Remediation of petroleum-contaminated site soil by bioaugmentation with immobilized bacterial pellets stimulated by a controlled-release oxygen composite.

Bioaugmentation techniques still show drawbacks in the cleanup of total petroleum hydrocarbons (TPHs) from petroleum-contaminated site soil. Herein, this study explored high-performance immobilized bacterial pellets (IBPs) embed Microbacterium oxydans with a high degrading capacity, and developed a controlled-release oxygen composite (CROC) that allows the efficient, long-term release of oxygen. Tests with four different microcosm incubations were performed to assess the effects of IBPs and CROC on the removal of TPHs from petroleum-contaminated site soil. The results showed that the addition of IBPs and/or CROC could significantly promote the remediation of TPHs in soil. A CROC only played a significant role in the degradation of TPHs in deep soil. The combined application of IBPs and CROC had the best effect on the remediation of deep soil, and the removal rate of TPHs reached 70%, which was much higher than that of nature attenuation (13.2%) and IBPs (43.0%) or CROC (31.9%) alone. In particular, the CROC could better promote the degradation of heavy distillate hydrocarbons (HFAs) in deep soil, and the degradation rates of HFAs increased from 6.6% to 33.2%-21.0% and 67.9%, respectively. In addition, the IBPs and CROC significantly enhanced the activity of dehydrogenase, catalase, and lipase in soil. Results of the enzyme activity were the same as that of TPH degradation. The combined application of IBPs and CROC not only increased the microbial abundance and diversity of soil, but also significantly enhanced the enrichment of potential TPH-biodegrading bacteria. M. oxydans was dominant in AP (bioaugmentation with addition of IBPs) and APO (bioaugmentation with the addition of IBPs and CROC) microcosms that added IBPs. Overall, the IBPs and CROC developed in this study provide a novel option for the combination of bioaugmentation and biostimulation for remediating organic pollutants in soil.

A metal-poor star with abundances from a pair-instability supernova.

The most massive and shortest-lived stars dominate the chemical evolution of the pre-galactic era. On the basis of numerical simulations, it has long been speculated that the mass of such first-generation stars was up to several hundred solar masses1-4. The very massive first-generation stars with a mass range from 140 to 260 solar masses are predicted to enrich the early interstellar medium through pair-instability supernovae (PISNe)5. Decades of observational efforts, however, have not been able to uniquely identify the imprints of such very massive stars on the most metal-poor stars in the Milky Way6,7. Here we report the chemical composition of a very metal-poor (VMP) star with extremely low sodium and cobalt abundances. The sodium with respect to iron in this star is more than two orders of magnitude lower than that of the Sun. This star exhibits very large abundance variance between the odd- and even-charge-number elements, such as sodium/magnesium and cobalt/nickel. Such peculiar odd-even effect, along with deficiencies of sodium and α elements, are consistent with the prediction of primordial pair-instability supernova (PISN) from stars more massive than 140 solar masses. This provides a clear chemical signature indicating the existence of very massive stars in the early universe.

The role of Xpert MTB/RIF using bronchoalveolar lavage fluid in active screening: insights from a tuberculosis outbreak in a junior school in eastern China.

Background: Tuberculosis (TB) outbreaks in schools present a public health challenge. In order to effectively control the spread of transmission, timely screening, accurate diagnosis and comprehensive epidemiological investigations are essential. Methods: In July 2021, a TB outbreak occurred in a junior high school in Y City, Zhejiang Province. Students and faculty were screened for TB by symptom screening, chest radiography, and tuberculin skin test during four rounds of contact screenings. For sputum smear-negative and sputum-scarce patients, bronchoscopy was used to collect BAL samples for Xpert Mycobacterium tuberculosis/rifampin (MTB/RIF). Whole-genome sequencing and bioinformatics analysis were performed on isolates to identify the strains of MTB isolates and predict drug resistance. Results: Between July 2021 and November 2021, a total of 1,257 students and faculty were screened for TB during screenings. A total of 15 students (1.2% of persons screened) aged 15 years were diagnosed with TB. Eighty percent (12/15) of the cases were laboratory-confirmed (10/12 [83%] Xpert MTB/RIF-positive, 2/12 [17%] culture-positive). Most cases (12/15 [80%]) were in students from Class 2. All cases were asymptomatic except for the index case who had symptoms for more than two months. Seven MTB isolates were collected and belonged to lineage 2. Conclusion: Our findings demonstrated the potential of Xpert MTB/RIF using BAL as a screening tool in school TB outbreaks for sputum smear-negative and sputum-sparse suspects, which may not only rapidly improves diagnostic accuracy, but also facilitates epidemiological investigations and homology analysis.

