Energy Resolution from a Silicon Detector's Interstrip Regions

In this work, we present a novel approach for improving the energy resolution from particles impinging on the interstrip regions of silicon strip detectors. We employed three double-sided strip detectors from the GRIT array and a triple α-source under laboratory conditions. The results showed that the interstrip resolution depends not only on the impinging side but also on whether it is a P- or an N-interstrip. We obtained the interstrip energy resolution down to 0.4%, and, depending on the scenario, the resolution was enhanced by a factor of 2. We believe that this new rotation method allows for the possibility of applying particle identification methods on interstrip events, which in most cases are dismissed during data recording.

Test Bench for Highly Segmented GRIT Double-Sided Silicon Strip Detectors: A Detector Quality Control Protocol

This work deals with the characteristics of highly segmented double-sided silicon detectors. These are fundamental parts in many new state-of-the-art particle detection systems, and therefore they must perform optimally. We propose a test bench that can handle 256 electronic channels with off-the-shelf equipment, as well as a detector quality control protocol to ensure that the detectors meet the requirements. Detectors with a large number of strips bring new technological challenges and issues that need to be carefully monitored and understood. One of the standard 500 μm thick detectors of the GRIT array was investigated, undergoing studies that revealed its IV curve, charge collection efficiency, and energy resolution. From the data obtained, we calculated, among other things, the depletion voltage (110 V), the resistivity of the bulk material (9 kΩ·cm), and the electronic noise contribution (8 keV). We present, for the first time, a methodology called "the energy triangle'' to visualize the effect of charge sharing between two adjacent strips and to study the hit distribution with the interstrip-to-strip hit ratio (ISR).

Monkeypox in humans: a new outbreak

Infection caused by Monkeypox Virus (MPVX) has small rodents as its natural reservoir and both monkeys and humans are occasional hosts. The causative agent is an Orthopoxvirus (MPVX) that was isolated in monkeys in 1958 and proved capable of passing to humans in 1970. It remained contained in Africa, causing isolated episodes of infection, until 2003 when an outbreak occurred in the United States following importation of animals from that continent. Since then, anecdotal cases have continued to be reported outside Africa, usually very clearly linked to travelers to those countries, but in May 2022, a broad outbreak of this disease has begun, now affecting several continents, with the emergence of human cases of MPVX (H-MPVX) infection mainly among Men that have Sex with Men (MSM). The disease has an incubation time ranging from 5 to 15 days and is characterized by the presence of pustules, fever, malaise and headache. The presence of significant regional lymphadenopathy is a differential feature with episodes of classical smallpox. Proctitis and pharyngitis, with minimal skin lesions, may be another form of presentation. Diagnosis can be confirmed by PCR testing of lesions or by demonstration of MPVX in other body fluids or tissues, although in the appropriate epidemiologic setting the clinical picture is highly suggestive of the disease. Effective drug treatment has been developed as part of programs to protect against potential bioterrorist agents and smallpox vaccinees are known to have high protection against monkeypox. New vaccines are available, but neither the drugs nor the vaccines are yet freely available on the market. The prognosis of the disease appears, at least in adults in developed countries, to be good, with very low mortality figures and much less aggressive behavior than that described in classical smallpox. Isolation measures, essential for the control of the outbreak, have been published by the health authorities.

P-601 Is Medroxiprogesterone acetate (MPA) an adequate alternative to GnRH antagonist in oocyte vitrification for non oncological fertility preservation (FP) and preimplantation genetic test (PGT-A) cycles?

Study question

Can we use MPA as a pituitary inhibitor instead of the GnRH antagonist in ovarian stimulation protocols in non-oncological fertility preservation and PGT-A cycles?

Summary answer

MPA can act as a substitute of GnRH antagonist for pituitary suppression in FP and PGT-A cycles, since the results are similar between both groups.

What is known already

Progestin-primed ovarian stimulation (PPOS) protocols using exogenous progesterone to replace GnRH analogs during the follicular phase of OS have emerged as an efficient alternative to prevent LH from peaking and have been used successfully in different types of patients.

Fertility preservation (FP) and preimplantation genetic testing (PGT-A) have become new emerging areas of assisted reproduction. FP gives women the ability to have children using their own gametes after age-related fertility decline, while PGT-A appears to improve reproductive outcomes in advanced maternal age at increased risk of aneuploid embryos. However, few data are available for both indications regarding PPOS cycle outcomes.

