Local Structure and Crystallization Transformation of Hydrous Ferric Arsenate in Acidic H2O-Fe(III)-As(V)-SO42- Systems: Implications for Acid Mine Drainage and Arsenic Geochemical Cycling

Hydrous ferric arsenate (HFA) is a common thermodynamically metastable phase in acid mine drainage (AMD). However, little is known regarding the structural forms and transformation mechanism of HFA. We investigated the local atomic structures and the crystallization transformation of HFA at various Fe(III)/As(V) ratios (2, 1, 0.5, 0.33, and 0.25) in acidic solutions (pH 1.2 and 1.8). The results show that the Fe(III)/As(V) in HFA decreases with decreasing initial Fe(III)/As(V) at acidic pHs. The degree of protonation of As(V) in HFA increases with increasing As(V) concentrations. The Fe K-edge extended X-ray absorption fine structure and X-ray absorption near-edge structure results reveal that each FeO6 is linked to more than two AsO4 in HFA precipitated at Fe(III)/As(V) < 1. Furthermore, the formation of scorodite (FeAsO4·2H2O) is greatly accelerated by decreasing the initial Fe(III)/As(V). The release of As(V) from HFA is observed during its crystallization transformation process to scorodite at Fe(III)/As(V) < 1, which is different from that at Fe(III)/As(V) ≥ 1. Scanning electron microscopy results show that Oswald ripening is responsible for the coarsening of scorodite regardless of the initial Fe(III)/As(V) or pH. Moreover, the formation of crystalline ferric dihydrogen arsenate as an intermediate phase at Fe(III)/As(V) < 1 is responsible for the enhanced transformation rate from HFA to scorodite. This work provides new insights into the local atomic structure of HFA and its crystallization transformation that may occur in AMD and has important implications for arsenic geochemical cycling.

Pelvic Pseudotumor Associated With a Ceramic Bearing Total Hip

Pseudotumors have been well documented to occur most frequently in metal-metal bearing total hip arthroplasties and less frequently in metal-polyethylene bearings. There are few cases in the literature of pseudotumors occurring in ceramic-ceramic articulations. We report a case of a large pelvic pseudotumor in a patient with a ceramic-ceramic bearing articulation in a 67-year-old man. In addition to the usual investigations, we did a detailed wear analysis of the ceramic implants and an examination of the soft tissues for particulate debris. The detailed wear analysis did show evidence of stripe wear; however, the volumetric wear was within the expected range. Synchrotron imaging identified strontium and zirconium debris arising from the ceramic surfaces. Although association does not mean causation, no other cause for the large pseudotumor could be identified and presumably represents an idiosyncratic reaction to ceramic debris.

Direct immobilization of Se(IV) from acidic Se(IV)-rich wastewater via ferric selenite Co-precipitation

The attenuation of acidic Se(IV)-rich wastewater, including those associated with acid mine drainage (AMD) and nonferrous metallurgical wastewater (NMW), presents a serious environmental challenge. This study investigates the effects of diverse factors from pH values to Se(IV)/Fe(III) molar ratios, initial Se(IV) concentrations, and alkali neutralization agents on the direct co-precipitation of ferric selenites in AMD and NMW systems involving different orders of Fe(III) and alkali addition. Our results show that amorphous sulfate-substituted ferric (hydrogen) selenite and Se(IV)-bearing ferrihydrite-schwertmannite are the major Se(IV)-attenuation solids except that gypsum is an additional phase in the NMW system with Ca(OH)2 neutralization. Produced ferric selenites achieve 98-99.8% of Se(IV) immobilization under optimal conditions of pH 4.5, Se(IV)/Fe(III) molar ratios of 0.0625-0.5, and initial Se(IV) concentrations of 0.15-1.3 mmol·L-1. Moreover, completing FeSO4+ and FeHSeO32+/FeSeO3+ complexes as well as different ferric selenite co-precipitates are shown to collectively control aqueous Se(IV) remaining. Specifically, three distinct trends of aqueous Se(IV) concentrations separately correspond to changes in the four factors. The co-precipitation in the NMW system via pH adjustment followed by Fe(III) addition is more efficient for Se(IV) fixation than that in the AMD system because of minimal complexation, concurrent Fe(III) hydrolysis, and enhanced ferric selenite co-precipitation in the former.

