Optimal NH4 + /NO3 - ratios enhance the shade tolerance of soybean seedlings under low light conditions

In the maize-soybean intercropping system, shade is the major chronic restraint that affects normal growth of soybean. Different spatial patterns of this system affect the microclimate of soybean through shading from maize plants. However, the negative impacts of shading stress can be mitigated by providing optimal ratios of different fertilizers. Therefore, to test this hypothesis, soybean plants were grown under different light conditions (normal light or shade) to evaluate the response to varying NH4 + /NO3 - ratios. Seeds of soybean (Glycine max L. cv. Nan-99-6) were grown in nutrient solution with a total concentration of 5 mM N using different NH4 + /NO3 - ratios (T0  = 0:0, T1  = 0:100, T2  = 25:75, T3  = 50:50 and T4  = 75:25) for 40 days in a greenhouse at PPFD 320.95 μmol m-2  s-1 (low light) or 967.53 μmol m-2  s-1 (normal light). Under low light, growth and photosynthesis of soybean seedlings significantly decreased as compared to normal light conditions. However, the optimal ratios of NH4 + / NO3 - improved growth and photosynthesis of soybean seedlings under both light conditions. Our results indicated that soybean seedlings supplied with optimal NH4 + /NO3 - ratios (25:75 and 50:50) have maximum biomass yield, chlorophyll pigments, leaf gas exchange, photochemical activity and root growth as compared to low and high NH4 + /NO3 - ratios (T1 and T4 ). High ratios of NH4 + /NO3 - (T4 ) resulted in reduced plant growth due to nutrient accumulation in plant tissues; therefore, we suggest that optimal ratios of NH4 + /NO3 - (T2 and T3 ) can enhance the shade tolerance of soybean seedlings.

Silver decorated 2D nanosheets of GO and MoS2serve as nanocatalyst for water treatment and antimicrobial applications as ascertained with molecular docking evaluation

In this work, synthesis of graphene oxide (GO) and reduced graphene oxide (rGO) was realized through a modified Hummers route. Different concentrations (5 and 10 wt%) of Ag were doped in MoS₂and rGO using a hydrothermal technique. Synthesized Ag-MoS₂and Ag-rGO were evaluated through XRD that confirmed the hexagonal structure of MoS₂along with the transformation of GO to Ag-rGO as indicated by a shift in XRD peaks while Mo-O bonding and S=O functional groups were confirmed with FTIR. Morphological information of GO and formation of MoS₂nanopetals as well as interlayer spacing were verified through FESEM and HRTEM respectively. Raman analysis was employed to probe any evidence regarding defect densities of GO. Optical properties of GO, MoS₂, Ag-rGO, and Ag-MoS₂were visualized through UV-vis and PL spectroscopy. Prepared products were employed as nanocatalysts to purify industrial wastewater. Experimental results revealed that Ag-rGO and Ag-MoS₂showed 99% and 80% response in photocatalytic activity. Besides, the nanocatalyst (Ag-MoS₂and Ag-rGO) exhibited 6.05 mm inhibition zones againstS. aureusgram positive (G+) and 3.05 mm forE. coligram negative (G-) in antibacterial activity. To rationalize biocidal mechanism of Ag-doped MoS₂NPs and Ag-rGO,in silicomolecular docking study was employed for two enzymes i.e.β-lactamase and D-alanine-D-alanine ligase B (ddlB) from cell wall biosynthetic pathway and enoyl-[acylcarrier-protein] reductase (FabI) from fatty acid biosynthetic pathway belonging toS. aureus. The present study provides evidence for the development of cost-effective, environment friendly and viable candidate for photocatalytic and antimicrobial applications.

