.9 (4.7, 40.2) vs. 16.2 (6.1, 40.0), P=0.381], and they were significantly correlated (r=0.914, P<0.05), with mean difference of -0.06 (95%CI:-18.44, 18.31). The ROC curve showed that if REI ≥5 events/h was used as diagnostic criteria, the sensitivity and specificity of diagnosing OSA were 91.2% and 58.0%, respectively. The sensitivity and specificity of the contact-free sleep apnea monitor REI≥13.3 in diagnosing moderate and severe OSA were 90.1% and 71.1%, respectively. Conclusion: The REI obtained from the contact-free sleep apnea monitor showed a good agreement with the PSG-AHI, and therefore, the contact-free sleep apnea monitor can be used for the screening of patients with moderate and severe OSA.

PMID:34565114 | DOI:10.3760/cma.j.cn112147-20210131-00088

Zhonghua Jie He He Hu Xi Za Zhi. 2021 Oct 12;44(10):873-879. doi: 10.3760/cma.j.cn112147-20210210-00105.

ABSTRACT

Objective: To investigate the effects of daytime hypercapnia on logical memory and working memory in patients with obstructive sleep apnea hypopnea syndrome (OSAHS). Methods: This prospective study recruited patients complaining of snoring and diagnosed with OSAHS at the Sleep Center of the Second Affiliated Hospital of Soochow University from January to November 2020. Patients were assessed clinically and scored for their memory function. All patients underwent daytime transcutaneous carbon dioxide (PtcCO₂) test, and overnight polysomnography (PSG). Logical memory was scored using the Logical Memory Test (LMT), while working memory was evaluated by Digit Span Test (DST) and Cambridge Neuropsychological Test Automated Battery (CANTAB) which included Pattern Recognition Memory (PRM), Spatial Span (SSP), and Spatial Working Memory (SWM). Patients were divided into the normocapnic group and the hypercapnic group using the daytime PtcCO₂ test. The clinical and PSG parameters and the memory test scores between the two groups were compared. Binary logistic stepwise regression was conducted to identify risk factors of memory impairment in OSAHS patients. Results: Among the 123 enrolled OSAHS patients, 79 were normocapnic and 44 were hypercapnic. There was no significant difference in the general clinical parameters between the two groups. The snoring history in years in the hypercapnic group was longer than that in the normocapnic group (P<0.05). Compared with the normocapnic group, the apnea-hyponea index (AHI), oxygen desaturation index (ODI) and percentage of total sleep time with oxygen saturation level<90% (TS90) of the hypercapnic group were higher (all P<0.05), while other PSG parameters exhibited no statistically significant differences. There was no statistically significant difference in the immediate logical memory and PRM immediate accuracy rate between the two groups, while the delayed logical memory, verbal and spatial working memory, and executive function were worse in the hypercapnic group, as shown by lower total LMT scores, lower DST, lower SSP scores (all P<0.05), and higher between errors and strategy scores (P<0.01) of SWM in the hypercapnic group. Binary logistic stepwise regression showed that PtcCO₂ ≥45 mmHg (1 mmHg=0.133 kPa, OR=3.055, 95%CI 1.359-6.868, P=0.007) and higher body mass index (BMI) (OR=1.132, 95%CI 1.005-1.275, P=0.041) were risk factors for poor performance in Digit Span Backwards Test. Therefore, PtcCO₂ ≥45 mmHg was an independent risk factors for poor performance in delayed LMT, SSP, and between errors and strategy scores in SWM (OR=3.109, 3.941, 3.238 and 2.785, respectively, all P<0.05). Conclusion: Hypercapnia had negative impacts on logical memory and working memory of OSAHS patients, especially on the delayed logical memory, verbal working memory and spatial working memory impairment.

PMID:34565113 | DOI:10.3760/cma.j.cn112147-20210210-00105