Study design, size, duration

Multicenter, retrospective, observational, cohort study conducted in eleven IVIRMA centers attached to private universities.

We included a total of 4,961 cycles of non-oncological fertility preservation that were distributed as follows: n = 494 were stimulated under a PPOS protocol while n = 4,467 received a GnRH antagonist. Regarding PGT-A cycles, we analyzed 12,461 treatments, of which n = 686 and n = 11,775 received MPA and GnRH antagonist, respectively. Cycles were performed from January 2017 to December 2021.

Participants/materials, setting, methods

Patients were divided according to the protocol used for preventing premature luteinization during follicular phase of OS. In the MPA group, participants received 10 mg daily administered orally, while in the control group, women received an antagonist once the main follicle reached 13 mm.

In FP cycles, ovarian response specific parameters were evaluated, such as endocrine profile and mature oocytes; in PGT-A treatments, main variables were number of biopsied and aneuploid embryos and reproductive outcomes.

Main results and the role of chance

Regarding FP's baseline characteristics, age was statistically but not clinically significant between the two groups. Length of ovarian stimulation and total dose of hMG administered were similar in both groups, despite the significantly higher total dose of FSH administered in MPA compared to the GnRH antagonist group (p = 0.008) . Number of mature oocytes retrieved (10.2 [95% CI 9.6-10.8] vs 9 [95% CI 8.8-9.2]) was significantly higher in MPA compared to antagonist group; this trend continued regardless of age (≤ 35 or > 35 years).

PGT-A cycles followed the same tendency in terms of demographic characteristics. Length of OS was comparable between groups, whilst the total dose of rFSH and hp-HMG administered in the MPA were significantly higher than that in the GnRH antagonist group. Although the number of MII was comparable and despite the lower number of embryos biopsied in the MPA group (4.5±0.2 vs 4.7±0.06, p = 0.031) the number of aneuploid embryos was similar between the two groups (2.3±0.1 vs 2.4±0.04, p = 0.474), as well as implantation (56% vs. 54% p = 0.359) and clinical pregnancy rate (64.1% vs. 62.1, p = 0.316). The miscarriage rate was significantly lower in the group treated with MPA compared to GnRH antagonists (4.7% vs. 8.2%, p = 0.001).

Limitations, reasons for caution

The retrospective nature of this study may be a reason for caution and only association, not causation, can be inferred from the results. Despite being the largest sample size ever reported with PPOS in no oncological FP and PGT-A, the number of patients included is still low.

Wider implications of the findings

The administration of PPOS yielded similar or even better results than those observed with GnRH antagonists in terms of oocytes retrieved, rate of aneuploid embryos or clinical results. Therefore, PPOS could be recommended for ovarian stimulation in non-oncological FP and PGT-A cycles as it allows for a more patient-friendly approach.

Trial registration number

Not applicable

Baseline 18F-FDG PET/CT quantitative parameters as prognostic factors in esophageal squamous cell cancer

AIM

To determine the utility of [¹⁸F]FDG PET/CT quantitative parameters as prognostic factors for the response to neoadjuvant treatment, progression-free survival (PFS) and cancer-specific survival (CSS) in patients with esophageal squamous cell carcinoma (SCC).

MATERIAL AND METHODS

Thirty patients (29 men) diagnosed with SCC were retrospectively evaluated over a 6-year interval. Metabolic parameters were determined: maximum SUV (SUVmax), mean SUV (SUVmed), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) from baseline PET/CT study. After treatment with chemotherapy and/or radiotherapy, response to treatment and patient survival were assessed. The comparison of parameters between groups of responders and non-responders was carried out using a Mann-Whitney U test ROC curves and the Kaplan-Meier method were used for analysis of prognostic factors and survival curves.

RESULTS

The average follow-up was 22.4 months, with 22 recurrence-progressions and 25 deaths. Significant differences were demonstrated between responders and non-responders with respect to tumor size, MTV and TLG. Survival analysis found significant differences for SCE and CSS depending on these three parameters.

CONCLUSION

Metabolic parameters MTV and TLG, and tumor size were prognostic factors for neoadjuvant treatment response, PFS, and CSS in patients diagnosed with SCC. Neither SUVmax nor SUVmed were predictive for any of the evaluation criteria. Results could help to personalize patient treatment.