Impact of wind speed and air pollution on COVID-19 transmission in Pakistan

This study investigated the effect of wind speed and air pollution on COVID-19 from March 10, 2020, to October 04, 2020, in Pakistan. Wind speed and COVID-19 had positive correlation in Pakistan and its provinces. The inverted U-shaped dose-response curve was found for wind speed and COVID-19 in Punjab. Initially, the dose-response curve showed a positive link between wind speed and COVID-19 in Pakistan, Sindh, Khyber Pakhtunkhwa, and Islamabad Capital Territory. Later, it becomes downward sloped in Sindh, Khyber Pakhtunkhwa, and Islamabad Capital Territory. The expected log count of COVID-19 was increased by 0.113 times (Pakistan), 0.074 times (Punjab), 0.042 times (Sindh), and 0.082 times (Khyber Pakhtunkhwa) for a 1 km/h increase in the wind speed. The correlation between particulate matter and COVID-19 was positive (Pakistan, Punjab, and Islamabad Capital Territory) and negative (Sindh). The dose-response curve for particulate matter and COVID-19 had inverted U-shaped (Pakistan, Punjab, and Khyber Pakhtunkhwa) positively sloped (Islamabad Capital Territory), and negatively sloped (Sindh). The inverted U-shaped association shows that the COVID-19 initially increased due to a rise in the particulate matter but reduced when the particulate matter was above the threshold level. The particulate matter was also responsible to wear face masks and restricted mobility. The expected log count of COVID-19 cases was reduced by 0.005 times in Sindh for 1 unit increase in particulate matter. It is recommended to reduce particulate matter to control respiratory problems. The government should use media (print, electronic, social) and educational syllabus to create awareness about precautionary measures.

Corrosion and Heat Treatment Study of Electroless NiP-Ti Nanocomposite Coatings Deposited on HSLA Steel

Corrosion and heat treatment studies are essential to predict the performance and sustainability of the coatings in harsh environments, such as the oil and gas industries. In this study, nickel phosphorus (NiP)-titanium (Ti) nanocomposite coatings (NiP-Ti nanoparticles (TNPs)), containing various concentrations of Ti nanoparticles (TNPs) were deposited on high strength low alloy (HSLA) steel through electroless deposition processing. The concentrations of 0.25, 0.50 and 1.0 g/L TNPs were dispersed in the electroless bath, to obtain NiP-TNPs nanocomposite coatings comprising different Ti contents. Further, the effect of TNPs on the structural, mechanical, corrosion, and heat treatment performance of NiP coatings was thoroughly studied to illustrate the role of TNPs into the NiP matrix. Field emission scanning electron microscope (FESEM) and energy dispersive spectroscopy (EDX) results confirm the successful incorporation of TNPs into the NiP matrix. A substantial improvement in the mechanical response of the NiP matrix was noticed with an increasing amount of TNPs, which reached to its ultimate values (hardness 675 Hv, modulus of elasticity 18.26 GPa, and stiffness 9.02 kN/m) at NiP-0.5TNPs coatings composition. Likewise, the electrochemical impedance spectroscopy measurements confirmed a tremendous increase in the corrosion inhibition efficiency of the NiP coatings with an increasing amount of TNPs, reaching ~96.4% at a composition of NiP-0.5TNPs. In addition, the NiP-TNPs nanocomposite coatings also unveiled better performance after heat treatment than NiP coatings, due to the presence of TNPs into the NiP matrix and the formation of more stable (heat resistant) phases, such as Ni₃P, Ni₃Ti, NiO, etc., during the subsequent processing.

Dye degradation performance, bactericidal behavior and molecular docking analysis of Cu-doped TiO2 nanoparticles

Copper-doped TiO2 was prepared with a sol-gel chemical method. Various concentrations (3, 6, and 9 wt%) of Cu dopant were employed. Several techniques were implemented to assess the structural, optical, morphological and chemical properties of the synthesized samples. Evaluation of elemental composition using SEM-EDS and XRF techniques showed the presence of dopant element in the prepared samples. XRD analysis confirmed the presence of anatase (TiO2) phase with interstitial doping. Incorporation of dopant was observed to enhance the crystallinity and increase the crystallite size of the synthesized products. SAED profiles revealed a high degree of crystallinity in the prepared specimens, which was also evident in the XRD spectra. Optical properties studied using UV-vis spectroscopy depicted a shift of the maximum absorption to the visible region (redshift) that signified a reduction in the band gap energy of Cu-doped TiO2 samples. Examination of morphological features with scanning and high-resolution transmission electron microscopes revealed the formation of spherical nanoparticles with a tendency to agglomerate with increasing dopant concentration. Molecular vibrations and the formation of Ti-O-Ti bonds were revealed through FTIR spectra. PL spectroscopy recorded the trapping efficiency and migration of charge carriers, which exhibited electron-hole recombination behavior. Doped nanostructures showed enhanced bactericidal performance and synergism against S. aureus and E. coli. In summary, Cu-doped TiO2 nanostructures were observed to impede bacteria effectively, which is deemed beneficial in overcoming ailments caused by pathogens such as microbial etiologies. Furthermore, molecular docking analysis was conducted to study the interaction of Cu-doped TiO2 nanoparticles with multiple proteins namely β-lactamase (binding score: -4.91 kcal mol-1), ddlB (binding score: -5.67 kcal mol-1) and FabI (binding score: -6.13 kcal mol-1) as possible targets with active site residues. Dye degradation/reduction of control and Cu-doped samples were studied through absorption spectroscopy. The obtained outcomes of the performed experiment indicated that the photocatalytic activity of Cu-TiO2 enhanced with increasing dopant concentration, which is thought to be due to a decreased rate of electron-hole pair recombination. Consequently, it is suggested that Cu-TiO2 can be exploited as an effective candidate for antibacterial and dye degradation applications.