Tension-free thyroidectomy (medial thyroidectomy)-a prospective study: surgical technique and results of 259 operations

Background

Thyroid surgery is associated with a number of surgical complications including recurrent laryngeal nerve (RLN) injury and hypoparathyroidism. The existing methods share the same principle-the mobilization of the thyroid from the lateral side. The aim of this study was to evaluate the safety of a novel technique of thyroidectomy-tension-free thyroidectomy (TFT) based on the medial approach to the laryngeal nerves and parathyroid glands (PTGs).

Methods

The study was conducted between August 2021 and July 2022 in Saint Petersburg State University Hospital. A total of 261 patients with thyroid diseases were enrolled in the study and operated on using the TFT technique.

Results

The operations with the use of TFT technique were completed in all but two cases which required the conversion to the standard lateral approach. Of 259 TFT cases unilateral laryngeal paresis was registered in 6 (2.3%) cases or in 1.7% of the number of RLNs at risk. In all but one case the vocal fold function recovered in less than 6 months of the follow-up. Among 87 patients who underwent total thyroidectomy transient postoperative hypoparathyroidism was found in 10 cases (11.5%), rate of persistent hypoparathyroidism was 0%. One case of postoperative bleeding was recorded (0.4%).

Conclusions

The TFT technique demonstrated high safety and several advantages over the traditional method of performing operations on the thyroid gland.

PSAT383 Tension-free Thyroidectomy in the Treatment of Thyroid Cancer and Follicular Neoplasia: Experience of the First 100 Cases

Background

and aims. The safety of thyroid surgery in terms of recurrent laryngeal nerve palsy and hypoparathyroidism was increasing in the last decade. In this study, we present a new method of tension-free thyroidectomy (TFT), which could be used to further decrease the complication rate after thyroidectomy.

Patients and Methods

The procedure is based on the medial approach to the recurrent laryngeal nerve and the parathyroid glands after the division of isthmus and successive total dissection of Barry ligament. One hundred consecutive patients (128 nerves at risk) underwent "tension-free thyroidectomy" (TFT) from August to November 2021 performed by one surgeon. There were 80 females and 20 male patients (ratio 4: 1) with a mean age of ninety-two 46,4 (range from 17 to 75). Lobectomy was carried out in 74 (74%) patients, total thyroidectomy in 26 (26%). In 42 cases patients additionally underwent central or/and lateral neck dissection. Indications for surgery were papillary carcinoma (N=52), medullary cancer (N=2), follicular neoplasia - Bethesda IV group after fine-needle biopsy (N=46). Mean thyroid nodule size was 25,3 mm (ranged 7 - 120 mm). Intraoperative transient neuromonitoring was used in all the cases (5 mA), in 20 cases permanent neuromonitoring was also used. Translaryngeal untrasound or direct laryngoscopy were routinely used prior and after surgery to evaluate vocal cords mobility. Calcium and parathormone level were measured in patients after thyroidectomy on the first, 14th and 30th postoperative days.

Results

The mean operating time of lobectomy was 80±39 (range: 25-120), for total thyroidectomy 80 ±36 (range: 55-130). There was no conversion to the conventional lateral-to-medial approach. No fluctuation of electric activity of laryngeal nerves during surgery was revealed. Intraoperative loss of signal (LOS) due to thermal effect of electrocautery and subsequent transient unilateral laryngeal nerve palsy occurred in 3 cases (2,3% from the total number of nerves at risk). In all these patients normal vocal fold function was confirmed on the 30th day after surgery. No permanent nerve palsy cases revealed. Three patients (out of 26 in the total thyroidectomy group – 11,5%) exhibited a decrease of parathyroid hormone level on the postoperative day 1 which was resolved in two weeks under the substitution therapy with calcium and alfacalcidol. No cases of permanent hypoparathyroidism occurred.

Conclusion

TFT (tension-free thyroidectomy) can be considered a safe and feasible operation in patients with thyroid cancer and follicular neoplasia. Larger and comparative (randomized) studies with conventional dissection technique should be performed to investigate the hypothesis that this approach can provide a lower complication rate.

Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.

Observation of surface precipitation of ferric molybdate on ferrihydrite: Implication for the mobility and fate of molybdate in natural and hydrometallurgical environments

Adsorption of molybdate (Mo(VI)) on the surfaces of ferrihydrite is one of the most critical processes that control its mobility and fate in the environment. However, the sorption mechanism and the effect of pH on the speciation of Mo(VI) on ferrihydrite surfaces are not well understood. In this study, X-ray diffraction (XRD), Raman, Fourier transform infrared (FTIR), and Mo K-edge and L₃-edge X-ray absorption spectroscopy (XAS) have been utilized to characterize the Mo(VI) species sorbed on ferrihydrite under various pH conditions. XRD, Raman, and FTIR results show that at acidic pH, surface precipitation of poorly crystalline ferric molybdate (PCFM) occurs under apparently undersaturated conditions (theoretical log IAP < log K_sp) and is enhanced by the aging process, whereas Mo(VI) is mainly present as surface adsorbed species at circum-neutral pH. The Mo K-edge and L₃-edge X-ray absorption near edge structure (XANES) analyses show that a mixture of tetrahedrally and octahedrally coordinated Mo(VI) simultaneously exists at pH 3-7 and the octahedral Mo(VI) species decreases with increasing pH. The Mo-Fe interatomic distances (3.52-3.56 Å) derived from EXAFS fittings suggest the corner-sharing complexation of both MoO₄ and MoO₆ with FeO₆ octahedra. As the pH decreases from 7 to 3, the coordination number of the Mo-Fe shell (CN_Mo-Fe) increases from 0.6(3) to 1.9(3), possibly due to the gradual transformation of surface adsorbed Mo(VI) to PCFM. These findings on the observation of Mo(VI) complexation, surface precipitation, and their marked pH dependence during the Mo(VI) adsorption on ferrihydrite have important implications for both understanding the mobility and fate of Mo(VI) in natural and hydrometallurgical industry impacted environments and developing optimal applications for the remediation of Mo contamination in aqueous environments.

MO414ACUTE KIDNEY INJURY AFTER ELECTIVE ENDOCRINE SURGERY: ARE PATIENTS WITH PRIMARY HYPERPARATHYROIDISM AT RISK?

Background and Aims

Development of acute kidney injury (AKI) after elective endocrine surgery is underreported. We aimed to assess the prevalence of AKI among patients underwent surgery for primary hyperparathyroidism (PHPT) and thyroid surgery and compare risk of AKI between these cohorts.

Method

A retrospective cohort study included 299 patients who underwent successful selective parathyroidectomy (PTx) for PHPT, and 40 patients after thyroid surgery with comparable scope of the intervention (thyroid follicular cells tumor, non-invasive papillary thyroid carcinoma). AKI was defined according to KDIGO-2012 criteria.

Results

Change of serum creatinine before/after surgery differed significantly between PHPT and thyroid surgery group: type of surgery*time interaction p&lt;0,0001 (repeated measures ANOVA after Box-Cox transformation) – fig.1. 109 patients (36,5%) in the PHPT group and 2 patients (5%) in the thyroid group met AKI criteria after PTx. Most of the patients developed AKI stage 1. Risk of AKI was significantly higher in the PHPT patients: RR=7,3 [2,19; 26,6], OR=10,9 [2,82; 46,6], р&lt;0,0001. Patients in the thyroid surgery group were significantly younger than those in the PHPT group (41,5 [Q1-Q3: 30; 51] years vs 59 [Q1-Q3: 50,8; 67] years, respectively, p&lt;0,0001), had higher mean baseline estimated glomerular filtration rate (eGFR) (91,1 ± 18 vs 78,8 ± 18,6 ml/min/1,73 m2 respectively, p=0,0001) and had less comorbidity index (p&lt;0,0001). Hypertension encountered much more often in PHPT group vs thyroid group (69% and 22,5%, respectively, χ2 p&lt;0,0001). Duration of surgery also differed between groups: 25 min [Q1-Q3: 20; 40] min in PHPT group vs 50 [Q1-Q3: 31; 62,5] min in thyroid group, p&lt;0,0001.