O-014 How effective is oocyte cryopreservation?

The challenge of cryopreserve, store for prolonged period, and successfully implant the female gamete is nowadays feasible thanks to vitrification. The technology that was initially validated in oocyte recipients is currently applied to a vast population, including women at risk of losing their ovarian function due either to iatrogenic causes as occurs in cancer patients, or due to the natural depletion of the ovarian reserve as a result of age related fertility decline. That is the case of a growing population of women who wish to postpone childbearing and decide on oocyte vitrification as a means of fertility preservation (FP). At present, there is a growing body of evidence regarding the use of vitrified oocytes by many women under different indications, which makes it possible to evaluate the approach from different scenarios. So that vitrification can be evaluated in terms on survival rates, embryo development and the rate at which vitrified oocytes develop into live-born children in IVF cycles using vitrified oocytes which were initially stored due to different reasons. The effects of vitrification at the subcellular level and its impact on oocyte competence is of interest in the evaluation of the efficacy of the technology. Some studies have indicated that vitrification may affect ultrastructure, reactive oxygen species (ROS) generation, gene expression, and epigenetic status. However, it is still controversial whether oocyte vitrification could induce DNA damage in the oocytes and the resulting early embryos. Recent studies show that oocytes survival and clinical outcome after vitrification can be impaired by patients’ age and the clinical indication or the reason for vitrification. These studies show that age at oocyte retrieval strongly affects the survival and reproductive prognosis. In our experience, oocyte survival, pregnancy and cumulative live birth rates are significantly higher when patients are aged 35 years or younger versus patients older than 35 years at oocyte retrieval. Therefore, elective-FP patients should be encouraged to decide at young ages to significantly increase their chances of success. There is also evidence that the reason for vitrification is associated to the success rates. Poorer reproductive outcome was reported in cancer patients, low responders and endometriosis patients when compared to healthy women in age matching groups. Moreover, there are certain individualities linked to specific populations, as occurs when endometriosis patients had cystectomy earlier than the oocyte retrieval for FP. These women achieved lower success rates as compared to non-operated age matching counterparts. In this case, the lower cumulative live birth rates observed in operated women are, most probably, due to the smaller number of oocytes available, as a consequence of the detrimental effect of the surgery on the ovarian reserve. In this regard, several reports show that the number of oocytes available per patient is another variable closely related to the outcome in all populations using vitrified oocytes after FP. Thus, a significant improvement in the cumulative live birth rates can be achieved by adding a few oocytes, especially in healthy young patients. Different populations using vitrified oocytes under several indications achieve differential results in terms of pregnancy rates, when calculated in overall. Nonetheless, when the calculations for the cumulative probability of achieving a baby are made according the number of oocytes used per patient belonging to the same group of age, the results become comparable between different populations, as shown by the comparison between elective freezers versus endometriosis patients. Undoubtedly, vitrification can be recognized as one of the latest brakethrough in the ART field, but certainly the next step forward would be the successfull automatization of the vitrification and warming processes to achieve fully consistency among different laboratories.

P–135 Artificial neural networks (ANNs) for live birth prediction in frozen embryo transfers: the strength of post-warmed blastocyst dynamics

Study question

Does the post-warmed blastocyst dynamics have an impact over the likelihood of achieving a live birth?

Summary answer

Variables related to dynamics of vitrified/warmed blastocysts have shown a greater effect on the live birth prediction than only embryo morphological quality through artificial intelligence.

What is known already

Morphological dynamics of vitrified/warmed blastocysts were described by Coello et al., in 2017. The investigated markers were the thickness of zona pellucida (µm) and blastocysts area (µm2) after warming and before transfer, the area of the inner cell mass (µm2), time of initiation of reexpansion (in minutes), and presence of collapse or contraction. They found a correlation between blastocyst reexpansion and implantation rate and developed a hierarchical model for implantation prediction. In our study, we evaluated the post-warmed blastocyst dynamics for live birth prediction by using novel artificial intelligence techniques.