Treatment outcomes of patients with multidrug and extensively drug-resistant tuberculosis in Zhejiang, China.

BACKGROUND: The aim of this study was to assess the treatment outcomes of multidrug and extensively drug-resistant tuberculosis (M/XDR-TB) in Zhejiang, China and to evaluate possible risk factors associated with poor outcomes of M/XDR-TB. METHODS: Two-hundred-and-sixty-two patients having M/XDR-TB who received the diagnosis and treatment at nine referral hospitals from 1 January 2016 to 31 December 2016 in Zhejiang, China were included. All patients received second-line regimens recommended by WHO under the DOTS-Plus strategy. RESULTS: Among the 262 patients, the treatment success rate was 55.34% (n = 145) with 53.44% (n = 140) cured and 1.91% (n = 5) who completed treatment, 62 (23.66%) failed, 27 (10.31%) died, 16 (6.11%) defaulted and 12 (4.58%) transferred out. Forty (64.52%) of the 62 M/XDR-TB patients who failed treatment were due to adverse effects in the first 10 months of treatment. Eighteen patients (6.37%) had XDR-TB. Treatment failure was significantly higher among patients with XDR-TB at 50% than that among patients with non-XDR-TB at 21.72% (P = 0.006). Failure outcomes were associated with a baseline weight less than 50 kg (OR, 8.668; 95% CI 1.679-44.756; P = 0.010), age older than 60 years (OR, 9.053; 95% CI 1.606-51.027; P = 0.013), hemoptysis (OR, 8.928; 95% CI 1.048-76.923; P = 0.045), presence of cavitary diseases (OR, 10.204; 95% CI 2.032-52.631; P = 0.005), or treatment irregularity (OR, 47.619; 95% CI 5.025-500; P = 0.001). CONCLUSION: Treatment outcomes for M/XDR-TB under the DOTS-Plus strategy in Zhejiang, China were favorable but still not ideal. Low body weight (< 50 kg), old age (> 60 years), severe symptoms of TB including cavitary disease, hemoptysis and irregular treatment were independent prognostic factors for failure outcomes in patients with M/XDR-TB.

Analysis of the etiologies, treatments and prognoses in children and adolescent vitreous hemorrhage.

AIM: To determine the etiologies, treatment modalities and visual outcomes of vitreous hemorrhage (VH; range from birth to 18y). METHODS: A total of 262 eyes from 210 patients between January 2010 and September 2016 were included. All children underwent an appropriate ocular and systemic examination. Data collected included demographics, clinical manifestations, details of the ocular and systemic examination, management details, final fundus anatomy and visual acuity (VA). RESULTS: The most common etiologies were non-traumatic VH (64.89%), most of which were due to retinopathy of prematurity (ROP; 37.10%); while traffic accidents, including 16 (21.00%) eyes, was the most common ocular traumas. Surgery, performed in 143 (54.58%) eyes, was the most common management modality. The initial mean baseline visual acuity was 2.77±0.21 logarithm of the minimal angle of resolution (logMAR) in children and adolescent with traumatic VH, which was significantly improved to 2.15±1.31 logMAR (P<0.05). CONCLUSION: VH in children and adolescent has a complicated and diverse etiology. ROP is the primary cause of non-traumatic VH, which is the most common etiology. Appropriate treatment of traumatic VH is associated with obvious improvement in visual acuity. The initial VA is one of most important predictors of outcome.

Multidrug-resistant tuberculosis transmission among middle school students in Zhejiang Province, China.