International Nosocomial Infection Control Consortium (INICC) report, data summary of 45 countries for 2012-2017: Device-associated module

BACKGROUND

We report the results of International Nosocomial Infection Control Consortium (INICC) surveillance study from January 2012 to December 2017 in 523 intensive care units (ICUs) in 45 countries from Latin America, Europe, Eastern Mediterranean, Southeast Asia, and Western Pacific.

METHODS

During the 6-year study period, prospective data from 532,483 ICU patients hospitalized in 242 hospitals, for an aggregate of 2,197,304 patient days, were collected through the INICC Surveillance Online System (ISOS). The Centers for Disease Control and Prevention-National Healthcare Safety Network (CDC-NHSN) definitions for device-associated health care-associated infection (DA-HAI) were applied.

RESULTS

Although device use in INICC ICUs was similar to that reported from CDC-NHSN ICUs, DA-HAI rates were higher in the INICC ICUs: in the medical-surgical ICUs, the pooled central line-associated bloodstream infection rate was higher (5.05 vs 0.8 per 1,000 central line-days); the ventilator-associated pneumonia rate was also higher (14.1 vs 0.9 per 1,000 ventilator-days,), as well as the rate of catheter-associated urinary tract infection (5.1 vs 1.7 per 1,000 catheter-days). From blood cultures samples, frequencies of resistance, such as of Pseudomonas aeruginosa to piperacillin-tazobactam (33.0% vs 18.3%), were also higher.

CONCLUSIONS

Despite a significant trend toward the reduction in INICC ICUs, DA-HAI rates are still much higher compared with CDC-NHSN's ICUs representing the developed world. It is INICC's main goal to provide basic and cost-effective resources, through the INICC Surveillance Online System to tackle the burden of DA-HAIs effectively.

Promising performance of chemically exfoliated Zr-doped MoS2 nanosheets for catalytic and antibacterial applications

Nanostructured materials incorporated with biological reducing agents have shown significant potential for use in bactericidal applications. Such materials have also demonstrated considerable efficacy to counter effects of chemical toxicity. In this study, nanostructured molybdenum disulfide (MoS₂) was doped with various concentrations (2.5, 5, 7.5, 10 wt%) of zirconium (Zr) using a hydrothermal route in order to assess its antimicrobial and catalytic potential. Doped and control samples were characterized with various techniques. X-ray diffraction (XRD) analysis confirmed the presence of the hexagonal phase of MoS₂ and identification of various functional groups and characteristic peaks (Mo bonding) was carried out using FTIR spectra. Micrographs obtained from FESEM and HR-TEM showed a sheet-like surface morphology, while agglomeration of nanosheets was observed upon doping with nanoparticles. To seek further clarity regarding the layered features of S–Mo–S planes, the defect densities and electronic band structure of pure MoS₂ and doped MoS₂ samples were investigated through Raman analysis. Optical properties of Zr-doped MoS₂ nanosheets were assessed using a UV-vis spectrophotometer and the results indicated a red-shift, i.e., movement of peaks towards longer wavelengths, of the material. Dynamics of migration and recombination of excited electron–hole pairs were investigated using PL spectroscopy, which was also used to confirm the presence of exfoliated nanosheets. In addition, the synthetic dye degradation potential of pure and doped samples was investigated in the presence of a reducing agent (NaBH₄). It was noted that doped MoS₂ showed superior catalytic activity compared to undoped MoS₂. The nanocatalyst synthesized in this study exhibited enhanced antibacterial activity against E. coli and S. aureus at high concentrations (0.5, 1.0 mg/50 μl). The present study suggests a cost-effective and environmentally friendly material that can be used to remove toxins such as synthetic dyes and tannery pollutants from industrial wastewater.