Study design, size, duration

This retrospective analysis included 415 vitrified/warmed blastocysts with known live birth data. Blastocysts after warming were placed in EmbryoScope (Vitrolife) immediately until embryo transfer. Embryo evaluation and selection were performed by senior embryologists according to fresh blastocyst morphology (before vitrification). Then, parameters related to post-warmed blastocyst dynamics were calculated. Finally, these variables and the embryo morphological grade before the vitrification were used as input data for ANNs optimized with genetic algorithm for live birth prediction.

Participants/materials, setting, methods

Blastocysts were vitrified and warmed by the Cryotop method (Kitazato,Biopharma). During the period between the warming procedure and the embryo transfer, the following variables were measured with the drawing tools provided by the EmbryoViewer workstation: zona pellucida thinning (µm), blastocyst expansion (um) and the speed of these two events (µm/h). Finally, multilayer perceptron neural networks were trained with data of 331 embryos by using the backpropagation learning algorithm and tested with data of 84 embryos.

Main results and the role of chance

We trained and tested three architectures of ANNs with different input variables as follows: post-warmed variables (thinning of the zona pellucida, blastocyst expansion, thinning speed and expansion speed) and morphological grade (A, B or C) for ANN1, only post-warmed variables for ANN2 and only morphological grade for ANN3. The highest success rate when ANNs classified embryos as positive and negative live birth (LB+ and LB-) was achieved by combining post-warmed variables and morphological grade before embryo vitrification. The general accuracies for the blind tests were: 73.8% for ANN1, 66.7% for ANN2 and 71.4% for ANN3. Likewise, this combination achieved the highest AUC on test dataset to predict LB- (0.76 for ANN1, 0.74 for ANN2 and 0.67 for ANN3). However, the ANN2 trained with only post-warmed variables showed the best capacity to predict LB+ with an AUC of 0.73 (versus 0.46 for ANN1 and 0.5 for ANN3).

Limitations, reasons for caution

The main limitation is the subjectivity of manual annotations, although only one embryologist participated in this task.

Wider implications of the findings: The dynamics of vitrified/warmed blastocysts prior to embryo transfer could be more relevant variables than the morphological quality on day 5 before the cryopreservation. The analysis of embryo behavior after warming could improve clinical outcomes in frozen embryo transfers.

Trial registration number

none

Baseline 18F-FDG PET/CT quantitative parameters as prognostic factors in esophageal squamous cell cancer

AIM

To determine the utility of 18F-FDG PET/CT quantitative parameters as prognostic factors for the response to neoadjuvant treatment, progression-free survival (PFS) and cancer-specific survival (CSS) in patients with esophageal squamous cell carcinoma (SCC).

MATERIAL AND METHODS

Thirty patients (29 men) diagnosed with SCC were retrospectively evaluated over a 6-year interval. Metabolic parameters were determined: maximum SUV (SUVmax), mean SUV (SUVmed), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) from baseline PET/CT study. After treatment with chemotherapy and/or radiotherapy, response to treatment and patient survival were assessed. The comparison of parameters between groups of responders and non-responders was carried out using a Mann-Whitney U test. ROC curves and the Kaplan-Meier method were used for analysis of prognostic factors and survival curves.

RESULTS

The average follow-up was 22.4months, with 22 recurrence-progressions and 25 deads. Significant differences were demonstrated between responders and non-responders with respect to tumor size, MTV and TLG. Survival analysis found significant differences for SCE and CSS depending on these three parameters.

CONCLUSION

Metabolic parameters MTV and TLG, and tumor size were prognostic factors for neoadjuvant treatment response, PFS, and CSS in patients diagnosed with SCC. Neither SUVmax nor SUVmed were predictive for any of the evaluation criteria. Results could help to personalize patient treatment.

18F-FDG PET/CT quantitative parameters as prognostic factor in localized and inoperable lung cancer

AIM

To assess the utility of ¹⁸F-FDG PET/CT quantitative parameters as prognostic factor in patients diagnosed with localized and inoperable lung cancer treated by stereotactic body radiotherapy (SBRT).

MATERIAL AND METHODS

Fifty patients (42 men) diagnosed in the last 7years with early-stage lung cancer and treated with SBRT alone were assessed by a prospective study. After PET/CT study, metabolic parameters maximum SUV (SUVmax), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were determined at different thresholds. The prognostic factors for overall survival (OS), cause-specific survival (CS) and disease-free survival (DFS) were analysed by Cox proportional hazards model and the survival analysis by Kaplan-Meier method.

