Validation of Low-Cost Sensors in Measuring Real-Time PM10 Concentrations at Two Sites in Delhi National Capital Region.

In the present study, we assessed for the first time the performance of our custom-designed low-cost Particulate Matter (PM) monitoring devices (Atmos) in measuring PM10 concentrations. We examined the ambient PM10 levels during an intense measurement campaign at two sites in the Delhi National Capital Region (NCR), India. In this study, we validated the un-calibrated Atmos for measuring ambient PM10 concentrations at highly polluted monitoring sites. PM10 concentration from Atmos, containing laser scattering-based Plantower PM sensor, was comparable with that measured from research-grade scanning mobility particle sizers (SMPS) in combination with optical particle sizers (OPS) and aerodynamic particle sizers (APS). The un-calibrated sensors often provided accurate PM10 measurements, particularly in capturing real-time hourly concentrations variations. Quantile-Quantile plots (QQ-plots) for data collected during the selected deployment period showed positively skewed PM10 datasets. Strong Spearman's rank-order correlations (rs = 0.64-0.83) between the studied instruments indicated the utility of low-cost Plantower PM sensors in measuring PM10 in the real-world context. Additionally, the heat map for weekly datasets demonstrated high R2 values, establishing the efficacy of PM sensor in PM10 measurement in highly polluted environmental conditions.

Lumbar parafacetal cyst-spinal segmental instability is the cause and stabilization is the treatment: A clinical report of eight surgically-treated patients.

Objective: The authors report the results of "only-fixation" of the affected spinal segment without any decompression of the bones or soft tissue or manipulation of the cyst wall or contents in eight cases having lumbar parafacetal cyst (LPFC). This surgical strategy was based on the concept that LPFCs are secondary to spinal instability, has a protective or adaptive role, and is reversible following stabilization. Materials and Methods: During the period from January 2018 to January 2023, eight consecutive patients having LPFC were surgically treated. There were 5 males and 3 females, and their ages ranged from 48 to 72 years (average 63 years). Seven patients had a single cyst and one patient had multiple cysts. The patients presented with symptoms classically attributed to lumbar canal stenosis. Apart from the cyst-affected spinal segment, degenerative alterations were observed in adjoining spinal segments in six out of seven patients having a single cyst. All patients underwent "only fixation" of the unstable spinal segments without any kind of bone or soft-tissue resection and without any manipulation or handling of the cyst wall or contents. Results: During the follow-up period that ranged from 12 to 57 months (average 29 months), all patients improved from their symptoms. The recovery was observed in the immediate postoperative period and was lasting. Conclusions: LPFCs are one of the several secondary alterations observed in spinal degeneration. Identification of unstable spinal segments and their fixation constitutes rational treatment of lumbar parafacetal cysts. Direct handling and resection of cysts are unnecessary.

Defining role of atlantoaxial and subaxial spinal instability in the pathogenesis of cervical spinal degeneration: Experience with "only-fixation" without any decompression as treatment in 374 cases over 10 years.

Aim: The authors analyze their published work and update their experience with 374 cases of cervical radiculopathy and/or myelopathy related to spinal degeneration that includes ossification of the posterior longitudinal ligament (OPLL). The role of atlantoaxial and subaxial spinal instability as the nodal point of pathogenesis and focused target of surgical treatment is analyzed. Materials and Methods: During the period from June 2012 to November 2022, 374 patients presented with acute or chronic symptoms related to radiculopathy and/or myelopathy that were attributed to degenerative cervical spondylotic changes or due to OPLL. There were 339 males and 35 females, and their ages ranged from 39 to 77 years (average 62 years). All patients were treated for subaxial spinal stabilization by Camille's transarticular technique with the aim of arthrodesis of the treated segments. Atlantoaxial stabilization was done in 128 cases by adopting direct atlantoaxial fixation in 55 cases or a modified technique of indirect atlantoaxial fixation in 73 patients. Decompression by laminectomy, laminoplasty, corpectomy, discoidectomy, osteophyte resection, or manipulation of OPLL was not done in any case. Standard monitoring parameters, video recordings, and patient self-assessment scores formed the basis of clinical evaluation. Results: During the follow-up period that ranged from 3 to 125 months (average: 59 months), all patients had clinical improvement. Of 130 patients who had clinical evidences of severe myelopathy and were either wheelchair or bed bound, 116 patients walked aided (23 patients), or unaided (93 patients) at the last follow-up. One patient in the series was operated on 24 months after the first surgery by anterior cervical route for "adjacent segment" disc herniation. No other patient in the entire series needed any kind of repeat or additional surgery for persistent, recurrent, increased, or additional related symptoms. None of the screws at any level backed out or broke. There were no implant-related infections. Spontaneous regression of the size of osteophytes was observed in 259 patients where a postoperative imaging was possible after at least 12 months of surgery. Conclusions: Our successful experience with only spinal fixation without any kind of "decompression" identifies the defining role of "instability" in the pathogenesis of spinal degeneration and its related symptoms. OPLL appears to be a secondary manifestation of chronic or longstanding spinal instability.

ESR and optical study of Mn2+ doped ammonium selenate single crystals.

ESR and optical absorption studies of manganese doped ammonium selenate single crystals are performed at X-band and room temperature to ascertain the site symmetry and location of impurity ions in the lattice. Manganese ions are expected to enter the lattice interstitially. Various spin Hamiltonian parameters are determined. Optical absorption study is also done and associated distortion in the crystal lattice is estimated.