BACKGROUND: Despite significant advancements in the treatment and diagnosis of tuberculosis (TB) over the past decade, drug-resistant TB remains an increasing threat to public health. TB outbreaks are most commonly reported in schools considering the delay in TB diagnosis, sustained contact, and overcrowding observed in schools. This report describes multidrug-resistant TB (MDR-TB) transmission in a school in Zhejiang Province. We aimed to raise awareness regarding MDR-TB transmission among students. CASE PRESENTATION: The index patient was a 16-year-old girl in the second year of junior middle school in Zhejiang Province, China, who had been experiencing persistent cough and expectoration for 37 days since 1 March 2014. She tested positive for smear pulmonary and extrapulmonary TB on 8 April 2014 and was subsequently diagnosed with MDR-TB on 1 May 2014. However, the patient was resistant to isoniazid, rifampicin, ethambutol, and streptomycin. Thus, she was suspended from school for anti-TB treatment. All 54 students who were in close contact with the index patient in the same class were screened, and 5 tested positive on the tuberculin skin test. Their exposure time to the index patient was approximately 37 days. Three classmates were subsequently diagnosed with MDR-TB, with similar resistance profiles nearly two years later. Their average discovery delay was 55 days. These three classmates were also suspended from school for anti-TB treatment. During the treatment period, four students visited the local TB-designated hospital for further consultation every month and were followed up once a month by the local community health service center until they were completely cured. CONCLUSIONS: Discovery delay for an index patient played a primary role in MDR-TB transmission inside the school. To immediately detect TB, morning examinations in schools should be performed. TB trackers and case managers should work closely with public health workers and physicians in cases of TB outbreaks or transmissions involving students. Moreover, individuals who are in close contact with MDR-TB patients should undergo careful clinical follow-up for at least two years. Implementing a joint examination strategy to ensure early detection, diagnosis, and treatment of MDR-TB transmission is recommended.

Phenotypic and genotypic characterization of pyrazinamide resistance among multidrug-resistant Mycobacterium tuberculosis isolates in Zhejiang, China.

To explore the phenotypic and genotypic characterization of pyrazinamide (PZA) resistance among multidrug-resistant Mycobacterium tuberculosis (MDR-TB) isolates in Zhejiang province, a total of 274 MDR-TB isolates were collected. Drug susceptibility testing and spoligotyping were performed on all clinical isolates. In addition, the mutated features of PZA-resistant loci, including pncA and rpsA, were also analyzed by DNA sequencing. Our results showed that the prevalence of PZA resistance among MDR-TB strains in Zhejiang province was 43.07% and that PZA resistance was associated with concomitant resistance to streptomycin. The majority of PZA-resistant MDR-TB isolates belonged to the Beijing family. Mutations within pncA, not rpsA, constituted the primary mechanism of PZA resistance. Among 118 PZA-resistant isolates, 53 different mutations were observed in pncA, and most of them were point mutations. Compared with the phenotypic data, DNA sequencing of pncA has sensitivity and specificity of 77.97% and 96.79%, respectively. Analysis of pncA provided a robust tool for rapid detection of PZA drug resistance.

[The upconversion luminescence characteristics of Ho3+/Yb3+ codoped ZrO2-ZnO].

Samples of Ho3+/Yb3+ codoped ZrO2-ZnO powder were prepared by a solid-state reaction. Upconversion luminescence of Ho3+ /Yb3+ codoped ZrO2-ZnO powders was reported in the present paper. The excitation spectrum detected at room temperature suggests three excitation peaks centered at 540, 671 and 762 nm respectively, corresponding to 5S2/5F4 --> I8, 5 Fs --> 5 I8, and 5S2/5 F4 --> 5 I7 or 5 I4 --> 5 I8 of Ho3+ ions. The contents of rare-earth ions could influence the property of upconversion lumunescence. When the Ho3+ content was 0.1 mol%, with the increase in Yb3+ content, the intensity of red luminescence and green luminescence decreased first and then increased, but the intensity of infrared luminescence increased first and then decreased. Furthermore, the ratio of the intensity of green emission to red emission decreased. When the Yb3+ content was 4.7 mol%, with the increase in Ho3+ content, the intensity of all emission decreased, but the ratio of the intensity of green emission to red emission was almost constant. The logI - logP curve shows that all the upconversion luminescence is double-photon processes. And the upconversion mechanisms of the samples were introduced. It is shown from the XRD spectrum that the powder of samples is uniform.

[Studies on the properties of frequency upconversion of Yb3+/Er3+ codoped absolute oxides].

Samples of Er+3/Yb3+ codoped 3CaO-Al2O3-3SiO2 compounds were prepared, and the properties of frequency upconversion of the samples under the excitation of 980 nm diode laser were studied. Green and red emissions centered at 523, 547 and 656 nm, corresponding to the transitions 2H(11/2)-->4I(15/2), 4S(3/2)-->4I(15/2), and 4F(9/2)-->4I(15/2), respectively, were observed. The dependence of the upconversion fluorescence intensity on the pumping power, and the phonon energy of each sample were observed, and the mechanism of frequency upconversion based on these two items was discussed.

[The upconversion mechanisms for the red and green emissions in Er3+ doped and Er3+ -Yb3+ codopoed fluoride materials based on experiment].