RESULTS

The average follow-up was 39.6months, with 21 recurrences and 24 dead. Univariate analysis determined MTV₃₀ and MTV₄₀ as predictors for OS; MTV₃₀, MTV₄₀, TLG₃₀ and TLG₄₀ for CS, and MTV₂, MTV₃₀, MTV₄₀, TLG₂, TLG₃₀ and TLG₄₀ for DFS. Survival analysis found statistically significant differences for CS and DFS depending on tumor size and for DFS considering the cut-off values of MTV₂ and TLG₂ (threshold SUVmax=2). SUVmax, age and sex were not shown to be significant factors.

CONCLUSION

Pre-treatment quantitative assessment using metabolic parameters MTV₂ and TLG₂ as well as tumor size proved to be prognostic factors in patients diagnosed with localized and inoperable lung cancer treated by SBRT. Results could help to personalize treatment.

Elective and Onco-fertility preservation: factors related to IVF outcomes

STUDY QUESTION

Is the indication for fertility preservation (FP) related to success in IVF cycles after elective-FP (EFP) for age-related fertility decline and FP before cancer treatment (Onco-FP)?

SUMMARY ANSWER

Although success rates were lower in cancer patients, there was no statistically significant association between malignant disease and reproductive outcome after correction for age and controlled-ovarian stimulation (COS) regime.

WHAT IS KNOWN ALREADY

FP is increasingly applied in assisted reproduction, but little is known about the outcome of IVF cycles with vitrified oocytes in FP patients.

STUDY DESIGN, SIZE, DURATION

Retrospective, observational multicenter study of vitrification cycles for FP and of the warming cycles of women who returned to attempt pregnancy from January 2007 to May 2018.

PARTICIPANTS/MATERIALS, SETTING, METHODS

In all, 6362 women (EFP = 5289 patients; 7044 cycles + Onco-FP = 1073 patients; 1172 cycles) had their oocytes vitrified for FP. A logistic regression analysis was performed to examine the impact of indication for FP corrected for age at vitrification. The protocol used for COS was also included as a possible confounder. The main outcome measures were oocyte survival and live birth. A detailed description of the baseline and clinical data is provided, with comparisons between EFP and Onco-FP. The cumulative live birth rate (CLBR) per utilized oocyte according to age at vitrification was analyzed in those patients returning to use their oocytes.

MAIN RESULTS AND ROLE OF CHANCE

Age at vitrification was significantly older in EFP patients (37.2 ± 4.9 vs. 32.3 ± 3.5 year; P < 0.0001). Fewer oocytes were retrieved and vitrified per cycle in EFP (9.6 ± 8.4 vs. 11.4 ± 3.5 and 7.3 ± 11.3 vs. 8.7 ± 2.1, respectively; P < 0.05), but numbers became comparable when analyzed per patient (12.8 ± 7.4 vs. 12.5 ± 3.2 and 9.8 ± 6.4 vs. 9.5 ± 2.6). Storage time was shorter in EFP (2.1 ± 1.6 vs. 4.1 ± 0.9 years; P < 0.0001). In all, 641 (12.1%) EFP and 80 (7.4%) Onco-FP patients returned to attempt pregnancy (P < 0.05). Overall oocyte survival was comparable (83.9% vs. 81.8%; NS), but lower for onco-FP patients among younger (≤35 year) subjects (81.2% vs. 91.4%; P > 0.05). Fewer EFP cycles finished in embryo transfer (50.2% vs. 72.5%) (P < 0.05). The implantation rate was 42.6% and 32.5% in EFP versus Onco-FP (P < 0.05). Ongoing pregnancy (57.7% vs. 35.7%) and live birth rates (68.8% vs. 41.1%) were higher in EFP patients aged ≤35 than the Onco-FP matching age patients (P < 0.05). The reason for FP per se had no effect on oocyte survival (OR = 1.484 [95%CI = 0.876-2.252]; P = 0.202) or the CLBR (OR = 1.275 [95%CI = 0.711-2.284]; P = 0.414). Conversely, age (<36 vs. ≥36 y) impacted oocyte survival (adj.OR = 1.922 [95%CI = 1.274-2.900]; P = 0.025) and the CLBR (adj.OR= 3.106 [95%CI = 2.039-4.733]; P < 0.0001). The Kaplan-Meier analysis showed a significantly higher cumulative probability of live birth in patients <36 versus >36 in EFP (P < 0.0001), with improved outcomes when more oocytes were available for IVF.