Nanostructured materials incorporated with biological reducing agents have shown significant potential for use in bactericidal applications.

Photocatalytic and bactericidal properties and molecular docking analysis of TiO2 nanoparticles conjugated with Zr for environmental remediation

Despite implementing several methodologies including a combination of physical, chemical and biological techniques, aquatic and microbial pollution remains a challenge to this day. Recently, nanomaterials have attracted considerable attention due to their extraordinary prospective for utilization toward environmental remediation. Among several probable candidates, TiO₂ stands out due to its potential for use in multifaceted applications. One way to improve the catalytic and antimicrobial potential of TiO₂ is to dope it with certain elements. In this study, Zr-doped TiO₂ was synthesized through a sol–gel chemical method using various dopant concentrations (2, 4, 6, and 8 wt%). Surface morphological, microstructural and elemental analysis was carried out using FESEM and HR-TEM along with EDS to confirm the formation of Zr–TiO₂. XRD spectra showed a linear shift of the (101) anatase peak to lower diffraction angles (from 25.4° to 25.08°) with increasing Zr⁴⁺ concentration. Functional groups were examined via FTIR, an ample absorption band appearing between 400 and 700 cm⁻¹ in the acquired spectrum was attributed to the vibration modes of the Ti–O–Ti linkage present within TiO₂ nanoparticles, which denotes the formation of TiO₂. Experimental results indicated that with increasing dopant concentrations, photocatalytic potential was enhanced significantly. In this respect, TiO₂ doped with 8 wt% Zr (sample 0.08 : 1) exhibited outstanding performance by realizing 98% elimination of synthetic MB in 100 minutes. This is thought to be due to a decreased rate of electron–hole pair recombination that transpires upon doping. Therefore, it is proposed that Zr-doped TiO₂ can be used as an effective photocatalyst material for various environmental and wastewater treatment applications. The good docking scores and binding confirmation of Zr-doped TiO₂ suggested doped nanoparticles as a potential inhibitor against selected targets of both E. coli and S. aureus. Hence, enzyme inhibition studies of Zr-doped TiO₂ NPs are suggested for further confirmation of these in silico predictions.

Despite implementing several methodologies including a combination of physical, chemical and biological techniques, aquatic and microbial pollution remains a challenge to this day.

Medium-term outcomes of the Universal-2 total wrist arthroplasty in patients with rheumatoid arthritis

AIMS

The aims of this study were to evaluate the clinical and radiological outcomes of the Universal-2 total wrist arthroplasty (TWA) in patients with rheumatoid arthritis.

PATIENTS AND METHODS

This was a retrospective review of all 95 Universal-2 TWAs which were performed in our institution between 2003 to 2012 in patients with rheumatoid arthritis. A total of six patients were lost to follow-up and two died of unrelated causes. A total of ten patients had bilateral procedures. Accordingly, 75 patients (85 TWAs) were included in the study. There were 59 women and 16 men with a mean age of 59 years (26 to 86). The mean follow-up was 53 months (24 to 120). Clinical assessment involved recording pain on a visual analogue score, range of movement, grip strength, the Quick Disabilities of the Arm, Shoulder and Hand (DASH) and Wrightington wrist scores. Any adverse effects were documented with particular emphasis on residual pain, limitation of movement, infection, dislocation and the need for revision surgery. Radiographic assessment was performed pre-operatively and at three, six and 12 months post-operatively, and annually thereafter. Arthroplasties were assessed for distal row intercarpal fusion and loosening. Radiolucent zones around the components were documented according to a system developed at our institution.

RESULTS

The mean worst pain was 8.1 (3 to 10) pre-operatively and 5.4 (0 to 10) at latest follow-up (p < 0.001). Movements were preserved with mean dorsiflexion of 29^o (0 ^o to 70 ^o) and palmar flexion of 21^o (0^o to 50^o). The mean grip strength was 4.8 kg (1.7 to 11.5) pre-operatively and 10 kg (0 to 28) at final follow-up (p < 0.001). The mean QuickDASH and Wrightington wrist scores improved from 61 (16 to 91) to 46 (0 to 89) and 7.9 (1.8 to 10) to 5.7 (0 to 7.8) (p < 0.001). A total of six patients (7%) had major complications; three required revision arthroplasty and three an arthrodesis. The Kaplan-Meier probability of survival using removal of the components as the endpoint was 91% at 7.8 years (95% confidence interval 84 to 91).