The rare earth Er3+ doped and Er3+ -Yb3+ co-doped fluoride samples were prepared. Under 980 nm laser excitation, the intense red (650 nm) and green (545 nm) upconversion luminescence was obtained corresponding to the transitions 4S3/2, 2H11/2--4I15/2 and 4F9/2--4I15/2, respectively. For the Er3+ -Yb3+ co-doped fluoride samples, it was found that the ratio of the red upconversion luminescence to the green one decreases as the Er3+ concentration increases. The dependence of upconversion intensities on excitation power indicates that two-photon absorption processes are responsible for the upconverted luminescence. The possible upconversion mechanisms of the red and green emissions are discussed based on the energy-matching conditions and the quadratic dependence on excitation power.

[Study on red up-conversion luminescence of fluoride glasses doped with Er3+, Yb3+ and Tm3+].

When the quality of Er2O3 is 10 times the former, the authors found that its character of up-conversion luminescence is distinct. Then the authors studied the luminescence system of Es3+ /Tm3+, Er3+ /Er3+ and Er3+ /Yb3+ /Tm3+ and their character of upconversion and fluorescence spectrum at 980 nm. In addition, the authors studied the relation between the three systems and the consistency of Er2O3. The authors found that the intensity of green and red light changed with the consistence of Er3+ in the experiment. It's the consistence of Er3+ that is the most causative. The chance is equal for each lanthanonion that makes up the luminescence system in the uniformity matter. With the distance between each pair of lanthanonions in the luminescence system is changed, the luminescence system and the color of the up-conversion luminescence also changed.

[Direct sensitization up-conversion mechanism from Yb3+ to Ho3+ and Tm3+ in fluoride].

The direct sensitization up-conversion processes from Yb3+ to Ho3+ and Tm3+ in fluoride were studied. The properties of the up-converted spectra of Yb3+ /Ho3+ and Ho3+ /Yb3+ /Tm3+ co-doped fluorides pumped by a 980 nm laser were compared. Their up-conversion mechanism has been analyzed and discussed. Two strong up-conversion luminescence bands have been observed, which were the transitions of 5 F4 5 S2 (Ho3+) -->18 (Ho3+) in the Yb3+ /Ho3+ co-doped fluoride system and 3 H4 (Tm3+) --> 3 H6 (Tm3+) in the Ho+ /Yb3+ /Tm3+ co-doped fluoride system. The addition of Tm3+ into Yb3+ /Ho3+ co-doped fluoride decreases the up-converted emission intensities of Ho3+ in the visible region.

[Luminescence properties and up-conversion mechanism of Er3+ -Yb3+ -Tm3+ co-doped CdF2: PbF2-based glass].

Under 980 nm excitation, we obtained five intense up-conversion luminescence bands in Er3+ -Yb3+ -Tm3+ co-doped CdF2: PbF2-based glass as follows: infrared (800 nm), red (645 nm), green (545 nm and 525 nm), blue (480 nm ) and violet (407 nm) up-conversion luminescence. With the addition of Tm3+ , the intensity of 480 nm blue luminescence increased notably compared with that of co-doped Yb3+ -Er3+ sample, which attributed to Tm3+ special energy level structure; logI-logP plot of the luminescence intensity versus pump power shows that 480 nm luminescence emission is a two-photon excitation process induced by the cooperative up-conversion between two Yb3+ ions and the slope of logI-logP plot decreases gradually with increasing pump power and shows a tendency to bend down. The up-conversion mechanism is analyzed in detail under 980 nm semiconductor laser excitation; the dependence of 480 nm up-conversion luminescence intensity on the pump power under the steady states is discussed by using rate equation and the results agree well with the experiments.

[The study of up-conversion fluorescence in Er3+:Yb3+ co-doped oxy-fluoride glasses].

Er3+:Yb3+ co-doped oxy-fluoride glasses with composition of (50-x) GeO2.PbF2.WO3.(6 + x) CdF2.1.4Yb2O3.0.6Er2O3 (x = 10,20,30) were prepared. Their up-conversion fluorescence characteristics were investigated under excitation of 930 nm diode laser. Three strong fluorescence bands of Er3+ whose central wavelength lie in 543, 550 and 655 nm have been observed. The maximum phonon energy is obtained by measuring anti-stokes Raman shifts of the samples, and the up-conversion mechanism is briefly discussed. The influences of host materials composition on up-conversion efficiency are also discussed adopting the average electronegative difference and the cationic field strength of the host. It is found that relative small average electronegative difference and large cationic field strength of host benefit to energy up-conversion.