LIMITATIONS, REASONS FOR CAUTION

Statistical power to compare IVF outcomes is limited by the few women who came to use their oocytes in the Onco-FP group. The patients' ages and the COS protocols used were significantly different between the EFP and ONCO-PP groups.

WIDER IMPLICATIONS OF THE FINDINGS

Although the implantation rate was significantly lower in the Onco-FP patients the impact of cancer disease per se was not proven'. EFP patients should be counseled according to their age and number of available oocytes.

STUDY FUNDING/COMPETING INTEREST(S)

No external funding was used for this study. The authors have no conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

A new system of sperm cryopreservation: evaluation of survival, motility, DNA oxidation, and mitochondrial activity

BACKGROUND

Sperm vitrification (V) is a method for cryopreservation, without the use of conventional cryoprotectants, by plunging the sperm suspension directly into liquid nitrogen (LN25).

OBJECTIVE

This study aimed to compare the new system of V with conventional freezing (CF) protocol using fresh spermatozoa as reference (C).

MATERIAL AND METHODS

Prospective cohort study. A total of 47 sperm samples from men attending the infertility clinic at Instituto Valenciano de Infertilidad Valencia. The sperm V solution was 0.3 M trehalose-sucrose and plunged directly in liquid nitrogen in microdroplets of 5-10 lL, using a new system collector of V. Sperm viability indicators such as sperm motility, vitality rates, mitochondrial function, and sperm DNA oxidation were assessed before and after cryopreservation. Sperm motility and vitality analysis were performed according to published guidelines of the World Health Organization (WHO, 2010). Mitochondrial function was evaluated using JC-1 (fluorescent cationic dye, 5,50,6,60-tetrachloro-1-10,3,30-tetraethyl-benzamidazolocarbocyanin iodide). Sperm DNA oxidation was determined using a fluorescent assay (Oxy-DNA test) for the detection of 8-oxoguanine. The evaluation was carried out before and after cryopreservation using flow cytometry. Statistical analysis was performed using ANOVA and chi-square test, and p < 0.05 was considered statistically significant.

RESULT(S)

Sperm parameters, including progressive motility, total motility, and viability, observed after cryopreservation were as follows: C = 74.9% [1] 12.3, CF = 27.2% [1] 8.4, V = 42.3% [1] 9.3, p < 0.001; C = 90.1 [1] 6.8, CF = 42.0 [1] 12.9, V = 61.4 [1] 11.8, p < 0.001; C = 90.0% [1] 7.4, CF = 42.5% [1] 14.6, V = 70.9% [1] 6.5, p < 0.001, respectively. Regarding Oxy-DNA and mitochondrial activity, they were significantly affected in both groups (V and CF) when compared to the control group.

DISCUSSION

The sperm V and CF have negative impact on sperm parameters as well as DNA integrity and mitochondrial activity. However, sperm V presented improved sperm motility recovery, similar levels of DNA oxidation, and, moreover, a slightly increase in mitochondrial activity when compared to the conventional method.

CONCLUSION(S)

V as an optimal protocol for sperm cryopreservation.

Contribution of early SPECT/CT to 99mTc-MIBI double phase scintigraphy in primary hyperparathyroidism: Diagnostic value and correlation between uptake and biological parameters

AIM

To evaluate the value of ^99mTc-MIBI double-phase scintigraphy (DPS) and early SPECT/CT in the pre-surgical assessment of patients with primary hyperparathyroidism (PHPT). Also, to calculate the correlation between uptake and some biological parameters.

MATERIAL AND METHODS

Forty patients with PHPT were included: 37 solitary adenomas, 1 hyperplasia, and 2 double adenomas. Fifteen patients had ectopic glands. DPS and early SPECT/CT were acquired in all patients. Ultrasound was performed in 31/40. All patients underwent surgery, intra-operative iPTH measurements, and histopathological examinations. Qualitative DPS uptake was assessed and correlated to pre-surgical calcium, iPTH levels, gland weight, and maximum diameter.