CONCLUSION

The Universal-2 TWA is recommended for use in patients with rheumatoid arthritis. Cite this article: Bone Joint J 2016;98-B:1642-7.

Pragmatic randomized controlled trial of a structured allergy intervention for adults with asthma and rhinitis in general practice

BACKGROUND

It is widely believed that in patients with allergic rhinitis and asthma, avoidance of specific triggers can help improve symptom control and reduce need for medication. Whilst most patients with asthma or rhinitis are sensitized to airborne allergens, primary care diagnostic and management decisions are often made without either obtaining a detailed history of the patient's allergic triggers or performing skin prick tests. Thus, management decisions are empirical and allergen avoidance advice is either not given or, if given, not tailored to the patient's sensitivities.

METHOD

To ascertain whether allergy assessment and tailored advice in general practice for patients with asthma and rhinitis enhance well-being, we conducted a pragmatic, open, randomized controlled trial of allergy intervention (structured allergy history and skin prick testing and appropriate advice on allergy avoidance) versus usual care in adult patients with a working diagnosis of asthma and/or rhino-conjunctivitis. Outcomes were assessed after 12 months by an observer who was blinded to allocation. The main outcome measures were asthma and rhinitis symptoms, disease-specific health-related quality of life, generic quality of life and lung function.

RESULTS

There were no significant differences in baseline demographics or disease characteristics between patients assigned to immediate or delayed skin prick testing. No significant differences were observed between groups for any measures of symptoms, quality of life or lung function at 12 months (all P > 0.05).

CONCLUSION

Amongst adults with known asthma and/or rhinitis in primary care, taking a structured allergy history with skin prick tests and giving tailored advice on allergy avoidance made no difference to their symptoms, quality of life or lung function as measured twelve months later.

The diversity of young adult wheeze: a cluster analysis in a longitudinal birth cohort

BACKGROUND

Cluster analyses have enhanced understanding of the heterogeneity of both paediatric and adult wheezing. However, while adolescence represents an important transitional phase, the nature of young adult wheeze has yet to be clearly characterised.

OBJECTIVES

To use cluster analysis to define, for the first time, clinically relevant young adult wheeze clusters in a longitudinal birth cohort.

METHODS

K-means cluster analysis was undertaken among 309 currently wheezing subjects at 18 years in the Isle of Wight birth cohort (N = 1456). Thirteen disease-characterising clustering variables at 18 years were used. Resulting clusters were then further characterised by severity indices plus potential risk factors for wheeze development throughout the 1st 18 years of life.

RESULTS

Six wheeze clusters were identified. Cluster 1 (12.3%) male-early-childhood-onset-atopic-wheeze-with-normal-lung-function had male predominance, normal spirometry, low bronchodilator reversibility (BDR), intermediate bronchial hyper-responsiveness (BHR), high atopy prevalence and more admissions. Cluster 2 (24.2%) early-childhood-onset-wheeze-with-intermediate-lung-function had no specific sex association, intermediate spirometry, BDR, BHR, more significant BTS step therapy and admissions. Cluster 3 (9.7%) female-early-childhood-onset-atopic-wheeze-with-impaired-lung-function showed female predominance, high allergic disease comorbidity, more severe BDR and BHR, greatest airflow obstruction, high smoking prevalence, higher symptom severity and admissions. Cluster 4 (19.4%) female-undiagnosed-wheezers had adolescent-onset non-atopic wheeze, low BDR and BHR, impaired but non-obstructed spirometry, high symptom frequency and highest smoking prevalence. Cluster 5 (24.6%) female-late-childhood-onset-wheeze-with-normal-lung-function showed no specific atopy association, normal spirometry, low BDR, BHR and symptom severity. Cluster 6 (9.7%) male-late-childhood-onset-atopic-wheeze-with-impaired-lung-function had high atopy and rhinitis prevalence, increased BDR and BHR, moderately impaired spirometry, high symptom severity and higher BTS step therapy.

CONCLUSIONS AND CLINICAL RELEVANCE

Young adult wheeze is diverse and can be classified into distinct clusters. More severe clusters merit attention and are associated with childhood onset, atopy, impaired lung function and in some, smoking. Smoking-associated undiagnosed wheezers also merit recognition. Better understanding of young adult wheeze could facilitate better later adult respiratory health.