We hypothesized that acute decline of parathyroid hormone after PTx increases risk of AKI in the PHPT group. To evaluate whether type of surgery (PTx/thyroid surgery) is independently associated with risk of AKI, we used 1:1 pseudorandomization (Propensity Score Matching, “matchit” package, “nearest” method in R) to balance the baseline characteristics (age, BMI, comorbidity, baseline eGFR, duration of surgery, presence of hypertension). The 40 patients in the thyroid surgery group were matched to 40 patients in the PHPT group according to these confounders. After PSM the prevalence of AKI remained significantly higher in the PHPT group than in the thyroid surgery group (30% vs. 5%, respectively, RR=6 [95%CI: 1,7; 23,1], p=0,006), confirming that PTx is the independent risk factor of AKI.

Conclusion

We observed higher prevalence of AKI after PTx for PHPT comparing with patients after thyroid surgery. Our data suggests that PTx itself is the main risk factor of AKI development after elective endocrine surgery.

Bilateral Neck Exploration May Not Reduce the Risk of Persistence but Shows a Perspective Advantage

There is still no consensus for an optimal surgical treatment of primary hyperpararthyroidism (PHPT). Virtually, most of the patients could be successfully treated with the selective parathyroidectomy (SPTE) based on preoperative visualization. However, this approach still has a “blind area” of undetected multiglandular disease (MGD). Bilateral neck exploration (BNE) may serve as a reasonable alternative but it meets the higher requirements for the surgical technique. A retrospective cohort study was conducted in order to reveal factors associated with the persistence of PHPT. 587 cases of PHPT patients who had received surgical treatment at SPSU Hospital in 2017–2018 were included. All the patients have at least one preoperative visualization study (neck ultrasound performed by a surgeon) before the operation. In 356 cases two studies were performed (additional 4D CT or MIBI scan) and 116 cases had all three. A surgeon was free to choose a type of the operation (selective or explorative) according to their strategic preferences. Bilateral neck exploration was performed in 160 cases. There was no difference in bilateral exploration rate (p = 0.3896) between the groups (with 1, 2 or 3 studies performed) indicating that the additional visualization does not allow to avoid bilateral exploration. MGD rate accounted for 7.4% (40 cases). It is important that any set of preoperative visualization modalities prove the absence of MGD reliably and select patients for SPTE precisely. Negative predictive value for different combinations of concordant studies (US+MIBI, US+CT and US+CT+MIBI) did not differ significantly and was 96.95%, 97.4% and 97.7% respectively. 26 cases of persistent disease were reported with no significant difference between BNE and SPTE groups. (6 vs 20 respectively, p = 0.792). A history of the thyroid or parathyroid operations was found to be the only factor predicting the higher risk of persistence (OR = 7.98; 95% CI [2.62 - 24.27]), while neither the number of parathyroid glands found during the surgery nor the number of preoperative visualization studies showed statistical significance. Only 47,5% cases of BNE was reported to have all four glands visualized. There rate of failure to found each gland was similar. Surprisingly, the superior parathyroid adenomas (P4) were more likely to be removed (chi-squared 10.378, p = 0.0006) but not in the cases with all four glands visualized intraoperatively (chi-squared 1.822, p = 0.0884). The true rate difference due to a hypothetical feature of parathyroid physiology seems to be not very likely. One may rather suggest than it is not an uncommon for a surgeon to identify a P3 gland as a P4 unless all for glands are visualized. This fact shows a perspective advanantage which may prevent some cases of persistence.

Observation of pressure-induced electron transfer in SnC2O4

We examined the high pressure behavior of stannous oxalate via Raman and X-ray absorption spectroscopy (XAS) inside a diamond anvil cell. Phase transitions were observed to occur near 2.6 and 15 GPa which were reversible upon decompression to ambient conditions. When further pressurized above 15 GPa, the colorless material sustains irreversible chemical alterations and becomes bright red colored - darkening at higher pressures. Another irreversible phase transition occurred above 20 GPa. Concomitant with color change of the sample, we observed a softening of the ν(C-C) modes of the C2O42- anion via Raman spectroscopy. We performed a separate XAS experiment which indicates that the Sn2+ cation undergoes a partial reduction of the 2+ oxidation state with pressure which persists when the sample was depressurized to ambient conditions. Thus, electron density within the C-C bond in the oxalate anion appears to migrate toward the tin cation with pressure. This observation suggests that pressure can offer a very controllable means to vary cation-anion and unit cell dimensions (and thus the electric interactions causing electron movement) and thus the pressure-induced synthesis of novel materials.