RESULTS

In the planar study, there were 23 positive cases, 8 doubtful, and 9 negatives. With the SPECT/CT, 8/9 negatives cases were located. All doubtful cases were confirmed as positives. Gland location improved in 16 cases (12 ectopic). DPS+SPECT/CT failed to detect a solitary adenoma and at least one gland in three cases of multiglandular disease (MGD). The sensitivity by patient was: DPS 72.5%, DPS+SPECT/CT 90%, and ultrasound 42%. Ultrasound and scintigraphy (DPS+SPECT/CT) were concordant in 16/31 patients. For the rest of them, scintigraphy proved correct in 14/15, and both techniques failed in one case. There was a significant correlation between level of uptake and iPTH level, gland weight, and maximum diameter.

CONCLUSION

Early SPECT/CT improves sensitivity and the locating of parathyroid pathological glands and increases diagnostic confidence. iPTH level, glandular size, and weight are related to the qualitative assessment of ^99mTc-MIBI uptake in early DPS.

Effect of virgin and refined olive oil consumption on gut microbiota. Comparison to butter

There is increasing evidence of the health benefits of olive oil consumption in the diet. Some authors have studied the effect of high fat/high calorie diets and have detected changes on the microbiota. However, these studies are mainly based on saturated fats. Here we present a study on the specific effect on gut bacterial populations of extra virgin olive oil, rich in monounsaturated fatty acids and phenolic compounds, in comparison to refined olive oil, rich in monounsaturated fatty acids but low in phenolic compounds, and to butter, rich in saturated fatty acids and cholesterol. Four groups of animals were studied: one group of mice received a standard chow diet, and the other received three high fat diets, rich in extra virgin olive oil, refined olive oil or butter. Evolution of symbiont population in feces was studied using culture-dependent and culture-independent methods. In the latter, the V3 region of 16S rDNA was amplified and separated by denaturing gradient gel electrophoresis; followed by sequencing of the most representative bands. Culture-dependent studies and comparison of the different DGGE profiles throughout the experiment demonstrated that different dietary fats had different effects on gut microbial composition. Butter-induced changes in the microbial counts resembled those previously described in obese individuals. Interestingly, a different behavior between extra virgin and refined olive oil was also observed, extra virgin olive oil being most different from butter. To our knowledge, no studies have analyzed gut microbiota depending on diets with different fatty acid saturations including different types of olive oil. This may offer new data supporting the benefits for health of extra virgin olive oil, so important in the Mediterranean diet.

Recovering a fiber Bragg grating axial strain distribution from its reflection spectrum

A processing scheme able to obtain any arbitrary intragrating strain distribution of a fiber Bragg grating (FBG) is proposed and demonstrated. The processing method employs just the intensity of the FBG reflection spectrum to obtain its deformation profile by combining a geometrical processing scheme with the particle swarm optimization technique. The technique has been evaluated using several spectra generated from very heterogeneous strain distributions and with a real spectrum obtained from a 5 mm length FBG under an asymmetric perturbation. The achieved results exhibit a good spatial resolution (Δ≈0.5 mm) and repeatability.

Laser-Induced Breakdown Spectroscopy: Fundamentals, Applications, and Challenges

Laser-induced breakdown spectroscopy (LIBS) is a technique that provides an accurate in situ quantitative chemical analysis and, thanks to the developments in new spectral processing algorithms in the last decade, has achieved a promising performance as a quantitative chemical analyzer at the atomic level. These possibilities along with the fact that little or no sample preparation is necessary have expanded the application fields of LIBS. In this paper, we review the state of the art of this technique, its fundamentals, algorithms for quantitative analysis or sample classification, future challenges, and new application fields where LIBS can solve real problems.

Sampled Fiber Bragg Grating spectral synthesis

In this paper, a technique to estimate the deformation profile of a Sampled Fiber Bragg Grating (SFBG) is proposed and experimentally verified. From the SFBG intensity reflection spectrum, any arbitrary longitudinal axis deformation profile applied to a SFBG is estimated. The synthesis algorithm combines a custom defined error metric to compare the measured and the synthetic spectra and the Particle Swarm Optimization technique to get the deformation profile. Using controlled deformation profiles, the proposed method has been successfully checked by means of simulated and experimental tests. The results obtained under different controlled cases show a remarkable repetitiveness (< 50 με) and good spatial accuracy (< 1 mm).