A new concept for temporal gating of synchrotron X-ray pulses

A new concept for temporal gating of synchrotron X-ray pulses based on laser-induced thermal transient gratings is presented. First experimental tests of the concept yield a diffraction efficiency of 0.18%; however, the calculations indicate a theoretical efficiency and contrast of >30% and 10-5, respectively. The full efficiency of the pulse picker has not been reached yet due to a long-range thermal deformation of the sample after absorption of the excitation laser. This method can be implemented in a broad spectral range (100 eV to 20 keV) and is only minimally invasive to an existing setup.

Arms-qPCR Improves Detection Sensitivity of Earlier Diagnosis of Papillary Thyroid Cancers With Worse Prognosis Determined by Coexisting BRAF V600E and Tert Promoter Mutations

OBJECTIVE

The coexistence of BRAF V600E and the telomerase reverse transcriptase (TERT) promoter mutation C228T/C250T is extensively associated with thyroid cancer prognosis. Our study aimed to establish a sensitive method for mutation detection and explore the correlation in detail.

METHODS

The BRAF and TERT promoter mutation status of 250 papillary thyroid cancers was determined using amplification-refractory mutation system quantitative polymerase chain reaction (ARMS-qPCR) and Sanger sequencing to compare the sensitivity of the 2 methods. Associations between the mutation status and clinicopathological features were then analyzed.

RESULTS

ARMS-qPCR was more sensitive than Sanger sequencing (BRAF V600E: 75.2% [188 of 250] vs 52.4% [131 of 250], P < .001; TERT promoter C228T/C250T mutation: 12.0% [30 of 250] vs 3.6% [9 of 250], P = .001; comutation: 9.6% [24 of 250] vs 3.2% [8 of 250], P = .005). Both ARMS-qPCR and Sanger sequencing indicated that patients with coexisting BRAF V600E and TERT promoter mutations had an older diagnosis age, higher recurrence rate, and were associated with a more advanced TNM stage and higher metastasis, age, completeness of resection, invasion, and size score. Moreover, ARMS-qPCR helped identify an earlier group stage, which was younger and had smaller tumors and a lower recurrence rate, compared with the group with coexisting BRAF V600E and TERT promoter mutations identified by Sanger sequencing. The newly identified group had a lower metastasis, age, completeness of resection, invasion, and size score and TNM stage.

CONCLUSION

Patients with coexisting BRAF V600E and TERT promoter mutations had a worse prognosis. ARMS-qPCR, the more sensitive method, can be used to identify patients who have a potentially worse prognosis earlier.

Anion-exchanged and quaternary ammonium functionalized MIL-101-Cr metal-organic framework (MOF) for ReO4-/TcO4- sequestration from groundwater

There are few effective technologies for the sequestration of highly water-soluble pertechnetate (TcO₄^-) from contaminated water despite the urgency of environmental and public health concerns. In this work, anion exchanged and cetyltrimethylammonium bromide (CTAB) functionalized MIL-101-Cr-NO₃ were investigated for perrhenate (ReO₄^-), a surrogate of TcO₄^-, sequestration from artificial groundwater. Cl^-, I^-, and CF₃SO₃^- exchanged MIL-101-Cr proved more effective at ReO₄^- removal than the parent MIL-101-Cr-F. Compared to the parent framework, CTAB functionalized MIL-101-Cr-NO₃ increased ReO₄^- removal capacity from 39 to 139 mg/g, improved the reaction kinetics from ~30 to <10 min to reach full adsorption capacity and the selectivity for ReO₄^- over competing NO₃^-, CO₃^2-, SO₄^2-, and Cl^-. Spectroscopic data indicated that the chemical speciation of Re in the exchanged MIL-101-Cr remained ReO₄^-, indicating synergistic sequestration through both anion exchange and non-ion exchange binding with the positively charged ligand of CTAB. These studies foreshadow potential applications of MOFs for the remediation of ⁹⁹TcO₄^- from contaminated environments.

P1428PERSISTENT HUNGRY BONE SYNDROME AND HYPOPARATHYROIDISM AFTER PARATHYROIDECTOMY FOR SECONDARY HYPERPARATHYROIDISM: ARE THERE RISK FACTORS?

Background and Aims

Hungry bone syndrome (HBS) and postoperative hypoparathyroidism both are important postoperative complications after parathyroidectomy (PTx) for severe secondary hyperparathyroidism (SHPT). There is still a lack of data in the literature concerning associated risk factors of the prolonged HBS and hypoparathyroidism after PTx. We aimed to explore the risk factors for HBS and postoperative persistent hypoparathyroidism development in a long-term period after surgery.

Method

We performed a retrospective analysis of 55 severe SHPT patients who underwent subtotal PTx or total PTx+AT in our clinic between 2011 and 2015 with follow-up period not less than 12 months. A general cohort was divided into subgroups according to their laboratory parameters in a year after PTx. Prolonged HBS was defined as a total serum calcium concentration less than 2,1 mmol/l after 1 year from surgery. Postoperative hypoparathyroidism was defined as a iPTH value less than 10 pg/mL after one year from surgery.

Results

In terms of prolonged HBS persistence a general cohort of 55 patients was divided into two subgroups: a HBS group of 27 patients (49,1%) with mean age of 45,6 ± 9,02 years and a non-HBS group of 49,6 patients (50,9%) with mean age of 45,6 ± 10,8 years. Mean dialysis vintage for HBS and non-HBS groups was 107,8 ± 52,4 and 97,4± 54,5 months, respectively. The PTH level dropped significantly in both groups on the 1st day after surgery when compared with preoperative values: from 134 [92,7-186] to 5,0 [2,1–17,7] pmol/l in non-HBS group (p&lt;0,001) and from 126 [101-223] to 4,1 [1,5-14,5] pmol/l in HBS group (p&lt;0,001). The immediate ionized calcium levels also decreased significantly in both groups: from 1,26 [1,2-1,3] to 0,89 [0,79-1,09] in non-HBS group (p&lt;0,001), and from 1,2 [1,11-1,29] to 0,88 [0,8-1,0] in HBS group (p&lt;0,001). In univariate analysis the postoperative iPTH showed no significant difference between the HBS and non-HBS groups (p= 0,614) as well as ionized Ca level (p= 0,5653), difference of PTH before/after surgery (ΔPTH) (p= 0,9133), age (p= 0,2575) and dialysis vintage (p= 0,6165). Neither gender (RR 0,75 [0,44; 1,277]; p = 0.4088), nor type of surgery (RR 0,81 [0,45; 1,456]; p = 0.5815) were associated with the long-term HBS persistence.

For 51 patients data of iPTH level in a 1 year after PTx were available; 21 patients (41,2 %) were included in the postoperative persistent hypoparathyroidism-positive group (hypoPT-positive), and 30 patients (58,8%) were included in the postoperative persistent hypoparathroidism-negative (hypoPT-negative) group. In both hypoPT-positive and hypoPT-negative groups postoperative iPTH levels were decreased after surgery with significant difference being compared between groups (1,0 [0,8-2,5] vs 12,6 [3,7-17,7] pmol/l, respectively; p= 0,0001). We observed a moderate positive correlation between iPTH levels on the 1st postoperative day and in a 1 year after PTx (ρ=0,548 [95% CI 0,314; 0,72]; p&lt;0,0001). Type of surgery was not associated with increased risk of prolonged hypoparathyroidism (RR=1.03 [0,569; 1,866]; p=0.922).

Conclusion

Prolonged persistence of HBS and postoperative hypoparathyroidism are common after PTx in patients with SHPT regardless the type of surgery. Neither laboratory (postoperative iPTH, ΔPTH, ionized Ca), nor demographic (gender, age, dialysis vintage) factors were not associated with HBS persistence in a long-term period after PTx. Only serum iPTH level on the 1st day after PTx is associated with prolonged hypoparathyroidism after surgery.